UV filters ?

jazzywheelz

jazzywheelz

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I've had my first DSLR (a used Canon 450D) for around a week now and I've just noticed that both the lenses that came with it have got Jessops UV filters screwed onto them.
I was just wondering what UV filters are for? I mean I guess they are to block out UV light, but why is this? Are there certain situations where UV light affects exposure? Or on the other hand, are there situations when having a UV filter in place would adversely affect the picture?
My kit didn't come with any storage cases for the filters, so I'm basically wondering if I can just leave them fitted.
Can anyone explain the in's & out's?
 
The main reason for leaving it on is that it offers another layer of protection for the front lens element.

The argument against would be that if something was able to break that UV filter (and they're nowhere near as durable as the lens element itself) then it will almost certainly damage or scratch the front element of the actual lens.

Also given that you're putting another layer of glass between the light entering the lens and the camera sensor the effect is only to degrade image quality especially if its a low quality UV filter like the Jessops ones. If you're looking to retain the best in image quality the advice would be to only use a filter when in sandy and windy conditions that would likely scratch the element. In terms of protection it seems a lens hood is better.
 
Jessops seem to be rather keen on UV filters, but their own ones aren't very good quality, as BL says. When I bought a camera from them a little while back I ended up having a rather bad tempered argument with the salesman, who was very pushy in trying to get me to buy their UV filters.
 
Some leave them fitted, some do not use them, there are plenty of posts on here debating the pro's and con's of using filters for protection.
 
Martyn... said:
Some leave them fitted, some do not use them, there are plenty of posts on here debating the pro's and con's of using filters for protection.
Click to expand...

Yes, please search, or just scroll down a bit ;)
 
Thanks for the replies.
(I did try searching first, but the term "UV" is too short for the forum search engine so it was ommitted.)

So when people talk about using UV filters for protection, they mean protection against physical damage to the lens as opposed to protection against ultraviolet light?
If this is the case, why aren't they just made from plain glass and sold as 'lens protectors' or whatever?
:thinking:
 
It basicly stems from film days, where you did need protection from UV light, as it could screw up the film.
Digital doesnt have this problem, and almost all DSLR's have AA filters in front of the sensor which also cut out UV.

The companies that make them and more so the shops that sell them and make huge profits on them, then decided to force sell them onto everyone and anyone as "protection for your lens".
I have never used UV or "protection" filters, and in my 10 years or so of using DSLR's have never damaged or scratched a front element, and I dont treat my gear with cotton wool gloves.

The one time I did use one, was when it came on a lens I bought. I took 3 or 4 shots and it looked like someone had painted over the lens with mist. I took the filter off and it was sharp as a tack and super clear images. (the lens was the famously sharp Canon 100mm L IS macro).

The only time I would possibly consider it, is if I was shooting in a sandstorm, or at a rally and there was a likelyhood of stuff being flung at the lens element, but as I never shoot sandstorms or rally's, I shall never use them.
 
jazzywheelz said:
Thanks for the replies.
(I did try searching first, but the term "UV" is too short for the forum search engine so it was ommitted.)
Click to expand...

Tip ... add some **** to make up the shortfall of characters, but "filter" would have thrown up plenty of threads :thumbs:
 
@Martyn
Thanks for the tip. I'll give that a try next time :thumbs:

@Tom
Thanks for your reply. I understand now :)
I guess the manufacturers and retailers are cashing in on the naivety of customers like myself (although thankfully I didn't pay for mine).
At least I can take them off now, and only put them back on if I'm worried about scratches etc.
Thanks again.
 
TCR4x4 said:
It basicly stems from film days, where you did need protection from UV light, as it could screw up the film.
Digital doesnt have this problem, and almost all DSLR's have AA filters in front of the sensor which also cut out UV.

The companies that make them and more so the shops that sell them and make huge profits on them, then decided to force sell them onto everyone and anyone as "protection for your lens".
I have never used UV or "protection" filters, and in my 10 years or so of using DSLR's have never damaged or scratched a front element, and I dont treat my gear with cotton wool gloves.

The one time I did use one, was when it came on a lens I bought. I took 3 or 4 shots and it looked like someone had painted over the lens with mist. I took the filter off and it was sharp as a tack and super clear images. (the lens was the famously sharp Canon 100mm L IS macro).

The only time I would possibly consider it, is if I was shooting in a sandstorm, or at a rally and there was a likelyhood of stuff being flung at the lens element, but as I never shoot sandstorms or rally's, I shall never use them.
Click to expand...

Likewise, I have some hoya pro and hoya hd, but I only use them when I am in situations with salty seawater spray or kicking up sand/dirt etc otherwise they are just stored away. You don't need it for UV protection and whether you do in the situations you mention is individual preference.
 
I actually remember reading an article on the internet a while ago where they tested about every major UV filter around on a spectrophotometer to measure UV absorption as well as testing flare etc with a standard image and they actually found that the midrange Hoya HMC filters came out the best of all the brands including some which cost many times more than they did. I'll try and find the article and post a link here.
 
But considering that the Camera doesn't care about UV does that actually matter?
 
For me it does as I shoot mostly film, but the level of flare etc does matter with digital cameras as thats a problem thats universal to all cameras and lenses.
 
Sure fair enough but the op doesn't :)

Flare still gets handled by the lens doesn't it?
 
