Purple Fringing on Oly and Pany Bodies: Causes and Remedies

Started Jun 7, 2013 | Discussions thread
Steve_ Senior Member • Posts: 2,869
B+W 415 and 420 threaded UV filters

I have found two well-documented screw-in UV filters made by B+W. I see no evidence that these (nor the Formatt 2A) have ever been produced in single or multi coated versions. Here are the descriptions from the B+W filter handbook:

B+W UV-Blocking Filter 415 (≈ 2 B) [GG 400]

This sharp-cutting, nearly colorless B+W filter blocks UV radiation up to the limit of visible light. It is used in ultraviolet fluorescence photography for the prevention of unsharpness caused by the intense UV illumination (which is due to chromatic aberration in the UV range). It can also prevent the fluorescence that may occur in the cement between lens elements. Because of the usually rather colorful fluorescent subjects, the delicate yellow cast in color photographs is negligible. Its filter factor is 1.

B+W UV-Blocking Filter 420 (≈ 2 A) [GG 420]

This even more stringent UV-blocking filter behaves like the filter 415 described above, except that its filtering slope completely blocks the UV radiation all the way into the visible violet region. As a result, it has a noticeably yellow tint. It is used for fluorescence photography on black-and-white film, where it is even more effective. Its filter factor is 1.2.

Here are the transmission curves (shown along with a few other filters):

B+W describes the 420 as ~2A in strength, with the 415 as ~2B. The published data I have found on 2B looks ever so slightly weaker.

To the point: do you think there is any chance the 415 filter is strong enough or do I need to go straight to the 420? I of course would prefer the filter factor of 1 the 415 produces on general principles, but this in itself may be indicating the filter is too weak to have the desired effect. How do you appraise these curves in the context of your understanding of the UV rejection of the Panasonic and Olympus bodies?

 Steve_'s gear list:Steve_'s gear list
Olympus OM-D E-M5 Olympus E-M1 Panasonic Lumix G Vario 7-14mm F4 ASPH Olympus Zuiko Digital ED 50-200mm 1:2.8-3.5 SWD Panasonic Lumix G 14mm F2.5 ASPH +13 more
Post (hide subjects) Posted by
(unknown member)
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow