“Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”
Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2
"Light meters in the dark." Yup. E. von Hoegh has accurately described the basic way that a light sensing cell or element of a light meter works. In fact, one of the standard rated qualities for that cell is called "dark current" or how much current may flow through the light sensing cell in total darkness at a standard specified test voltage. It is inversely related to "dark resistance."
Back in the early 1960s when the then new Minolta SR-7 came out with its built-in Cadmium-Sulphide (Cd-S) light meter on the front of the camera, the owner's manual recommended storing the SR-7 in the optionally available leather case. While the manual did not specifically say why, one reason was to keep the Cd-S cell covered and dark. The SR-7 developed a reputation as "a battery eater." It seems that many American photographers were just leaving the camera sitting on a shelf or table or something, and the light meter faithfully kept metering the light of room where it was. The next year, in response to the complaints by owner's, Minolta installed a small 2 position rotary switch on the bottom of the SR-7, producing the variant I call the SR-7a. (The later SR-7b had a 3 position rotary switch with the "BC" or Battery Check position.) Then if the owner did not put the camera into the leather case, and left it on the shelf or desk, and also remembered to turn the light meter switch "OFF," nothing happened. The light meter battery lasted for a year or more.
Well, the owner's manual did suggest storing the camera in the leather case, although not explaining that you were also storing the camera light meter in the dark and saving the PX-13 or PX-625 battery. This was an incident where the ability of the average American photographer to ignore the owner's manual, and to complain about the result, did produce a modification of the camera.
Last edited by Ralph Javins; 09-28-2013 at 08:25 AM. Click to view previous post history.
Ralph Javins, Latte Land, Washington
When they ask you; "How many Mega Pixels you got in your camera?"
just tell them; "I use activated silver bromide crystals tor my image storage media."
With the Nikon FE, the film advance was the meter switch. When pushed against the body, it locked the shutter release and turned off the meter.
The Minolta XD 11 didn't have an on-off switch. The LEDs in the meter would go off after a short period. Magazines, at the time, warned photographers to ensure that nothing was resting on top of the camera and pressing the shutter release, which activated the meter. They said it could drain the battery in a short amount of time.
The Olympus OM-2 does have an on-off switch for the meter.
The Pentax MX has a shutter release lock, which keeps the meter from being activated accidentally. Same goes for the Rolleiflex SL35 E.
Last edited by elekm; 09-28-2013 at 09:51 AM. Click to view previous post history.
Reason: Fixed the Minolta model