Most lenses "sweet spot" of sharpness is 2 stops from wide open, but this lens will produce great sharpness in the center of the image right from wide open, and sharpness will increase. As you stop down the aperture. Ens construction, all Metal, no cheap plastics anywhere, built to last. It can be fitted to almost any camera with an suitable M42 adapter.
For all digital SLRs including NIKON, SONY ALPHAS AND NEX, PENTAX, PANASONIC to name a just a few brands. Try searching "M42 to canon" or "M42 to nikon" or "M42 to the camera brand that you own". On digital cameras you will be shooting in. Aperture priority or manual mode, depending on your confidence, focusing at the widest aperture and then taking the shot there or at the desired aperture setting.When used on APS-C (crop factor) digital cameras, this lens becomes a nice portrait lens, as it is effectively an 90mm on Canon's and a 82mm on Nikon's. As normal with used lenses, there might be some insignificant speckles of dust inside which do not affect in any way the use of the lens and the lovely pictures it takes. This particular lens has very little/hardly any dust. Supplied complete with both caps and well protected for transit.