86MM UV Ultra Violet Filter For Sigma 150-500mm f/5-6.3, 180mm f/2.8 APO Macro EX DG OS HSM Lens, Tamron 200-500mm f/5-6.3 SP AF Di LD (IF) Lens Compatible With SIGMA 150-500mm f/5-6.3, 180mm f/2.8 APO Macro EX DG OS HSM Lens, --TAMRON-- Tamron 200-500mm f/5-6.3 SP AF Di LD (IF) Lens UV filters reduce haze and improve contrast by minimizing the amount of ultraviolet (UV) light. Especially useful in areas of high altitude or snow, eliminating the undesirable blue cast. Filters serve as a great and inexpensive lens protector. Use one at all times to protect your delicate lens from dirt, scratches and accidental damage. Better to scratch or break a UV filter than an expensive lens. 86mm Lens Thread