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Thread: 24-70mm CA issue

  1. #11
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    Re: 24-70mm CA issue



    Interesting.


    It may be, then, that the Chromatic Abberation issues arise moving out of focus. I noticed that in the focal plane, in the middle of the screw, there isn't any to speak of. If that's just the way it is, it is, and it's up to post-processing and stopping down to deal with it.

  2. #12
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    Re: 24-70mm CA issue



    <span style="font-family: 'Arial','sans-serif'; color: black; font-size: 11pt;"]Areijnders,


    <span style="font-family: 'Arial','sans-serif'; color: black; font-size: 11pt;"]I would photograph a bright white object outdoor that has sharp edges. Then if you have excessive CA I could compare it to similar images that I have taken. By the way, the 24-70'sCA is at is worse at 24mm and the aperture does noteffect the amount of CA on this lens.<o></o>

  3. #13
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    Re: 24-70mm CA issue



    If it is by design, I guess the follow up question is, why? The 28-135 posted above does better in this regard, at the same apertures and focal length, both for full-frame use. I wonder how my 24-105 would compare. I'll try it when I get it back from a friend who 'forgot' to take it off his camera... Though I now have my 28-135mm back to try the same test with...

  4. #14
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    Re: 24-70mm CA issue



    I did a comparison at 70mm between the 28-135 and the 24-70mm. The widest the 28-135 would go at 70mm was f/5, so I used it for both. Didn't see any CA in either, but the 24-70 was significantly sharper.

  5. #15
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    Re: 24-70mm CA issue



    So, the saga continues...


    At this point, the question is, "Is the 24-105 lens actually superior to the 24-70 when it comes to chromatic aberration beyond the focal plane, or did I (and a few others) just get bad copies of the 24-70?"





    Now, I realize that this isn't an exact duplicate, as the natural lighting changed a little and I didn't hold the paperclip exactly the same, but I think the results are still valid, particularly since I tried this several times and got similar results on each...





    Both at f/4, both at 70mm focal length.


    I'm wondering if Canon is going to give me an excuse, admit to the particular design shortcoming of the 24-70, or actually step up and fix the damn thing.

  6. #16
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    Re: 24-70mm CA issue



    Quote Originally Posted by Colin
    For the sake of illustration, here's the same image with the color saturation cranked up...

    Wow, really stripped that screw! Better get that fixed [H]

  7. #17
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    Re: 24-70mm CA issue



    Yeah... If I ever need to remove that screw, it'll probably require a drill..


    I can't complain about the detail...


    I wonder if it's one of those design choices.. Something about allowing more chromatic aberration as you move out of focus lets you really nail what's in focus, or does something for the bokeh, or whatever....


    Stupid real world. If the CA I'm seeing is just inherent to the lens, that doesn't make it a deal breaker. It's so fantastic in other ways. But, if i can NOT have the CA that I'm noticing, that'd be MUCH better. However, if it's inherent, it's one more reason to keep the 24-105 around.

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