coproc (03/23/83)
Correct me if I'm wrong, but I thought that although F stop was based on focal length and lens opening, it really gave an indication of how much light would hit the film. F4 would mean the same amount of light roughly from lens to lens. Then how come when I compared a 1.8 lens set at F4 and my 3.5 zoom set to F4, the camaras indicated completely different shutter speeds? The camaras were different, but set to the same film speed. But the shutter speeds differed by about a factor of eight (my zoom being slowest). Also, how does my camara know when I'm using my 3.5 zoom versus my 2.0 normal lens? Or does it care (I think it would since meter readings are taken with the lens fully open)? I have a K mount, by the way, if that matters. Thanks, John Wallace ihuxb!coproc