A&P Probably a stupid question....

Discussion in 'Lifestyle' started by mattsb2000, Feb 8, 2006.

  1. mattsb2000

    mattsb2000 OT Supporter

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    I bought a sigma 10-20 a few weeks ago. None of the pictures I took with it at first seemed sharp. f8 af. The only time it seemed sharp is when the subject was right in front of the lens.

    I finally started looking at the distance scale, and I noticed that it never goes to infinity in af. It stops at 3'. When I put it in mf and turn it to infinity the pics seem sharper. When the camera hunts for focus it will go to infinity, but it comes back to 3', so the focus motor works....


    Is my camera too stupid to focus it? Or does the lens have too much distortion and the af sensors don't know what to do with the image?


    Ps it focuses all of my other lenses just fine.
     
  2. IntheWorks

    IntheWorks windin film.. takin pics Moderator

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    can't answer your question, but I've been wanting to buy that lens... it does mount to EF mount EOS camera's right?

    mind showing some sample shots?
     
  3. mattsb2000

    mattsb2000 OT Supporter

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    Well, it will mount to a full frame camera. (It's an ef mount) But it will viginette untill 15mm from what I've read.


    Give me a minute, I'll resize a few pics
     
  4. mattsb2000

    mattsb2000 OT Supporter

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    [​IMG]

    [​IMG]

    This is a 100% crop of the image below it. It seems to only be sharp up close.

    [​IMG]

    [​IMG]
     
  5. mattsb2000

    mattsb2000 OT Supporter

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    Yes I know about dof. What I meant to say was that the camera doesn't seem to focus to infinity in af. It goes to 3' and the pics are really soft. :wtc:
     
  6. mattsb2000

    mattsb2000 OT Supporter

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  7. Mr_Penut

    Mr_Penut Elitist Member OT Supporter

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    shoot in manual focus then
     
  8. mattsb2000

    mattsb2000 OT Supporter

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    :wtc:

    I have a 300d :wtc:
     
  9. 00soul

    00soul halfsharkalligatorhalfman

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    isnt the manual focus switch on the lens?
     
  10. Valence

    Valence Gustav Refugee

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    does it go to infinity in the other lenses?
    Could just be the camera settings do not differentiate and use pre set auto focus meters.
     
  11. Mr_Penut

    Mr_Penut Elitist Member OT Supporter

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    set lens on mf, use ring:hsugh:
     
  12. eof

    eof New Member

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    It is not a limitation of the camera...it might be a problem with that particular camera but a perfectly working DSLR will autofocus to infinity.
     
  13. mattsb2000

    mattsb2000 OT Supporter

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    Yeah, but the viewfinder is microscopic. :hsugh:
     
  14. mattsb2000

    mattsb2000 OT Supporter

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    All of my other lenses will go to infinity. This one will too, when it's hunting. But it never stops there.
     
  15. Mr_Penut

    Mr_Penut Elitist Member OT Supporter

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    how hard can it be to know when you need to go to infinity:mamoru:
     
  16. mattsb2000

    mattsb2000 OT Supporter

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    Well, that's easy. But if the camera is fucking that up then it's probably fucking everything else up too.
     
  17. mattsb2000

    mattsb2000 OT Supporter

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    The camera front focuses every once in awhile. It's rare, and generally not too bad.
     
  18. Mr_Penut

    Mr_Penut Elitist Member OT Supporter

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    whats the distance scale on that lens?
     
  19. canonshooter

    canonshooter New Member

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    its not the lens, its your cameras resolution. since everything is further away with a lens that wide, there is less detail in the objects. when you are filling most of the frame with the object more detail is recorded which makes it look sharp.
     
  20. mattsb2000

    mattsb2000 OT Supporter

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    .8ft -3' is the last mark before infinity

    .24m - 1m
     
  21. Mr_Penut

    Mr_Penut Elitist Member OT Supporter

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    you should be able to guess for the most part then :eek5:
     
  22. mattsb2000

    mattsb2000 OT Supporter

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    Well, yeah. But but... :hsugh:
     
  23. mattsb2000

    mattsb2000 OT Supporter

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    Interesting. Shouldn't it still go to infinity when an object is along way past 3'?
     
  24. CRC

    CRC New Member

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    Underexposure for the lose
     
  25. mobbarley

    mobbarley Active Member

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    Ive got the same lens on my 350d. I dont have the same problem, is it new? try a replacement??

    I have noticed mine stops a little short of the infiniate mark when shooting at things in the distance, but mine is definately sharp, I'll get pics tonight for you.
     

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