Help. 30D AI Focus accuracy, its front focusing.

Discussion in 'Photography Equipment & Products' started by Prophet, Feb 12, 2009.

  1. Prophet

    Prophet TPF Noob!

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    Last night I was shooting my first basketball game in years. I was using my 30D 85mm f1.8. Shooting either ISO800 or 1600. Shooting between f/2.8 and f/4 at 1/250 or 1/320 I believe. Well when I went to proof (when I got home) the photo and even while I was test shooting (before the game) I realized the focus was off bad. I started off with the 9 point AF AI Servo then moved down to center point AF AI Servo.

    All of my keepers were all soft and I had to run them through PS. I am content with them, but man, there isn't a single sharp photo and I know I can do better. I'm a little peaved, but I'm hoping its something I did and not my gear. Any tips or help would be appreciated. I will post some photo's but if you want good examples of the flaws, I'll have to go home and look for something and hope I didn't delete them.

    This shot is probably the sharpest of the night. 100% crop of the original would reveal the flaws.

    [​IMG]

    [​IMG]

    This shot had the potential of a really great shot.

    [​IMG]

    -JD-
     
    Last edited: Feb 12, 2009
  2. Overread

    Overread has a hat around here somewhere Staff Member Supporting Member

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    if you want to check for a focusing error stick the camera and lens on a tripod and then shoot some fixed static subjects with the AF and review the results. I think a wide aperture would be best so that you can see right where the plain of focus is landing - a smaller aperture might cover over a focusing error by simply being too wide.

    Also make sure that your not shooting faster than the ai focus - I have many shots where I have hit full on the shutter when the ai focus has not got a lock onto the subject (often in dimmer lighting the focus can miss the subject and then keep hunting as well).
    If it is a focusing problem (back or front focusing) I forget if it is camera or lens which is at fault - and I am pretty sure that the 30D does not have focus correcting for lenses - so you would have to send the kit in for repair
     
  3. Prophet

    Prophet TPF Noob!

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    What I was doing was trying to focus lock on the subect (half pushed shutter release) then as he was moving on the court I would track and then pull the trigger to capture the shots. I was watching the view find and I would notice that if the object was static, the focus would "pop" in and out. It was visibly out of focus and back.

    A few test shots of the JV game revealed that while trying to focus on the player moving slowly or not at all.... and the signs in the background up high about 20 to 30 feet behind were tack sharp! I cannot recall if it was center point or 9-point AF. It did get better as the night went on, but I'm still peaved.


    I have thought about sending all my gear in for calibration but I want to be sure I'm on the body and gear I'm going to be using for a long time before I commit.

    -JD-
     
  4. Overread

    Overread has a hat around here somewhere Staff Member Supporting Member

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    do try tripod testing the focus - with motion in a dimm lighting condition its never going to be easy work - the af has less light to work with and moving targets are going to test your camera handeling skills - there is a lot of scope for things to go wrong in a shoot like that. Testing out the AF in good lighting on the tripod with static subjects will at least show you if the AF is working right or not.
    If the AF is not working right then its a kit problem
    If the AF is working right then it a you problem ;)

    I always stick to the belief that the problem in my shots is not my kit but me getting things wrong - I think that if you start subscribing to the other school of thought you will never be able to get shots you are happy with until you own a 1D (since you will not try to improve your shooting skills as much). Not saying that if I could afford one I would not get it - I would, I go for the best kit I can since it does help.
     
  5. Prophet

    Prophet TPF Noob!

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    I've done some testing and I know the AF on single shot is pretty dead nuts on. Maybe I need some handling tips on how to shoot in AI Servo mode. I'm just trying to be as smooth as possible with my panning. But I still can't get out of my mind when I'm steady and the subject is steady and the AI Servo is still going in and out of focus.

    -JD-
     
    Last edited: Feb 12, 2009
  6. gryphonslair99

    gryphonslair99 Been spending a lot of time on here!

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    One thing that you should do is get your focus off of the shutter button and onto the * button on the back. I believe it is custom function 4. Check the book. Fulltime tracking with the * button and shutter release with the shutter button. It wil cut down a split second of lag, at least that was what was explained to me when I switched to Canon Digital for sports.

    It takes a bit of getting used to but I prefer it for all moving action.
     
  7. Prophet

    Prophet TPF Noob!

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    Yeah someone mentioned that on fredmiranda.com. I think that may be the fix. I can't wait to find out.

    -JD-
     
  8. gsgary

    gsgary Been spending a lot of time on here!

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    Give back button focus a go it's great for sports, i use it for everything
     
  9. gryphonslair99

    gryphonslair99 Been spending a lot of time on here!

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    Keep in mind the conditions as well. You are shooting in a low light venue, from the color cast there looks to be some florescent lighting mixed in, your shooting pretty wide open with a shallow DOF at a high ISO with what I consider barely acceptable shutter speeds. 1/250th is the bare minimum to me with 1/320th an improvement. 1/500th would be much better.

    If you are not comfortable shooting in that environment with a good understanding of the variables then shoot in raw and post process. If you do have a good understanding then jpg will be be sharper unless you have modified the in camera processing settings.

    My main venue I shoot at I shoot jpg as I have that venue down to a T. Other places I opt for raw for that bit of post processing safety net that raw provides.

    One thing that I find completely invaluable for indoor sports is my Sekonic 358. I get there early and meter the court, I mean all over the court, and find the darkest spot and set my camera for those readings. It is very rare for me to find a venue that the light changes that much, causing overblown highlight in the bright areas. Indoor high ISO shots overall will turn out better if you exposure is dead on. That really helps with cleaning up noise.
     
  10. Prophet

    Prophet TPF Noob!

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    The 1st photo I changed a lot of settings in photoshop. If you would like to see untouched photo's let me know. On my 30D I have custom function 4. Options are

    1. AE Lock/AF
    2.AF/AF lock, no AE Lock
    3. AE/AF, no AE lock
    0. AF/AE lock.

    I have it set to 3.

    -JD-
     
  11. gryphonslair99

    gryphonslair99 Been spending a lot of time on here!

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    Yep that should be it. Now go practice using that. It feels a bit weird the first time or two.
     
  12. Prophet

    Prophet TPF Noob!

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    I also have:

    +2 Sharpness
    +1 Saturation
    +1 Contrast

    -JD-
     

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