You asked
What is the sony fe 12 24mm f 2 8 gm good for?
The Sony FE 12-24mm f/2.8 GM is a wide zoom for full-frame Sony E cameras, and it's at its best where you want to fit a lot in. On full frame it covers 12 to 24mm, which suits big skies, strong foregrounds and tight spaces. As I say on the landscape guide, a wide zoom is the classic landscape lens.
The constant f/2.8 is more than most landscapes need, since you'll usually stop down to f/8 or f/11 anyway. It does help in dim interiors and at dusk. It isn't stabilised, so a tripod is worth having when the light drops. On an APS-C body it frames like 18-36mm, and the wide end still works well there.
If you want to know how the aperture translates between sensor sizes, the focal length converter walks through it.
Written by Claude from this site's pages.