Hi. I have been battling with my little MS Optical Perar for the last 7 months, and I'd love to hear your insight on my situation, even if you don't own the lens.
Last February, after owning the lens for a month or two, I began noticing that my Perar's corner resolution was incredibly asymmetric. While I didn't expect the corners of this tiny lens to be world-beating, I am using it on an aps-c NEX camera, so I'd expect the corners to be reasonable. Regardless, it isn't the lack of corner resolution that I'm concerned about. It is the unevenness of the corner resolution. In using a liveview camera, I'm obviously able to accurately focus into each corner with high magnification, and I've been stunned at how much sharper one corner is compared to the others. It seems like this lens has heavy decentering. If I extend the collapsable lens barrel upside down, with the aperture markings facing downward, the sharp corner moves with it, and I've tried multiple adapters, so I've ruled out that it is an issue with my setup.
So, I sent the camera back to Dirk at Japan Exposures, so that he could take a look, as I'm apparently the first Perar user to complain of this. Dirk inspected the lens, tested it on his M9, and he found nothing wrong with it. The horrible Japan earthquakes ended up happening during this time, so Dirk sent the lens back to me while he could, and, while I was skeptical of his tests, I was in the middle of a house and business move, so I left the lens in the box, and I didn't retest again until Aug. Well, the same issues were very apparent to me, so I sent the lens back to Dirk for a second time for him to test.
This is where things get interesting. Now, Dirk claims that not only does he see my lens issues on his M9, but his copy of the Perar apparently does this as well! So, now I'm being told this lens isn't designed for very sharp corners, and this could be a product of field curvature, and it isn't a modern aspherical design, and I should try not to shoot things perpendicularly, etc. Huh? As I mentioned before, I didn't expect ZM 35/2.8 corners at f5.6 or anything, but the resolution asymmetry is hard for me to ignore. While I know that I could probably just sell the lens on ebay, and maybe even make a profit, I feel strange listing a lens that I believe has a major issue, despite it being ok'd twice by the retailer.
All that I really want at this point, despite spending over $100 to ship it back to Japan twice, is a refund of my original purchase price, but Dirk refuses to oblige my request. Do you think I'm out of line here? If you're a Perar owner, have you noticed the same issues? Even if you're not a Perar owner, have you ever heard of asymmetric corners being part of a design? Even on an aps-c camera?
Below are a few samples to give an idea of what I'm talking about. This was on a tripod shot at f5.6, and I liveview focused into each corner. This certainly isn't a perfect, technical test, but I can reproduce it over and over again, and have more examples that jive with this.
p.s. I apologize for cross-posting this on a bunch of forums, but there aren't a lot of Perar owners, so it's tough locating them.
Full shot (ignore the red circle I added.)
Top right corner crop
Bottom right corner crop
Bottom left corner crop
Top left corner crop
Am I being unreasonable to ask for a refund or repair? I've personally never seen this kind of corner disparity in a lens before. Thanks!