Upload & Sell: Off
Show me your worst!
There are many old manual-focus lenses available for a pittance that are gems of optical excellence. However, not every lens ever made is optically spectacular. Some, perhaps, even transcend mediocrity into the realm of sheer imaging horror. Have you got any in your lens drawers? Perhaps some guilty pleasure that you hastily bury under a pile of Zeiss whenever company is coming over? Here's a thread for you to post your (least) favorite so-bad-that-it's-good (at being bad) lens.
I'll start off with a lens I just acquired, based on the reputation that preceded it ("Nikon's worst lens, ever."): the Zoom-Nikkor 43-86/3.5, in the original 9-element optical formula (before it was later revised to a merely poor lens with 11 elements). I did go for a multicoated Nikkor-C version, because I'm not a complete barbarian. Picture of the lens in the recent lens purchases thread.
The lens itself is a solidly-built one-touch zoom, compact with easy handling and smooth mechanics despite being almost four decades old. On the outside, actually quite nice --- attach it to a camera (Canon 5D) to see what lurks within. Through the viewfinder, you can see the distortion bowing from serious barrel to pincushion as you zoom; towards the long end, a "soft focus" haze is visible even in the viewfinder. Take a few shots, and you'll see the strong abrupt vignetting in the corners (that doesn't really go away with stopping down). You might be able to get one tiny spot, right at the center, in acceptably sharp focus, surrounded by a smearing vignette. Wonky focal plane curvature (I'm not exactly sure where it goes, and I bet it changes a lot with zoom) makes it somewhat unpredictable what else in the image will be in focus. Surprisingly, there's little lateral CA, and veiling flare / contrast is well controlled.