In another thread I made a comment how the controls and interfaces on today's DSLRs are still firmly rooted in the analog age. On this occasion I wanted to start a discussion about how exposure controls should ideally work on a modern computerised DSLR.
Let's summarize the current state, we have P/Av/Tv/M to choose from, one or two wheels that control time or aperture depending on the mode we are in, then there's ISO which can be set manually by using the menu or extra buttons or, with restrictions, automatically, and exposure compensation, which also doesn't always work (e.g. doesn't affect auto ISO in M).
Obviously ISO, the third parameter besides time and aperture that controls the exposure, is still a second-rate citizen, otherwise we would have 8 insteaed of 4 major shooting modes, ISO auto/manual * time auto/manual * aperture auto/manual.
So how about three switches or buttons to toggle each individually from auto to manual?
Or how about three wheels, that each control one of these three parameters and toggle auto/manual with a click?
That way in full manual I have full control over all three; if all three are in manual, there's no exposure compensation; as soon as I switch one of the three to automatic, it becomes free to control exposure compensation!
And if two are in automatic and one in manual then one of the wheels whose parameter is on auto can be used for exposure compensation, and the other to control the bias of the automatic because in this scenario the automatic has two values under its control, so there are many combinations that are valid, and I'd like to tell the automatic whether to prefer large apertures or higher ISOs, for example.
