Can a UV filter affect IQ (sharpness) on a lens?

[carlc]

Using a 7D, ef-s 17-55mm and a Hoya HMC SUPER UV(0) and without the filter my results seem more precise at the intended focus point (usually center spot).  I don't understand and I have never experienced this before.  I have used this filter on my 70-200 f2.8 MkII and never noticed any loss in IQ.

Is this an issue with the 17-55 lens?  I just purchased this lens 30 days ago and without the filter the lens performs flawlessly and I love the results.  At first I thought I might have a slight front focus issue and then I tried the lens without the filter, bingo, much better.

Thanks for any help or suggestions.

[pdirestajr]

So then why not just keep the "filter" off? All it really offers is protection- so instead, you can always just add a lens hood for protection... Unless you are in an extreme environment, or running through the woods where a branch can jump out and attack your lens, you should be fine.

[Random Orbits]

Used a Canon and a B+W filter on my 17-55 and never had an issue with either of them.  I'd suggest trying another filter brand (at a camera store or a friend's) just to see if it is a lens issue or not.  Tolerance stack ups vary from lens to lens, so yours might be more sensitive naturally to filter variation.  Another consideration is that longer lenses have longer focal lengths which may lessen the impact of bad filter.  There are many videos showing that lenses with slightly damaged front elements don't perform noticeably different than those with perfect front elements.  However, at the shortest focal lengths (i.e. fisheyes), dirt on the front element can be visible.  You might be able to test this hypothesis by seeing if the image IQ hit is worse at the wide end than the tele end, but in any case, I'd suggest trying another filter.

[Tcapp]

Used a Canon and a B+W filter on my 17-55 and never had an issue with either of them.  I'd suggest trying another filter brand (at a camera store or a friend's) just to see if it is a lens issue or not.  Tolerance stack ups vary from lens to lens, so yours might be more sensitive naturally to filter variation.  Another consideration is that longer lenses have longer focal lengths which may lessen the impact of bad filter.  There are many videos showing that lenses with slightly damaged front elements don't perform noticeably different than those with perfect front elements.  However, at the shortest focal lengths (i.e. fisheyes), dirt on the front element can be visible.  You might be able to test this hypothesis by seeing if the image IQ hit is worse at the wide end than the tele end, but in any case, I'd suggest trying another filter.

+1.

Whenever you use a filter, it is going to affect you image quality. Fact of life. I keep filters on most of my lenses, unless it has a recessed front element like the 50 1.4. I like not having to worry about fussing with lens caps when i need to switch lenses real fast at a wedding. UV filters let me not worry about it.

[Dylan777]

Not when you use this filter:

http://www.bhphotovideo.com/c/product/756818-REG/B_W_66_1066111_77mm_XS_Pro_NANO_Clear.html

All my lenses are protected by B&W Clear...no problem at all

[Quasimodo]

[/quote]

+1.

Whenever you use a filter, it is going to affect you image quality. Fact of life. I keep filters on most of my lenses, unless it has a recessed front element like the 50 1.4. I like not having to worry about fussing with lens caps when i need to switch lenses real fast at a wedding. UV filters let me not worry about it.
[/quote]

What do you mean with a recessed front element? Also, I have always used a Kenko Pro 1 W filter on my 50 1.4, and have never had any issues. Are you saying that the IQ will be better if I remove it? (so far I have had nothing but good thing to say about this particular lens).

[Tcapp]

+1.

Whenever you use a filter, it is going to affect you image quality. Fact of life. I keep filters on most of my lenses, unless it has a recessed front element like the 50 1.4. I like not having to worry about fussing with lens caps when i need to switch lenses real fast at a wedding. UV filters let me not worry about it.
[/quote]


What do you mean with a recessed front element? Also, I have always used a Kenko Pro 1 W filter on my 50 1.4, and have never had any issues. Are you saying that the IQ will be better if I remove it? (so far I have had nothing but good thing to say about this particular lens).
[/quote]

Good quality filters will have a very small effect on IQ. But one danger of filters is creating reflections from certain light sources. Example:
http://www.flickr.com/photos/chris28mm/4446223418/#


When I say recessed front element, i mean that the front lens is set back in the lens, rather than flush with the filter thread. Example of recessed: http://i468.photobucket.com/albums/rr48/bullitt411/Siggy%2010-20/Tokina/DED_3739.jpg

Not recessed: http://www.yacart.com/blog/wp-content/uploads/2011/12/canon_ef_70_200mm_f2.8_l_is_usm_lens.jpg


When the lens element is set farther back in the body of the lens, it is more protected and unlikely to be damaged.

