You asked
What is the sony fe 28 70mm f 2 gm good for?
The Sony FE 28-70mm f/2 GM is a standard zoom for full frame cameras, and it's as bright as a fast prime. That f/2 aperture lets in a lot of light, so it suits dim rooms, evening events, and people shots where you want a soft background. The aperture guide explains why that matters: wider apertures give faster shutter speeds and more blur, and a constant f/2 keeps the exposure steady as you zoom.
It's not stabilised, so keep shutter speeds up when you shoot handheld. On full frame it covers 28-70mm as marked. On an APS-C Sony E body it frames like 42-105mm, which makes it a good portrait zoom there too. For more on standard zooms, see your first lenses.
Written by Claude from this site's pages.