Help with focus issue

Discussion in 'Photography Beginners' Forum' started by GaryG, Mar 1, 2007.

  1. GaryG

    GaryG TPF Noob!

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    After reading a lot of information about sports photography issues, I have just bought a Cannon 30D and a Cannon 70-200 f2.8 USM lens primarliy to shoot pictures of my daughter's gymnastic meets. After my daughter's first meet, I found that I missed the focus on many shots. If I was in focus, the shots were very clean. However, I noticed that even in 5 fps burst mode, I would have some pictures that were focused on her and some that were focused on the nearest object or wall behind her. The problem seemed to get a little better if I had zoomed in tight on her. However, I don't want to have only closeup shots of her performance to be in focus. Any suggestions?
     
  2. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

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    Welcome to the forum.

    It can be a learning process when using these cameras. What you describe can be a problem sometimes.

    What focus mode are you using? Do you have a specific focus point selected, or is it set to use them all?

    If she is a relatively constant distance away from you...then you don't really need to focus more than once. Just focus on her and then don't refocus. Also, if she's not moving all over the place, you may be able to just use one focus sensor (the centre one) otherwise the camera may pick up things on the other focus points.

    Here is a good tip. Change custom function #4 so that AF is activated by the * button with your thumb. Then you are free to start and stop the AF separately from the shutter button. This is the way I use my 20D cameras and I love it...but it does take some getting used to.
     
  3. GaryG

    GaryG TPF Noob!

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    I was using the center focus setting and the AI Servo focus setting. However I was not sure that was not part of my problem. Because she is moving so much during her routines, I can't always keep her in the center of the picture (maybe with time I will get better). In reading the manual, I thought that it should pick up motion and maintain focus with the autofocus, but it didn't work as well as I would have hoped. I'll try your tip on the autofocus shortcut button. I think that would have helped on some specific events (especially the high beam). Would another focus setting besides the center focus be better if I am wanting it to focus on the motion?

    Another problem with the any single focus setting was I wanted to frame some shots with her on one side of the picture. Again from reading, I learned that it is supposed to be more appealing for a moving subject to have some open space in from of them. I didn't even try to get that shot because I was sure I would miss the focus for all the shots after the first frame. Is there a way to get that type of shot for a fast moving object and have the camera pick up focus on the motion afterwards?

    I know these are specific questions, but I want to get these pictures of my daughter's first ventures into gymnastics.

    Thanks for the help...
     
  4. tr0gd0o0r

    tr0gd0o0r TPF Noob!

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    One thing that helps me out a lot when taking action shots is changing from continuous focus to single focus. What this does is makes it so when you 1/2 depress the shutter release button, the camera focuses and keeps that focus until you depress a second time. I find doing that gives me better control over focusing (essentially the same thing as recommended earlier, but through a different method). Of course, this is largely preference. About the composition on the side, doing this would enable you to focus, then recompose (which will take a while to get a hold of, especially if they're running toward you).
     
  5. JIP

    JIP No longer a newbie, moving up!

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    That's part of your problem right there if you use the center focus and don't keep your subject centered the camera will focus on whatever is in the center. I think the focus lock is a good idea with Nikon it is called single servo I'm not sure of Canon. I think this may not solve all of your problems you also need to change from the center focus to a wider focus point or try manual focus and some wider apertures.
     
  6. EOS_JD

    EOS_JD TPF Noob!

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    try using the * button oin the back of the camera to focus (separating focus and metering).

    To lock focus you press the back button to sort where you want focus and let the button go and then shoot away using the shutter button.

    This is how I use AI servo on the canon. I think it's custom functikon 4/1

    Takes some getting used to but now is second nature to me. I actually can't understand why anyone would want to have metering on their shutter button anyway!

    To get the space in front that you want is difficult but best achieved by not going in too tight in the camera and then cropping the final image so it looks closer and you have the space in front.

    Don't think you have to get composition right in-camera...... I bet most use the crop tool to enhance composition - especially in sports images :)
     
  7. DSLR noob

    DSLR noob TPF Noob!

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    Wow, just leanred how to do that custom function on my XT thanks to this thread. Thanks guys.
     
  8. EOS_JD

    EOS_JD TPF Noob!

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    Good to hear it. There's a lot of features there.
     
  9. tr0gd0o0r

    tr0gd0o0r TPF Noob!

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    This is absolutely true. I interned at a paper this past football season and we turned out photogalleries of each game we attended. Every single image I took through the season was cropped to some extent. If you look through sports galleries, then you will find images that have extreme crops (even to the extent of panoramic status) to enhance the composition.
     
  10. GaryG

    GaryG TPF Noob!

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    Thanks for the tip about the custom function #4 (* button). I just tried that and I can see how it would be VERY useful in many of the pictures that I missed at my daughter's last gymnastics meet. I am definitely going to try that at one of her practices before her next meet. :wink:

    I really need to use a f2.8 aperature setting in order to get a clean stop action photo in such low light conditions. I was having to use ISO 800 to ISO 1600 in different areas of the gym in order to get a high enough shutter speed (high enough actually varying depending on the apparatus she was on). However, if I fix the focus using the custom function, I know that such a open apperature will cause a narrow depth of field. Is there an easy way to estimate the depth of field that is useful. I wandering how to know when I will need to refocus? I have seen a rather lenghty calculation in a book to determine depth of field, but is there a rule of thumb answer?
     

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