|
Hmm, not sure about that Leon? AV is aperture priority I think?
If you set the exposure mode to AV then effectively you are telling the camera that you will set the aperture (e.g. F4 or F5.6) and the camera will then calculate the relevant exposure based on your chosen aperture.
Most cameras try to balance the exposure to achieve an 18% tone in the image. That is, the sensors measure tones around the frame and then averages them all out to produce a mid tone exposure of 18%.
If there is a lot of white in the frame, (e.g. snow) then the snow will come out an 18% grey colour; that is, under exposed and not nice and white.
If there is a lot of black in the frame, (e.g. dark skies) then the dark areas will come out an 18% grey colour; that is, over exposed and not black.
The risk in letting the camera decide, even with today’s incredibly sophisticated auto exposure algorithms, is that the scene may not be recorded as you intended, so I would recommend experimenting with a few manual settings until you have the aperture and shutter settings combination that produces, e.g. an acceptable amount of star trailing, the Moon not too over exposed and showing earthshine, etc.
Cheers
Dennis
|