You asked

Should I upgrade from the sony a7s ii?

The answer depends on what you shoot. If you mostly make video or work in low light, the Sony a7S III is the natural step up, since it's built for that. For stills, don't upgrade for resolution: it has 12.1 megapixels, the same as the a7S II, so you won't gain detail.

If your lenses are the limit, that's often the better place to spend. The Sony FE 24-70mm f/2.8 GM II is a strong all-round zoom for the a7S II. If you do buy a newer body, buying used is a good way to keep the cost down, since a body one generation old is often most of the camera for much less money.

Written by Claude from this site's pages.

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