The Industar 69 lens is a Leica thread lens, but needs a shorter flange distance, making this adapter slightly smaller than a regular ltm to nex adapter. These lenses are often altered to make them focus on 28.8mm rangefinders, which is pointless, since they only cover a half frame. If you don't want to alter the lens, use this adapter to get 27.5mm flange, like the Chaika camera it was designed for.

The vignetting, I can't help you with.