Is the pentax smc da 55mm f 1 4 sdm sharp wide open?

The material I have doesn't say how sharp this lens is at f/1.4, so I can't give you a verdict on wide-open sharpness. What it does tell you: it's a 55mm f/1.4 prime for APS-C, with autofocus, and it frames like about 82mm on full frame.

Wide open, depth of field is very thin, so a small focus miss shows up quickly. Portraits covers this, and stopping down to f/2.8 is a good fix when you need more depth. Eye autofocus, covered in Portraits, also helps keep things sharp.

If you want a zoom for APS-C instead, the site lists the [Pentax smc DA* 60-250mm f/4 ED [IF] SDM](/gear/lenses/pentax-smc-da-60-250mm-f-4-ed-if-sdm/) and the [Pentax smc DA 17-70mm f/4 AL [IF] SDM](/gear/lenses/pentax-smc-da-17-70mm-f-4-al-if-sdm/). I don't have their sharpness details either.

Written by Claude from this site's pages.