UV filters.Worth having?

[senatore]

Since I bought my Canon 400 f5.6 lens several people have told me to get a UV filter attached but I'm not sure if it's worth doing.

Have you got one and if so why.Lens protection?Are your pics affected?

I think I'll need a 72mm one (?).Are any makes better than others because prices vary quite a lot?

Max.

[paul goode]

Since I bought my Canon 400 f5.6 lens several people have told me to get a UV filter attached but I'm not sure if it's worth doing.

Have you got one and if so why.Lens protection?Are your pics affected?

I think I'll need a 72mm one (?).Are any makes better than others because prices vary quite a lot?

Max.

Hi Max,

I think there have been a few threads on this resulting in distinctly mixed opinions. A search should find them but I think the upshot is, if you are going to fit a filter buy a very good one, and on a 72mm filter size thats a lot of money.
However the most common opinion is that they can cause image degredation problems and shouldn't really be necessary for lens protection when your lens has a fixed lens hood.

I'm sure the contributors to the previous threads can offer more specific advice.

Paul

Edit: found the thread http://www.birdforum.net/showthread.php?t=63988&highlight=filters

[Roy C]

Since I bought my Canon 400 f5.6 lens several people have told me to get a UV filter attached but I'm not sure if it's worth doing.

Have you got one and if so why.Lens protection?Are your pics affected?

I think I'll need a 72mm one (?).Are any makes better than others because prices vary quite a lot?

Max.

Max, I think the filter size is 77mm for this lens.

[postcardcv]

In my experience filters tend to slightly soften an image, so I no longer use them. I have just taken some test shots using my Sigma 100-300 f4 to show the effect of a filter. Shots were taken on a tripod with flash at ISO 100 to give them the best chance. First to shots are with and without filter shot at f4, second two are shot at f8. For me these tests prove that a filter can degrade image quality and that my lens is much better stopped down...

Since the first time I did such a test I have nto used filters, I rely on the lens hood to offer protection to the lens.

[bkrownd]

Hooooboy...yeah, but the thought of exposing my good lens to dirty air and unwashed photons makes me want to cry. :(

[baillieswells]

In my experience filters tend to slightly soften an image, so I no longer use them. I have just taken some test shots using my Sigma 100-300 f4 to show the effect of a filter. Shots were taken on a tripod with flash at ISO 100 to give them the best chance. First to shots are with and without filter shot at f4, second two are shot at f8. For me these tests prove that a filter can degrade image quality and that my lens is much better stopped down...

Since the first time I did such a test I have nto used filters, I rely on the lens hood to offer protection to the lens.

I contacted Canon a few weeks ago about this and was subsequently telephoned by one of their technical staff. He told me that he had no evidence to suggest that a good filter degraded the image. Something I have found myself, flare is more pronounced if a filter is used without a lens hood. Otherwise all my tests have been negative. (See earlier threads)

[gmax]

In my experience filters tend to slightly soften an image, so I no longer use them. ...
Since the first time I did such a test I have nto used filters, I rely on the lens hood to offer protection to the lens.

Good test .. useful to erase from my mind the need of filters
PS do you have some more spare samples to send me so I can take the same tests? |;|
Cheers,
Max

[Recurvirostra]

In my experience filters tend to slightly soften an image, so I no longer use them. I have just taken some test shots using my Sigma 100-300 f4 to show the effect of a filter. Shots were taken on a tripod with flash at ISO 100 to give them the best chance. First to shots are with and without filter shot at f4, second two are shot at f8. For me these tests prove that a filter can degrade image quality and that my lens is much better stopped down...

Since the first time I did such a test I have nto used filters, I rely on the lens hood to offer protection to the lens.

A lot of people appear to be damning all UV filters on the basis of a test with one (usually unamed) filter - not a terribly scientific test. There are few people posting who say that the filter doesn't degrade the image at all. It is probably understandable that those that have had a bad experience are more likely to publish their woes than those that are happy with the results.

I would also question the validity of the test. The test subject was obviously quite close to the camera so the UV filter has not had a chance to do what is does best - i.e. reducing atmospheric haze which becomes more significant as the distance from the camera increases. I would also doubt that the flash unit would produce much (if any) UV light so that, once again, the filter has nothing to do except, perhaps, add a little flare as the flash bounces back off the note.

Finally, I might add that my son has a large scratch across a UV filter that was installed on a Sigma 50-500 with a lens-hood.

[Roy C]

It is easy enough to test your own filter. Set the camera on a tripod (with remote release) and focus on something like a bar code (I used a distance of about 25ft with my 400m f5.6 lens).
Take a few shots with the filter on and then take a few shots with the filter off. do not do any post processing and compare the images.
If you cannot see any image degradation with the filter on then carry on using it. If you can see a fair amount of degradation then you have three choices:
1) Do not use a UV filter
2) Try a better quality filter
3) Carry on using the filter regardless

I tried this test myself and plumped for option 1.

