You asked
Is the leica vario elmarit sl 24 90mm f 2 8 4 asph good on aps c?
On APS-C, it works as a versatile standard zoom, but it's a big, heavy lens for the job. It's made for full frame, and on an L-Mount APS-C body it frames like 36-135mm, so you get a useful range from a normal view up to a short telephoto. The f/2.8-4 aperture gives roughly the depth of field of f/4.2-6 there, and the image stabilisation helps when the light drops.
It fits these APS-C bodies:
If you mostly want a light, cheap landscape or everyday kit, the landscape guide suggests f/4 zooms instead. For people, the portraits guide explains why a longer reach works well for flattering faces. Check the full lens page for every detail before you buy.
Written by Claude from this site's pages.