« Reply #8 on: April 06, 2014, 07:04:09 PM »
The front element of the 50/1.8 is set well back from the front of the mount and is well protected without the need for a filter. I do protect expensive lenses that have the front element flush with the mount, but that is just a personal foible. There is absolutely no need for a uv filter with the 50mm.
Just to make it clear: If you want a filter to protect the front element of a lens, it doesn't have to be an UV filter. A clear filter works just fine. UV filters are sometimes easier to find, that's why they are also used for lenses on digital cameras.
The protection mentioned here is protection from mechanical impact and/or moisture. There is no need to protect lens or sensor from UV light. For a $120 dollar lens it is in my opinion overkill.
UV protection for your skin however is recommended 
Agree on all accounts. I bought a Marumi clear filter for my Tamron 150-600 a couple of weeks ago as I was intending to use the lens occasionally without its lens hood in crowded areas and because of reports in another thread that the front element did not look sealed. I am pretty impressed with it. It doesn't appear to have have affected picture quality, and I dropped it onto concrete and it survived without even a mark on the ring!

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5D IV, 5DS R, 400mm DO II, 1.4xTC III, 2xTC III, EF 1.8 STM, EF 24-105, 100-400 II, EF-S 15-85, Sigma 150-600mm C, EOS-M5 15-45, f/2 22, 11-22, Samyang 8mm f/2.8 fisheye: sold 7D II, EOS-M, Powershot G3 X, Sigma 10-20, EF 300/2.8 II, 70-200/4 IS.