The point is that until you try a simple test like this you will never know.

[Leif]

I read in the user manual (or rather, the user sheet) for my Nikon micro lens that use of a protective filter is recommended. Both Canon and Nikon manufacture colourless high quality filters for exactly that purpose. I use a Canon protective filter on my spotting scope. (The Nikon cost more.) They are pricey, but if there is a danger of damage to the front element, then obviously they are worth using. Do the high quality ones degrade the image? Dunno.

postcardcv: I can see that the F8 image is much sharper without the filter. What make was the filter? I would guess Jessops or similar.

[bkrownd]

Good test .. useful to erase from my mind the need of filters


We should first ask which filter this was, though.

[macshark]

I am using my 400 f/5.6L with a Hoya Pro-1 UV filter and so far, I haven't noticed any severe IQ degradation issues. I do take bird photographs in a wetland location which is very windy (and obviously wet). I had to clean quite a bit of dirt, etc. from my UV filter several times despite the fact that I always have the hood in extended position. I would not be very comfortable if I had to clean the actual front element of the lens this often.

[Ragna]

I took a few shots of the back of the filter box with and without filter( Hoya HMC SUPER UV) this at a distance of about 14 feet at 5.6 by overcast daylight on a tripod with cable realease,viewed @ 100% i can see no difference between the 2 but to be more sure i think i need to do this again at a distance of about 25-30 feet.So will try to do this later so for now i will continue to use a uv filter.

[JohnZ]

Max, I have the same lens as you and do not use a filter. I prefer to use the built-in lens hood as protection. With the hood extended, even just a little bit, unless you walk lens first into a twig or branch there is little chance of damage. Touch wood !
My reasoning for this came about when I looked at the price of filters. Even accepting that it is an expensive lens I could bring myself to spend up to £90.00, shock horror, on a piece of tinted glass that may, or may not, affect the final image.
I do take into account what MacShark said about continually cleaning his filter but I tend to leave the cleaning of the front element until I think it is necessary.

[hollis_f]

I would also question the validity of the test. The test subject was obviously quite close to the camera so the UV filter has not had a chance to do what is does best - i.e. reducing atmospheric haze which becomes more significant as the distance from the camera increases. I would also doubt that the flash unit would produce much (if any) UV light so that, once again, the filter has nothing to do except, perhaps, add a little flare as the flash bounces back off the note.

Er, just how much light does a UV filter absorb that's not already absorbed by the lens and the anti-alias filter?

Can somebody point me to a pair of photos that show this reduction in atmospheric haze that a UV filter produces?

[postcardcv]

A lot of people appear to be damning all UV filters on the basis of a test with one (usually unamed) filter - not a terribly scientific test...

I would also question the validity of the test. The test subject was obviously quite close to the camera so the UV filter has not had a chance to do what is does best - i.e. reducing atmospheric haze...

My test was purely an illustration of my experience with filters, the filter used in this test was a Hoya UV. I have tested filters on three different lenses in the last year or so and had similar results with all of them. I guess doing the test with the subject further from the lens may have given the filter a better chance, but this is the sort of distances that I use this lens at so this is what I was interested in. I will try the barcode test (at greater distance) when I get the chance and will post the results.

[Recurvirostra]

Er, just how much light does a UV filter absorb that's not already absorbed by the lens and the anti-alias filter?

Can somebody point me to a pair of photos that show this reduction in atmospheric haze that a UV filter produces?

It doesn't absorb any visible light. It only absorbs UV light which is the whole point of using this type of filter. Optical glass doesn't absorb light in the UV part of the spectrum.

I don't have a pair of photos, but years ago I took several colour transparencies of a smoke-filled landscape (due to the nearby presence of bushfires). The resulting slides showed a scene that had virtually no smoke in it, thus spoiling the effect I was trying to capture. This was a case when I should have removed the filter.

[Leif]

My test was purely an illustration of my experience with filters, the filter used in this test was a Hoya UV. I have tested filters on three different lenses in the last year or so and had similar results with all of them. I guess doing the test with the subject further from the lens may have given the filter a better chance, but this is the sort of distances that I use this lens at so this is what I was interested in. I will try the barcode test (at greater distance) when I get the chance and will post the results.

I would naively expect the Hoya to be a good brand. I am tempted to get a neutral filter for my micro lens as protection. But if I do, I will do the before and after tests as you have done. I recall someone saying they dropped their scope onto gravel, and stones were propelled by the impact into the front element, causing severe damage.

[macshark]

I would naively expect the Hoya to be a good brand. I am tempted to get a neutral filter for my micro lens as protection. But if I do, I will do the before and after tests as you have done. I recall someone saying they dropped their scope onto gravel, and stones were propelled by the impact into the front element, causing severe damage.

