Does UV filter attachment to lens reduces sharpness of images?

[pinakibaidya]

Whenever i have taken pics after buying new lens pics used to be super sharp. But after few days i procured lens-filter and attached it to the same lens and took photos using same technique but was frustrated seeing the final result.Images were not so sharp. I don't know the reason. Again the effect varies from filter to filter and in between brands. would you please help me out from this problem!

[DanK]

There are endless threads about this, and people are often vehement in their disagreement. I'll give you my view:

1. Cheap filters will degrade images. Use only high-quality, multi-coated filters.
2. Even good filters can cause problems (flare and hazing) if a light source is in front of the camera.
3. When lighting is behind the camera, so you don't have reflections on the lens, a good filter has only minimal effects on quality. Often, it is hard to see a difference.

I keep filters on for protection but remove them when they are likely to cause a problem, or if I am in an environment where there is no risk.

For good, moderate priced filters, I use Marumi and Hoya.

[Manfred M]

If you are using an inexpensive, uncoated filter, the answer could very well be yes. I write from personal experience here.

Basic sharpness should not be a problem (unless the filter itself is defective), but it can produce internal reflections that result in a less sharp looking final image. If you are using a better (name brand) multi-coated filter, you should not see any image deterioration; assuming of course that the filter is clean.

[rpcrowe]

I have done some quite unscientific tests using a Canon 50mm f/1.8 Mark-I lens and a B+W UV filter. Shooting with a lens hood and ensuring that the filter is clean, I really did not notice any great discernible difference in the quality of the imagery produced with and without the filter. Granted, the B+W filter is top line (I got it when I purchased the lens on the used market many years ago) and, I don't normally shoot straight into the sun because I really don't like sun flare images and... I always use a lens hood when I am shooting.

Unfortunately, the tests were done simply to satisfy my curiosity and I did not keep the results... This is on the back burner for me since I have many other pressing duties with my rescue dogs but, if I have time, I shall repeat the tests and publish the results. In the interim, I suggest that anyone who has a UV filter do the same type of test. It would be great is someone has a low quality and a high quality filter. Perhaps someone who has replaced a low quality filter with a higher grade one could perform a test with both filters...

My own (again - unscientific) results indicated to me that proper post processing sharpening had more of an impact on the clarity of the image that the use or non-use of a high grade filter. However, if you are considering using a high grade, expensive filter, to protect a very cheap lens; that may not be enough payback to make it worthwhile.

Additionally, I am more likely to use a filter protect a high value lens, especially one with a large front element that is vulnerable because the lens hood is quite shallow. An example of this would be my 17-55mm f/2.8 IS lens. Also, I will frequently use a CPL filter when shooting scenic shots outdoors and I will remove my UV filter when I use the CPL...

BTW: I usually remove most filters from my lens when shooting night shots since spots of light may have a flare problem when a filter (even a top-line, multi-coated filter) is used. The only filter I ever use for night shots is star filter and I seldom use that because star filter results can be quite overdone and you can sometimes duplicate the star effect by stopping way down or adding it with an editing program.

Some very good information on protective filters as well as other type filters can be found in this tutorial:
https://www.cambridgeincolour.com/tu...ns-filters.htm

[NorthernFocus]

I've got a simple formula that works well for me for clear or UV filters. If the filter costs more than 10 percent of the price of the lens, then I use them. Otherwise I shoot the bare lens. The formula doesn't apply to special purpose filters like CPL, ND, NDgrad, etc. When you need them, you need them.

on edit: Another important point is that I never spend more than $50US for clear/UV filters.

[DanK]

I do have results from a test--sort of. Here are two images, both shot with a 50D and an EF-s 60 macro lens, with flash, on a tripod. Everything is the same except that I had a Hoya UV filter on for one of the two. The reason I say "sort of" is that I can't remember which is which! See if you think you can tell. I will post a link to a larger version with each one so that you can pixel peep if you want.



Link to a larger version of the image above.



Link to a larger version of the image above.

[jcuknz]

Based on "Knowingf what Students Know" I would suggest the second is using the filter ... but my solution is not to use them but to have a deep lenshood on the camera 7/24 and protect the camera from dangerous surrounds ... but if I went into a seriously dangerous place I hope I would have warning so I could buy a cheap cover and rely on editing to bring it up to scratch.

[zen]

Yes, I also think the second image is the filtered one.

As to use of the UV for protection, I won't take a new lens out without a UV on it for protection. I use only Heliopan multi-coated, and have seen absolutely no image degradation. They are expensive, but well worth it to protect a $2500 lens!

OTH, years ago when first starting, I did have a few cheapies that DID cause some softness, long before I could afford the good, multi-coats I use now.

Zen

[CP140]

This might be interest... if a bit tongue in cheek...

http://www.lensrentals.com/blog/2011...th-bad-filters

[Glenn NK]

I do have results from a test--sort of. Here are two images, both shot with a 50D and an EF-s 60 macro lens, with flash, on a tripod. Everything is the same except that I had a Hoya UV filter on for one of the two. The reason I say "sort of" is that I can't remember which is which! See if you think you can tell. I will post a link to a larger version with each one so that you can pixel peep if you want.
Link to a larger version of the image above.

If there is a difference, it does not appear significant. There are other factors that probably affect IQ more than the use of a high quality filter.

I have two simple rules:

1) If it isn't made in Germany, I don't want it.

