couldn't it be a pure electronic problem? All M exposures on my roll were 100% ok. I agree this is without use of the stop down lever which acts only in S and P.
I made all A and P exposures identical to my M exposures . So the meter performed ok in M which was the same exposure on the meter in P and A.
I made some shots of the aperture's action in S. See attachements. I could clearly see the aperture closing at max f22 when pointed to the light blue sky in spot metering mode, shutter speed on 2s and 4s . When pointed to a dark subject the aperture widens up to almost maximum f3.5 in this case.
I really appreciate your input!
Were your pics taken at the 80mm end of your lens?..If so then 5.6 is the max aperture. Some lenses with a "macro" mode on will lose up to a stop further than that in reality, when used in close up mode. Perhaps when you used it in auto mode you thought you were getting 3.5, when in effect it was 5.6?
I didn't note the zoom setting but you're right @ 80mm it's limited to f5.6. I'll check that again. I posted the images to show the stopping down lever actually works as it's opening up in S mode from f22 to f3.5 or f5.6 or in between depending on the (spot)metering.
Thanks for your input.