Filters are a source of flare as your essentially adding another element to the lens, so using an uncoated filter for instance is just inviting flare as in essence the filter is the front element which light can reflect off rather than the actual lens front element. Poor filters can also cause loss of sharpness and other aberrations like vignetting, plus some can actually block some visible light as well, so thats why its best to get good filters.

I found the filter test article that I mentioned:

http://www.lenstip.com/113.1-article-UV_filters_test_Introduction.html
 
s162216 said:
For me it does as I shoot mostly film, but the level of flare etc does matter with digital cameras as thats a problem thats universal to all cameras and lenses.
Click to expand...

TBH, even with film, the whole UV filter thing has been pushed for ever by salespeople for their commercial benefit rather than any real photographic upside. Some things never change!

Modern films are not as sensitive to UV as they were in the early days, plus modern multi-element lenses are pretty effective UV filters anyway. But there was an upside with film, albeit a slight one, and the downside of ghosting that we get today with digital didn't exist becuase film isn't shiny like a sensor.

There is still the problem of flare, but that's relatively slight compared to the double-image ghosting that you can get with digital where very bright subjects bounce light off the sensor which then gets reflected back off the rear of the filter. The problem is basically two flat mirror-like surfaces facing eachother.

Edit: that Lenstip article. It would be a lot more useful with less irrelevant science and a bit more emphasis on the practical.
 
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HoppyUK said:
Edit: that Lenstip article. It would be a lot more useful with less irrelevant science and a bit more emphasis on the practical.
Click to expand...

I was thinking that, and also it is 4 years old, lots of other filters on the market as well.

But then again imo you just don't need a filter in the first place, but I appreciate that that is another can of worms :)
 
better to scratch a £10 filter than a high price lens.

I always remove these when attached different filters though... ie CPL as then add extra lengh on the front which wideangle shots vignette

But are a must
 
Gauntey said:
better to scratch a £10 filter than a high price lens.

But are a must
Click to expand...

Ive been using DSLR lenses for over 10 years and have never scratched or marked a single one.

Im also the clumsiest person in the world.

They are most definately not a must.

Sticking £10's worth of crap quality glass in front of a "high price lens" is just plain silly. Might aswell buy a bean can and stick a bit of plastic on the end.

If you insist on using a filter, use a decent one.
 
Plus even if you did scratch the front element chances are it won't effect image quality. There is a very good article kicking around that demonstrates that. Resale value maybe..
 
If you had a camera that had a cheap & nasty low pass, it MIGHT benefit slightly from a UV filter optically, but chances are that any camera that cheap is likely to lack a filter thread and have a fixed (mega-zoom) lens.

In terms of the protection from physical things aspect, while I agree that anything likely to damage the front element will make easy work of the filter, lets remember our physics and bear in mind that the filter breaking is going to absorb some of the energy before that impacting object gets to the front element, so saying that you might as well not have one, isn't necessarily accurate, a pebble that has lost most of its energy to the filter will not do as much damage to the front element as if it had not had the filter in the way.

But overall, probably the best use of UV filters is as a cheap source of filter rings to make homemade 10-stops :)
 
jazzywheelz said:
I've had my first DSLR (a used Canon 450D) for around a week now and I've just noticed that both the lenses that came with it have got Jessops UV filters screwed onto them.
I was just wondering what UV filters are for? I mean I guess they are to block out UV light, but why is this? Are there certain situations where UV light affects exposure? Or on the other hand, are there situations when having a UV filter in place would adversely affect the picture?
My kit didn't come with any storage cases for the filters, so I'm basically wondering if I can just leave them fitted.
Can anyone explain the in's & out's?
Click to expand...

uv does not affect digital - uv filters were used for film.
 
POAH said:
uv does not affect digital - uv filters were used for film.
Click to expand...

The film gurus over at Luminous Landscape still recommend taking the UV filter off except in extreme circumstances.

"In the old days, often the objectives (front elements) of lenses were made out of glass so soft that merely by cleaning it overenthusiastically you could make tiny scratches on it. (Especially if –and this shows the changing of social customs over time –you were in the habit of rubbing your lens with the end of your tie, as many working photojournalists did in ye olden days when men almost always wore ties when appearing in public.) Also in past times, lenses passed UV light, which could throw off TTL (through-the-lens) light meters and/or cause film to respond in weird ways."

"The solution seemed both elegant and sensible: use a UV filter to both cut the UV transmission and protect the objective from scratches. That's been a part of photography's "received wisdom" ever since."
 
TCR4x4 said:
Ive been using DSLR lenses for over 10 years and have never scratched or marked a single one.

Im also the clumsiest person in the world.

They are most definately not a must.

Sticking £10's worth of crap quality glass in front of a "high price lens" is just plain silly. Might aswell buy a bean can and stick a bit of plastic on the end.

If you insist on using a filter, use a decent one.
Click to expand...

Got my Hoya Digital Pro 77mm Thread Brand New for £10, I've scratched a couple of UV filters due to taking photos on beaches and sand getting on the lens and sticking, then causeing minor scratches when cleaning. Offen dont make any different to photos but i find these very small makes (normally not visable to the eye) make star burst effects on lights etc.

As for scratches from knockes etc well i not had any from them as the lens hood seem to take all the impacts
 
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