You asked
Leica apo summicron sl 90mm f 2 asph vs 7artisans af 85mm f 1 8?
Both of these are full-frame autofocus primes for the L-Mount, so they fit the same bodies, including the Leica SL and Panasonic S series. The Leica is APO-Summicron-SL 90mm f/2, and the 7Artisans is the AF 85mm f/1.8. Neither is stabilised.
The 7Artisans is the one I'd pick for portraits on a budget-minded setup. It's the faster lens, and 85mm is the classic full-frame portrait length. The Leica's 90mm frames a little tighter and gives you a bit more room between you and your subject, which suits headshots. The Leica is a stronger pick if you already shoot Leica and want the longer view.
For how much background blur each one gives at a given framing, see aperture and depth of field. For more on focal lengths, see portraits.
Written by Claude from this site's pages.