Use UV as lens protector. I recommend B+W UV MRC filter :thumbsup: . Its brass metal, construction, glass and MRC (Multi Resistant Coating) coating is very good.
IIRC, UV filter does reduce light, but the amount is insignificant. Depending on brand, multi coating, single coating and no-coating. some very good coating like B+W MRC can transmit 99.7% light. While single coating may only transmit 97% of light.