Sharpness f/4 The lens is sharp from corner to corner at f/4 and I dont hesitate to use it at this aperture. 100 crop: f/5.6 Contrast and sharpness improve noticeably and reach an excellent level, this is the optimal aperture. I prefer to use it on a monopod which makes focusing much easier because it stabilizes the lifeview and also allows me to use about 2 stops slower shutter speeds, I get very good results at 1/160 sec. There is also a Canon FD 4/300 nonL, I havent ford windstar stero manual 2002 used that either but from the reports I read and because of the lack of low dispersion glass I assume that it will be significantly worse. The tripod collar is quite big and sturdy, it can be rotated from landscape to portrait orientation and it is detachable. The lens hood is fixed to the lens and rather small, a larger one would be more effective but would make the lens a. Distortion didnt check, sorry Flare Resistance It is rather sensitive to flare, most problematic are light sources just outside the field of view. Shading it with your hand can help. Bokeh I think it is quite pleasing, there is no outlining of highlight discs. 100 crop: f/8 I think I see a very minor drop in sharpness. f/11 Diffraction becomes noticeable but sharpness is still very good in absolute terms. Compatibility FD lenses can be used on all mirror-less cameras like Sony Alpha, Fuji-X or MicroFourThirds, all you need.