Just picked up an excellent condition used one (MM) but notice that the f/stop ring and focus ring are a bit loose and seem to almost knock around. Action and focus seem tight otherwise. Normal? Anything to be concerned about?
The Zeiss sonnar 135mm F2.8 is one of the most underrated Zeiss lens in the lineup. This lens is very sharp and in fact it can beat the famous Canon EF 135mm F2.0L especially in the corners. Also the other area that this lens outperformed the Canon EF 135mm F2.0L is the micro-contrast and macr-contrast. Thus, yielding a 3D effect. The built of this lens is very strong and the mechanic of the focusing system is also very sturdy. This lens is cheap right now thus I would not buy a copy that has issue especially in term of mechanical function.