You asked
Is the sigma 50 120mm f 2 8 dc os contemporary weather sealed?
I don't have a weather sealing rating for the Sigma 50-120mm f/2.8 DC OS Contemporary, so I can't confirm it either way. Its listing does say it's stabilised and has autofocus, but nothing about sealing.
If you plan to shoot in wind, spray or drizzle, check the manufacturer's spec sheet before you rely on it. My landscape guide explains why sealing matters at dawn in the wild, and the travel guide covers it for rain, sand or snow.
Written by Claude from this site's pages.