Welcome to the forum!

As an adjunct to the Tangents blog, the intention with this forum is to answer any questions, and allow a diverse discussion of topics related photography. With that, see it as an open invitation to just climb in and start threads and to respond to any threads.

focus problems

RubyRuby Member
edited March 2012 in news & discussions
Did some shots yesterday of some family groups, I was using the canon 7d with 24-70mm 2.8 lens. My settings were iso 100 f5.6 1/200 M mode. At 70mm the shots are smack sharp but at 24mm soft. Any ideas what could be going on? Cheers


  • TrevTrev Moderator
    edited March 2012
    Ruby, unfortunately one of the things that I found [as did Neil] with the Canon 24-70mm was some softness at the wide end of this lens, and when I did not need the wider aperture, I stuck to the 24-105 f4 lens a lot.

    Also, it depends on how you focussed, either focus/recompose or using the outer edges of the focus points.

    If you had to tilt the lens more at the wider end when focussing and then recomposing that will affect the outcome also, and the outer points sometimes are not the greatest.

    Other then that, your technique holding, but that seems unlikely given at 70mm they are sharp.

    Also, are you talking about the overall softness, or it's sharp in center then falls off soft to outer edges at the 24mm end, as that is generally a problem with wider lenses, particularly this Canon lens I have found.

    Having owned 2 [1 got destroyed, bought another thinking it may be better] but found it the same; I have also used a friend's 5D with his 24-70 lens and it produced same results at the wide end, fairly sharp in center but falling soft to edges.

    If you only have this lens, do Iike I used to do, frame fairly loosely with plenty of space around people, then crop to suit, that way helps eliminate the edge softness.

    Hint with 'cropping'. I don't 'crop' per se, before doing anything, I duplicate the background, then transform [Ctrl T] and drag out proportionally to fill to suit, then flatten image. That way you maintain the pixel perspective/size like an original image shot.

  • Neil vNNeil vN Administrator
    Ruby ... what you describe is exactly the problem I had with the two copies of the Canon 24-70mm f2.8 lenses that I had. They back-focus easily, especially towards the wider focal length. They also easily go out of calibration.

    So the bad news is ... it is most likely your lens.
    The good news is .. it is most likely not something *you* are doing.
  • RubyRuby Member
    Thanks Guys for that....... I was focusing using center point with expansion enabled. The whole image is soft not just the edges. What is a good replacement lens for this one? Can this problem be fixed, I'm glad it's not me!! Thanks for your help Ruby.
  • RubyRuby Member
    I just looked at some shots, and the lens seams fine at close range 1-2m @ 24mm but when I stood back to get the groups in soft. I will be able to us them but only to A4 size. Thanks.
  • Neil vNNeil vN Administrator
    When I sold most of my Canon gear, I kept the 24-105mm f4
    It's a consistent lens, unlike the 24-70 f2.8
  • Neil vNNeil vN Administrator
    The new Canon 24-70mm f2.8 II might solve this problem, but I am loathe at throwing more money at Canon in the hope a problem gets solved.
Sign In or Register to comment.