Canon EF 16-35mm MFA and color fringing

[jcphoto]

Hi,

I've just re-registered all of my lenses on 7D body and included my just-purchased EF 16-35mm f/4.  It is the only lens to give me trouble, no matter at what focal length or distance from test pattern I AFMA, when I increase distance and zoom in I am seeing significant color fringing and soft focus.

First AFMA was at 5.7ft, 35mm f/4.  At this distance test photos show extremely sharp focus.  However, when I increase the distance to 20ft and fire off a test shot, this is what I see (image has been cropped and resized to simulate LR 3-1 view)

I have also gone through the exercise of AFMA at 20 ft, which is more realistic than the default focal length mm x 50 with same results.

I am not seeing this type of result with any of my other lenses, a mixture of EF and EF-S, both primes and zooms.

Do I have a faulty lens?  I still have a few days before my return window is up, advice appreciated.

[jrhoffman75]

Since you are unsure, and can still exchange for a new one, I would do it.

[ebiggs1]

Same lens?  Same camera? Same settings except distance in a few feet?  You shoot at 5.7' at f4 at 35mm and all is well but if you move that same set-up to 20' all is not good?

I think I would do the test again and really check my set-up.  

[jcphoto]

Yes, Same lens, same camera.  No on same settings.

The first execution of AFMA was at a distance of 22' from target.  Since I will be using this as a landscape lens it made little sense to do it at 50 x focal length (Canon recommendation).  DotTune method was used.  When completed I did an AF test photo.  At 22' the results are shown above, zoomed and cropped to simulate Lightroom 3-1 view.

These results looked terrible, so I thought OK I will use Canon's recommendation.  AFMA re-executed at 5.7ft (50x35mm), f/4. AF test photo looked spot on when taken at 5.7 ft.  When I dropped back to 22ft, test shot when zoomed in is the same as above.

If I can do this test better your advice would be great.  Since my AFMA methodology on

EF-S 10-22mm

EF-S 15-85mm

EF 50mm f/4

EF 100mm F/2.8 L

EF 70-300mm L

worked fine with no issues and satisfactory results, and the 16-35mm is causing problems, I can confidently state that the test process is not at fault.  But then, what do I know? 🙂

[ebiggs1]

This lens is reported as the sharpest WA zoom Canon has ever made.  I don't have one so I don't know personally.  But how do your photos look?  Forgetting the focus tests, real world photos?

If you are truley worried about it, I would return it and get another copy.  If you don't you will always suspect it and won't enjoy it even though it may be fine.  If you do decide to return it and get another one, don't test it.  Just use it and enjoy it.

Unless I see something in a photo that perks my suspicion, I never test anything.   I do get pretty paranoid when I get third party lenses and usually put them through stiff "testing" because I distrust them so much.

I seem to have been pretty lucky on the micro fine focus adjustmernts as they have been minor to none.  And like you, when you get a top of the mark lens you expect top of the mark performance.

[jcphoto]

Thank you for your response.

I will be taking delivery of a new 6D today (can I get a yippee?), hopefully the results will be different.  The purchase of this lens was a first step in migrating all but wildlife photography (I will keep the 7D) over to FF. There have been limited photos taken at this point, but I can say that I am extremely impressed, I am not seeing the color shift evident with the test pattern.

The worst part, I'm afraid I might become a pixel peeper.

Thanks again for the help and advice.

[ebiggs1]

Yippee!  

"I'm afraid I might become a pixel peeper."      <---- Don't be that guy.   They really are a PINTA and I am sure they are not happy people.

One thing more, shoot RAW and get PSE, or LR and/or PS.  Almost any lens aberations you think you see can be fixed with ease in one of these.  Adobe just released ACR 8.7 and I am told it has the new EF 16-35mm correction factors in it.

Not having the len, yet, I have not checked.  Plus I understand it has the new 7D Mk II also.

[ebiggs1]

I just checked it and ACR 8.7 does have your lens.  Should be no problem.  Here is a look at what I mean although this is not your lens it is representive.  This is my 1D Mk IIn and the "lowly" EF 28-135mm but you see the process. 

[jcphoto]

Yes, I've already downloaded the latest LR, just haven't had a chance to play with it yet.  Canon 6D is here and coming to room temperature, I hope to dedicate some time this weekend to thoroughly test the 16-35mm.

Cheers.