GB2269460A - Photographic Flash Apparatus; Exposure Control Apparatus - Google Patents

Abstract

The apparatus has a control CPU which determines a proper exposure value by selecting one of a plurality of exposure correction values on the basis of the detected voltage on a main flash capacitor C1. A pulse generating circuit TR3, TR4, Ne, C3 generates a pulse RLS having a width which is dependent on the voltage on the capacitor C1, and the CPU measures the pulse width to select the exposure correction value is correspondence therewith. <IMAGE>

Description

2269460 STROBE CONTROL APPARATUS The present invention relates to an

apparatus for controlling a strobe used in a camera.

Conventionally, the charged voltage of a main capacitor in a strobe circuit is checked to see whether it reaches a predetermined level according to which flash permission or an indication thereof is given.

In the case of only one predetermined level being set, strobe flashing cannot be accurately controlled according to the present charged voltage.

2 on the other hand, in the case of a plurality of levels being set, arrangements become necessary to divide the charged voltage, to A/D convert and to check whether the charged voltage has reached each level.

Thus, the circuit size becomes large and the circuit becomes complicated resulting in increased costs.

3 Furthermore, as the amount of current which flows in present.cameras has recently been increased because the performance of batteries used therein have been improved, there is a tendency that the charging time of a strobe is shortened. Thus, the strobe can be frequently flashed and thereby the amount of heat generated due to charging also increases.

If the circuit is heated with the generated heat, paraffin which secures a winding of a boosting transformer may melt and thereby the circuit may be damaged. In addition, the winding itself or transistors may also be damaged by heat.

4 To prevent the circuits from being unduly heated, large capacity transistors or large capacity transformers can be effectively used. However, in small cameras such as lens shutter type ones, the circuits should be of compact form so it is preferable not to use large capacity transistors and transformers.

According to the-present invention there is provided an exposure control apparatus comprising:- voltage detecting means for detecting a charged voltage for application to a strobe; and determination means for determining a proper exposure value based upon said detected charged voltage.

Reference is made to parent patent application number GB-A-2 230 663 from which the present application has been divided and co-pending divisional patent application number:- Examples of the present invention will now be described with reference to the accompanying drawings, in which:- Fig. 1 is an external top view of a camera, to which the apparatus embodying the present invention is applied; Fig. 2 is a front view of the camera of Fig. 1; Fig. 3 is a rear view of the camera of Fig. 1; Fig. 4 is a block diagram of the control circuit; Fig. 5 is a circuit diagram of the strobe and the adjacent section; Fig. 6 is a timing chart showing a voltage check processing; and Fig. 7 is a chart showing the relation between RLS wilse LITTIC I)IPI-Io(IS.111(1 F-1g. 8 Lo Fig. 25) af-e flow (111,11-1s qllowftl,r functions of the camera which is equipped with an apparatus for controlling a strobe embodying the present invention. 5 Fig. 11 Is I rlow -;tlowitlg n 1-Pset, l fig; FIgs. 12,.111(1 13 II-C [low qilowillfr a F1g. 10 Is a (low qilowillg a Lool) exit, 1)1o(tess 1 n lr,-, FI.g..1.4.1.9 a Flow c;liowiti,r n charge St.ol) Is 11 rl.ow sliowhig a charge prohibiting processing; Is a I'LOW S1lowhig all RUS 11.111e ss 1 fig Fig. 17 1,9 a rl.()w l,iyllt- (),It.

1 18 lS 11 rlOw CIUM-1. SIRM1111-, 1 charge l)rolill)i(.iovi I.Ivii(! F1g. 19 Is a 11ow e.111 silowitill. a lo(,.1 Figs. 2o. 21, 22 al-Q I'low 51lowillir '111 AE.AF. (.oviti-ol.

F 1 2:1 1 1 1 oWc 11. 11 - C S 110 W 1 11 W, 1 v 0 1- 1, 1 gC CI 1 C, C. k Figr. 2,1 1.:; a Flow silowilitr 111 F-M 1)1o(',(-.qs 1 ylkr,- F 1 gr. 25) 1 S 'I r 1 ow (A1,11- t sIlow 1 lig, a 1-(? wa rig 1)v-o(ess] ng., Is 11 [tow C111.111; Sil()wivltr, 1 will(] and 27 Is a Flow lit-o(,essillg.

11) FIgs. I 1.1)1-oligli.3 Is 'I ?-,.IIVIII(A1 employs an apparatus for controlling a strobe embodying the present invention.

111C as s)lowil Ill F.I.gr. 1, a 1)ody J. WIII(A1 fills a gt:,i(,lovllll.y In-11-1-M 2 alld 11 Illovillt., 3. 'I'll(l Fl-olit. of U)e hody 1 S11OW11 1.11 F1K. 2, a 17111del- willdow 5. a a as a c(is, liti(i a se.ir-f;ivviet- 1.11111) 7. 1)a(.k of 1.11(1 camera body.1. cori(,.ilviq, as silowil 111 171K. 3, '1 covet- 8, 1111 LGA) 9. a Fir-fl. ivio(f( 1)tjt.t.oti A, a se.ori(f ino(f( 1)ti(;1,oti 11. 1)xjt,t.oti G. a zoont Inv(!l- 10, a green jamp re(l _jallip cc se C 11(11 ca 1,0 1. (LED) 1. a Imic k cove r r (1 1 a,, 1 v r 11 (late display sectLon 12 an(l a (late swItcli 13.

Witen Hic back cover release lever 11 Is move.(] rrom an tipward stop position to a downward sLop I)OSI-L1.011, Llie back cover 8 opens. Wlien Lite back cover 8 Is opene(J. Clie 1)ack cover release lever 11 Is In Llie downw,ard stop positi.on, wliil.e wlien the back cover 8 Is closed. tite back cov-t-r release Lever.1.1 reltirns to Llie 1 upward stop posItIon.

A rewInd btitton, not shown, Is locale(l on Clie bottom of Lite camera body 1.

The tipper section or Llie camera bo(ly 1. contains, as shown in Fig. 1, a power or lock lever 14, a shutter button 15 and a macro button 16. The power lever 14 is slid.able between power-ON and power-OFF positions.

The zoom lever 10 can be moved In a rti-st direction Indi.cated by an arrow rl. In Fig. 1, ancl a second dIrectIon In(licall-ed by anollier arrow 1-2.

Tlie movable lens barrel 3 Is moved. upon operatIng the lock lever 1.4 andjor. Llin macro btilLon 10, among a lock posItIon willell I.s -in state, a zooll, area exteridIng between a w[de extremity wliere a rocal Lengull becollies 35 111m a Lele (xt.revitil,y wliere a rocal leng-LI1becollies 70 111111, '111(1 a macro position For close-tip -g- In Llie zoom area, llie movable lens bart-el 3 is move(]. npon ol)ei-, ilivig Lbe zoom Lever 10, bet.weell the wide ex(;t-eiiii.(-.y and 1.he Lcle ext-.t.enif.ty.

1-,1gr. 4 qilowc; a cono-of (.oriflgxir,.it.loil employe(l In the camern deserfbed above.

Thl.s (toiiil)t-.ises a maln (AT llroce.,.3,9i,tjg Uni.1) and a sub CIT which Is conneeled Lo Lhe IllaIll (AT via a drive IC 'I'lle slit) CPU execules processIngs In parallel with processings executed by the maLn CIT.

The main CPU perforins 0ie Followl.ng runct.lons In response Lo liirormattoit I-Yil)titt.ed Lo Llie cainera:

(1) Control of a zoom motor and a film motor Via motor (Irl.ve (.lrcxi,i Ls; (2) Control of illumination and blinking of the green lamp indIcator 1) whIch provi.des a distance measurewent-related 1.ti(Ateat;ioii, Lhe red lainj) IndleaLor E which provides a strobe-related indication, and the a self-timer 1.amj) 7 wlilch provides -related lll(llcfltJo11; (3) Control of indication on the LCD 9; and (4) Control of charging of a strobe circuit.

InforiviaLlon Is Inputted t;o t.he cavitera by 1he rollow I figs:

(1) Lock switch LOCK, wh1ch Is seL Lo ON when Llie power -Iever 14 Is set, fri Ils F)ower-017F 1)osit.loij; (2) PholomeLry switelt SWS, willell JS set; L0 ON wheti Lhe sliijt.t.ev. 1)titt.oii 15 Is depressed li,-.ilfw.-ty', (3) Rel.ease switch SWIZ, witich ts set Lo ON wheii Lhe shut.Ler 1)tjt.t,oti 15 Is rtil.ly depressed; (4) Macro swIL-ch MCRO, which Is set Lo ON when Uie macro but.Lon 16 Is depressed; (5) Zoom Lele switch TE7LE.. which Is set. to ON when the zoom -lever 1,0 Is d[splaced rrom a center. neutral 10 posi Lion Loward Lhe Lele side r2; (6) Zoom wide swItch W1.1)15-, whIch Is set; 1.o ON when the zoom lever 10 Is displaced rrom a center, neutral. position toward the wide side rl; (7) Mode A switch IVIDA, mode 13 switch M1)13 atid elear 15 switch MDC, which are set to ON when the mode butLons A, B and C, respectively. are depressed; (8) Bacl( cover swItch BACK, whIch Is set; to OFF when Ute bacic cover release lever 11. Is pressed (]own, and set, lo ON when t-he back cover fl Is closed It](] Lhe 20 lever 11 return.% to 11-s Lock position: and (9) Rewttl(l swiLell REW, whi.ch Is set; Lo ON when a rewfild but,Lon is pressed.

