Pylon Posted July 19, 2015 Share Posted July 19, 2015 I have several UV filters (the clear ones you can see through), however when I shine a 365nm UV LED through them, I can still see the light coming through the other side when looking in live-view mode on my full spectrum D7000 camera with a Baader-U filter on the CoastalOpt UV-VIS-IR lens, as if the filter wasn't even there. They should stop advertising the filter as a "UV" filter and just call it a clear filter. In any case, are there any filters that DO block UV-only? Has anyone used these for their photography before? Link to comment
enricosavazzi Posted July 19, 2015 Share Posted July 19, 2015 Many of the cheap "UV filters" do not block UVA. Some of these non-blocking filters are more honestly identified as "protector" filters, i.e. meant only to prevent accidental damage to the front element of the lens. There may be UV-cut, VIS- and NIR-pass filters, but I am not able to recommend any. In general, with a multispectral camera one needs to isolate the UV, VIS and NIR bands, and for this purpose a VIS-pass, NUV- and NIR-cut filter is more useful. I have used with success both the B+W 486 and the Baader UV- and IR-cut. They are similar but not identical. Some users recommend one over the other, but opinions vary. There are also third-party filters with similar characteristics, but I have not tested them. These are not transparent filters. All these VIS-only filters I have seen have a distinct greenish/bluish tinge and require a custom white balance. Link to comment
Shane Posted July 19, 2015 Share Posted July 19, 2015 Not all UV blocking filters have the same cut-off and they do pass UV. This is an old but general introduction to the problemhttp://www.bobatkins.com/photography/technical/filters.htmlAlso take note that the 365nm LED is not a narrow band source and can often "reach out" into the visible. If you are looking for a cheap UV (only) blocking filter you could try the obsolete (ebay) Kodak 2 gel filter series.i.e. 2A, 2B, 2C and 2E. Link to comment
Andrea B. Posted July 19, 2015 Share Posted July 19, 2015 The typical "UV filters" are a leftover from film days. The purpose was to block some UV in order to avoid the distant hazy look in landscapes. Link to comment
nfoto Posted July 19, 2015 Share Posted July 19, 2015 The old type "UV" filters have a quite gradual cut-off starting around 390-400 nm and might only cut 1-3 stops around 350 nm. So no wonder it didn't make much difference through your camera. Link to comment
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