Originally posted by PhotoHeron The discussion is about two wheels vs one wheel. Explain the advantages of dual wheels vs a single wheel or disadvantages.
When taking a picture you decide on lot of things. Framing, when to take the photos etc.
But on the the camera you set the apperture, you set the shutter speed, you set the exposure and you set the isos.
Technically, if you set 3 of theses parameters, the last can only be deduced from the other 3.
So you have really 3 things to think of. So even with 2 wheels, you might need to use some button or menu to control the third parameter.
Most of the time through, you can reduce futher reduce the parameters you are really interrested into. You really keep 1 or 2 parameters to work on.
Having 2 wheels give you direct access to control 2 parameters on all modes. You can configure what the wheels does on all theses modes and different for each if you feel so. Wheels can change the apperture, shutter speed, isos, exposure, change the hyper program priority or can even be disabled (at least 1). I think there even a few things more you can do.
Having 1 wheel force you either to go through a menu or use your wheel in combination with a button to change the setting. This take a bit more time, is a bit less practical and this is bit more cumbersome.
If you plan to stay always on mostly automatic mode, this is of no importance... if you want to control what you do, this is real comfort. In TAv or M mode, this is a must. Even on Av or Tv, changing the iso with the second wheel directly is really practical.
But it depend really how advanced you intend to be with your camera... so how much you want to grow your practice with it.