On Lhe olher hand, 1-he stib CAT (!c)rit.rol..; a disLance file,isill-itig 111111. witi.ch in Infr-ared I.E.1) (Light, Emitting Diode) and a f)o.c;il.lovi serisor PSI) via aii aulof'o(.,tis I.c. 1'1)e sub (xti sen(Is co uic mail, (,i,Ii (1,1L,1 based 111)oll of' Oie autoroctis JC as we] 1. is 1)Iiot.oiiie(.t.-1(., dal.a. tmased xjl)oil oxjt.l)tiL or the I)Iiol,oiijet.ti(.. elemetil C(IS.

The (]v]-ve IC coiiLrots the shutter elrexii 1 ae(tc)r(l.iiikr to commands From the sub (AT and otit.1)xit.s q trIgget. signal 'I'MY to a.strobe circuit.

Fig. 5 shows the detailed construction of the strobe elf-exill. fl.gtire, the maln CPU and Llic sub CPU are 1.ntegrally Illustrated as a CPU.

riiis eircult comprises a CPU, a regulator ['of stablll.zlrig supply voltage to the CPU regardless of voltage change In a battery BATT due to cliirg.i.iig and so on, a boosLIng elreul.t for ralsIng battery voltage lit response to a charge enabling signal CHEN from the CPU to start char g.I. ii g a maIn capac.ltor Cl. a trigger for -111.tinil.itat.Lxig a Xe (xenon) Lamp lit response lo a trigger signal TRG from the sub CPU, and a voltage For charged vo[lage ill lhe malit capaellor CA lit Ghe rorill or RLS 1)111ses In lo 'I Voi(,,11,'(,' ebeek sIgnal (MICK rroill (.11(1 (A1U.

The 1)oost,Itilr, (Arcull, 1)oosi.fitg,, (.v-.irisist,or-s Ti-1 atid T1.2.

r(,slst.ot.s R1-, W2 and W3, a capaellor C2,.111(1 dlodes DI and D2. When the charge sIgnal CHE.N becomes 1, (low level output), i.t st.arls Wheti llie siglial becomes 11 (opeti), lt stops The voltage (Ielecting ctrcult comprises a Ne (neon) hititp, a sw 1 lcli 1 iig traiis 1 s tot- Ti-3,,lit RIS pti 1 se generating transistor Tr4, resistors R4 Clirotigli RS, at)(] a cil)ael tor C3. Wheri tile voltage clieck (MICK changes rrom 11 (hIgh level oxitl)xjt.) to L, (low].eve] outptjt), the vollage (letecting (..irctjlt gerierales the RLS pulses lit proportion to the voltage. The Ne lamp Is turned ON when a vol.tage exece(II.rig 270 V ls appl-led, ati(l a volt;,ige arotind 220 V As ni,-,ilnLa.lyie(l, regardless of the exirretit value, whilst the Ne lamp is Curited ON. Tlie Itysteresis or Lite voltage required to enable turn ON and that required to hold an ON state is used for generating the RLS pulses.

llow voltage ls (lelected ls liereliiarter explahie(l by referr.hig to F1g. 6.

When Che voltage clieck signal G1ICK becomes 11. Clie t.r,iiisist.ot, Tr.1 is ON iti(l lhe (,:; ls (11.sciiirge(l, iti(l sliiiiiit.-aticotisJ-y the tittinis si(te of' Lite Ne I;J-1111) IS (.()1)11e 1,11e (le t.lirotirii Ule resi.stor R4 ati(l Clic travisist.or Tr.3. All (Ails Chile, if the charged voltage VIT. Is 270 V or vitore, Llic Ne hamp Is turned ON after a certain delay time has passed since the sIgrial GAICK becamc 11, current. Ilows through the Ne lamp, Llie resistor R4 and the transistor Tr3. 'Flills.

the voj.t-.,,ige or the resi.ster R4 on the Ne lamp si(le beconies V17 VN, wliere the ON-state vol.lage VN ror the Ne lautp l.s subtracted rrom Clie charged vollage V17.

Then. wheri the sIgnal. C1ICK Is Curried to 1, and tliereby Clie transIstor TrZ3 ls Curned OFF, the currelit which flowed rroin Clie i-esi.stor R4 to llie Irans-Istor Tr3 now flows from the resistor R4 to the capacitor C3 for Llie L1.111e being. Consequently. Clie capaeltor C3 Is cliarged ti)(] Llie Cransi.stor Tv-4 Is Curried ON, an(l 1,1111s the line RLS becomes L.

As (,ltirgl.tig or the capaelLor G3 progresses, the on the capaeltor G3 s.1de or 1-he resister R4 gra(lually increases, and Llie currevit beconies to hol.d Clie Ne 1.amp 1n lts ON-slate Thus, the Ne 1.amp turns OFF and the current does not r.low rrom Llie resist.or R4 to the C3.

Consequently, Clie Iratis.1.91or Tt-4 Is Lurried OFF an(l I'lle line RLS becomes H.

The lurn-OFF (AmIng oF the Ne lamp Is correspondingly (Ielayed as the eliarged voltage VF Increases. nius, a uivie r (= tite ms wiise wi(i(,it) during which the line RLS is L, is determined by (VF - VN).

Tlitis, by ptilse wi(lt,It T, Llic vollage V1.7 can be F.I.g. 7 sliows -ill example of Llie reJaLlon bet.ween the charged voltage,in(] Lhe RI.S 1)tii.se w1AL11.

When Lhe (.,1iirgi.iigr voltage Is 270 V or less, even If Lhe transi.stor Tr-3 Is turned ON, 1-be Ne lamp does not turn ON and thereby the line RLS remains H.

Next. rinictions or the mode bill.tons A and 13 are explained below.

The mode Witton A furictioiis Go set; art expostire mode. As exposure modes, 6 modes are available, i.e., an auto mode (automatle strobe emIsslon. mode), a strobe ON mode (forced strobe emIsslon mode), a strobe OFF mode (strobe ettiJ.ssiori rorl)J.cl(livig mode)..,ill expostire comperisat-lon mode, a bulb mode and a bulb -in(] strobe ON mode.

For the bulb mode or the bull) and strobe ON mode, 8 tYPes or inanualshutter 1Ame are available.

The, mode WALL011 13 1 ' 1111(.1.1olt.s lo set. a mode. As photograplilrig modes. 6 modes are available, 1.e., a otie.-rrtivtje ng Illode, l (, I'll Photograplitng mode. a sel.r-tlint-.r pholographIng, mode, a double self-timer photographing mode. a iiiiii.t,Ii)le photographing mode, and Ill Interval pholograpill rig mode.

For llie Interva.l. I)Ito(.-ogr.iiiiiittg mode, 16 Lypes or Int.erval perf.od are avallable.

['it(, InLLI.al. valtic of' Che manual. (Ame is bull), itl(l 11,11 or Llic perlod Is G0 sc.c. TI i c y are set. by execuLIng a MODE, JNL'I'JAI IZE subrout-hic or by turning ON Che c'l.eai but.Lon Cl.

Next. the programs stored]it the inal-n CPU w11.1 now be descrIbed wit;li reFeretice to FIgs. 8 L-hrough 27.

((MAIN o[)erat.l.on)) Fli-sG, a MAIN operatIon and associated RIESEIT operat-lon wIll be described, w[th reference Lo F1gs. 8 through 1.3. The MAIN operation executes Che basic operatIon of the camera. Other f'tjtictloiis ire perrortned 15 by branchIng from or beIng controlled by the MAIN operaLl. on accord.Ing to the varlous conditlons.

When power 1s Lurned ON, reset of the mahi CPU Is released and the RE.SET operat.ton shown It) F1g. 8 st.arls. The nialn CIT InILIal.1zes Che camern meniory and 20.1.riptit;s switelt data (qteps USI. and IRS2) before perf.oriiiitig a MODE. INITIAIAZATION lit slep RS.3 and a ZOOM INITIALIZATION subroutIne In sLep RS4. A serles or Instructlons Cliat. comprise Lite MAIN operat.toti shown lit Figr. 9 are then execuLed. The MODE.

I.NITI.AL-1ZATION sxji)totit.lit(i reset.s vai-Jous mode set.t.lyllr.c; 1 and oije-ft-,xiii( phot.ographIng modes.

lit Llic MAIN operatJort, a 1-second 1-1mer, used for IndIcaLlon holdIng. Is cl.cared In step MI.J lit st.cps M12 Chrough MCA, Lbe phoLometry switch SWS, tAie release swit-.eli SWR, Lbe wIde swItch WIDE,, the tele switch TELE, Llic mode swItch MI)A, Lhe mode swilch M1)13, Llic (.-]-ear swItch MDC, and Llic macro sw1Ach MCIZO are set; to OFF and a sw[Lch CIag [.,WOFF, Is se 1. The flag FSWOFF Is set to 0 1 r some or the aforervientloned swItches Is turned ON.

lit steps MI5 through M18, when Lhe photometry switch SWS, the release swItch SWR, Lbe wIde sw-ltch WIDE and the tele switch TELE are set to OFF and 1-5 forbIdden I)Iiot;ograplilrig combinat-lon modes are not selecLed, a 1)Iiot;oinetry swItch errectIve rlag FSWSII-.N Ls set to l. When some or Lhe aroreinevit.-loned swiLches Ls set Lo ON or Forbidden conibtti,.,iltori modes fire seL, Lite rlag I.SWSE'N Is set Lo 0.

lit stl-el) M19, the statils of' each or the -11)ovc-fllell(,iotl(l(l swilches are 1111(1 Che process.Ingr Is execuLed (AterearLer accorolvig Lo Llic When t.lic. rewInd swlt,(.li IZEW Is 1 lo be ON (sLeli M110), Llic MODE. INITIALIZING subroutAnc Is per rorivic(i (s 1-cp M 11. l.) LOOP E.SCAPE. subrou L 1 tie, shown 1 ri F. 1 gr 10, Is then execute(l In st-el) M1.12. Tl 11 s stjt)roxit.f.iie comprises two s(,el)s. or which stel) 1,01 stops chargIng of' Llic st.robe ciretill. and sLel) 1,02 011-11s OFF the ved Jamp cliargre Indi-callon, and Is cal.1ed every time the processing braviclies From the MAIN operaLl-on to another operation.

