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 p.3 #5 · Galbraith - better test 16 shot burst | |
Photon wrote:
I have the feeling that the problems Galbraith had with the sprinters had to do with pumping arms and constantly changing clothing contours. The plane presents contours that only change as its angle changes, which occurs in a pretty steady fashion. Since Mark did a great job of tracking it with the center point, the MkIII did its job (not perfectly, but very well). If the MkII really does have any advantage in tracking sprinters (or birds in flight), maybe it's because it doesn't react to minute changes in subject position quite as quickly as the MkIII does. That would also fit with RG finding that adjustments to C. FnIII-2, AI Servo Tracking Sensitivity were the only ones that affected his particular problem.
I don't have a lens comparable to the 300/2.8, but my MkIII with 100-400L tracks soccer players well, with a slightly higher hit rate than my MkII. f/4.5-5.6 is obviously not as demanding as 2.8, but the MkIII AF has been working fine for me....Show more →
J. Allen wrote:
His problems were clearly due to his cf settings. With runners coming straight at him he had expansion points selected, III-4 at 1 and III-3 in 1 or 2 to get 10 fps but also tell the camera that the focus of subsequent and possibly the first shot in a sequence was not a priority. His settings should have been III-3-0, III-4-0 and III-8 at 0.
The problem is we don't know with certainty how often he used III-8-1 or 2 and therefore had III-4-1 active. And his statement about III-4-1 is contradictory. He indicated it was set to '1' yet his explanation would lead one to believe it was at '0'. Quote: "All downloadable photos were shot with C. Fn III-4 [AI Servo AF Tracking Method] set to III-4-1, [Main Focus Point Priority] (which would indicated III-4-0). When Assist AF points are switched on, this Custom Function is supposed to give priority to the manually-selected AF point as well as whatever's closest, but as you'll see it does neither of these things." (which would imply III-4-1 was set...)
Additionally we don't know that III-3 was always set to 1 or 2. Quote (Aug. 1, 2008 update): "We also experimented with Custom Settings C.Fn III-4 [AI Servo AF Tracking Method] and C.Fn III-3 [AI Servo Tracking Sensitivity), to see if fiddling with the former would bump up the number of in focus frames when Assist AF points were enabled, and the latter to see if it would help to reduce the slight AF system lag introduced by the new firmware as well as reduce the cameras' tendency to shift focus when a focus shift trigger - such as a swinging arm - would come through the frame. The answer was no in all cases."
That's not to confirm his assessment that those two CFs will have little or no effect. Just that we don't know from the results he shows whether or not those settings were active, and to what degree.
From my own personal experiences shooting a variety of sports with the III using the 400 2.8 IS, 600 IS and 300 2.8 IS (to a lesser degree), it is not difficult for the camera to maintain 10 fps when set to III-3-0. I experience this all the time with well lit football, soccer, running... Interestingly though, if I use the 300 f/4 IS, I rarely ever get the full 10 fps.
And I just want to comment on III-2. Even though Canon indicate this setting has the least influence on the camera's behaviour when III-4-1 and III-8-1 or 2 are set, testing I did today shows a considerable change in the AF behaviour when III-2 is set to -2 (slowest), with momentary obstructions rarely causing the AF to shift compared to III-2 at default (and naturally at +2 it shifts faster).
This is not to say I disagree with your assessment of proper CF combinations. In fact your well written explanation has me carefully re-reading the Canon guide you linked to and reinvestigating my CF settings for sports and action.
I will need to do more testing. And I guess that's my point, that we can endlessly debate the merits of the RG tests but ultimately each of us needs to figure this out for ourselves. Some have achieved good results, others not so much.
Areas where the III annoyed me to no end was static subject AF consistency in both One Shot and AI-Servo and soft, mushy looking images in bright, hot conditions due to oscillating AF behaviour. Firmware 1.2.3 and now the latest AF fix appear to have quite effectively addressed static subject AF consistency. Time will tell with the hot and bright conditions (haven't had a chance to test this yet for myself) but it looks like others are getting good results.
Ron
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