600D AF Patterns aren't quite working.

Issue #1412 resolved
One Percent created an issue

So I've been using the AF patterns and noticed something that explains alot after the new zoom on AF point feature was implemented. I usually shoot in this pattern:

1...2

..x..

3...4

At first everything seemed OK but I did notice that the lens would hunt a lot sometimes missing focus completely or bouncing back and forth through the range, etc. Well with the new feature it turns out most of my photos are focusing on #2. It seems as if the middle point is ignored as are the other ones usually. If middle and other points are over the target the lens will hunt or bounce until #2 is positioned. It all looks as if only #2 was selected with manual/individual even though the other dots light up.

Also wish you could turn off focus on AF point during review..... maybe I missed it in the setting somewhere.

Comments (17)

  1. Alex

    Does it matter if, before you set AF patterns, you select all AF points from Canon menu? or if you select only the center one?

  2. One Percent reporter

    It switches to manual as soon as you try to pick a focus pattern. I switched to the top 3 points and center and while performance improved, every pic focuses on that same AF point.

  3. Alex

    In af_patterns.c, try looking at values of afp[1] or maybe changing them. They might have some effect.

  4. One Percent reporter

    I need to find a way to reproduce consistenly. The diamond pattern works like the X should have. Ever since I got frustrated and flipped through a bunch of patterns it started behaving differently... like a cross between auto pick and manual. 60D has all cross AF points so maybe thats why you can't reproduce. Should have waited for T4i :)

    The most consistant test for me was airplane on a blue sky. With the X pattern I could focus manually on the plane and when I would go to shoot with AF on it would hunt back and forth through the whole range until that one AF point was also over the plane.

    Also on my table... #2 side would focus even though middle and 1 and 3 were left unfocused. So 2/4 points were winning over 1,3 and middle. All points would flash in unison. With diamond pattern individual points flash on their own when focus is obtained... i.e only middle will flash and you can take the pic or they twinkle as they catch focus and finally all flash when focus is locked.

    Gonna mess with the values and keep testing.

  5. Alex

    Try this: print on the screen the values of afp[0] and afp[1] and try all the combinations from Canon firmware. I believe there is a flag that indicates auto select or manual select or something like this.

  6. One Percent reporter

    I looked into the af point files.

    This is what works.

    1. define AF_PATTERN_TOPDIAMOND AF_POINT_T | AF_POINT_TL | AF_POINT_TR | AF_POINT_C

    This favors TR/BR

    1. define AF_PATTERN_SQUARE AF_POINT_C | AF_POINT_TL | AF_POINT_TR | AF_POINT_BL | AF_POINT_BR

    Only difference is order of AFC.

  7. Alex

    Can't explain. Can you print the values of afp on the screen, while you change AF points from Canon menu?

  8. One Percent reporter

    That will be the next step. Just need to write or copy something that will do it. Would it be better to go to a file? Maybe I can change audio_reg_dump_600D() to do it. They are both arrays of register values. Would the console work for this too?

  9. scrax

    Those are values for afp[0] in manual

             200
          800    1000
     8000    100       1
          2000   4000
             400
    

    auto is: 1ff01

    groups are sum of single points (example X is 7900, 3 central oriental 8101...)

    afp[0] is always:ff000000

  10. scrax

    I think that they are working now, I'll do more test and if they are ok close that. One percent what's your impression?

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