I just bought a Canon T2i and I'm concerned that I need a UV filter (for protection) and I have some questions.
What are the best brands of filters?
What (side)effects filters brings to the table?
Other tips from you pros are very welcome!
Photography Stack Exchange is a question and answer site for professional, enthusiast and amateur photographers. It only takes a minute to sign up.
Sign up to join this communityA UV filter will provide protection for your lens at the expense of image quality.
Under normal circumstances a UV filter is not needed and better protection is afforded by using a lens hood. When the lens is in eminent danger from flying particles of sand or salt water, then it is time to use a UV filter since the lens hood will not protect against that.
Tests have been done with plenty of UV filters. Different brands also have different grades. The better ones within a brand are usually labelled 'Super Multi-Coated' or at least 'Multi Coated'.
Hoya makes the best filters I have used but, well, I have not tried all the brands but I stay away from B+W which are not color-neutral as a UV filter should be.
NOTE Some shops confuse UV and Skylight filters which add a pink cast to everything unless you use Automatic White-Balance computed by the sensor which will cancel out the cast.
TIP Save money on filters buy buying the largest size and step-up-rings to avoid needing one filter-per-lens. The catch is that you use either a filter or a lens hood but not both because the step-up ring gets in the way.
Lens-Tip has compared 20 different UV filters (results are here). Hoya is holding the first three positions, but it also has a model in the middle and another one near the bottom, so brand is not all you need to look at, different models really are different.
Other questions have already covered effects and side effects.