Hi, I just acquired this lens in Nikon mount, and since there is not a ton of Internet information on it like their is on the Cosina-built Zeiss, I wanted to start a thread on it. I have been shooting with it for almost two weeks now. I think it is outstanding. It manages to be very sharp without being bitingly so. (The fellow I bought it from suggested that this is because it is a lower contrast lens than some. Makes sense to me. It is very sharp while still being "smooth.") It is more than good enough for me wide open, and seems to get rolling well enough by f/2.0 that I cannot see any improvements past that f stop, except in regards to D of F and in the very corners. In a lab setting, I am sure there would be differences, but for the pictures I take, this is completely usable for sharp pictures at all apertures...except in the case that something I want tack sharp is in one of the corners. This is not likely for me in the real world unless shooting something totally flat straight on – almost never. If something in the corners needs to be sharp in a real world shot, I more than likely will not be wanting to shoot wide open anyhow. I could not be happier with the build quality; it is way better than I expected. It focuses like butter, and has a nice screw-in metal hood (which must be purchased separately). I lucked out and got them both together, NOS. It's weak spots that I have noticed so far: 1) 58mm filters. 52mm like all my other Nikon lenses would really be nice. Good thing I don't rely on filters a whole ton to shoot what I shoot. 2) No IR focusing indicator. I don't shoot IR a ton, and often not with a standard lens, but this really is a gross oversight IMO, considering that all they needed to do was scribe a single line on the lens. 3) Out of focus areas are nothing to write home about. Not terrible, and not great. If this thing gave amazing "bokeh" I think it would be much more widely lauded. Fortunately, I do not care that much about this feature, and what the lens does in the blurry areas is good enough for my purposes. 4) Lens cap is barely usable on bona-fide Nikon lenses. It fits too loosely, so pressure must be applied so that it does not find it's way off. I wrap my lenses in Ziplocs and rubber bands when I travel, so this is not a huge issue for me. But I like being able to throw whatever cap on whatever lens without thinking too much about it, so it is mildly annoying. I've not managed to look at distortion or light falloff yet, and I don't think I will bother. In the real-world pictures that I take, I haven't noticed it being any better or worse than any other of my "normal" lenses. I've also not noticed the overexposure issue, though I have not really tested for for it in a reliable way. I have always liked 55 and 58mm lenses better than 50's, so that is a big plus as well (for me, anyhow). It is what initially drew me to the lens more than anything else. A brand new, modern-designed, slightly long, fast, and sharp normal lens that works on film and digital with no hassles. It is pricey at about $500 brand new with hood. But if you want to spend the money for a brand new standard lens, this is very worthy of consideration alongside the Zeiss and the Nikon AI-S.