When You buy a new lens in store, one of the favourite up-sells is to offer you a UV filter. This comes with the warning that it could save your expensive new lens from damage if banged or dropped. They say it also has the added advantage of filtering out ultra violet light thus improving your images.
But are UV filters really worth having and more importantly will they protect your lens and improve your images?
Well having used UV filters on occasion I can say there is a case for them protecting your lenses but only to a certain point. In the past I’ve accidentally scrapped one of my lenses against a wall and thanks to the UV filter being in place it was only this that got scratched and not my beloved lens.
Having said that I have also dropped a lens onto a concrete car park floor and unfortunately on that occasion the attached UV filter did nothing to prevent the lens being damaged and having to be sent away for a very expensive repair.
As for improving image quality this is unlikely.
In fact I would go so far as to say it will more likely be detrimental to the quality of your final image. The simple reason being, you are putting another layer of (usually poorer quality) glass on the front of your lens.
If you are using a cheap filter on an expensive lens then you are going to seriously impede the performance of the lens and so reduce the quality of your final image.
Another disadvantage of adding the extra layer of glass is an increase in the likelihood of lens flare – extra glass equals more chance of the light bouncing around between the added layers.
Personally I have long since stopped using UV filters on my lenses and instead ensure that I do everything to protect my lenses in other ways, for instance I always have a lens hood attached as this helps protect from any bumps as I’m moving around.
If I’m moving from one place to another or not going to be shooting for a time then I ensure that my lens cap is attached to protect the front of my lens.
However if you still want to attach a UV filter to your lens for protection then You should buy the very best quality filter that you can afford that way you will be getting higher quality glass and the chances of it affecting image quality will be reduced.
A good way to test any filter is to hold it over a piece of plain white paper in natural daylight, then looking to see if there is any colour cast on the paper.
An alternative to the UV filter is a multi-coated ultra clear filter, these are designed to protect your lens without affecting the final image, but again go with the best you can afford and do the ‘white paper test’ to be sure its not affecting the quality of your final image.
