DE737145C

DE737145C - Electric light meter

Info

Publication number: DE737145C
Application number: DEI52021D
Authority: DE
Inventors: Dr John Eggert; Dr Richard Schmidt
Original assignee: IG Farbenindustrie AG
Current assignee: IG Farbenindustrie AG
Priority date: 1935-04-05
Filing date: 1935-04-05
Publication date: 1943-07-07

Description

Die vorliegende Erfindung betrifft einen elektrischen Belichtungsmesser für photographische Zwecke mit drei zur Ablesung der zusammengehörigen Belichtungszeiten, Blendenöffnungen und Empfindlichkeiten des photographischen Materials dienenden Skalen, von denen eine jeweils mit der einen der beiden anderen Skalen für sich koppelbar ist. Derartige Belichtungsmesser sind bereits bekannt. Sie hatten jedoch den Nachteil, daß bei ihnen eine die Empfindlichkeit regelnde Vorrichtung fehlte und daher der Skala, auf der der Zeiger einspielt, eine derartige Form gegeben werden muß, daß dieser die ganze Skala überstreicht. Eine solche Anordnung ist räumlich sehr ungünstig und kann leicht zu Ablesefehlern Anlaß geben. Es ist auch schon bekannt, den Meßbereich des Belichtungsmessers durch Einschaltung von Filtern,The present invention relates to an electric light meter for photographic use Purposes with three for reading the associated exposure times, aperture openings and sensitivities of the photographic material serving scales, one of which each with one of the the other two scales can be coupled individually. Such light meters already exist known. However, they had the disadvantage that they had a sensitivity control There was no device and therefore the scale on which the pointer reads was lacking such a shape must be given that this sweeps the whole scale. One such arrangement is spatially very unfavorable and can easily give rise to reading errors. It's also beautiful known, the measuring range of the light meter by switching on filters,

ao Blenden oder Widerständen zu verändern. Wenn aber die Empfindlichkeit des Meßinstrumentes verändert wird, so muß dies auch irgendwie in der Skala des Instrumentes berücksichtigt werden. Man hat zu diesem Zwecke vorgeschlagen, zwei Skalen mit verschiedenen Meßbereichen am Belichtungsmesser vorzusehen. Eine derartige Skalennnordnung kann aber leicht Anlaß zu Verwechslungen geben. Eine andere Möglichkeit besteht darin, die Skalen mit Änderung der Empfindlichkeit auszuwechseln. In diesem Falle sind jedoch immer zwei Tätigkeiten notwendig, nämlich einmal die Änderung der Empfindlichkeit und das andere Mal die Skalenauswechselung.ao diaphragms or resistors to change. But if the sensitivity of the measuring instrument is changed, this must somehow be taken into account in the scale of the instrument. One has to this Proposed purposes, two scales with different measuring ranges on the light meter to be provided. Such a scale arrangement can, however, easily give rise to confusion give. Another possibility is to change the scales with a change in sensitivity. In this However, two activities are always necessary, namely changing the Sensitivity and the other time the dial change.

Die vorliegende Erfindung besteht nun darin, daß bei einem Belichtungsmesser der ?uerstgenannten bekannten Gattung eine der Skalen mit einer die Empfindlichkeit des Belichtungsmessers regelnden Vorrichtung kop-, pelbar ist. Die vorgenannten Nachteile werden somit dadurch vermieden, daß die Skalenverstellung mit der Regelung der Empfindlichkeit des Belichtungsmessers koppelbar ist. Alit einem einzigen Handgriff können dabei Skala und Vorrichtung zur Empfindlichkeitsregelung verändert werden. Außerdem besteht dabei die Möglichkeit, die Empfindlichkeit allmählich zu ändern.The present invention consists in that in a light meter The first known genus is one of the scales with the sensitivity of the light meter regulating device is coupled, pelbar. The aforementioned disadvantages will be thus avoided that the scale adjustment with the regulation of the sensitivity of the exposure meter can be coupled. With a single movement you can do it Scale and device for sensitivity control can be changed. In addition, there is with the possibility of gradually changing the sensitivity.

