Quote Originally Posted by annelouise
Hello everyone. I'm a student and I've been set a photography question as part of my course and wondered if anyone is able to help please ? I don't have a digital SLR (but want one!) the question set is:

When taking photographs with a Digital SLR camera (using the Manual mode) , how do you keep the exposure TTL indicator in the middle of the continuum?

As well as answering this question generally, please calculate the following:

If you take a photograph using the cardinal aperture of f stop 11, at a shutter speed of a tenth of a second, what shutter speed would you need to achieve the same exposure using f stop 22 (for example, if you wanted greater depth of field)?

does anybody know the answer? I'd be grateful for any replies, thank you!
annelouise
Hello...
please check out the wikipedia page on reciprocity. It essentially talks about EV (Exposure Equivalent) values and the amount of light available (non flash) in the scene. There is a lot of great information there, but the bottom line is that whenever you begin to use long exposure times then the rules for shutter speed,aperture, and film speed or ISO begin to break down. This can happen if you are using film or a light sensor. Hope that helps.