Update: The lens isn’t really a “fail”. It’s just quirky. I decided to keep it, but I just won’t try to use it in full manual mode without first adjusting the exposure compensation on my camera. As I said below, when I put my camera in Aperture Priority mode, the photos are fine (aka properly exposed). So, I’ll probably just only use this lens in that mode.

…..
So, I finally got the lens Saturday. But, I had to head out of town at the last minute on Sunday, so I didn’t get to take any test shots until I got back and recovered from the trip. From looking at the lens, it looks fine. No oil on the aperture blades, no fungus on the glass, no scratches or chips in the glass, and the body was okay, etc.

However, when I put the lens on my K10D and started taking test shots, I noticed that the photos taken with the lens wide open at f2.8 were DARKER than the photos taken stopped down to f5.6. In fact, the f5.6 aperture setting seemed to be this lens’ “sweet spot”, as it got the exposure right. The photos taken at f8 through f22 were all supposed to gradually get darker as the aperture got smaller. Looking at the photos in the order taken (from largest to smallest aperture: f2.8, f5.6, f8, f11, f16, f22), the darkening of the photos should have followed an easily detectible progression from brightest/lightest to darkest. That didn’t happen.

The weird thing is that when I took the camera out of full manual mode and put it in Av mode (aperture priority), the exposure in the shots was balanced correctly. But, if I want to grow my technical skills, I can’t get into the habit of shooting in Av mode all the time. But, if I only shoot in Av, without understanding how to use manual mode, how would I know what to do if I needed to use full manual mode in a difficult lighting situation? Exactly. I’ve contacted the seller to arrange a return and refund.