You asked

Fujifilm xf 50 140mm f 2 8 r lm ois wr vs sigma 50 120mm f 2 8?

Here is what the site says about that.

From Fujifilm XF 50-140mm f/2.8 R LM OIS WR: Fujifilm XF 50-140mm f/2.8 R LM OIS WR: A zoom lens by Fujifilm for APS-C cameras, 50-140mm f/2.8. Specs - Maker: Fujifilm - Focal length: 50-140mm (zoom) - Maximum aperture: f/2.8 - Made for: APS-C sensors - Mounts: Fujifilm X - Stabilised: yes - Autofocus: yes What it frames like - On APS-C (Fujifilm X): like 75-210mm on full frame; f/2.8 gives about the depth of field of f/4.2 there. Cameras it fits - Fujifilm X-E1: APS-C - ...

From Travel: My picks by type: - The one-camera answer: an APS-C mirrorless body with a travel zoom in the 18-135mm or 16-80mm range (roughly 27-200mm or 24-120mm in full-frame terms). Small, flexible, good in most light. - The pocket answer: a 1-inch compact with a 24-200mm-equivalent zoom. It fits in a jacket, and the pictures are clearly better than a phone's when you zoom. - The fixed-lens answer: a compact with a large sensor and ...

Quoted from this site's pages.

From these pages