Buying your first DSLR can be a big investment. There's not only the price of the camera itself, but the lenses that come with it. It's the sort of cost you can't take lightly — and the last thing you want is for something to go wrong.
Thus, protection is a big business for camera retailers and manufacturers, and part of the reason why UV filters sell so well. These are thin, circular pieces of glass that fit over the front of your lens, and according to numerous photographers and retailers, can protect from scratches, smudges or cracks. But others aren't so sure. Do a quick Google search and you'll see exactly what we mean.
After all, what difference — good or bad — can that extra slice of glass really make?
When shooting film, color is physically split into red, blue and green layers. However, the blue layer is particularly susceptible to ultraviolet light. In scenarios with excessive UV light — for example, a sunny day on the blue ocean, or at higher altitudes, where the atmosphere is thinner — a blue-tinted haze can result.
Modern film, however, is designed in such a way that the effects of UV light are almost imperceptible. And digital cameras have blocks and filters of their own to stop everything from Infrared to UV light from interfering with your pictures. With that in mind, a UV filter doesn't make a whole lot of sense — at least, not for the purpose it was originally conceived
But people continue to use them — precisely *because* they don't do anything. Because a UV filter's glass is clear, it's suitable for protecting a lens without adversely affecting image quality. As Ken Rockwell has so elegantly put it, "The UV is just a mechanical prophylactic, it doesn't do anything optically today." After all, it's much cheaper to replace an $100 filter than an $1000 lens.
But there are those that disagree. Just as the glass in various manufacturer's lenses aren't created equal, the same holds true for UV filters. Some see little point in buying a $2500 lens, only to put an $80 piece of glass in front of it. This example might be a bit extreme, but the argument is that there's simply no way the quality of a filter's glass can compare to a pro-model lens. Some tests of both low-priced and high-end filters have also proven inconclusive, leading some to believe that putting any sort of glass in front of your lens — regardless of price — is asking for diminished image quality too.
But if you're really concerned about protection, and unsure of whether a UV filter is for you, a good alternative is a lens hood. These are the big plastic extensions used on lenses to prevent flaring from the sun or bright lights. However, in the event you drop your camera or lens, they also do a great job at preventing any physical damage to the front of your lens — perhaps more so than a tiny filter ever could. If you're in the camp that believes UV filters degrade image quality, a lens hood can give you all the protection you need without stacking another piece of glass on top.
We realize this isn't a conclusive piece, and the topic of UV filters will likely be debated for years to come. The choice, simply put, is up to you. Just remember — you can always take it off.