How to test backfocus with my new 70-200 f/4?

Discussion in 'Canon EOS' started by fernando lopez, Sep 15, 2005.

  1. All going well, tomorrow UPS will deliver the newest member of my
    lens- family, the 70-200 f/4 USM L. I know this lens is notorious for
    backfocus problems especially on a 10D. Is there any reliable way for
    me to test if my newly acquiered lens is backfocussing? If that's the
    case, I assume BHPHOTO will fix it right? (I bought the USA-
    version). Is it just a matter of re- calibrating?
     
  2. In addition to the above, are there any known series of serial numbers that have backfocussing problems?
     
  3. no problems with mine on the 20d make sure that you know that the AF points are larger than they appear in the view finder any problems I've had I caused myself (focus/recompsose) /awesome glass beautiful color
     
  4. The 70-200 f4L Canon is known for being notoriously sharp for a zoom and the backfocus myth is internet bullshit, more due to poor camera technique by owners than anything else. Just enjoy your new lens and take a month or so to get used to using it, after that period, if you can then see anything that can be attributed soley to a lens problem, (highly unlikely) that is the time to look further. There is no USA version, either one size fits all.
     
  5. the backfocus myth is internet bullsh*t--Erin Boyd
    LOL. Better to remain silent and appear ignorant than to post and remove all doubt.
    I know this lens is notorious for backfocus problems especially on a 10D.--Leon Fassbender
    Not sure that it is the lens's fault. The camera controls the feedback loop.
    Anyway, just do a normal focus test, use a tripod. But if your camera body has a back focus problem, don't post it on photo.net or the Canon shills will get you.
     
  6. If that's the case, I assume BHPHOTO will fix it right? (I bought the USA- version). Is it just a matter of re- calibrating?

    The "USA version" you would send to Canon if need of repair and the "Imported version" you would have had to send back to BH Photo.
     
  7. I just bought the same lens from BH. It will be here tomorrow, so we will see.....
     
  8. ky2

    ky2

    It's funny. No matter what I do, I never succeed with my back focus. This is even harder in the mornings.
     
  9. Change your focusing screen to a split image one so you can check bakfocus ;-)
     
  10. Yaron, though you may have back focus problems in the morning, your portfolio is absolutely beautiful. Very well done.
     
  11. It appears Mr William Wallace is a troll, just registered today. May he suffer the fate of his namesake and be hung drawn and quartered mercilessly.
     
  12. That said, just go aout and shoot with the damn thing! If their is a problem, and noticeable at f4 (unlikely) then worry about it, not before it even arrives.
     
  13. I know that in spite of all these answers you are still going to doubt the autofocus... Your best bet is to go to the first website that was posted by MAD Wand in this forum and download the attached pdf file. Make sure you print atleast the last 2 pages to test out your camera with. If precision in focus is of great importance to you, you will perform the test just to satisfy your mind. I am going to be doing that test tonight when I get home.<br><br>Best wishes on your new purchase ^_^
     
  14. >>I know this lens is notorious for backfocus problems especially on a 10D.<<

    LOL! Notorious? Said who? The NET morons? The only "notorious" thins here is the amount of BS circulating on the NET, including this idiotic rumor started by someone who *may* have had a poor sample of the lens. I have it, NO backfocus, NO front focus. ONLY sharp, in focuse, great looking images.

    Erin, if I were you I'd definitely e-mail Brian Motterhead (sp) or Bob Atkins about this idior troll who placed a link to your e-mail. It's against forum rules and his account should be removed immediately. Further, he should be prevented from joining again.
     
  15. .... also even if this lens had backfocus problems on just the 10D - I would fault the 10D not the lens. It works pretty darn sharp (read fine) on my Elan 7E

    - Harman
     

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