Diagonal marks on image after zooming (1 Viewer)

GarethH · May 21, 2006

Hi,

I have noticed diagonal marks in the backgrounds of a number of photos taken with my brand new second hand Canon 100-400mm IS lens. It is not noticable on the original image but when i zoom in and trim on the computer it becomes apparent. This was not the case with my old lens, the 55-200mm. I attach am image as example.

Can anyone explain the reason?

Saphire · May 21, 2006

GarethH said:
Hi,

I have noticed diagonal marks in the backgrounds of a number of photos taken with my brand new second hand Canon 100-400mm IS lens. It is not noticable on the original image but when i zoom in and trim on the computer it becomes apparent. This was not the case with my old lens, the 55-200mm. I attach am image as example.

Can anyone explain the reason?

Gareth

I wouldn't have thought it was anything to worry about. I think it is a common occurance with an out of focus background. I have a similar thing happen with my sigma 170-500mm when I have the lens wide open to get a shallow depth of field.

Keith Reeder · May 21, 2006

Are you using a filter by any chance, Gareth?

Saphire · May 21, 2006

Gareth

I have just found this photo taken with my husbands Canon 100-400 IS L USM lens it has similar marks to yours.

Mickymouse · May 21, 2006

You said you zoomed in from the original if I understood right which makes me wonder if it is to do with the resizing algorithm causing a feint moire type pattern which only shows in the out of focus areas.

Mick

Keith Reeder · May 21, 2006

Christine, is a filter involved in your hubby's pic?

We've had a few threads about this kind of aberration, and it's generally traced back to the use of a UV filter...

Saphire · May 21, 2006

Hi Keith

Yes at the time there was a filter on the lens, I totally forgot about that. About a month ago I removed all the filters on all our lenses after running some tests as I noticed a marked difference in sharpness.

You have pointed out an area I hadn't checked so will take some test shots tomorrow with both 170-500 and the 100-400 and see if the aberration has gone that would be a clear indication that it was the filters that were causing the marks.

Keith Reeder · May 21, 2006

I think you'll find the problem doesn't exist with the filter gone, Christine.

SMC2002 · May 22, 2006

FWIW, I agree with Keith, That is distortion and not normal. The only time I see that sort of "strange" bokah, is when I use a TC on a lens. A filter can do the same thing. For example, I get a cross-hatch pattern in images, on occassion, when shooting IR with an R72 filter, with my Sonys.

Another reason to "go bare"....lol

Steve

Roy C · May 22, 2006

I had the same problem with one of my lenses - turned out to be the UV filter as Keith suggest's.

GarethH · May 22, 2006

Hi All,

Thanks for the responses. Yes Keith i do have a UV filter on this lens, i will remove it at once. I also battle to get my photos crisp and clear, are the other guys that get this effect using a lot of computer tricks to clean up their photos or could it also be the filter that causes this?

What effect does the filtering of UV light have on the image?

This is a great forum for getting help!! I still have so much to learn.

Regards

Gareth H
(from a cold Pretoria!! min 3 max 13)

GarethH · May 22, 2006

Saphire said:
Gareth

I have just found this photo taken with my husbands Canon 100-400 IS L USM lens it has similar marks to yours.

Nice bird Christine, he looks about as cold as i was today!! :'D
Thanks again for all the help!

jasnjohn · May 23, 2006

I have seen this diagonal hatching on several of my images (EF 400mm f5.6L).
It is aggravated with a 2x tele, and after reading the above, it makes a lot of sense to point the finger at the filter.
I'll have a play without it later.

Nobody has mentioned what type of UV filter they're using.
Could it be possible that a high-grade multi-coated UV filter could be less problematic? Perhaps throw a bit of money at it to make it go away. Don't really like the idea of using my new lens without that extra bit of protection at the front.

My existing filter is a HOYA UV (single-coated). Fairly cheap.

Does anyone have experience with better filters, and do they experience the diagonal stripes?

35°C, Partly sunny.
8-P

Cheers
John

Roy C · May 23, 2006

jasnjohn said:
I have seen this diagonal hatching on several of my images (EF 400mm f5.6L).
My existing filter is a HOYA UV (single-coated). Fairly cheap.
Cheers
John

I was using the same filter on my 400 f5.6 and had the same problem. I removed the filter and not only did the hatching disappear but the lens was significantly sharper. Try doing a test shot with and without the filter and see the difference! (My test was of a label on a drinks bottle from about 25 feet).
This lens has a built-in hood so I always use the hood as protection.

GarethH · May 23, 2006

I am using a Kenko UV filter, not sure of the cost as it was on the lens when i bought it!

Lovely hot weather you're having, send some back our way ...... please!

baillieswells · May 23, 2006

GarethH said:
I am using a Kenko UV filter, not sure of the cost as it was on the lens when i bought it!

Lovely hot weather you're having, send some back our way ...... please!

We had this argument about UV filters a couple of weeks ago. I did some tests using my Sigma 170-500mm DG lens with a Sigma multicoated filter, and a Canon 70-200mm f4 L lens with a B&W multicoated filter and could find no difference with or without the filter. The only exception was when sunlight was coming from the side producing flare. The flare was greater with the filter and without the lens hood (not surprising with an extra glass surface).With the lens hood in place there was no difference.

jasnjohn · May 23, 2006

I've just snapped some test shots with and without the HOYA, and sure enough, the problem has gone away.
I know that Canon manufacture their own range of filters (UV/Skylight/Protect/CPol), would be interested in finding out whether they will pose the same problem. Perhaps the "Protection" filter would be more suitable if you're only interested in keeping the end glass dust/scratch free.

Anyone used the protection filter and had these problems?

nigelblake · May 23, 2006

This is very definitely a filter issue, this is a problem that seems to occur on higher pixel density sensors.
Personally I do not use UV or similar filters for 'protection' as I feel that putting inferior quality glass on the front of a good lens defeats the object of using expensive glass in the first place!

Keith Reeder · May 23, 2006

It amazes me that in face of all this empirical evidence from people who have had this exact problem, and dealt with it instantly by removing their filters, we still have people who are determined to tell us we're all wrong..!

baillieswells · May 23, 2006

Keith Reeder said:
It amazes me that in face of all this empirical evidence from people who have had this exact problem, and dealt with it instantly by removing their filters, we still have people who are determined to tell us we're all wrong..!

I have read through all the correspondence and I cannot find anyone saying you are wrong. If you are referring to my contribution, all I said was that with my set-up I could find no difference whether a filter was present or not.

However with the weight of evidence which has appeared in the correspondence I immediately got the camera out and took a new set of photos. I can find no difference with or without a filter using a Sigma 170-500mm DG lens set a 200mm, f8 with a Sigma filter and with a Canon 70-200mm f4 L set at 200mm f8 using a B&W filter.

HOWEVER I also tested a cheapy Canon 100-300mm f4.5-5.6 which I have had since 1990, set at 100mm,200mm and 300mm f8. and with a Hoya HMC 1B filter. There I found a considerable difference in the presence and absence of the filter at all focal lenghts. The filter degraded the image, particularly in contrast.

So!

Diagonal marks on image after zooming (1 Viewer)

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