This most delicate reddish-yellow conversion filter absorbs violet and some blue plus a minimal amount of green, but it passes yellow and red undiminished; the color of the light becomes “warmer” by 15 Mired. That is mostly the optimal amount for correcting the light blue cast in the shadows under a blue sky. It also absorbs UV radiation and hence it provides better sharpness. With color films and/or developing processes that generally yield results that are too “cool," this filter can be kept on the lens at all times. With this filter, skin tones in particular will be rendered more naturally. Its filter factor is approximately 1:1.
This filter uses our Slim-Line mount for wide angle lenses. They do not have a front accessory thread to avoid vignetting with lenses as wide as 17mm in 35mm format. Some report success with lenses as wide as 16mm. A slip on cap is supplied with Slim filters, sizes 49mm through 82mm.
The height is only 3mm, in the case of rotatable polarizing filters 5mm.