Zur Regelung der Empfindlichkeit können bekannte Maßnahmen dienen. So kann z. B. die Photozelle mit einer Abblendevorrichtung versehen sein, die so mit der einen Skala des Belichtungsmessers gekoppelt ist, daß bei Änderung der Empfindlichkeit auch die Skaleneinstellung wechselt. Die Empfindlichkeit kann auch durch Vorschalten von Widerständen, die natürlich gleichfalls mit der einenKnown measures can be used to regulate the sensitivity. So z. B. the photocell can be provided with a dimming device, which is so with the one scale of the Light meter is coupled that when changing the sensitivity also the scale setting changes. The sensitivity can also be increased by connecting resistors, which of course also with the one

') Von dem Patentsucher sind als die Erfindtr angegeben worden:') The patent seeker specified as the inventor:

Dr. lohn Eggert in Leipzig und Dr. Richard Schmidt in Kleii}machnow b. Berlin-Zelihndorf.Dr. lohn Eggert in Leipzig and Dr. Richard Schmidt in Kleii} machnow b. Berlin-Zelihndorf.

Claims

Scale are coupled, are regulated in the photocell circuit.

In the figures, an embodiment of the invention is in one not the one Subject of the present invention forming exposure meter shown.

Fig. Ι shows the actual exposure meter, Fig. 2 the coupling device of the cylinders, on the surfaces of which the graduations are located, and the Fig. 3 the developed cylindrical surfaces of the scales.

As can be seen from Fig. Ι, are located on one side of the housing ι of the Belielitungsmesser Windows 2, 3, 4, behind which the ones with the scales for exposure time, Aperture and sensitivity of the material provided cylinder are located. the Windows allow easy reading of the associated exposure values. In the middle window is the pointer 5 of the electrical measuring instrument connected to the photocell visible. It is positioned depending on the sensitivity of the photocell and the brightness of the object to be measured set a specific value for the aperture. On both sides of the light meter there are two knurled disks 6 and 7, which bring about the coupling of the scale cylinders.

Now the object to be photographed is replaced by the one on the light meter Viewfinder 8 (or the viewfinder of the camera, if the exposure meter is on the housing attached to the camera), the photocell, not shown in Fig. 1, should be aimed (on the other side of the instrument) light at the same angle as that photographic layer obtained on exposure. The button 9 is now the Locking of the pointer 5 canceled, which is now aaf of the aperture scale any Value. The button is released again before the instrument is set down. As a result, the pointer stops at the value reached, so that the reading is now possible can be done in peace.

From Fig. 2 it can be seen in which way the coupling and adjustment of the scale cylinder takes place. The exposure times, the aperture and the sensitivity numbers are each printed on a cylinder that can be rotated for itself. B. on the cylinder 10 the values for the sensitivity of the photographic material, on the cylinder the aperture openings and on the cylinder 12 the exposure times are located. Fig. 3 shows the developed surfaces of the cylinders. The 6 _U cylinders io, 11, 12 can be coupled to one another in pairs in the following way. By means of the knurled wheel 6, the clutches 13 and 14 are pressed against the cylinders 11 and 10, respectively, against a spring, not shown, so that both cylinders rotate equally when the knurled wheel is turned. As a result of the pressure on the knurled wheel 6, the clutch disks 17 and 18 are automatically disengaged by the disks 15 and 16 that are released. The cylinder 12 thus remains stationary during the joint rotations of the cylinders 10 and Ii. On the other hand, you can press the clutch disks

17 and 18 with the help of the knurled wheel 7 to the cylinders and 12 the latter two aiifinanderkoppel. In this case, you cylinder 10 stops.

If you want to increase the overall sensitivity of the device, pull the knurled wheel 7 all the way to the left until the wheel κ), which is on the axis of the cylinder 12 located, through the clutch disks 17 and

18 is coupled to the cylinder 12. A dimming device for the photocell 21, for example a curtain 20, is coupled to the wheel 19. When the curtain is pulled away from the photocell, the cylinder 12 is rotated by the corresponding factor after longer exposure times.

The dimming device can also serve at the same time to point the pointer to a middle Adjust position on the aperture scale. It can e.g. B. turn out that the pointer swings out of the scale due to excessive light intensity of the object to be photographed. In this case, with the help of the knurled wheel 7, the sensitivity of the system reduced so that the pointer is in a desired central position on the Scale plays. The same applies if the sensitivity should be too low.

P A T EXTANSPR U C II:

Electric light meter with three for reading the related Exposure times, apertures and sensitivities of the photographic material serving scales, of which one can be coupled to one of the other two scales by itself, thereby characterized in that one of the scales with one the sensitivity of the light meter regulating device is kojipelbar.

1 sheet of drawings