2) And it must have one of the following names on it: B+W or Rodenstock

Glenn

[Colin Southern]

it must have one of the following names on it: B+W or Rodenstock

I'd add Heliopan to that (short) list.

[Colin Southern]

Whenever i have taken pics after buying new lens pics used to be super sharp. But after few days i procured lens-filter and attached it to the same lens and took photos using same technique but was frustrated seeing the final result.Images were not so sharp. I don't know the reason. Again the effect varies from filter to filter and in between brands. would you please help me out from this problem!

What Brand / make / model UV filter are you using?

[RustBeltRaw]

We should also confirm that the OP was shooting similar subjects in similar conditions with similar settings before we examine the filter. But for what it's worth, I've been quite happy with my Hoyas. Not the best, surely, but they're quite good for the money. There's been only one time in the last two years I removed it from my EF 28-135mm F3.5-5.6 IS USM, suspecting that it was causing an undesirable flare. Removing the filter helped, but the shot itself wasn't brilliant, so I didn't keep it. But I was shooting about two degree off directly into the sun, so that was a rare and fairly extreme case, but still easily dealt with.

It's worth noting that Hoya quotes light transmission "over 97%" for their entry-level multicoated UV-C filters (spectral distribution not specified), so even they don't claim that their filters are perfect. However, they also claim 99.35% transmission (again, no spectral distribution) for their more expensive high-end UV-HD filters. And I would challenge anyone to notice a 0.65% drop in light, regardless of resolution and equipment quality.

[AB26]

See if you think you can tell.

Dan, no1 was shot without a filter.

[DanK]

Dan, no1 was shot without a filter.

Possibly. I honestly no longer know.

[Colin Southern]

I'll just come right out and say it in my typical and un-PC style: A quality UV filter will have none-zero-nada effect on real-world image sharpness. In terms of image sharpness, a quality filter can be left on without hesitation nor regret.

Flare due to lighting position CAN be a different story though (as others have quite rightly mentioned), but that's outside the scope of the current discussion.

[dottore]

For a proper test and measurements of many UV filters see: http://www.lenstip.com/113.1-article...ters_test.html
I also highly recommend very high quality new Cokin Pure Harmonie series, full details here: http://www.cokin-filters.com/pure-harmonie/ I can confirm all claims made by Cokin. Mechanically the filter frame is unbelievably thin (great for ultra wide optics) yet sturdy.

[Colin Southern]

For a proper test and measurements of many UV filters see: http://www.lenstip.com/113.1-article...ters_test.html
I also highly recommend very high quality new Cokin Pure Harmonie series, full details here: http://www.cokin-filters.com/pure-harmonie/ I can confirm all claims made by Cokin. Mechanically the filter frame is unbelievably thin (great for ultra wide optics) yet sturdy.

Hi Dottore,

Welcome to CiC.

Thanks for the link to the tests, but "unfortunately", they're only testing UV attenuation (which is irrelevant to digital photography anyway) (sensors don't respond much to UV), and flare resistance (which to a large degree is pretty much a moot point anyway because generally in an extreme-contrast scene shooting into incident light - especially with point light sources - most good photographers remove the filters). Plus, they didn't test sharpness, which was the OP's concern.

[dottore]

Hi Colin,

Thank you for the welcome message! Yes, you are largely correct, though I would not completely dismiss usefulness of flare resistance testing. My reference link was more along the lines "flawed, possibly, but better than nothing" source of formalized information. Interestingly (maybe someone can correct me if I am wrong) I have not seen any proper tests, only individual experiences with different filters on different lenses.

I received Cokin Pure Harmonie UV filter only a few days ago, and on ultra wide lens so far it is great, but again, this is hardly a formal test, just my limited experience. Somehow, from my past experience, I tend to trust the brand as well, but this is of course my biased opinion

Hi Dottore,

Welcome to CiC.

Thanks for the link to the tests, but "unfortunately", they're only testing UV attenuation (which is irrelevant to digital photography anyway) (sensors don't respond much to UV), and flare resistance (which to a large degree is pretty much a moot point anyway because generally in an extreme-contrast scene shooting into incident light - especially with point light sources - most good photographers remove the filters). Plus, they didn't test sharpness, which was the OP's concern.

[Colin Southern]

Hi Colin,

Thank you for the welcome message! Yes, you are largely correct, though I would not completely dismiss usefulness of flare resistance testing. My reference link was more along the lines "flawed, possibly, but better than nothing" source of formalized information. Interestingly (maybe someone can correct me if I am wrong) I have not seen any proper tests, only individual experiences with different filters on different lenses.

What's your first name? (so I can put it in your profile for you)

For me, flaring/ghosting has only ever come down to two situations - the first when I have direct sunlight hitting the front element of the lens at an obtuse angle, resulting in veiling flare, and the 2nd, more an issue with ghosting from point light sources.

For the first situation, testing would probably reveal a particular brand that would reduce it the most, but I've always felt that the "A" answer was always to just eliminate the light hitting the front element (lens hoods usually do a great job on longer lenses due to them being deep, but WA lenses sometimes don't fare so well). Often all it takes is a hand to just block the light, or in the case of long exposures, sometimes one needs to get a little more creative ...



(it was worth it though, although case-in-point, I decided to leave another source of flare in the image in the end)



For the 2nd situation, I usually just remove the filter, as no filter will improve things in that circumstance -- and infact, even with the filter removed, one typically still gets ghosting anyway.