Wheis. the LOOP E.SCAPE. stibroijtl.rje I.s compIeted, the MAIN operatAon dIverges to a series or instructions that comprIses a REWIND operation. When Cite REWIND operatlon has compIeted rewInding the 1711.m In the camera. a rewind compIete fIag FREWEND Is set to 1 and the processing I.s advanced by Jumping to the begInnIng of Cite MAIN operatIon.

is When the back cover 8 Is cIosed (ttiriti.tig ON the back switch BACK). step M114 Is perrormed to determIne whet'lier the F11m has rivilshed Ioading. 'I'lils Is hy cheekingr the FIng FLDE.ND. Ir tile f11m Ilas #sol. [iiii.;ijt!(] (.. Llic Flagr VLDEND I.L; 0), Hic processingr (,ollt,illljes to stel) M115, wherein 1.11e MODE INITIALIZATION Is perrormed once 111ore. Thell, It st,e[) M11.6. the 1,0011 E.SCAPIS. stibroilt.tiie Is perFormed before diverging to a series of instructions that comprise a LOADING operation. Wher) Llic WADING operation Is f'l.tiistic(i Che rtair, FLDEND Is 1), Lhe processing groes to Step M119.

Upon collip 1 cl. loll of' loading. tlie rlag FLDEND Is set to 1. avid the processing Is advanced by jurriphig to Cite, begInnIng or Cite, MAIN c)pei-,-iLJoil.

When the back cover 8 ts open, both and FREWEND are reset to 0 (steps M11.7 -in(] MJ1,13).

In steps M119 through M124 in Fig. 11, the processing to be executed when the lock switch LOCK is turned from OFF to ON is shown, that-is when the power lever 14 is 0 inoved rrom the power-ON 1)os-itJozi to Llie power-OFF position. Ir the pi)otogr.-.ipli.trig lens is riot lit the lock position, Cite display changes from indicating the Filin rrarne number to IndIcat-Ing the roeal length or Cite lens (step M1.21). Thert. lite 1,0011 117SCAPE, siffirotillne (stel) M122) Is executed. 'rite rear C-er, processIng dEverges to a serles or Instructions thal comprise a ZOOM REIVEIRSE operat.1011 so I'llat the lens IS 1)11.11ed back to llie loCk pos-1.11on. Wlien the 1-evis l_s already lit the lock position and c llic REV1 NI) operall on has not, ri it 1. It(!(], Ut, processIng goes to stel) M124 so as to exectile the 1,0011 ESCAPE subroutine and processing diverges to a series of Instructions thal comprise a LOCK operall.on (1 c C3 c r 1. 1) e (1 1 a 1 e r. Ir (Ate RE.WIND operallon has rinislied, Llic I.S advanced by J11111ping, to "MID,' of' Ille MAIN operation, shown lit Fig. 1.3.

When the lock sw] telt LOCK 1 s OFF and.1 t 1 s inated stel) MJ25 (Alat the lens discriln Is In the lock posUlon, the rocal tength Is IndIcated on the display (stel) M.126) ror a pertod or olle second (st.el) M127) by setting an indication hold flag FWAITED to 1.

rhereafter, a macro command flag F.RQMCR Is set to 0 (step M128). Then, the LOOP ESCAPE subroutine (step M129) is - X e c 1,1 t v (1 and the processing can diverge to a series of Instructions that comprise a ZOOM FORWARD to operation. In this operation, when the macro request flag FlIQMCRO Is 0, the lens Is moved from the lock Position to the wide extremity, while, when this flag Is set to 1. the lens Is moved to the macro position. In steps MI30 through M136. If the macro switch MCRO Is ON, the focus length Indication Is displayed and the Indication hold flag FWAITD Is set to 1. Then. the test Is made to determine whether the photographing lens Is In the macro Position (step M133). If It is In the macro Position. the Indication hold timer Is cleared (step M1.34) sind restarled. The 1)rocessivi[r, Ulerl advances by jumping to---MIC-,show,, in ing. 13. ir the lens Is 1101; In the macro position, the macro command flag FRQMCRO Is set to 1, and the processing diverges to the ZOOM FORWARD operation via the LOOP ESCAPE subroutine so that the lens moves towards the macro extremity.

I.n 9 Leps M1,37 1.brougb M 143. wlien L-be Ce 1 C. sw! Leb TEL1.71 LS ON, Lite f'0CM1 lerlkrt,ll]ll(lic.,1t.1011 IS (11.si)1,1Ye(l and Llic Iii(li.eat-.1.ori hold fl.ag F1WAVIT Is set to 1. Wlien Llie lens. Is not, In Clie Le.l.e ext:rcmit..Y, J1, Is (lesertinl.iiit.e(l whetlier tlie [Cris Is In the macro 1)o.c;itlori or In Llie zoom area, upoii (oinl)i,eLIoii of Llic 1,0011 ESCAPE, subrou 1, 1 tie. Wbeit Clie levis Is lit Llie zoom area, Llie (11,V(,1-ges 1,0 a serles of Instructions C11,11 a StilFT operat.lon Lo inove Ibe lens Lo Llic Lel.e side. If It; I.s lit Lite inaero posi.tton, Llie processing dIverges to Lite ZOOM RE.VERSE operat.lort to Lake back Cite lens to tbe tele extremity.

Wlien the teris Is al.ready.].it the tele Lite disp.hty lio.l.d timer I.s cleared and the count or ofic 1-5 second Is restarted.

hi steps M144 titrotigit M150, wlien the wide switeli WIDE, Is ON, the foeiJ. 1-crigt.lt Indlentlon Is displayed and Llic Indication fjoId rIng F-WAITI) is set Lo 1. 1 f' the 1-ens Is lit Cite wide exLreivilt,y, Llie flisplay bold Limer Is cleared and restarLed. Wlien the 1.cris Is not, Iri the Lele ext.re.iiil(,y, It, 19 discriminated whether the leris Is I.n the uincro position or lit 1,1)e Z00111 C11"ez-11 upor) C0111plellon or Che 1,0011 ESCAPE, subroutine.

WItell Llic levis Is Ill Ille zooill arell, Lile fit,' diverges to a serle s of Instructions Llint. a WIDE SILEFT operation Lo inove the lens to the wide side.

s i it Clic macro pos 1 t, 1 oil. Llie process 1 ng (11 verges to Llie ZOOM RETE,RSE. opet-atton to Cal(e back Lhe lens Lo (Ale (,c](, 'I'llus, 1he [)ilot;ogl.,11)11111g lells is set to 1.1le macro wlien Cite macro switch MACIRO Is ON. TO retraet. the](,its rrom Clie macro posil-lon to Cite zoom area, the zoont tever shoul.d be moved rrout Its center, neutral. posILIon towards elther (I1rection.

lit steps MI51 through M154].it Fi.g. 12, Lit case 11 Is necessary to sli[rl. Cite lens, lhat Ls, 1.17 the macro tele slilft rlag ts set to 1, L-lie focal 1.ciigtli oC the lens ls dIsplayed and the [ndleatIon hoLd flag FWAITI) Is set; to 1. Therearter, the processing dIverges to the ZOOM REVE,RSE. operatlon to siiirt; cite lens to 1-he te-le extreinity via the LOOP ESCAPE' subroutIne.

With this lens, the dislance 1111111, for 1.1king- macro pliotogrtaphs Is approxinately 1 ineler (in). Thus, wilen the lens Is lit Llie inacro posit.lon and 11m distlatice measurement IndIcates a d[stance greater than.1 in. It.

Is ImpossIble to take an Itirocus photograph. 1 r 1,11e shutter bu Llon Is depressed under Lit 1 s cond 1 t, 1 on, 1 it this ciiibo(li.iiievit, shutter release Is locked and 1he levis 1 r LC(I Lo (-lie Le LC ex Lrein 1 LY rroill Lite Illacro pos 1 11 on. 'I'lie rlag. 17MTSIFT Is set, In a LEINS LATCH (U) subroxitAne I.Ital. Js by a series or -1.tist.rtic.t..ioris Lliat coinpri-se an AUTOMATIC EXPOSURE/AUTOMATIC FOCUS (AEAF) CONTROL operat;lori.

Jit MI55), t-.lie (-oti(litl.ort or the rewirt(l cornplete rlag FREWE.ND Is cliecked. Ir the rew.lrul opernt.ton lias "00 E.W' 1.9 (11splayed on Illie LGI) (Ilsl)l<iy (stet) M156) 1 r I.lie r] ag 1 s 0, 1 e., L-lie rewInd operatIon 1 s riot rlii.tsi)e(l, a MODEP, SEITTJNG subrouLlne Is performed (step M157).

After the swItch Judgement flag 17SWOFF lias been set In steps M12 Uirough M14, the MODE, SETTING subroutIne Is exectiLed only when all swItelies are set to OFF by the prevIous J,iipuLs. ir sonie switelies are set to ON, the procedure returns to Llie MAIN operat.lon wIthout cliangIng any sett;lrig.

If Lliere Is a ino(le change lit Llie MOD117 SEITTING subrou tA ne, a ino(le eliangre flag F-MOGARY Is seL Lo 1 whIle If Uiere Is no cliange, It Is set 1,o 0.

