The focotar 2's are stunning lenses. I have the 50mm and the 100mm. Both Focotar 2's. The 50mm can be used wide open.... Ralph Gibson does this. F5.6 might be best for the 50mm but not by much over wide open. The 100mm at f8 is great.These are the sharpest corners you will find if you use either a Valoy-2 or a 1C. Amazing!