You're right about the time of day ... but this isn't about the time of day, it's about the light level. I want to have a photograph at the point where the light first reaches a pre-determined level. I've gone out and metered it -- the exposure would be 1 sec. @f8, EI 100. I'm going to run some tests with a photocell before deciding on a condensor lens. It turns out that the light level I'm waiting for is pretty much at the low end of the photocell's practical measuring ability. A condensor moves the effective brightness (on the photocell) into a resistance range that allow for more accurate measurements.
If this were just one photograph, I'd not be building this thing. But it's for a project that entails a photograph every two weeks, for a year, to document seasonal changes on the prairie. I simply cannot expect to be available to take the photograph on every one of those mornings, but I can expect to be able to set up the camera sometime during the day before and have it capture the scene as planned.
If this were just one photograph, I'd not be building this thing. But it's for a project that entails a photograph every two weeks, for a year, to document seasonal changes on the prairie. I simply cannot expect to be available to take the photograph on every one of those mornings, but I can expect to be able to set up the camera sometime during the day before and have it capture the scene as planned.