When Llie. processing relurris froin Llic MODE, S1111ANG subrout.lne lo Llie MAtN operation. Llic state or Llie fing FMDCIIG is checked (step (M158). If there is a mode eliange. the lii(lie,.iLlott tiol(l flag FWA.111) Is t.o 1 In stet)M159 before, 1he processing junips Lo Che 1)(iLrlittilrig of the MAIN operation via the 1,001) ange, the photometry switch SWS Lr there 1.s no ch, and the photometry swtLeh errectf.ve rlag F.SWSEIN are checked In steps M1-61. and M162. Whell the Specified cori(l.tt.f.oiis ire s,.ittsfie(i, the focal LerigLli Is displayed In steps M163 through M.165 and the hold rlag FWAIT1) Is cleared. The proceSS1.11g then diverges to the AEAF ('.ON'1'10f., operation, via the L.0011 ES('.AVE operatlon, so as to execute the shutler-related controls.

The AEAF. CONTROL operatIon is execute(] when 1-he photometry switch SWS Is ON, every switch data stored in each memory or the SWS, SWR, TELE an(] WIDE are OFF and the mode that allows a photograph to be taken is set. That Is, the AEAF CONTROL operation Is performed only when the SWS Is switched from OFF to ON.

There-Core, If the zoom lever Is operated, for Instance, the MAIN operation (,.oritJtxxies wtt-iioijt; executing the AEAF GONTROL operallori.

In step W66, a G11ARGE, ('.ON'IIROI, stjl)roxitiric descr[bed later. which controls the strobe fillsh circuit. Is called. IndIcatIon cluringe Is then exectiled In steps M167 throxigh M1.71.

If holding of the display indication is requested,it I.S checke(l whether L second has passed since Lhe Indication hold Illnel. was Before 1 secolld has passe(!. Llic presenLl-y d[splayed coillifilles.

When holding of the display indication is not requested, or 1 second has passed. the flliii Frame.

riumber Is t-e-(ltspl.,,lye(l and tlie Iii(ii-catlori Ijo.ld rl.ag FWAITI) Is cleared.

Thus, the IndIcatIon or Cite rIlm rravile iltimber Is given prererevice over other.111(1 I.Cati oils. 1111.1ess Ule other data to be shown Is only temporarily displayed.

Arter pausing for 1.25 nis Ill step M1.72. a CHARGE, PROHIBIT TIME subroutine described later Is called.

The processing then jumps to step M12 of the MAIN operation.

In this camera, the start of strobe charging is delayed for a charge prohibiting time which is set depending upon the frequency of strobe flashing, so as to prevent the strobe circuit from being over heated due to continuous use or strobe flash-Ings. The CHARGE, PROHIBIT TIME. stji)r-otit.iije Is to sbort.cri Life prolilbltl,vtg t-lme.

The above is an explanation for the MAIN operation. and varlotis subroutInes and o;)crit.l,oti.t; (liverlrJvig Lliererrom will flow be described.

CONTROL The CHARGE CONTROL subroutine is called in the MAIN operation, a RELEASE- WAIT CHARGE subroutine or an INTERVAL CONTROL subroutine, the latter two being both described later. Referring to Fig. 14, this subroutine is principally 5 to execute the charge 01)erllt[Ofl. and Is Periodleally called 111 every 125 fits from any operatlon or qtibi-oxillite.

In step ccl, it is determined whether the charge prohibiting time has_elapsed by checking a prohibiting time completion flag FWTCY1P. When the time has not elapsed (FWT= = 0), in step CC2, a CHARGE PROHIBITING subroutine described later Is executed. Then, In step CC3, It Is descrIminated whether charging Is prolilblted by checking a charge prolill)-1.Lliig Lime flag FW'I'S'1'1..1 r charging Is prolilbited (FWTSTR = 1), the processing diverges to step CC7 and a CHARGE ST013 operation Is excel] ted.

When the charge prohibiting time has elapsed and the 1) roh 11) 1 11 11 g. 11 111e comp 1 (11. 1 oil 1 la g-]-'WI'(,'Mll I.S H (11. lo 1 ' o 1 when Cite 1)i-olilt).1,t,lripr 11me el.apsed lit the G11ARGE, PROMBITING subrotillne and the charge prolilbiling 1Ame Flag F.WTSTIZ ls set to 0. the charge request I'lag F(A1Gl?q is checked lit step CG5. 1r strobe charge 1.9 requested the processing advances to st-el) CG0. 1 f no t, the processIng advances to step CG4.

A prohibit-ing time reduclion flag FCNTST11 Is set to 0, in.step CC4, so as to PriabIE? t-.ilp charge prolilbiting time to be shortened in a CHARGE PROHIBIT TIME subroutine. Then, in the CHARGE STOP operation, in steps CC7 through CC9, after charging and voltage (..ttecklrig are stopped and the red lamp Is turned out, the processIng returns back to the step from which it was called.

If charging Is requested, It Is Judged, In step CC6, whether 8 seconds or more has passed after charging started by cheeking a 1Ame out rlag FTOW1' set in a TIM171 OUT CHECK subroutine (lescr[bed later. 1 f 8 seconds or more (FTOUT = 1) have passed, a charge on flag-FCIIG, the prolilbitIng tIme completlon flag F.WTCW and the charge request rl.ag 1-.CIIGIQ are set Lo 0, In step CC10, the CHARGE STOP operation is performed.

If 8 seconds has not yet passed, in steps CC11 through CG-1-5, the charge on flag F(A1G Is set to.1 so Lhat Lhe chargIng Llmer starts. and a voltagecheck signal Is W1111.a charging]s p roil 11) 1 led.

This ls because the presetiL voltage berore charghig sLart.s Is If charging is already being started, the processing dIverges rrom stel) CC.I.I. in(] a WLS PULSE TIME MEASUREMENT subroutine and lhe 1'1-MI.'. 0k1T G.111.X.K suhroullne are execuLed In steps G(A.03 and CG17. By cheeking the charge completIon flag F.CM whIch Is set; 1.11 1)oLl) stibrout.lnes, IL Is Jtj(lge(f wheLlier cliargIng Is completed. ThIs flag 17CCIVIP Is set (1o 1. when the charged voltage exceeds 330 V In the RLS 1-11JLSE. TIME. MI,"ASIJIZI,-,MI-,,N'I' subroutine. In the case that the voltage does not reach 330 V after 8 seconds have passed from the start of charging however, the flag FCCM1P is set to 1 if the charged voltage exceeds 270 V.

When chargIng Is compleled (1.-("CMP =1), Lhe CHAIWE, STOP operal-foll Is exectiLed V1a stel) CC10. If eflarging Is riot; the charge enable si.gria.l. CHEN and the voltage elicel{ sIgnal are otitpulted and Wie processIng returns to the MAIN opernt.lon (st-cps CG19 through CC21).

is Thus, before start; of cliarglrig, steps CC12 through CC15 are executed once, and the charge check sIgnal Is outputted to clieck the present voltage.

Charging Llicit starts, tr the voltage does riot. reach 330 V in 125 ms via steps CC16 through CC21 the process returns.

During charging, steps CC16 through CC21 are repeatedly exectiLed. AL the Lline of' complellorl of (X7 throxigh CC9 are executed.

((CHARGE PROHIBITING SUBROUTINE)) Fig. 15 shows a CHARGE PROHIBITING subroutine, which Is caLled lit step CC2 or tlie- CHARGE CONTROL subrc)tjt.i.iie.

This subroutine Is eal.led when the charge prohibiting time has not been completed, and a charge 5 protilbttl,itlg Lline 'IT and the value or the 1)t-o)ilt)it.iiig tline thiter are compared so Cluat strobe cliargIng Is postponed by the charge prohibiting time to prevent heating or Llie strobe cl.retil.t.. The charge 1)rolill)lt;i-iig Llme 'I'W Is delerinIned ae(.ordi.tig to a 1)rolil.1)1t.-1,Yig (Ante data it wlit(.lt Is set tit the RLS PULSE, r.Tmi.-, MEEASUREMEENT subroutlite and the CHARGE, PRO111131T TIME subroutIne.

if Llie prohibiting tline Lliner has not yet started In step CS1 (F.WTSTR=O), It is started and the 1)rolilt)llj.vjg L.1me rlag and a 1)rolil.1)1.t.liig Lime reducLion 1-5 flag are set; to 1, In steps CS2 and CS3, so that charging is stopped lit the GRARGE G0WrROL subroutine or Fig. 14.

Lti steps CS4 through CS8. ir the l)roli.11)1t;liig Lline data it Is larger Clian 50, a 1)rolill)lt.li)g (Ame 10 see.

setting flag F.WT:1OS is set to 1 and the data n is forcedly sel lo 50 in(] Uic 1.1nie becoules 10 seconds. 1. r Ote dala it 1 s larger Chan 7 and sina 1 1 (it, than 50. Lhe 10 see. sel.f.lrir, rlag PYTIOS Is cleared alld the processIng returns to Che MAIN operation.

If Llie data it Is 7 or less,].it steps CS5) through CS11,Ule CIIIA1WE III?011,1131T TIME subl-ou 1 -tie Is cancelled and ule Lo Lhe MAIN ope 1'n L- 1 oil.

In the case that the CITARGE PROHIBITING subroutine is exectiled the CIIAKW 111ZO111131T TIMES subrouL file Is st-,irt;e(l, Llie processing a(lyances ri-om st;el) CSI, f.o CS 1. 2.

I.n s tleps CIS1 2 tAirough CS 15, 1 r 1he.10 sec. r lag FWT1.0s ls #lot; set; Co 1 ' Lite 1)1.o)111)1 1.111g Little TW Is se(-.

