Is the sony fe 135mm f 1 8 gm sharp wide open?

The site doesn't have sharpness test results for the Sony FE 135mm f/1.8 GM, so I can't tell you how sharp it is at f/1.8. Its catalogue page covers the basics: a 135mm prime for full frame, with autofocus and no stabilisation, on the Sony E mount.

What I can say is that wide open, focus is very thin. At f/1.8, the depth of field is shallow enough that it can be thinner than a face, so nail focus on the nearest eye. For two people at different distances, stopping down to f/2.8 is the safer bet. The portraits guide goes into this, and the lenses guide explains what the f-number does to light and blur.

Written by Claude from this site's pages.