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Post by ppaaoolloo on Oct 20, 2009 8:02:43 GMT
When I shoot moving objects I choose AI Servo and manually select an AF point (normally center). For moving subjects like birds, wildlife, vehicles or people is this the correct thing to do or am I better off keeping the the AF point set at automatic and start focusing at center then let the camera track the subject. If ever I lose the subject in frame I just reacquire a center AF lock on moving subject then let the camera track it again. This is in relation to the 40d, 5d and 5d Mark II bodies. I ask this as my keeper rate isnt as high as I would want it to be.  |
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Post by Romy Ocon on Oct 20, 2009 9:16:17 GMT
When I shoot moving objects I choose AI Servo and manually select an AF point (normally center). For moving subjects like birds, wildlife, vehicles or people is this the correct thing to do or am I better off keeping the the AF point set at automatic and start focusing at center then let the camera track the subject. If ever I lose the subject in frame I just reacquire a center AF lock on moving subject then let the camera track it again. This is in relation to the 40d, 5d and 5d Mark II bodies. I ask this as my keeper rate isnt as high as I would want it to be. Think of the AI servo performance as a flashlight with a fixed lighting power and with a focusable beam. If the beam is made large (all focus points), it's easier to catch an object but the lighting intensity (AF system speed) is weak. If the beam is focused to a narrow spot (center point AF), the lighting intensity (AF system speed) is very intense and laser-like but it's tougher to keep the tiny beam on the moving object. In AF systems, you may use a wide net (all points AF) when the BG is the sky. But if the subject is against a busy BG, you need to concentrate to smaller AF areas (less AF points or even just the center point) to have the fastest AF system speed that your DSLR + lens can deliver. The consequence of the latter is you need to have more accurate panning so as not to let the bead wander off the subject at anytime. |
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Post by ppaaoolloo on Oct 20, 2009 10:10:05 GMT
When I shoot moving objects I choose AI Servo and manually select an AF point (normally center). For moving subjects like birds, wildlife, vehicles or people is this the correct thing to do or am I better off keeping the the AF point set at automatic and start focusing at center then let the camera track the subject. If ever I lose the subject in frame I just reacquire a center AF lock on moving subject then let the camera track it again. This is in relation to the 40d, 5d and 5d Mark II bodies. I ask this as my keeper rate isnt as high as I would want it to be. Think of the AI servo performance as a flashlight with a fixed lighting power and with a focusable beam. If the beam is made large (all focus points), it's easier to catch an object but the lighting intensity (AF system speed) is weak. If the beam is focused to a narrow spot (center point AF), the lighting intensity (AF system speed) is very intense and laser-like but it's tougher to keep the tiny beam on the moving object. In AF systems, you may use a wide net (all points AF) when the BG is the sky. But if the subject is against a busy BG, you need to concentrate to smaller AF areas (less AF points or even just the center point) to have the fastest AF system speed that your DSLR + lens can deliver. The consequence of the latter is you need to have more accurate panning so as not to let the bead wander off the subject at anytime. Thanks for the descriptive explanation Romy. May I ask what your preference is? |
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Post by Romy Ocon on Oct 20, 2009 12:34:15 GMT
I stick to center point + expansion (6 assist points for the 1D2 and 5D2) as default. When the bird is uncontrasty and BG is busy, I disable the assist points and dump all AF CPU resources to the center point. For the 40D, always center point only.
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