- to it x 125 ms, and It f.s checked whether Che Yii,xje Lit the prohibiting time timer exceeds the calculated prohibiting time TW in step CS14. If the 10 sec. flag FTW10S is set to 1, it is checked whether the value in the prohibiting time timer exceeds 10 seconds (step CS15).

Before the prohibiting time timer has counted past the prohibiting time TW or 10 sec., the processing directly returns to the MAIN operation. After the timer has counted the prohibiting time TW or 10 sec., the prohibiting time timer is reset and then the processing returns to the MAIN operation.,steps CS9 through Csil.

Thus, the 1)rolill)lt;lng (.1me Is 0 ins IF it < 7. rt x ms 1. r 7 g n < 50, and 1-0 seconds 1, r rt 50. As described later, 2 is added to n at every one charging cycle after charging and before flashing. While 1 is subtracted from n at every 4-seconds. Accordingly, the charge prohibiting time can be set correspondingly to the frequency of the strobe flashing.

(MLS PULSEE TIME ME.ASUREMEINT Fig. 16 shows Llie RLS PULSE, TIME.

stibrotillne called ill stel) CG16 or the CHARGE, CONTROL stjl)roiit;liie. 'I'lils subroutine Is executed Lo det.ect tile vol.Lagre or Lhe strobe maln (t,-ipac,..i.Lor as a pulse time obtallied by Voltage - 1.1111C corivers loll.

En steps R1,1 Mirougli RL4, the voltage check 10.91-gnit. ts set. to L, and It Is cliecked whether Llie RLS becomes L berore a 2 ms timer Llines tip.

As described above. the RLS becomes L only when the charged voltage exceeds 270 V ind thereby Che Ne lamp turns ON. Thererore, Che cliarged vollage l.s discriminated to be 270 V or less, if the line RLS remains H for more than 2 ms, and a charged voltage 270 V flag FC11270 and a charged voltage 280 V flag FCI-1280 are both cleared, i.e., set to 0, in step RL5, and then a value DGV is set to 0/4 before returning to the MAIN operation.

rlie strobe capacitor I.S rtilly at 3.10 V, and Che gulde number Is determlried hased upoll tile light quantity of a flashing at this full-charge voltage.

However, even If' Clic st.robe Is not rully charged, Lhe strobe ls, prepared lo correspondingly, at the charged voAtige. Accord 1 ng 1 Y, Cite gui.de rittinber musC [)c correcLed- in accordance w1111 the charged voltage to obtain a proper exposure. DGV is a which represents Llie corre(.ti.iig aiviotitit.- or Che gulde number (,otres;)ovi(iiiiir Lo Lhe charged vollage.

The paraivieter I.s set to 2/4 at., 315 V or more, 1/4 a(, 285 V to 315 V, and 0/4 at 285 V or less.

In the case that the RLS becomes L before the 2 ms timer tinies tip, i.e., in the case that the charged voltage exceeds 270 V, the time that elapses until the RLS becomes H is measured by an RLS pulse time timer to set the pulse tinte T, fit steps R1,7 through RIA.

When the charged voltage exceeds 270 V and 1-he RLS pulse appears ror the fIrst tIme arter charging started, steps RL11 through RL14 are executed once to is correct the measurement reference tline T1 accordIng to the measured RLS pulse time T. In the case that 500 ms has elapsed arter chargIng started, T1 Is deterintned based 11Pon the average v,,i-itie nAV or past. T11s stored in the RAM. Then, TI wIlle-11 Is newly Is sel, I.-; Ule new average val.ue TJAV, and 2 Is added to the prolilt)I.L-I,tig C.I.ine data it.

When the RLS becomes L before 500 ms has elapsed since the charging time timer starts, it is assumed that Llic capnellor wns already charged at. 270 V or itjore berore started, and the value of' TIAV Is set.

as T1 without correcting T1. llence, in this case, it 1,5 ass. Inned (.11,11 the (Ame ls short and that the temperature rise In Cite transformer Is small..

yl() v,-llxle lc s added to (,lie Ume Ae co r (1 t it Lrl. Y. 5 data ti.

The charged vol-tage VF and 1.11e RLS pilise 11-line have a relation,,is shown Lti F.I.g. 7 for a design. However, t.he value may deviate product by prodticl. So. by averaging Lit-,-- values or the rl-rst 1M,S pulses which substantlally correspond to t.he charged vol-tage 270 V at every charging Ll.me an(] by considering it In evaluating the pulse time, the above deviations In the products are corrected.

In steps RL15 arid RL16, Cite charging voltage 280 V flag FC11280 is cleared, I)GV Is set to 014 E.v arid the charging voltage 270 V flag FC11270 I.s set to 1.

When the RLS PULSE TIME MEASUREMENT subroutine is executed a second time or later arter the charge(] vo11,,19-(! 270 V, lit sleps R1.17 (.ltt,otjg,rli R1,25), (.1m 1.atesL 1?LS ptilse 11me T Is compared wit,Ii a volt,.ig(.

correspon(ling (Aine to Clie. cliarge(l rite voit.,ikre corresponding, tAine ls designed t,o be 30 V a 1 T1 /2 + 800 At c ', s; 285) V at, T112 + 500AS.' and 280 V at '1112 + 4001AS. 171gr. 7 shows an example where T1 Is 600 P 5.

Ir Lite voltage excee(Is 330 V, Llie charge complel loll ring 17C3CM11 Is Set, (.0 1 'llid W7V Is seL according to the voltage. In any case, if the charged voltage exceeds 280 V, the charged voltage flags are all set to 1 and then Cite processIng returns to the MAI.N operation.

If tile voltage Is 280 V or less, tile processIng returns to Cite MAIN operati-on vIa steps RL15 and R1,16.

((TIME OUT CHECK stjt)rotitliie)) Fig. 1.7 shows Cite TIM117 OUT CHISCK stibroutine executed In step CC.17 of tile CHARGE CONTROL subrouttne. This subroutine Is executed to determine the upper limIt of the charging Lline according to the counted Itme or 1 _5 the chargIng time Limer whIch Is started].it step CC12 or the CHARGE, CONTRO1, subroutlvie.

This subroutIne comprises steps TO1 through T09. lr charging Is beIng executed arter tile cluargIng Ifille 11met, comils 0, Seconds, 11m Ifille 111) 1,111g 1-(,11'1,tjfl 1m set to I.

When 8 seconds clapse, 1r the charging vollage has reached 270 V,the (.)large completion fl.,.ig FCAMil Is set to J 011terwIse, 1he Lime otil riag FTOUT Is set to 1. and the processing returris to Lhe MAIN operallon. When the Llme otit, rlag Is set. to 1, 34- chargIng is st.ol)l)e(l Ill tile CHARGE, CONTROL subrouLlne.

((CHARGE. PROHIBIT TIME subroutIne)) 1-.1g. 1.8 shows the CHARGE, PROILIBIT 111 1 ME subroutl-ne executed In stel) M173 or the MAIN operatton and In a LOCK operati.on (IescrIbe(l later. Th 1 s sub rou t- 1 ne serves to decrement Llie Lline data n being set, if the strobe is not used. With this subroutine, the 1)rolltl)it-.liig Ltine TW Is sliortene(l.

IF It, is IrldIcate(l by a prolill)l(;.trjg tline reduction i)rolil.1)1.t; Flag FGNTS11) Chat the reductlon or tile 1)rolitl)ltJ.iig lline -Is riot allowed narnel.y. when the charge prohibiting time is being counted or in the case that the charge prohibiting time is already set to be 0, the processing returns to the MAIN operation from step TC1 without executing any step.

When the re(luctlon ls riot 1)rolil.blted, Llie riag 1-.CNTST11 Is cleared. IF the i)l-olilt)it.lllg Urne data 11-1s 0 (step TC4), in step TC5, the prohibiting time reduction 1)rolil.1)1,t.lriLr F.1ag Is set to 1. an(] Uien the.

r(,11.tir-vis Lo Llie. MAIN OPERATION. Vroin 1he nexL call, Ule decretrient. In n Is riot. execut.ed.

IF the 1)rolill)i.t..I.rig Litne data n I.s not 0. In slei)s TC6 through TC12, the 4 sec. Unier Is used and n Is decremented by 1 at every 4 seconds passing through the subroutine.

lit other words, the pt'ollll) 1 L-1-11g tIme data it Is riot decrernented only when ri 1)ccomes 0.

( (LOCK operatIon)) Fig.19 shows the flow of the LOCK operation which dIverges rrom step M124 of' the MALN operation. Tlits operatton Is execute(] wheit the photographing lens Is stor-ed lit the posItIon after the locir.

sw-ltch Is Curtic(l ON.

Witen (Ails operatIon starts, llie rrame nuriffier on the LCD indication display is turned ON or OFF according to Cite state or a loadIng end rlag FLDEND lit steps LK1 through LK4 to set the ltilt.l.al ino(le.

The tool) or steps LK5 (Atrough Js repented 1.11 125 rris on condItIon that Cite rewiii(l swtt(,,)i RE1W Is OFF, Che Imck covet- swItch 13ACK ls OFF or Cite Loa(Ling Is rlril.slic(l evett. Ir the Imcit cover swItch BACK Is ON, and the lo(,) swItch LOCK I.s ON.

tri sCel) LK1.3, the CHARGE, PROMBIT TIME, sill) 1-oll (A rm Is executed 111e step M73 or the MALN operatlon.

In the case that the rewind switch is turned ON, the processIng dIverges rrorn LK6 to a REMIND operation.

In the case that the back cover is closed and loading is completed, steps LKS) iitt(l LK10 are to [()rtll a loop When 1-he Imck cover Is operi, Lhe erio flag -1.9 cleared and the ri-ame nutiffier IndleatIon Is t.-llrlie(l OFF. In the next loop, when the back cover is closed, the processing (][verges rrom stel) IX8 to a LOADI.NG operatton.

