in Rob Galbraith's Mark III autofocus analysis Dec 11 update, he states:
We're died-in-the-wool rear button focus users, and "lock" the focus when needed by releasing the AF-ON button.
could someone please explain this method?
regards,
Gregory
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I use the 1DMkII frequently for shooting birds in flight, and have found that the placement of the AF onto the "*" button helps tremendously. I leave it that way in all shooting situations.
In my camera, it is Custom Function 04: Shutter Button/AE Lock Button," and I have it set at "3: AE/AF, No AE."
With the camera in Continuous AF, I focus by pressing the "*" button. If I pan with a bird in flight, the exposure is not set until I press the shutter button. In some situations, even while the camera is in Continuous AF, you can prefocus on an area with the "*" button, and then let go of the button to maintain that focus. This also helps while panning when an object like a tree comes up in the viewfinder and there is some risk of the focus locking onto the tree. Just let go of the button and the bird will still be in focus after you pan past the tree.
As far as I can tell, when the camera is in AF/single shot focus, focus works the same way, but the AE will lock when you half-press the shutter button. I fequently shoot skyscrapers where the top is in the sun and the lower part in deep shade. I can keep the exposure at 0 compensation, lock the focus on the part of the building I want sharpest, let go of the "*" button, point the camera (in "evaluative AE mode" to include some of the highlights, half-press the shutter button and recompose, thus having separate control over focus and exposure.
Another of my favorite settings, which you didn't ask about, but I recommend for most people to try: I use the Center AF point as my default, and have "Custom Function 18: Switch to Registered AF Point" set to "2: Only while pressing "X" button (the too-small button to the left of the "*" button). " I registered the rightmost AFpoint in the middle row. That way, if I shoot a portrait, I press the "x" button, and while I hold it down, the focus point is at the top of the frame, making it easier to focus on the eyes without having to recompose. It also makes it easier in landscape mode to focus on something approximately 1/3 in from the right of the frame, again better than having to recompose.
