What does AI-Focus do?

Discussion in 'Photography Beginners' Forum' started by keith204, Sep 28, 2007.

  1. keith204

    keith204 No longer a newbie, moving up!

    Joined:
    May 20, 2007
    Messages:
    1,643
    Likes Received:
    2
    Location:
    Bolivar, MO
    Can others edit my Photos:
    Photos OK to edit
    I see three modes... normal, AI FOCUS, and AI SERVO. I use AI servo a lot, and normal a lot. What's AI FOCUS do?
     
  2. Garbz

    Garbz No longer a newbie, moving up!

    Joined:
    Oct 26, 2003
    Messages:
    9,713
    Likes Received:
    203
    Location:
    Brisbane, Australia
    Can others edit my Photos:
    Photos NOT OK to edit
    Page 76 and 77 of your manual.
     
  3. LaFoto

    LaFoto Just Corinna in real life Staff Member Supporting Member

    Joined:
    Feb 1, 2004
    Messages:
    34,814
    Likes Received:
    814
    Location:
    Lower Saxony, Germany
    Can others edit my Photos:
    Photos NOT OK to edit
    Oh come on Garbz!
    Please!
    Tell me if you don't what to tell Keith.
    I was so hoping that you, who you seem to know so much about the technical side of cameras and such, would GIVE the answer.
    PLEASE DO!
     
    • Like Like x 1
  4. TCimages

    TCimages TPF Noob!

    Joined:
    Aug 18, 2007
    Messages:
    1,978
    Likes Received:
    4
    Location:
    Northern Va
    Can others edit my Photos:
    Photos OK to edit
    AI Focus switches from one shot AF to AI Servo AF automatically if the still subjects start moving.
     
  5. keith204

    keith204 No longer a newbie, moving up!

    Joined:
    May 20, 2007
    Messages:
    1,643
    Likes Received:
    2
    Location:
    Bolivar, MO
    Can others edit my Photos:
    Photos OK to edit
    you jerk... :) :) no, not really...you've helped me on some other topics.

    yeah! Thanks for backing me up, (what do I owe you?)

    great! Whoa that's awesome! I could really use this! Thanks!
     
  6. usayit

    usayit No longer a newbie, moving up!

    Joined:
    Nov 15, 2003
    Messages:
    9,523
    Likes Received:
    344
    Location:
    North New Jersey, United States of America
    Can others edit my Photos:
    Photos OK to edit
    LOL

    "You Jerk", "Yeah!", "Great!"

    All rolled into one post.
     
  7. Garbz

    Garbz No longer a newbie, moving up!

    Joined:
    Oct 26, 2003
    Messages:
    9,713
    Likes Received:
    203
    Location:
    Brisbane, Australia
    Can others edit my Photos:
    Photos NOT OK to edit
    LOL. Not my place to comment on a Canon :p, especially since I had to look at a pdf of the 40D manual to answer the question :er:

    In reality though I didn't get it, which is one of the reasons why I posted like I did. AI Focus doesn't make sense to me. It's either one shot or continuous. Why bother having an extra mode if the subject starts moving. Surely a continuous servo could handle this like it does on the Nikons. The continuous would focus on the subject wherever it is if it's moving or not.
     
  8. keith204

    keith204 No longer a newbie, moving up!

    Joined:
    May 20, 2007
    Messages:
    1,643
    Likes Received:
    2
    Location:
    Bolivar, MO
    Can others edit my Photos:
    Photos OK to edit

    I actually agree with you, now. I tried it and it's not as cool as it sounds.

    Ideally, when I'm shooting cars going around the track, it would kick into AI servo, then for victory lane, it would know... ok one-shot. I am afraid it won't work as smart as it sounds.
     
  9. WDodd

    WDodd TPF Noob!

    Joined:
    Feb 20, 2007
    Messages:
    899
    Likes Received:
    1
    Location:
    Amherst (Cleveland), Ohio
    Can others edit my Photos:
    Photos OK to edit
    Its page 70-72 in my manual :lol:

    I actually don't really understand that either. It says after you focus with the center focus point it will track your subject using the other AF points. But doesn't AF-Servo do that too?
     
  10. neogfx

    neogfx TPF Noob!

    Joined:
    Nov 21, 2006
    Messages:
    387
    Likes Received:
    0
    Can others edit my Photos:
    Photos NOT OK to edit
    AI servo is not ideal for a stationary subject as it constantly tries to refocus, this can lead to a slightly out of focus image if you hit the button at the wrong moment, this doesn't matter with a moving target as you have to constantly refocus anyway, that's the point. So for a stationary subject use One Shot Focus, you will get much better shots much more reliably. For a moving constantly moving subject use AI Servo as it allows you to track and constantly refocus on your subject.
    AI Focus is for situations say like bird photography. A perched bird is best shot with One Shot Focus, however if that bird takes off it is best shot with AI Servo, AI Focus is supposed to handle this change where a subject can go from stationary to moving without warning.
     
  11. LaFoto

    LaFoto Just Corinna in real life Staff Member Supporting Member

    Joined:
    Feb 1, 2004
    Messages:
    34,814
    Likes Received:
    814
    Location:
    Lower Saxony, Germany
    Can others edit my Photos:
    Photos NOT OK to edit
    Wow, almost three years until we get a clear answer to this! I wonder if the OP is still around after all this time!?!?!
     
  12. csgrafix

    csgrafix TPF Noob!

    Joined:
    Mar 12, 2010
    Messages:
    103
    Likes Received:
    0
    Location:
    New York
    Can others edit my Photos:
    Photos OK to edit
    Didnt notice that at first
    lol that quote just put this thread @#1 for me.
     

Share This Page

Search tags for this page

ai focus

,
ai focus af
,
ai focus?
,
ai-focus
,
what does ai focus do
,
what does ai focus mean
,
what does ai servo mean
,
what is ai focus
,
what is ai focus?
,
when to use ai focus