In the case that the lock switch LOCK is set to OFF, the processing sets the charge request flag FCQ and the Indication liol.d I-Tag P-WAVIT to t, t-esl)ec(;lvei.y,].it steps LKI-4 and TX15, Llien jumps to 1he MAIN operat tort.

When Clie process-4ng returris to the MAIN operatIon 10 rrom the LOCK operallon. lite inain capaell-or lins ustially 1)een di.s(..Iiat-ge(l. 1,1111s, 1)y exectitilig a charging request., an operator need not wait for charge completion if stroi)e rl.,islilrig Is necessary at; a r-trsL shulter-release aCter power Ls ON.

is ((AEAF CONTROL oper,-11;loti)) Referring to FIgs. 20 through 22, the AE7.AF CONTROL operatIon [or (.otit;t.olj.tilg the sillitter Is (les(.rll)e(l. this operation (liver-g-es from slep M10.5) of the MAIN ol)f!t.iil.loii.

As (les(ti-l.be(l earlier, Mils operation Is wheri 1.1.)e I)Iiol.otiie.(.-ry switch SWS Is from OFF lo ON and the mode comt)lttati,oti Is proper. f_n arLer Ute AEAF CONTROL operation onec diverges to the RE.LEASEE WArr CHARGE operatIon or arter Ille WIND operal.lon Is performed lit the coritititious pholographl rig inode. the AE.AF. CONTROL Is execuled from the AEAF control 2 Lermlital. and at 1he AE,AF, covilro].5 LerinInal, In steps AF]. Ifirough AF3, a 1)Iiot;otnetrl(, dIslance J111111) FIng FAE1AF Is set, (Iel)ell(lill,r Orl Vroll' what processIng the AE,AF. CONTROL operation Cakes place. When the ol)er,-.itioii Is returned rrom the RISLE1ASE, WAIT CHARGE, operatIon (11.verged from the AEAF control operation. sInce the f)liotottietri.e measureinent, and olstance measurement detecti-ons lunve been completeo as descl-1bed later, FAE1AF Is set to 1. so as to juinp such processIngs.

In other cases, the flag FAII7AF Is set to 0.

- W1.ten the AEAF CONTROL operatlon dIverges froin tile MAIN operati-on, in steps AF4 and AFS, 1.17 an auto release Flag FAUTORE11, Is set to 0, the focal. lenglit I.s Indicated. Tlils flag Is set to A 1n the Interval mode or ln t.akl.i)g a second shot. lit the double seu mode. as descrIbed later. In these cases, even Ir tile PhotoinetrIc switch SWS and the release switch SWR are Lurned OFF, Clic photographing Is executed.

In stel) AF6., a VOLTAGE- G11E.C.K subrout.lne deserIbed later Is executed an(] the charged vollage of the sCrobe.

capacl-lor I.s iviensured.

In stel) AF7, the chargIng request. f'lag P-ClIGHQ wkilch Is set I.n an FM calculation described later Is set; to 0.

Steps AF8 through AF1l., do not take pI a c e ri-om ne. iiit.ei-vit. tito(it. or seconci siio(. or Llic doxible se.lr mode. btit. ['v-ovii Llie MAIN operaLlon (w the WIND operatlon. The photometric data is inputted from the sub CPU to execute LL (lens latch) calculation. In otlicr cases, uic roriner LL data Is used.

rtius, In performIng Interval. I)Iiotl-ogral)ltitig and Llie -lie same rocus as the fli-st sliot takes pJace.

like, t, In pet-foriii[tig Interval. pho Lograpli Ing, sInce Llie user Is norivial.ly away rrom the cainera, It 1s riecessal-y to prevent ti,e focus i)ojiit; rrorn t)e.itig moved wijeii tAip, subject Is moved froin the dIstance measurement itei at the center of the screen.

The LL calculation serves to deterinine L-lie arriount of lens iviovenierit for foctisIng the subject t.o the result of the dlstance measurement. In the LL calclilatlon, when the lens Is tn Llic zooin area and (.lie Is aL a near (11slance, Ille 1111111) bl 1111 flag Is set to 1 so as to generate an alarin to Llie tisci- and the release lock I'lag FRLOCK I.s set. to 1. Mien Llic lens Is In the inacro 1)osJtlori and the subject Is at a Far dl.starice, besIdes the above two r.lagrs, tAir macto Lele sh 1 f' t, 1 1 ag VVITS 1 FT 1 S se t, to 1.

In st.cps AF.12 1.1)roxiirfi AFIG, except. wIten 11w AF.AF CON,rizot. operation takes place igl.iii aRer otice (11 vergi tig lo the M-51,171ASE WAIT CIIAIME stibrotit.iiie, 1.1)e pho tome tr 1 c-rela ted 1)ro(,essi.tigs --ire exectited. TI la L 1. s in step AF13, the DX code is inputted, which is converted into an Sv value used to calculate an ISO sensitivity of the rllm.]it step AF14, the (alplia) of the open F riumber 1.s obtal.ned from Lhe focallength or the I.ens. WIth stich data and the photometi-le data being Inputted Prom the sub CPU In stel) AF15, the AE (automattc exposure) calculatIon As executed xiid the AE data Is obtalried.[it step AF16.

lit step AF17, an FM (flaslimal.1c) calculallon shown In F1g. 24 1s called and the FM data Is set. When the All"'AF control- operatJori Lakes p[ace agaln arter Cite RELEASE WAIT CHARGE operation has diverged therefrom, the AE calculation is skipped. However, since the value DGV may change due to cliargi.iig. the FM calculatIon Is exectiled a ga 1. 11.

Iii slep AVIS, It, Is checked Whelher 1,11(1 20 lock has been discriminated during the LL calculation in step AF11 according to the state of the release lock flag FlUMCK In slep A1718. The lock Is when the lens Is In 1he zoom area and the subjecL Is 1.oo close t.c) 1he leris or when tAic lens I.s. lrl 2-5 the macro posit-lon and the subjeel Is loo ral. From the tens. In I'llese cases,.91.11(!C phoLographs are 011L or rocus, lit sLeps A171.9 through AF.21-, Lite wreen Infill) blinks to al.arm lo the tiser. The processIng walts unt[l the I)Iiot;otiief-i-l.e swilch SWS Is release(l. Arler that, the processIng turn OFF the red an(] green lamps and then jumps to the MAIN operatIon.

lit steps AF22 through AF24. when the voltage oC the strobe c,--tl)acltor Is lower than a predetermined value and the charging request takes place, lit the event Lliat; the Interval mode does tiot take place, or in the event that; Cite first shot Is Photographed In the Interval mode, the processing diverges to tlie RELEASE. WAIT CHARGE operation shown].it F.I.g. 25. fit other words, in the second or later sliots In Cite Interval. mode, even 1.17 Lite charged voltage Ls lower Llian the predetermined vtil.tic. the strobe is rlashed and the rollowIng release sequence Is executed.

fit t.he Interval mode. as shown lit Fig. 27, lite CHARGE CONTIZOL operallon Is exectiLed oil every If the charged voltage does riot; reach Llic value with this operation, even if charging is again executed, there is only a small possibility in increase of Ule vol.t.lgre.

In st.cps AF.25 t.hrough AF27. ench (Int.a set is oxit,l)tjt.Lecl Lot.he sub G1111.

In the automatic photograph mode, the lamp IndicatIon, photometric measurement, and Judgment of' the release sw.ltch are skIpped and the processing jumps to AFA shown In FI.g. 21. In steps AF29 and AF.30. when the strobe Is flashed accordLng to FM data, the red lamp Is turned ON and the processing Is advanced to AICB shown In Fig. 21.

in steps AF31 through AF33, the green lamp is turned ON or blInks according to the green lamp blInk flag FGLMPFE whLch Is set In the LL calculation. The turn-on and blAnking of' the green lamp represent the photograph permiss-lon and the alarm. respectIvely.

In steps AF34 and AF35, when The photometrIc switch SWS Is turned ON, the processing waits unIll the release switch SWIR Js turned ON. When the shutter button Is released, In step AF34a, the red and green lamps are turned OFF and the processing Is jumps to the MAIN operation.

Ln steps AF36 through AF43, when the First shot is taken In the Interval photographing mode, the 3 sec 11mer Is started. When The first shot Is taken In the seir Ltmer mode or double self timer mode, the 10 see timer Is started. When the second or Vater shot Is taken. sInce the Interval timer has been started, the process 1 ng 1 s advanced to a L 1 me up wa 1 1, process 1 ng ComPrISI119 stops AF/14 and later. whell Llie fliodc is ill iielt.lier- Llic Interval. ino(le nor Llie selC mo(lc, Llic processing jumps to A17C shown fit FIg. 22.

Steps AF44 throxigh AF.54 are a loop ror walling xititil Lhe Interval Iliner, Llic 1.0 see Lliner, tile. 5 sec. Ilivier, and Illic 3 sce Limer Lime ill). Wheil cach (.inter Ilines ill) or when the inode button Is depresse(l, Llic processing exits From Clils loop. Ill these cases, Irt. s Le ps AF.55.1ti(l AF5G, the ie(i all(] green 1.amps an(l Che s c 1 r t. 1 ill(- r 1 ainp a re (.it rn cd OFF, Llie au Coma L A c phoLographing flag is cleared, Ill(., present nio(le is and the processIng jumps to the MAI-N operatloll.

AI the second or Ialer shot!.it the 1nterval mode. 15 the remalning ttme or Lite Interval Lfiner Is dlsplayed.

When the reni,.iiiitt)g tinte or Lite Interval. Littler, lite 3 see (; Liner, Lite 5 see Lliner, or I-lie 1.0 see Lliner becomes 3 sec. or Less. the sell' Lliner lanip Is blinked at 4 liz.

