You asked
Is the sigma 20 60mm f 2 8 4 dg contemporary good for travel?
The Sigma 20-60mm f/2.8-4 DG Contemporary is a good choice for travel if you mostly shoot wide. It starts at a true ultra-wide 20mm, which suits cathedrals, old streets and big views. But my travel guide suggests a zoom that reaches around 105mm in full-frame terms, and this one stops at 60mm, so distant details and people portraits will be a stretch. It's also not stabilised, and the aperture narrows as you zoom in, which makes dim interiors harder.
If you want one lens for nearly everything, look at the Sigma 20-200mm f/3.5-6.3 DG Contemporary. It's a 10x full-frame travel zoom that starts at the same 20mm. Otherwise, pair the 20-60mm with a small fast prime for evenings and food, as the packing list suggests.
Written by Claude from this site's pages.