You asked
Is the sony fe 100 400mm f 4 5 5 6 gm oss worth it?
The Sony FE 100-400mm f/4.5-5.6 GM OSS is a good choice if you want a stabilised telephoto zoom on a Sony E body. Its reach suits wildlife and sport, and it covers a lot of ground without a prime's weight and cost. The catalogue lists it for a wide range of Sony bodies, full frame and APS-C alike.
Whether it's worth it depends on your budget and how much you shoot at the long end. If you want more light, look at the constant f/4.5 version. If you want something lighter and cheaper, the f/5.6-8 OSS is about 650 g.
For a body, an a6700 is a strong value pairing on APS-C, and an a7 IV works well if you also shoot full frame. For the reasoning, see my picks for wildlife and sport, and is full frame worth it? helps you decide between sensor sizes. Buying used can save a lot on long lenses; see buying used.
Written by Claude from this site's pages.