K&F CONCEPT 67mm MCUV Lens Protection Filter High Definition Optical Glass

Product overview

K&F Concept 67mm MCUV Lens Protection Filter: What to Know

Thread size is the first thing to get right and the most common reason a filter goes back. This listing is 67mm, which is the filter thread diameter of your lens, not its focal length and not its front barrel size. The number is printed on the lens barrel or inside the cap, usually after a diameter symbol. K&F sells the same filter in 77mm, 82mm and most sizes in between as separate ASINs, and there is no adapting a 67mm filter onto a 77mm lens without a step ring.

The optical side is where the series matters. K&F builds these on Japanese AGC optical glass in a slim aluminium frame published at 3.3mm thick, which is thin enough to avoid vignetting on wide lenses, and the whole value of the filter rests on the coating: K&F's figures are 94% light transmission for the 18-layer K-Series coating and 99.6% for the 28-layer Nano-X, and the coating is what repels oil and water and resists scratching. A protection filter is a sacrificial surface, you clean the filter instead of the lens, and you replace it when it is too scratched to clean.

Now the discrepancy we are not going to paper over. The current listing title on this ASIN says only high definition optical glass, with no coating count. In tracing the listing we found title and URL variants on the same ASIN citing both 18 multi-layer coatings and 28 multi-layer coatings, and 94% versus 99.6% transmission is a wide enough gap to matter if you shoot into the sun or point lights. K&F's own site refused our requests, so we cannot settle it from the manufacturer. Read the listing bullets on the day you buy, and if the coating count is not stated, assume the cheaper 18-layer specification.

Key Listed Features