hfillmore
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 p.7 #1 · Does your MkIII have AF issues? | |
Perhaps a revelation here. Popular thinking says to either leave the MkIII focusing speed to either the default, or to slow it down. The following quote from LesZ on Naturescapes.net indicates this could be EXACTLY THE WRONG THING to do when using wxpanded focus points or the "ring of fire".
Posted: Sat Jun 23, 2007 11:22 am on Naturescapes.
QUOTE:
" I really didn't do a very good job, in my post above, of explaining what I'm seeing with CF III-2. I just ran another series of tests with different settings, and I'll try to do a better job of explaining. I was shooting a rapidly moving subject that filled a good part, not not nearly all of the viewfinder. The subject was moving toward me in an erratic fashion, and, to make the challenge more difficult, the background was quite busy. The camera was set to the selected center point with expansion to all surrounding points. I first tried several bursts of shots with CF III-2 set to the moderately fast position. Then, I shot several bursts with CF III-2 set to the moderately slow position. I looked at all of the pictures in ZoomBrowser, with the focus point visible. With CF III-2 set to the moderately fast setting, every picture that I took where the center focus point or one of surrounding points was on the subject (24 pictures) was sharply in focus, and every one of the 4 pictures that was not in focus was one where neither the center point or any of the surrounding points was on the subject. So, the camera seemed to be working the way I would want it to work. With the moderately slow position, however, the 14 pictures that were in focus were all ones where the center point or a surrounding point was on the subject (as you would expect). However, with the 12 pictures that were not in focus, 3 were ones where none of the active focus points were on the subject, but the other 9 were ones where the focus point or a surrounding point was, in fact, on the subject. So, what that tells me is that, with the slower setting, the camera was not switching from one of the active focus points to another quickly enough to keep the subject in focus. However, with the faster setting, it was switching from one active point to another fast enough to keep the subject in focus, which is, obviously what you would want.
Again, even though I was using the center point with focus point expansion, the same principle should apply to 45 point focus. Additionally, what is helping me significantly to figure out what is happening and why is happening is to make use of ZoomBrowser's ability to show the focus point, and, what I'm finding is that, with the faster focus tracking setting, even with a subject moving toward me and a busy background, the camera is switching from one focus point to another as it should. With the slower focus tracking speed, it is not. And, as I said above, the neutral position on the 1DIII seems to set to a similar speed as the slow or moderately slow speed on the 1DII, and that is consistent with what it said in the link to the dPreview thread.
Les "
END OF QUOTE ( From LesZ on Naturescapes.net )
Edited by hfillmore on Jun 24, 2007 at 04:58 AM GMT
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