I brought my Chaika 2M while on a trip to the city of Östersund in the Northern (half) part of Sweden.
I exposed on Fomapan 400 rated at 1600 ASA.
The lens is a 50 mm Industar-22
A few times the shutter decided to lag, giving me these star-shaped (aperture-shaped actually) photos. I hope that the stickiness won't last.
The above photo was cropped quite a bit to make it more focused on the centre.
I suspect that the rounded corners are a result of the lens barrel size. With the Chaika I am used to getting rounded corners, but not of this magnitude. I am not so surprised - the lens is not made for this type of camera, so I would expect varying results anyway.