UV Filters can cause mis-focus

Orville

Orville

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I finally resolved an issue whereby my 70-200mm f/4l front & back focussed 50% of the time. For weeks I have been playing with micro-adjust and wondering whether my 7D or 70-200 needed calibration. The 7D worked perfectly with every other lens and the 70-200 seemsd to work fine on a 40D. The problem was worst at the long-end where almost 100% of shots were soft to massively out of focus. Short end was mostly okay.

After much testing, and cleaning front/back lenses several times I suddenly started to get spot-on focus - every tme. Dumbfounder, I noticed that I had forgotten to screw my Hoya Pro-1 D filter back on. Sure enough, as soon as I put the filter back on focus problems resumed.

After digging through my garage I located an old Tiffen 67mm UV filter, which I fitted and that works perfectly.

The Hoya filter looks spotless, but for some reason just doesn't like my 70-200 & 7D combo.

Just a warning for anyone who experiences random focus issues. Check your filter and avoid :bang:.
 
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Was the filter bought off Ebay or some such other dodgy place?

Lot of sub standard filters out there that will cause exactly the problems you describe.

Personally I don't use them after having the same thing with a Sigma 70-200mm f2.8.
 
the interesting thing would be to establish whether HOYA was original.

Where was it purchased from and how does it look? Does it have weak coloured reflections, or more like a mirror? Is it FLAT? How do the markings on the side look?
 
I thought a lot of photographers do without filters altogether anyway.

I think the quote I always get is "why put cheap glass over the top of the expensive glass?".
 
The filter was purchased from Amazon direct (not Marketplace) about a month before Christmas. I can only assume it is genuine but defective. Either this or there is some strange incompatability between my 7D, the 70-200 and the filter. I will take a piicy of said filter when I get home from work.
 
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Orville said:
Just a warning for anyone who experiences random focus issues. Check your filter and avoid :bang:.
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quite a revelation.. got to admit to being suprised... but thanks for the info...
 
I use the same body-lens set up sometimes, if you are using the UV to protect the lens i prefer to use the lens hood to protect the front from coming into contact with something that might damage it, and keep some cloth/cleaning fluid in my bag incase i pick up any dirt on it.
 
Marmite subject really:nuts:

I personally have a Hoya UV Filters on ALL my lenses - Never had any issues :D

Les :thumbs:
 
Yet another reason not to bother with defunct UV filters.
 
Lez325 said:
Marmite subject really:nuts:
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not really.. not if it adversly effected his pictures...as it did... no decisions like/dislike ..it ruined the pics while on so take it off..
 
Can't say I have had any problems with my 5D Mk2, various L lenses and the aforementioned UV filters BUT I have noticed some degradation and differences in the build quality of the filters (all Hoya Pro D) so possibly have some dodgy ones - am now thinking of removing them altogether. Anyone got experience of the Canon Protection filters?
 
Just to add that I use the Hoya Pro-1 D filters on my other lenses and have not seen issues with them. It was only a problem with the 70-200.
 
I had UV filters on all of my lenses and seemed to be getting soft results on my 7D, I went out on a shoot with my 100-400 L and took the filter off and the difference was amazing. Lots of sharp photos for the first time, instead of a few per shoot. I took off all my filters when I got home and tried them and they were all much improved. I had 3 or 4 hoya, 1 tiffen and 1 other make (cant remember which) and had spent up to around £40 per filter to get some good ones.
Now I just shoot without filters and use hoods for protection instead. I only use filters now if its really dusty or wet, or if I want to use a CPL (which doesn't seem to degrade the image as much as the UV). Never tried the lenses with the filters on on my 5D2 so it may just have been a 7D problem but I'm happy enough not to try again with the 5D2 and filters.
 
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Nikon ( sorry) had an article on their website a while ago about this very issue. Seems a lot of filters cause this problem. One of the reasons I never fit filters on my lenses.
Any glass reduces light transmission, unless the filter is better than the objective lens, it will always compromise the quality.
Allan
 
Here's what a Hoya HD did to my 100-400...

Filter%20Comparison%20100-400.jpg


Unfiltered | Hoya | Cheapo

Here's a link that explains why 'protective' filters can be a big problem on long lenses.
 
I've had this problem on my 70-200 too. Don't use filters at all now.
 
hollis_f said:
Here's a link that explains why 'protective' filters can be a big problem on long lenses.
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hollis_f said:
D'oh! Here.
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That's interesting, Frank. Clarkvison is usually pretty good, but I just don't buy his argument-from-first-principles:

...consider a 20 mm f/2.8 lens with a 77 mm filter. The maximum aperture is 20/2.8 = 7.1 mm, quite small. So the lens sees only a very small portion of the entire filter.
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If that were true, vignetting wouldn't be a problem with wide-angle lenses.
 
StewartR said:
That's interesting, Frank. Clarkvison is usually pretty good, but I just don't buy his argument-from-first-principles:



If that were true, vignetting wouldn't be a problem with wide-angle lenses.
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Yup, agree 100%.
 
D'oh! I just bought a Hoya Pro-1 UV filter. Not used it yet but think i'll take some test shots before using it in anger to see if there is a difference.
 
Thought I'd see if this made a difference to my 50mm which seems to have a few focus issues, went to take the filter off and discovered it won't come off and is cross threaded - something that I hadn't noticed before. First task is to try and get the filter off as it ain't budging!
 
GeordieLass said:
Thought I'd see if this made a difference to my 50mm which seems to have a few focus issues, went to take the filter off and discovered it won't come off and is cross threaded - something that I hadn't noticed before. First task is to try and get the filter off as it ain't budging!
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So the filter used for "protection" (I assume that's why you were using it as dslr's obviously dont need a UV filter) and it's damaged the lens? How many more times do we have to say it, lol!
 
odd jim said:
So the filter used for "protection" (I assume that's why you were using it as dslr's obviously dont need a UV filter) and it's damaged the lens? How many more times do we have to say it, lol!
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To be fair, the problem is more my seeming lack of ability to screw things on properly and that's not the filter's fault! It did the job protecting my lens perfectly (yes, I was using it to protect the lens). It's just doing too good a job at the moment. :bonk:
 
I had a similar issue with my 50mm 1.8. I was convinced I must have knocked it but the problem turned out to be the UV filter (an el-cheapo own brand one from a well know online Channel Island store that's open all week ;)).

I use a Hoya Pro1 UV filter on my 70-200 and that seems fine, though.
 
GeordieLass said:
To be fair, the problem is more my seeming lack of ability to screw things on properly and that's not the filter's fault! It did the job protecting my lens perfectly (yes, I was using it to protect the lens). It's just doing too good a job at the moment. :bonk:
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Lol, time to get the hammer out!
 
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