UV Filters

[ashish]

I wanted some information on whether it is necessary to leave the UV filter on the lens in DSLR cameras. I have been reading various blogs and there seems to be a divided opinion on whether to permanently leave it on the camera. I am given to understand that leaving the lens on reduces the image quality but it helps to reduce damage to the lens.

Hope to hear your views on the same.

Thanks.

[Donald]

Ashish

We've just had a debate on that very subject.

Re the myth that there will be a reduction in image quality. That is wrong. There will not ... or there will not be a quality loss of any measurable degree for 99.99999% of the photographic community.

The vast majority of us strongly believe that you should fit a filter to your lens as soon as you buy it and never take it off. There are some people who do not agree with this view. I believe the risk factors are such that a risk assessment would always indicate that you should do so.

[ashish]

Thanks Donald.

I have not been able to notice any significant change in image quality with and without the lens filter. I agree with you that in the absence of a noticeable dip in image quality it is better to have the lens filter on.

[Colin Southern]

Hi Ashish,

Unfortunately, it's one of those topics that people tend to have polarised view on (a bit like Canon -v- Nikon, and Mac -v- PC).

Personally, I fit a UV filter to all of my lenses. They have saved my front element from damage on more than one occasion, and I have damaged a front element on an occasion when I wasn't using one. Even on some high-end Canon L-Series lenses, Canon specifically state that the weather sealing is not complete unless a filter is fitted - and it goes without saying that in the event of the likes of dried salt spray (which is very abrasive), it's a LOT easier to be able to remove a filter and run it under the tap than it is to run a lens under the tap (actually, that's not quite true ... it's actually very easy to run a lens under the tap, or perhaps I should say RUIN a lens under the tap!).

Many like to say that "fitting a UV filter degrades image quality" ... well ... it's a good sounding theory, but I live in the REAL world, not a theoretical one. In THEORY, the oceans of the world all rise everytime I launch my boat ... but in practice, that "rise" is undetectable to the human eye, as is any "loss of image quality" when using a UV filter.

Having just said that, there IS a situation that fiters may make worse, and that's what we call "extreme contrast" lighting ... an example would be photographing buildings at night in that the lights of the building - being so many times brighter than the buildings themselves - may generate certain artifacts that a UV filter makes worse (removing the filter is likely to reduce them, but not eliminate them). The solution in these circumstances is so simple it's ridiculous - just remove the filter for that occasion, and refit it afterwards.

You'll also read of people using both lens caps and lens hoods for front element protection ... if you think a UV filter degrades image quality, you should try shooting with a lens cap on! With regards to hoods ... hoods are superb at protecting a front element from stray light (which is what they're designed to do), but in reality they do a poor job of protecting the lens because they're either so small that the element is still exposed, or they're so deep that they pop off if you drop the lens of give it a good knock. In reality they're different tools for different jobs ... I'm not saying "don't use a hood" - I use a hood as often as I can ... just don't rely on it for protection anymore than you rely on the bumbers on your car instead of seatbelts protecting you in a crash; use both.

With regards to "never taking them off" ... it's a good thing to aim for it you can (with the exception of extreme contrast scenes as mentioned above), but there can also be other occasions where they mechanically interfere with other filters ... so I'd encourage you to think of using them as "best practice", but not necessarily "cast in stone on every occasion".

Hope this helps

[ashish]

Thanks Colin.

I really appreciate you writing in detail. I guess that seals it for me. The filter stays on.

[Colin Southern]

You won't regret it