The construction quality is excellent but the lens does not achieve absolute infinity focus. It focuses plenty far for me, though. I am using it with a Vivitar 28mm F2.5 MD mount so it may work better with other brands or glass, if their focus goes past infinity on an MD mount camera. On my Canon 5D III, the lens covers the full sensor, so it shouldn’t be a problem on any other full frame Canon EF camera. If you have an RF camera, just buy the correct adapter to directly put it on your camera.