MCS said:
Hi 2100,
I guess CCD will get effect by UV (correct me if I am wrong), I try to use the Canon IXUS to take the sky during sunset, I found that my canon camera could capture some blue sky which I could not see, so I did shot twice on the spot and compare my vision and the digital camera picture. Thanks
Hi, yeah, of course intrinsically CCDs are sensitive to UV as well, but they are much more sensitive to IR comparatively. If i am not wrong blacklight UV photography requires much longer exposures compared to IR photography, talking about dSLRs here. From my experience, in IR it can be around 1/20s to as long as 1s depending on your ISO/aperture settings + sunlight intensity.... If you wanna capture UV patterns on flowers and stuff, we are talking about several seconds here. And remember, dSLR bodies already have IR absorptive filter builty in and no UV filter.
of course the main grouse of UV contamination is a bluish cast in your pics, but that happens when you are shooting at high altitude where there is much much more UV. At sea level there really is very little UV, much less for your sunset pic. Probably it's just a saturation thingy or what.
Note, the bluish cast refers to the whole pic having the cast, not just a part of it like the shadows (you see, the sky is also blue, if it's not illuminated by the sun directly then of course it looks blue.
And not forgetting of course, modern multi-coated lenses filter off most of the shortwave UV. I have not seen a monocoated (say, pinkish only) lens even on a very budget lens (though i must admit i have not touched stuff like Vivitar before
).
Incidentally, if you are obssessed with blocking UV, i have come across a good reputable website showing a spectrophotometer transmission plot whereby a Hoya is better in filtering longer wave UV than the expensive B+W. So doesn't mean more $$$ means better performance.