Hi I'm new here, but to answer Seba question about UV filter:

DSLR is only sensitive to IR, but not UV; on the opposit film camera is sensitive to UV but not IR.

You do not need UV filter unless shooting in a higher elevation where UV is high.
I only use clear filters on all my lenses for protection of the front element.

Modern day lenses are well coated w/ UV protections.
UV filter will also cause flares in night photography.

Seba - keep asking the simple questions -- those are the ones that get us riled up the most, and therefore the most fun to answer.

Haha, yeah, your lens has different diameters. Have you bought it yet? Don't worry, we all had to start from somewhere you know.

ok, never mind. I figured it out... I'm buying my new dslr soon and there are soooo many things...

sorry I keep asking these questions, but I'm a bit confused. filters are offered for a whole range of mms, from 52mm to 82mm, what is the difference? is it related to the lens you are using?

I use B+W MRC UV filters on all lenses. B+W is a solid brass ring, and their glass is unsurpassed, IMO. Easier to keep clean than some of the other coated filters.

Nikon NC filters are not UV or Skylight but just neutral protecting filters, just as Hoya and others.
Digital sensors are protected by infrared filter in front, and behind it is so called Bayer color array so that almost everything but visible light is filtered.
High energy UV light can cause kind of chromatic aberration that could be visible as a loss of sharpness especially on film, and Skylight filters can improve the sky appearance as suggested by the name and add some warmth to your pictures.

Adamz, I don't believe that the clear filters branded by Nikon or B&W and others are UV or skylight. The clear filters are, in fact optically clear (yeah, more or less). UV and skylight do affect the quality of the light passing through them.

I use Hoya. Great protection. I'm not a professional and so I want to protect my equipment and I don't believe in photo degradation. Even so, as I stated earlier, I'm not a professional so any very minor degradation wouldn't be noticeable or effect any of my uses.

seba316 - the clear filters are either UV filters or sky. And the main reason of using both of this kind of filters is to protect the front glass. As for UV filters the main usability of this kind of filter is when You shoot in the mountains.
as for using polarizer filters on wide lenses I'll have to disagree, the only problem is that most of the time You have to use the more expensive slim versions or be prepared for some cropping as vignetting may occur, but as for results, sure You have to be very careful but the outcome is really worth it.

I think it just stems back to film usage, where film was affected in a negative aspect by UV rays during exposure.

The lens is unaffected, and I don't think digital sensors are affected... I think they may already be UV coated in some aspect.

-- Dave

I can see why clear filters are useful, but what's the point of having UV filters? Can UV rays cause any damage to the lens?

The Multi-coated filters help stop flare and ghosting from reflections inside the lens and from the digital sensor bouncing light back up to the inner filter surface.

-- Dave

Interesting question. I just bought a 67mm Heliopan UV (not the multi-coated version) and I was curious as to the noticeable difference between the multi-coated vs. the single-coated versions of the uv filters. More than anything, I'd like to protect the front of the lens and NOT obstruct the glass.

Are the MCs that much better?

One more thing, do not use polarizers on an ultra-wide lens, bad things will happen!

I personally prefer Nikon NC, but high quality UV filter is also a good choice.
They are useful mostly as a lens protection from dust, fingerprints and accidents, but you should not be cheap on them because they can negate the lens optical quality. Actually less visible it is on the picture it is a better filter.

I do use a cheap Tiffen one. I'm not sure how effective it is though. I do want to get a polarizer though.

Seba316 asked about UV filters, not filters in general. Two different questions in my book. To answer the UV question, No, I do not keep a UV filter on my digital camera lenses, only on my film camera lenses. I do keep clear multi coated filters on digital camera lenses.

I use them on all but the big telephoto lenses.
I use the Hoya for the main part, as they are a lot cheaper to replace than having a front element replaced or repaired.
A lot of people say not to bother with them for 'lens protection' and I tend to disagree with this, as in the last year, I have cracked 2, scratched one, and got pitting on another from molten metal sparks.

As for the terms of photography, I do find they make a difference in some situations, like landscapes, as with the reduction in the violet end of the spectrum, yellows are more pronounced, which in turn can make green look greener.

Sometimes, lenses require a filter to completely weather seal that lens.

As for camera filters in general, I still believe, that even with the increased ability to 'add' effects in post-capture, with digital, it still makes a better job when the shot is taken right on the camera to start with.

sure - B+W MRC on all lenses + B+W polarizer

I use Hoya filters. Mainly, my two large lenses came with them and I don't like the front lens element exposed to god knows what. My paranoia again.

Do you guys use UV filters? Are they necessary/useful?