The 49mm High-Transmission Circular Polarizing Multi-Coated Filter from Heliopan has incorporated High-Transmission technology into this filter. It will pass 99.8% of the light passing through it with only a 1-stop loss of light and with no color change to the image. In addition, their highly regarded SH-PMC 16-layer multi-coating (8-layers on each side) gives the filter an edge when it comes to durability, flare reduction as well as dust and moisture-resistance. Circular polarizers are specifically designed for use with auto-focus SLR cameras (They will also work on manual systems without problems) Same polarizing effect as regular polarizing filters that lose more light - High-Transmission design has a filter factor or 2.0 (loses only 1-stop of light) as compared to 2.5 of a traditional polarizers. The effect of the filter is greatest at a 90° angle to the sun.