Excellent addition to the app; this is what it really needs.

Quote Originally Posted by Curt View Post
Very nicely thought out and presented. I like the app and the old shutter speed levels will be a welcome addition. The light measuring phototransistor would be excellent. If one could be placed in a bellows near the front of the camera, perhaps at or near the rear of the lens, it might be possible to see and record the actual exposure for timed shots, that would be an incredible advance. Especially in the the range from one second to a few minutes.
This is a good idea except that the sensor will be outside of the image area of the lens, which means you're metering the wrong thing. However if you wanted to modify an LF camera for example, you could take the Minolta approach of metering off the film - google for "OTF meter". Requires a little sensor and very simple optics inside the camera body to average the intensity of the light diffusing off the film during exposure and when there's "enough", ends the exposure. Minolta used that for TTL flash metering with no preflash and I believe another 35mm manufacturer (Olympus?) used it for metering long exposures under varying light; both were in the 1980's.