I had the Meike 50mm 0.95 for a short while, it looks almost identical to this one (which is kinda odd) and it had a little slack in the focus ring. When I focused too far in one direction and needed to go back, it took like half a millimeter before the glass started moving. Does this 7Artisans lens also have this issue?
CA is not terrible, but it's definitely there. Most of the time it will be masked by the narrow depth of field though :) The dog is a mix yes, no idea of what. Both dogs are rescues... The one with the ears does look like a Cairn Terrier mix, but he's a bit bigger than that.