Hoya make many grades (too many IMHO) of UV filters. The low-end ones are pretty cheap, but I had a problem with at least one of those. The high-end ones very good but also are very expensive, especially anything above 67mm. So it is a trade-off. If you have a very expensive telephoto prime that does not have a protective front element, it may still be worth to put a filter on it, especially if you are going to work under "hazardous" conditoins. The repair cost for a damaged front element will cost you a lot more than the filter. Note that the very high-end Canon telephoto primes do have a built-in protective glass element in front of the actual front element lens, as front mount filters are not available for these.

[graham catley]

I use a Hoya Pro 1 Digital filter on my Canon 300f4 and tests in the garden failed to show any difference when tripod mounted at 20m---as regards getting things on the front element of the lens and expecting the lens hood to keep it off I fear many people are being rather hopeful--anyone who has done a seawatch with a scope with extended lens hood even in a 90 degree wind will appreciate just how much salt spray can attach itself to the front element of a lens---cleaning it off a filter is a) easier and b) safer than getting it off the front element of a camera lens--it is not only salt spray which affects lenses the pollution in the British air is decidedly obvious if you live anywhere near any industrial area or down-wind of Drax!--I managed to trash the front lens coatings of a Leica scope many years ago by taking off salt spray off after a seawatch and I have no intention of repeating the effect with a prized camera lens---clearly as with all glass the more you pay for a filter the better the quality; to me it is more peace of mind rather than any visible effect

[SMC2002]

Max,
So did ya get your question answered?....lol

From what I make of the responses, it seems to boil down to: If you feel comfortable using a high quality UV filter, go for it. I'm not sure you will ever get a straight answer on IQ issues using a good filter. All I can add is that filters can cause flare (sometimes even when using a hood-although the 400's hood is as deep as a sewer pipe...lol)

Where I have seen issues with filters is in the quality of bokeh. Maybe it's just me or my tired old eyes. But when I used a UV/Sky filter the bokeh seems odd. Like chunkier/more grainy globally and strange bokeh in some areas. Like the leaves in the background are moving. Yet, there was no breeze when the shot was taken. Kind of put me off using any filters, except for NDs.

Steve

[bkrownd]

Er, just how much light does a UV filter absorb that's not already absorbed by the lens and the anti-alias filter?

Can somebody point me to a pair of photos that show this reduction in atmospheric haze that a UV filter produces?

I really wish camera and filter companies included good transmission curves with their products, so you could really see what was going on. The transmission curves of different UV/haze/skylight filters can vary quite a bit, and I have no idea what's on the lenses. I'd like to get a set of sharp-cut filters for different wavelengths to play with. I do spectroscopy of optics and filters at work, so I'm picky about it. :brains:

I doubt the straight UV filters block much more than is blocked in the camera. Haze and skylight filters dip more into the blue, but they're pretty subtle as well.
You really have to drop cash on a polarizer to cut the haze well, though my cheap sunglasses do a pretty good job. ;)

[hollis_f]

It doesn't absorb any visible light. It only absorbs UV light which is the whole point of using this type of filter. Optical glass doesn't absorb light in the UV part of the spectrum.

Isn't one of the jobs of the coatings on our lenses to remove UV light?

[senatore]

Thanks everyone for your replies and the references to previous threads on the same subject.

I am very glad I asked the question as I was about to get one,probably from Jessops,not realising that these filters varied so much in quality and of course cost.

The replies have cast some doubt in my mind as to their worth and the fact that my lens has an attached lens hood which gives some protection I have decided not to buy.Thanks again everyone you've saved me some cash again.

Max.

[Recurvirostra]

Isn't one of the jobs of the coatings on our lenses to remove UV light?

No.

If that were the case, there would be no need for UV filters and this thread would not exist. UV filters are made to prevent UV light reaching the sensor/film, not to protect lenses.

[bkrownd]

No. If that were the case, there would be no need for UV filters and this thread would not exist. UV filters are made to prevent UV light reaching the sensor/film, not to protect lenses.

I thought most modern cameras had UV coatings on the lenses already. :h?:

[hollis_f]

No.

If that were the case, there would be no need for UV filters and this thread would not exist. UV filters are made to prevent UV light reaching the sensor/film, not to protect lenses.

Well, this thread exists to duscuss the necessity of UV filters. Having a search on the Web, I find that people who are interested in doing UV photography have many problems - because coated lenses don't transmit much UV light and because the sensors used in digital photography aren't very sensitive to UV light.

That's why I question the value of using a UV filter to prevent UV light from reaching the sensor.

[baillieswells]

Well, this thread exists to duscuss the necessity of UV filters. Having a search on the Web, I find that people who are interested in doing UV photography have many problems - because coated lenses don't transmit much UV light and because the sensors used in digital photography aren't very sensitive to UV light.

That's why I question the value of using a UV filter to prevent UV light from reaching the sensor.

There are clear glass filters available to protect the lens. Not many outlets stock them, and so it is much easier to buy UV filters. I doubt if it makes much difference. I use my filters to protect the lens, not to filter UV out.