I have mentioned several times in these forums that my Sigma 35mm f1.4 Art habitually overexposes by between 0.7ev and 1.7ev on my K3, especially outdoors in natural light. It's been driving me crazy. None of my other lenses do this (6 Pentax and 1 Tamron).
Well, I think I've solved it (sort of). There is a basically undocumented setting in the C1 menu page: "Auto EV Compensation". All the K3 manual says is "Sets whether to automatically compensate when the proper exposure cannot be determined".... whatever that means. For some reason, I had this turned on. I don't know why, in fact I didn't even know it was there. Testing in both dull and bright natural light since turning it off sees the Sigma 35mm exposing pretty much the same as my other lenses, i.e., correctly.
But that still begs a couple of questions:
- What is this "Auto EV Compensation" setting supposed to do?
- Why did it screw up the Sigma but leave all other lenses untouched?
Any theories?