B+W 77mm UV 420 Very Light Yellow Filter

Comments about B+W 77mm UV 420 Very Light Yellow Filter:

This may work well as a pricey lens protector, but as a UV blocking filter, I have not seen any proof.

I did several test photos of a Compact Fluorescent Black Light bulb which should peak it's emission at either 350 or 370nm. Regardless of which wavelength the bulb emitted, the bulk of the produced UV was well within the, as documented, attenuated band below 400nm.

I shot three photos, bulb off, bulb on no filter, bulb on with filter. My SD14 with a 28mm f1.8 EX DG recorded the lit bulb glowing a bright blue, Yes it can detect the 350 or 370nm light. With the B+W 420, I saw no reduction in the brightness or hue.

By contract, I hand held a 52mm Hoya K2 Yellow filter in front of the lens and the photographed lit bulb was nice and dark, just as it looks by eye, the only needed post processing would be to balance out the K2's yellow cast.

When I decided to order the 420, my decision was based on the B+W documentation showing it's transmission was 0% below 400nm and only climbed up for wavelengths above 400nm, hence the pale Yellow color of the filter, but the simple test above demonstrated otherwise.

I only gave this 1 star because of the physical quality of B+W's workmanship. Save your money and if you want true UV blocking go buy a Hoya K2.

I was considering a 415 too, but know now that it would do even less.