The UV filter

Beginners continually ask whether they should buy and fit a UV filter. It's like they feel their iPhone needs a rubber skin or case. Here are some points. I'll add more as discussion continues.

A few points

  1. Photo gear shops make good money on UV filters and bags. It's stuff they can sell in addition to the camera. Or give away as an enticement.
  2. Digital sensors are unlike film. We used UV filters (light yellow tint) and Skylight filters (light pink tint) often. While film was sensitive to UV light, digital sensors are not and hence do not need UV filters in even bright sunlight
  3. Manufacturers STILL MAKE UV filters - they are not lens covers, lens protectors (I think there is one) - they are filters - that means they are not designed to be impact resistant or super strong - they are designed to filter light. If they were designed to be lens protectors, they would be designed strong.
  4. UV filters add two glass/air interfaces into the optical path.
    1. Every glass/air interface means there is just one more way to cause reflections and flare. That's why the better and more expensive filters are multi-coated.
    2. Every glass/air interface means there is more risk to collect dust specks, stray hair, smudges.
    3. Every glass/air interface means there is the possibility that the glass is not perfectly flat. Unflat or rough glass reduces sharpness. How much, well that is what the debate is about and the reason why better filters cost more money.

Why some people use them

  1. Some people leave the plastic wrap on their new car interior. Some people buy a sleek, sexy smart phone and immediately get a silicone rubber skin or a mock leather case. So when they buy a camera, they buy a UV filter. Naturally.
  2. Some people are surrounded by little dears with greasy hands that love to touch things. Easier and less worrying to clean the filter than the camera lens.
  3. Some people live or work in the desert, near salt sea spray, love to shoot in light rain. Or in dirty industrial environments spitting chips and stuff. Makes sense.
  4. Some people are just clumsy. Some lenses just attract smudges.
  5. Some people want to protect their investment. That's number one. Who knows, they might sell the lens pretty soon and they have kept the box and all the wrappings and they can write on their eBay ad "always fitted with a UV filter from day one"
  6. They feel that if they see "flare" or unwanted reflections, yes, they'll take it off.
  7. They have seen evidence or they have themselves whacked the front of their lens against a tree, the concrete floor and the filter has broken in sacrifice to the lens. Yay! Point proven.
  8. They have shot thousands of shots and have never seen shots that needed throwing away just because of the UV filter.
  9. Some people keep losing their lens caps in the heat of shooting and when they chuck the lens back into the bag, capless, hoodless, there is the risk of abrasion of the front element by fretting with other gear in the bag. The UV filter sacrifices itself instead of the lens front element. Easy way to burn money as the filters need replacing sooner or later. Hey, it's your money.

Why some people won't use them

  1. They like "bare". Really.
  2. They want purity. Putting little bits of glass in front of their lens just gives them the irrits.
  3. They believe that they won't always be alert - I mean, here are you are shooting away, in the heat of the moment, will you suddenly pause and ask yourself - "I wonder whether there is a light veiling right now". These people would rather not take the risk.
  4. They don't live in the desert, near the sea, live in a factory and don't have little ones - IF they venture into these environs THEN they will fit a filter.
  5. They're into resolution numbers, lab tests and really, they can see / measure the degradation, no matter how slight.
  6. They don't feel they are that clumsy. If they do have moments of clumsy, they would rather use a lens hood.
  7. They actually fit their lens hood the right way round.
  8. They've seen evidence or experienced evidence of shards of broken filters cut into the front lens element coatings.
  9. Their lens isn't that expensive but has a large filter diameter. A premium priced UV filter of that diameter could cost another lens or part of a lens.
  10. Their lens is pregnant and has no filter ring or won't take a filter.
  11. They have seen examples where the AF worked badly and shots were degraded because someone fitted an el cheapo UV filter.

Ok, I get it but I still want to buy a filter. Which one? Is A better than B?

  1. Have a look at lenstip.com - http://www.lenstip.com/113.1-article-UV_filters_test.html

Further links

Navigate tp:

Recent discussion threads on UV Filter

Recent discussion threads on UV Filters

Ananda's Compilation of Tips

Ananda's Photoblog

The views and opinions expressed in this article are those of the author and do not necessarily reflect the views and opinions held by dpreview.com or any affiliated companies.

Comments

Total comments: 8
tingkr
By tingkr (5 days ago)

I am confused. I looked at the lenstip.com article cited at the end of this article. A direct quote from that article is:

"Although the human eye isn’t able to observe the photons of this kind of energy [ultraviolet radiation]; the CCD/CMOS detector or light sensitive film can actually register them."

I.e., the article cited says the CCD/CMOS sensor CAN detect UV radiation. This is in direct opposition to point 2 at the beginning of this article.

0 upvotes
william a luongo
By william a luongo (4 months ago)

The link just goes to a site that measures UV transmission which is of no interest. The digital camera doesn’t need UV protection. The question is simple, 1. Do they reduce resolion, 2 is there a problem with reduction in contrast or light reflections.
I think they probably don’t, but would like to see proof. There is an anti filter group that always say the same thing. It’s a cheap peace of glass over an expensive lens. Like drink beer from a paper cup. I don’t think they know what they are talking about. Just repeating some thing they see as revealed wisdom.

0 upvotes
Trumptipa
By Trumptipa (6 months ago)

I would be interested in knowing how much UV filters screw with IQ at close focus. There should be more chromatic and spherical aberration introduced as the object space f number decreases (in the extreme: http://www.microscopyu.com/articles/formulas/formulascoverslipcorrection.html)

0 upvotes
Rainerfirst
By Rainerfirst (6 months ago)

I got sucked in with buying UV Filters at first when i entered the Digital era.
I know better now. I have taken them off all my high end quality Lenses.
My view is ; I didn't buy high end quality Lenses just to end up having lower quality Hoya Filters in front of them.
In my opinion the Hood is adequate enough. UV Filters are NOT designed for a hard impact knock on to your Lens. Your UV Filter will shatter and it may still end up scratching your Lens anyway.
People should not get too paranoid or you may as well not use your Gear at all in case you may break it?

0 upvotes
Nikkar
By Nikkar (Jan 27, 2013)

Thanks for the review and the link.
May I suggest that, under the "why some people use them" section, a mention is made about completing weather sealing on some lenses. maybe its already covered under 3 and 5 tho :)
thanks again.

0 upvotes
Hawki72
By Hawki72 (Jul 6, 2012)

Thank you for the helpful review. Here is another interesting perspective I stumbled upon: The Dirty Lens Article

http://kurtmunger.com/dirty_lens_articleid35.html

1 upvote
Deleted1929
By Deleted1929 (Oct 6, 2011)

Under "A few Points" item 2.

Can I suggest this is not as clear to beginners as it may be more experienced users.

Perhaps rephrase as :

"While film was sensitive to UV light, digital sensors are not and hence do not need UV filters in even bright sunlight"

Good idea for a brief article, very handy.

2 upvotes
AnandaSim
By AnandaSim (Oct 7, 2011)

Thanks Stephen, will do

0 upvotes
Total comments: 8