Greetings, Dear Pentax Users!
I have a Pentax K10D. I just got myself a Vivitar Series 1 19-35mm f/3.5-4.5 lens. I noticed, that in Av mode, when I set the aperture to f/8.0 on the body, it only stops it down to about f/5.6. This is regardless of zoom position. This is a KAF mount lens. The lens stops down properly in M mode with green button metering, the viewfinder darkens accordingly as well. However in Av mode, it doesn't work properly. I just had a full day of shooting with this lens attached to my Pentax MX and all was well. I was using the aperture ring then. I came to the conclusion, that using this lens by aperture ring is the way to go, it works well. However it's quite disturbing. It either means there's a mechanical problem, or there is one in the firmware of the camera. This isn't he first lens, with which this problem occurs: I had a sigma P&P lens too, which also gave me overexposed pictures. So does my Tokina 28-70 MF lens. I highly doubt, that all of these lenses are faulty, since they (with the Sigma's exception) work perfectly on my MX. I'm thinking that it my be my good 'ol K10D, which is acting up.
Any ideas about the nature of the problem?
Last edited by gtxSeries; 07-16-2017 at 10:38 AM.
Reason: sent in by accident :(