[Quasimodo]

+1.

Whenever you use a filter, it is going to affect you image quality. Fact of life. I keep filters on most of my lenses, unless it has a recessed front element like the 50 1.4. I like not having to worry about fussing with lens caps when i need to switch lenses real fast at a wedding. UV filters let me not worry about it.

What do you mean with a recessed front element? Also, I have always used a Kenko Pro 1 W filter on my 50 1.4, and have never had any issues. Are you saying that the IQ will be better if I remove it? (so far I have had nothing but good thing to say about this particular lens).
[/quote]

Good quality filters will have a very small effect on IQ. But one danger of filters is creating reflections from certain light sources. Example:
http://www.flickr.com/photos/chris28mm/4446223418/#


When I say recessed front element, i mean that the front lens is set back in the lens, rather than flush with the filter thread. Example of recessed: http://i468.photobucket.com/albums/rr48/bullitt411/Siggy%2010-20/Tokina/DED_3739.jpg

Not recessed: http://www.yacart.com/blog/wp-content/uploads/2011/12/canon_ef_70_200mm_f2.8_l_is_usm_lens.jpg


When the lens element is set farther back in the body of the lens, it is more protected and unlikely to be damaged.
[/quote]

Ok, thanks

[7enderbender]

I leave clear filters on all of my lenses except the 50 1.4. On the latter I always (!) leave the lens hood on because the little motor and/or clutch in that lens can break from mechanical strain coming from the moving front element.

I personally can't see ANY difference in image quality and can't really imagine where it would be coming form.

[Dylan777]

I leave clear filters on all of my lenses except the 50 1.4. On the latter I always (!) leave the lens hood on because the little motor and/or clutch in that lens can break from mechanical strain coming from the moving front element.I personally can't see ANY difference in image quality and can't really imagine where it would be coming form.

+1...same here

[jebrady03]

I bookmarked this thread last year as a reference for myself and thought it may be useful here: http://forums.dpreview.com/forums/read.asp?forum=1002&message=37394169

The initial post is very common-sense-like and often pretty funny.  Worth the read whether you agree or not

[Dylan777]

I bookmarked this thread last year as a reference for myself and thought it may be useful here: http://forums.dpreview.com/forums/read.asp?forum=1002&message=37394169

The initial post is very common-sense-like and often pretty funny.  Worth the read whether you agree or not

I can't stand dpreview 

[Tcapp]

I bookmarked this thread last year as a reference for myself and thought it may be useful here: http://forums.dpreview.com/forums/read.asp?forum=1002&message=37394169

The initial post is very common-sense-like and often pretty funny.  Worth the read whether you agree or not

I can't stand dpreview 

Ditto.

2 good reasons to use a filter:

1. Weather sealing. A lot of L glass needs a filter to complete the seal.

2. Its nice not having to mess with lens caps at an event when you need to change lenses quickly.

[neuroanatomist]

3. Ease of cleaning.  A B+W MRC or Hoya HD filter is much easier to clean than the front element of most lenses.  There's a reason Canon is now putting a fluorine coating on the front/rear elements of the newest lenses.

[jebrady03]

I can't stand dpreview 

Just because you can't stand that site, doesn't mean there's not good info/posts there.  I can't stand politicians but occasionally they... okay... bad example.  But I think you know what I mean

1. Weather sealing. A lot of L glass needs a filter to complete the seal.

Says who?  Canon?  If Canon says it's weather sealed, shouldn't that mean it's weather sealed without a filter?  I'm not doubting you, just requesting a reference.