Here are some tests I ran with various lenses. Not the most scientific, but I did use a tripod and did my best to maintain a parallel plane to the wall. The exposures varied wildly due to p-ttl being employed so I just auto corrected them in lightroom.
https://www.dropbox.com/photos/album/yYfCHwWjbG9WD2N
My k-7 showed about the same. Looks like my k-5's mount is mostly ok, but a bit weak in the upper left. It was a refurbished camera from keh so I might see how much longer I have on the warranty and send it in for a checkup if I ever get a damned working k-3. Same goes for my 17-70 which is also about 5 months old. I don't know what's going on there at f4, but I don't like it. I think it should go in for a warranty check too while I still can, though I could probably mostly live with its deficiencies since I generally shoot at smaller apertures. Its certainly not a perfect lens. The 55-300 is looking downright awful! The 50-200 is looking much better at the same focal length so I really have to blame the lens here. The only lens that looks all that great is the 50mm. Even wide open it looks pretty decent for the most part.
What I can't help but notice is this: Even an imperfect copy of the 20-40 is currently outresolving every lens I own including A 50/1.7 which was previously the sharpest lens that I owned. Jpeg file sizes are 16mb compared to the 6mb or so the other files have. Also the 55-300 is churning out larger files than the 50-200 even though is is really decentered looking. The 50mm at F8 gives a 10mb file. It outresolved my k-7. On the k-5 IIs, not so much.
This makes me seriously want a good copy of the 20-40. Its really good!
On the other hand I just spent a total of 3800 on gear over the past few months that all has serious deficiencies and that is going to require time and more money to fix. Ugh! Am I being too picky here??
Originally posted by zosxavius 
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