Originally posted by bertwert Yep, you can set an auto iso range while in Av mode.
Normally use the green button, not the shutter botten half-way with non-A-lenses (or not set to A)
A on the lens is 'automatic' so that the body can adjust the aperture on the lens.
This is oposed to the old style 'automatic stop-down' since the modern body doesn't come with stop-down feeler.
In an older (before MZ-7) body there is such a feeler and thus the pressing half-way does only measure but also closes the aperture to the set value. With the modern (digital ) body there is no feeler and the only way to let the body know there is an aperture to close, you need the green-button.
When you don't use it or use the 'automatic' function, you will be taking pictures with the aperture fully open (for example f/3.5 instead of f/11)
I normally use the 'manual' function in the body, press the green button and the right value comes out for the exposure and you can adjust it the way you want to.
By the way, don't forget to change the user-setting for the 'old lenses' (aperture ring not set to 'A') in the user-functions, otherways it will only use the lens in 'A'.
With the lens in 'A'mode with the new lens you can still to the same, just make it 'non A' again.