When the LInter Clines up, Irt Ilic se-l.r Linter mo(le, the processing dIreelly advatices lo AVG shown In F1gr.

22. it, uic (jowne sci.r ino(ic, Cite processing to AFT lrt.or Ilie atilo release I'lag, FAUTORE.I. Is In slep AF-59. In tile, (lotible Self, IlnWe. al Llic shot. the Flag Is rrom 0 to 1.At, Llie secowl shOL, the flag is changed to 0 and the automatic fig 1110(JC is Ill Che 1111erval niode, t'lle 111Lerval. Lliner. Is c C; d 11 LIM]lltct'vll 1,1111C whiCh Is set In. leps AF-GO throligh AF.64. At Cite first.- shot. 0ie 111,rix]lilt ill, v,1111e or tile litilliber or pholographIng franies is set to 40. j ri additi.on, to axitoinatlea.lly take the second or later shot, Lhe auto rel-ease flag FAUTORESI, I.s set; Lo 1. When tile second of- 1ater shot Js taken, the reinal.ning Interwril. Linte Indleallon oil Che LC1) ci.Lsl),1-ciy ls set lo Os and Lhe processing advances to AF.G shown 1n Fig. 22. Stel) AF.64 Is executed to prevent the Ind-LcaLlon front being returned to a value other than 0 because Che timer Unies up.

is In. steps AF65 through AF.67 shown. In F1g. 22, before the exposure operation Is started, each 1amp Is turned OFF and Cite shutter start stgrial Is outpulted to the sub C1111J. In steps A1768 and AF65), I.n the overlap 1)11ocogi-jjl)lllllg fliode, (1111.(! prohibl.Led.

1.11 othel- C-11,111 Che, bull) Illode, Lite processing, dIverges froin step AF70 to step AF71. where 1.t I.s conCIrined that the shutter operalton cottil)l.etlori signal Is Inputted front Lite sub CIT. AI'Ler ChaL, Che processIng advances to the WI.ND operaLlon shown lit V1g.

26).

fit Ghe bul-1) illode, lit sLep AF72, It Is (.otirli-iite(i L11,1L Ille slititter i-el.el.qe signal Is Inputted rroin Lite sub CAT. 1 it s lep AF.73. 1 G 1 s checked whether Llic mode Is Lhe conventImial bull) mode or the manual slitit.t,et, mode. 1 f -1 1 1 s the bu 11) mode, 1. it s Leps AF74 and AF.75, the processing watts until. the slititter button Is released. I.n step AF.76, Lhe slititter close slgrial Is outputted. 1.17 11. is the manual slitiller mode. lit stel) AF.77, Lite manuaL shutler ll.me I.s counted and after the counting ls completed. the shutter close signal. 1-s outputted.

((VOI,'1'A(7'1,," CHECK is Fig. 2.3 shows a VOTAME CHECK subroutine which Is called 1n step AF.6 or the AE.AF. COWrim operatIon.

In steps VCJ through VC4. after the voltage clieck signal C1ICK is set to 11. tile processing waits for 50 ins so Lhat Che Ne lamp Curris ON. Thell Ule RI.S PUI.SE r1ME MEASUREMEEN,r subroutine deser-Ibed above Is exectiled and Che sIgrial C1ICK Is set to 1 lit sLeps VCB 11trough W7. Ir Lbe chargred vollage Is 270 V or more, ind the cavitera Is operated In Llie double self mode or Lite Interval mode, the prolilbiling time reducti.on 1)rolill)ltlng flag FWIST11 Is 1 ri other eases, Cite processing advarices to stel) VCS.

I'litis, -In the (10111)1e sel.r illode and I'lle Interval illode, the 1)roill.1)11,1,11g (Aille Is not shortened.

Therearter,.111 stel) VCS, hot.h the charge on F.CM; and Ghe (.)large rl.,ig F.GI1CM11 are cleared, and the processIng returns to the AE1AF CONTROL ol)eratioil.

The charge request rlag GAIGRQ Is set to 1, -Ill a later descrIbed FM calculation sijt)rotiLitie, by the charged voltage 270 V rIag FGHG270 set to 1. lit tlie VOLTAGE CHITICK stit)rotit.i.vie. Thereby, the processIng diverges to the RELEASE WAIT CHARGE. subroutine.

(FM calculation)) is Fig. 24 shows the FM calculation called fit step AF17 of the AEAF CONTROL operation.

Tlils operation serves to determine whether t.o flash the strobe and to determine Cite aperture number Avs aL Ilic (Ame when Uic st.robe ffashes.

In steps M1 through FM5, in the case of the strobe OFF inode, the exposure compensallon modr. and the, [)till) mode, or in the case that non-flash is determined in the AE 111 Ule alito ltiode. 1.11r FM (1,11,1 Is sel, Lo and 1he processing relurnes lo Uin. AEAF CONTROL operat.lon.

lit other cases, it, sIc aperture value Avs p FM(3, an c [s ob - -alried rrom tile illeIsill-ellicill; (AF stel)) and tlic reference guide number. f.n stel) 17M7, the (,liarg.ivig,- vollage liirot-init,loit W3V Is added and Llic aperture value Avs Is corrected. The above gulde number Is set accordIng to the rull charge state of the strobe capacitor. Therefore, unless decrease or Ule guide number at a low voltage Is considered. under exposure Lakes place.

In step FM8. the film sensitivity Sv Ls added to the aperture value Avs. In steps 17M9 and 17M10, lit the zoom area, Cite change amount ZDGV or C-lie guide number catised by zoomIng or the strobe Itself Is added.

In step FM11. the change amount 4 (alplia) or the release F number Is subtracted from the aperture value Avs.

In steps 17M1.2 through FM14. Lite tipper and lower I-ImIts or the aperture value Avs are rest.r.l(.LC(I. Whert Llic vol.tIiy(1 of' the Is 270 V or less lo the restill, of' 1.1te VOLTAGE, GUEICK stlt)l.otlt.itl(! called Ill Slel) AF6 of the AEAF CONTROL.

Lite chargIng. request ri..,g is set, t.o i iri(i uic processing returris to the MAIN operati.on.

WAIT CHARGE operation)) Fig. 25 shows Hie RELEASE WAIT CHAWIE which diverges from steps AF23 and AF24 of the AEAF CONTROL operation.

Steps C111. Uiroxigh (119 are a loop ror repealedly executIng charging In step (116 every 125 ms. When.1 t is judged that the charging time is completed or that the charged voltage exceeds 280 V according to Che lline lip flag FC1ITUP and the 280 V charge r.lag FGH280, the processIng exlis f'totii the IRIJ-.,1.,1.'ASII,- WAIT CHAIZG171 operation.

In autoinatle photographing such as the Interv:al mode, by LurnIng ON one of the mode swItches (the mode button. A, 1he mode button 13 or the (.]ear button C), the processIng exIts to stel) C11J.0. l_n other llian autoinatic.

photographing, when the user takes their finger off the shutter button 15, the processing emits from the RELEASE WAIT CHARGE operation.

Also, Ir the charged vo.ltage (toes riot reach 280 V 111 0 secovids and lhe 1,1111(1 Is 111), lhe froin the RELF1ASE, WAIT CHARGIE, operation. Whell lhe processing, exits frovii 1.1ie PE'LE.ASE. WAVI CHAWA.:

operation, In steps G1110 through (A112, the red and green lamps are turned OFF, the CHARGE, STOP operat.lon Is executeo autoinaLle pho lograph 1 rig I.s canceled,, ( Irl 1 the 1)ro(!essi.yig jumps to Ific MAIN operallon.

Wlien tile cliarged vo 1 tage renclies 280 V be Core Llie time Is tip, Llic processing advances to C111.4 - C111.6 via tile CHARGE7. STOP operatIon [it step C1113. Lit ocilel. 1.11,111 automatle 1)Iiol. oLrril)liltig. Clic red laivip Is Ltirned ON to inform Llic user lliat Lite strobe f.s ready to rLasli. In addition, Llie cliargIng request f'l.ag MIG1RQ Is cleared and tbe processIng jumps to Lbe AE.AF control 2 sliown In F.I.g. 20. Wlien Llic processing advances rrom tile RELE.ASE, WAIT CHARGE. operation to Llie AEW, CONTROL ol)erat;io[i. tile liliotoinet,t-i.(. measurement operation, Llic dIst-ance operatIon and so rortIl are olillt.ted and Lite Is executed tising Clic former data. DurIng cliargliig. the voltage Is cliecked lit comparison to 280 V. Arter charging. the voltage Ls cliecked lit comparison to 270 V. because the vol.tage drop and noise due to Clie cilarge stop are considered.

lit Clie CHARGE. CONTROL stibrotitlrie execute(] Ill Cite MAI.N operation, cliarging Is compLeted wlien Clic cliarged vol-Lagre reaclics.130 V or the time 111) ill f; N(!(.. l.q moll 1. to r c (1. llowever, Ill tfie RE.USAS E' WAIT CHARGE. operallon, siri(!e tile liser W"IJ(,s 11[1111 cliargring.Is completed wlille pressing Cite pliolometrIc swi.(,(,ii SWS, cliargIng Ls compl.eled wlien Lite voltage reaclics 280 V and the Llme Is monllored f'or 6 sec. 'I'lixis. sIvice 1.1)e 25 cliargIng request rtag F.GIUMQ Is not (lelre(l In st.(ii) (Xl-0 or Clip GHARGE, (-,ONTROL subroutine, the flag is cleare-d].it step (A116.

( (W 1 NI) OPEIRATI ON)) Fig. 20' shows Cite WIND oper-at-lon which 1g called after Cite AF,At.' (,ONTROL Is completed.

