Agree OP needs to be more specific. Some people want smooth out of focus areas/bokeh for shallow depth of field work, and some want sharpness from corner to corner and low geometric distortion for landscape and architectural work at medium and small apertures. And there are various mixes and compromises. I fall into the second category so I can only speak on that subject. If sharpness, flare control and contrast at medium or smaller apertures is what you're looking for, save yourself all the trouble (and possibly some $), get a Nikkor 50mm 1.4 AF-D, and focus it manually. It is as good as the Zeiss 50mm 1.4 ZF optically. The Zeiss is a little better with flare and ghosting (T* coating still the best) if you point it at the sun, but the Nikkor has slightly less barrel distortion, so toss-up. For sharp work where you'll be stopped down at least a few stops from wide open and want crisp definition/contrast across the frame I seriously don't think there is a better lens than the Nikkor AF-D, which is pretty cheap new. The alternative is the Zeiss ZF macro f2, which is an excellent performer both as a standard 50mm lens and a macro lens, and has slightly less distortion than the Nikkor. But it's very expensive.