UV Protection - Should I use a lens filter?

If you’ve ever walked into a retail shop to purchase a lens, the sales person probably suggested that you pick up a UV lens filter at the same time. Sceptics might categorize this as “up selling”, but there are good reasons to use a UV filter. Of course, like most things in photography, there are costs and benefits.

Since most DSLR camera sensors are not all that sensitive to UV light compared to film, the main reason for using a UV filter is to protect the front element of your lens from accidental damage. The theory goes that it’s much better for a relatively cheap filter to be exposed to threats than your expensive lens. This does make sense because the average photographer will come up against the following lens damaging scenarios regularly:

• Finger prints.
• Scratching.
• Airborne material like sand, salt spray or even small rocks and tree branches.
• Damage if the lens cap falls of in your camera bag.
• Running into objects if doing macro photography.

Some photographers rely on a lens hood to form a barrier between the glass and potential impact threats. This is probably OK for telephoto lenses where the lens hood extends well beyond the front element. But for an average standard zoom lens, the hood is too wide to provide any real peace of mind. Also, for reasons beyond my comprehension, Canon does not include a lens hood with their non-professional range of camera lenses. Even a $1,600 AUD 17-55 2.8 IS doesn’t get any special treatment. Shame Canon, Shame!

So, the argument for using a UV filter on your lens as insurance is pretty solid. But there is a catch. All filters are not made the same, and you generally get what you pay for. The issue is that cheap filters can degrade image quality. Some potential issues are:

• Softer images (loss of sharpness).
• Double images (shadow effect of one image over another).
• Los off contrast in backlit images.
• Ghosting and flaring. 

Most of these issues are eliminated or greatly reduced when using a good quality filter. My first set of UV filters were low quality. With no previous experience to work from, I didn’t realise that my shots were suffering from some of the problems listed above. Ghosting and flaring was the most common issue.

My lenses are now fitted with Kenko Pro1 Digital UV filters. They are multicoated to reduce flare, have a low profile frame to minimise vignetting and generally seem to do a good job.

Since filters are not the sort of item you would normally return to the manufacturer under warranty, I recommend buying them online from a reputable company. You can save a lot of cash. I made the mistake of purchasing my latest filter from a retail store in Sydney and didn’t realise until I returned home that I had paid twice as much as before.

In summary, I recommend that you purchase a high-quality UV filter for your lens. The image quality will be pretty much the same and the added peace of mind knowing that there is something solid between the outside world and your lens glass is worth the investment.

UV Protection - Should I use a lens filter?