best focusing choices - 1dsMK3 for birds in flight

[louis_greene]

<p>In the past with my 5D when shooting birds in flight I always chose Al-servo and a pretermined focusing point (box). Then I would just try and get that to line up so the eye was in focus.<br>

Now I have the 1Ds MK3 and I am planning to shoot eagles. I see that there is a choice to have the focusing point "expanded" on the 1DsMK3. I am thinking about using this and seeing how the system does at getting the focus point on it's own.<br>

Your thoughts on this? Would you manually set the point or see how the cemera does? Expanded focus points or standard? What's you choices for birds in motion?</p>

[colin_james]

<p>First up, you'll find the answers to these questions - along with more in-depth info if you have a read of Canons paper optimising the AF performance for 1D3 and 1Ds3 camera.</p>

<p>The following C/P from the guide should help you ...</p>

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<p>"AI Servo AF mode:</p>

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The camera always starts to track the subject with the <strong>center </strong><em>AF point. </em>If the subject then moves away from that AF point, the camera will "pass it off" to outer AF points to continue tracking the subject. Important — when Automatic AF point selection is combined with AI Servo AF, the active AF point <em>will not </em>

<p>light up red in the viewfinder. "<br>

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<p>Manual AF point selection:</p>

</strong></strong>The photographer selects one AF point, which is the only one used to focus upon subjects. Regardless of whether the camera is set forOne-Shot AF mode, or AI Servo AF, the user-selected AF point is the only one used. "

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<p>Shooting subjects with little detail — change the size of an AF point:</p>

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<p>This changing size of an AF point is similar to the EOS-1D Mark II’s C.Fn 17-1. Option #1 (below) is new to the Mark III series.</p>

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<p>C.Fn III-8-1</p>

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— adds a single additional "assist point" to the left and right of a user’s manually-chosen AF point<strong><em>C.Fn III-8-2 </em>

<p>— adds in invisible ring of six additional "assist points" surrounding the manually-chosen AF point"<br>

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[zml]

<p>On a practical side, always acquire focus witht the center point in AI Servo mode with auto AF point selectoin, so there is a smooth hand-off to whatever AF points kicks in. Try various AF assist point configuration and pick the one that works for you - it depends a bit on your style of shooting. I try to track with the center point in AI Servo with manual AF point selection with assist points enabled as much as possible. And I use a tripod or a monopod: I find accurate handheld tracking with 1Ds3 and a long lens (500 + 1.4x extender is the longest setup I've used) close to impossible. And, as pointed in the other reply, read the Canon's white paper on 1D3/1Ds3 configuration/optimization. There have also been a few relevant discussions on this forum.</p>

[louis_greene]

<p>Guess I have some experimenting to do. Thanks for the info. I like to idea of choosing a point and adding the 6 additional assist points. I will also try the Al-servo with the auto selection and see how it does. My fear with that is that the camera will just hunt and find the area of higest contrast, like a wing against a the background sky. Of course I'd rather lock on the eye is given the oppotunity to actually do so. </p>