The WIND operatlon serves to wind one Crame of' Clie 1711m whenever photograplitng takes pLace.

In Lhe WIND operation, In steps WD.I. and WD2. the 1() rrame number Is Indleated on the Lel) dlsplay (-.-x(.el)t; In Ille Interval mode. In Che overlap photograph.ltig- mode, the processIng branches Croin step WD3 to step WD4 to return to the fraine photographing mode, and Che processIng jumps to the MAIN operaLlon. In otlier wor(Is, Llic overlap photographIng mode ts cleared whenever one rrame Is photographed.

].it other than the overlap photographIng mo(le, I.n step WD5, one Frame Is wound. When the WIND operation Is not lit a predetermined Llme, Llm processIngr 1)ratiefies rrovit c;tel) WDO lo step WD7 wimre 11m atitomalle pholographing operation Flagr Is the processhig executes Cite RESWIND operal-lon and jumps to the MAIN operallon.

When the WIN]) operatIon Is completed, In slep WD8, the rrame counter Is (.otitite(l up.1.11 steps WDS) awl WDIO, 1 1 ot.licr Llian Uie Interval mode, the new Cl-affle number' I.s -lit the Interval mode, 1he Frame number Is riot IndIcated because the reitiiliil.iig (.1.ine to next. phol.ograph 1 rig Is Indicated as (IescrIbed 1.ater.

lm s(.el)s WDII through WDIS, the destination of divergIng. Is determined accordIng to the photographIng illode get.

].it Life continuous phoLographimg mode, while the slititter button Is beIng depressed, Cite 1)rocessi-iik J111111)s to the AEAF control 3 shown In F.I.g. 20 am] the exposure sequence Is coritInued. When the button Is released. the processIng Jumps to the MAIN operatIon.

lit the double self mode. when the fIrst shot. Is Laken, Cite processIng juvrips to the AEAF CONTROL operatlovi. Wheit tile secont:l shot Is taken. the processIng jumps to the MAIN operatIon.

lit the InterviI mode, the processing jumps to tile I.NTE.RVAL CONTROL operatIon shown lit 1.11r, 27. Ill ot.fl(.r.

modes, I.e., In the rrame photographIng mode or life self Llivier mode. the processing jurrips to Lhe MAIN operat-lon.

((IN,riI.-IZVAI-. CONTROL ol)eritl,.ovi)) F1g. 27 shows 1he INTISRVAL CONTROL operation W111C11 (HWA-ges Fr-orn S(;C.1) W1)15 or 1,11e WIND c)r)et-,1t,ioti described above. Tlils ol)et.,ilioti serves to wx.it. wiii.le itie,lstirl. t)gr Lite 1;1.iiie For Laking secon(I or Inter s)iots, wiicii Lite I)Iiot; obrt-,il)liiittr opernt.lon itio(le Is set. Lo 1-be Interval iiio(le. lit ot'lier Llian Cite Iiilervi.i. ivio(le, OiLs operatlon Is exectite(l -lit a loop of' Clie MAIN operation. flowever, [it Lite [nterval ivio(le, Lite operati.on Is executed while loopIng between Uic AE-Al-. CONTROL operatIon and the INTERVAL CONTROL operatIon wi.tlioul jo returning Lo Cite MAIN operatlon.

In Clie INTERVAL CONTROL operaLIon.]it sLep I.Nt, botli tbe cliargIng request flag ITIR1RQ art(] tite cliargIng rectfiest ineinory flag FC11G1RQ1V1 are cleare(l.

In steps IN2 and IN3. the hiterval fraine cotint number Is decremerite(l arid It Is cliecked wl)etlier Lt becoines 0. Ttie value of' the (.,ouliti.tig titjtnl)er Is frames whicii 1,9 set lit step AF62 of Cite AEA1-, CONTROL operation. When the 40 frames have been photographed, in sleps IN4 Uirotigh ING, (.It(! CHARGE' ST011 Is executed. the atitoin.it[e 1)Itotogrr,.il)iil rig Flag Is cleare(j, Cite MODIS INITIALIZE stjt)t.oxjt.lt)e I.s an(l Ole processing jumps-to the MAIN operaLLon.

witen ne Frame cotint rititnl)er Is riot. 0. st.cps IN7 t.liroxi,-lt IN21 are loope(I fiv(..,ry 125 tits an(l Ote processitur, waits iiiit.11. Uie next fraine Is Dii r 11 j r, L 11 -1 s 1) c r 1 o (1, wi i c it o i i c. o r mod c sw i L c 11 e 9 o r t, 11 e c. 1 ea r switch Is turned ON, Ilic. mode Is liii.t.i.a-l-lze(l and the processing jumps to Cite MAIN operation. tn Llils loop. norinall. y the 1.1mer decrement; 5 IndicatIon takes pl-nce. llowever, when the pholoniet.ric sw-tteli Is Lurned ON, the rrame vitimber is Iridlcal.ed. When the zoom tele/wide switch Is turried ON, the rocal length Is Indicated. When the reniiltitrig tline becomes 16 see or Jess. lit step I.NIS, both ITC11GRQ and FCIIGRQM are set to 1 ThIs tImer Is set and started In step AF.60 or the A171AF.

CONTROL operatIon.

lit the CHARGE CONTROL operaLIon in step IN20, when F-CHG11Q Is set to 1, chargIng Is executed. When the is rlag Is set to 0, cliargtng Is skipped.

Thus. lit the loop or steps IN17 through IN20.

charging I.s rorced to start. Witeri It. Is Judged that Lhe strobe capacl.tor Is rully charged, chargIng Js S to 1) 1) c (1. In 11m rtext. lool). 11m CHARGE. CONUT01.

operation is skIpped.

witell 1.1m 1-(1111,11[11111,r 1111m becotnes 4 sce. or less., the processing diverges rrom st.cp IN19. lit sIeps IN22 and IN23, chargIng As stopped and 1he rettiil.tiltig 1.1me lit the tlincr Is Indleated. The processIng jumps to llic AE1AFCONTR01. operation shown Art Fig. 27 and walLs unt-11 MIC Illu( Is till Ill qtel)s AF.44 all(] AF.54.

As described above, with the present invention, when Lhe st.robe elretilt Is liciitl-e(l due Lo frequent chargIngs. by Che ror a predeterm.l tied t[itic, it, is possible to preveriL Che circuit from being over heated and the circuit parts from beIng damage(].

In addition. since the charge protilblt Uine Is Increased and decrease(] according lo Life ri-equency or strobe flashings, in the event that the circuit is not going to be over heated, charging can be immediately executed just after the strobe is flashed, thereby reducing time lost for the user.

Fur Che rmore, the charged voltage of the strobe main capacitor can be detected on a fine level WICII a rela(Avely S1111ple 'I'litis, expostire corit.-rol and the Like (..an he accomp-lished accord.Ing lo Lhe flashing condition (.ort-esl)oritli.iig 1.o Che charged Vo 1 Lage.

By arranging Chat a pulse is oxit.l)tjt. otil-y when Lhe chargeo voltage exceeds a predeleritililed rererevice val-tie. a tnl.s.lti(ignierbL earl he reduced In fiieaslit-ii)gr I'lle pillse Llifte.

lly irriytglrir, Llial, (.1iirgitigr (Ame and chargre L11111.t.VolLage can be SelecLed accordIng Lo I'lle operation mode of the camera, It becomes possible for the u!ser to select the charged voltage or the charge waiting time according to the situation.

By arranging that the exposure can be corrected according to a change of the charged voltage, even If the charged voltage of the strobe main capacitor Is Insufficient, It is possible to prevent under exposure due to weak strobe flashing.

Claims (13)

1. CLAIMS t 1. An exposure control apparatus comprising:voltage detecting

   means for detecting a charged voltage for application to a strobe; and determination means for determining a proper exposure value based upon said detected charged voltage.
2. 2. Apparatus according to claim 1 wherein in determining said proper exposure value said determination means selects one of a plurality of exposure correction values on the basis of said detected charged voltage.
3. 3. Apparatus according to claim 2 wherein three exposure correction values are provided.
4. 4. Apparatus according to claim 2 or 3 wherein said voltage detecting means selects one of a plurality of voltage bands according to said detected charged voltage, each said voltage band being allocated a said exposure correction value.
5. 5. Apparatus according to any preceding claim wherein said determining means determines said proper exposure value when said detected charged voltage exceeds a predetermined reference voltage.

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6. 6. Apparatus according to claim 4 and 5 wherein a reference time value corresponding to said predetermined reference voltage is employed to determine said charged voltage corresponding to the measured time width.
7. 7. Apparatus according to claim 6 wherein on reaching said predetermined reference voltage, the measured time width corresponding thereto is added to form a weighted average reference time value.
8. 8. Apparatus according to claim 7 wherein on reaching said predetermined reference voltage, the measured time width corresponding thereto is set as said average reference time value when a predetermined charging time has not lapsed.
9. 9. Apparatus according to any one of claims 6 to 8 wherein said voltage selecting means selects one of said voltage bands by selecting one of a plurality of voltage levels as said charged voltage on the basis of whether the measured time width is greater than one half said reference time value plus a level dependent time constant.
10. 10. Apparatus according to any one of claims 5 to 9 wherein said reference voltage is a flash enable voltage for said strobe.

    57
11. 11. Apparatus according to any one of claims 2 to 10 wherein said correction value is zero for a detected charged voltage equalling the maximum charged voltage for application to the strobe.
12. 12. Apparatus according to any one of claims 2 to 11 wherein said correction value is related to the flash guide number.
13. 13. An exposure control apparatus as claimed in claim 1 and substantially as herein described with reference to the accompanying drawings.