1D IV Tracking Experiment

[Blake Cook]

It would be helpful if you posted all your C. Fn III AF settings.
--
Blake in Vancouver
Panasonic Stuff, Canon Stuff. Mac Stuff & annoying PC & Windows stuff.

OK:
2: Slow
3:0
4:1
5:1
6:0
7:0
8:3
9:0
10:0
11:1
12:2
13:0
14:1

--
A bird in the viewfinder is worth...

It is interesting to note that renowned football and sports photographer Peter Read Miller uses 4:0 while Art Morris bird photographer uses 4:1

It might be interesting to try 4:0 in your tests.

I use 4:0 most of the time and never have had issues of focus jumping.

--
Blake in Vancouver
Panasonic Stuff, Canon Stuff. Mac Stuff & annoying PC & Windows stuff.

 

[Scott Larson]

It is interesting to note that renowned football and sports photographer Peter Read Miller uses 4:0 while Art Morris bird photographer uses 4:1

Using "Main focus point priority" (1) will cause the AF to constantly scan all expansion points for the closest target. That is normally not what you want the AF to do in sports. I'm sure renowned football and sports photographer Peter Read does not share pictures of the wrong thing in focus.

Not only is "Main focus point priority" a terribly misleading description, it also conflicts with Canon's other notoriously misleading function, "Tracking sensitivity". Will setting "Tracking sensitivity" to "Slow" make "Main focus point priority" less likely to switch to the closest subject? Well reading Canon's AF Guide says roughly, "A little bit but not so much". Apparently the "tracking sensitivity" has less influence in "Main focus point priority" than "Continuous AF track priority" but how much less influence is anyone's guess.

It might be interesting to try 4:0 in your tests.

In this case "Main focus point priority" should help. It should see that the chart is closer than the background and give it priority. However, if the bright light in the background overwhelms the sensor, there's a chance that no focus point will see the chart and it will favor the higher contrast edge of the chart.

BTW, I strongly endorse tests like this. I used the simplest test possible by marking an "X" on a white board and seeing how the AF tracks it in various modes and light conditions. It gave me an idea on how quickly the AF can lock on a target and how easily it can lose this target as as I panned around. It's not as straightforward as it sounds.

I use 4:0 most of the time and never have had issues of focus jumping.

How many expansion points do you use?

 

[Blake Cook]

It is interesting to note that renowned football and sports photographer Peter Read Miller uses 4:0 while Art Morris bird photographer uses 4:1

Using "Main focus point priority" (1) will cause the AF to constantly scan all expansion points for the closest target. That is normally not what you want the AF to do in sports. I'm sure renowned football and sports photographer Peter Read does not share pictures of the wrong thing in focus.

Yet he claims that's his setting.

Not only is "Main focus point priority" a terribly misleading description, it also conflicts with Canon's other notoriously misleading function, "Tracking sensitivity". Will setting "Tracking sensitivity" to "Slow" make "Main focus point priority" less likely to switch to the closest subject? Well reading Canon's AF Guide says roughly, "A little bit but not so much". Apparently the "tracking sensitivity" has less influence in "Main focus point priority" than "Continuous AF track priority" but how much less influence is anyone's guess.

It might be interesting to try 4:0 in your tests.

In this case "Main focus point priority" should help. It should see that the chart is closer than the background and give it priority. However, if the bright light in the background overwhelms the sensor, there's a chance that no focus point will see the chart and it will favor the higher contrast edge of the chart.

BTW, I strongly endorse tests like this. I used the simplest test possible by marking an "X" on a white board and seeing how the AF tracks it in various modes and light conditions. It gave me an idea on how quickly the AF can lock on a target and how easily it can lose this target as as I panned around. It's not as straightforward as it sounds.

Tests are nice but I looked around for experienced photographer's settings when I received my 1D4 a year ago and began by using Miller's settings shooting aircraft, birds and sports. 4:1 produced erratic results, while Miller's suggested 4:0 worked well in spite of the apparent conflict of setting descriptions.

I use 4:0 most of the time and never have had issues of focus jumping.

How many expansion points do you use?

Surrounding points.

--
Blake in Vancouver
Panasonic Stuff, Canon Stuff. Mac Stuff & annoying PC & Windows stuff.

 

[Scott Larson]

Yet he claims that's his setting.

And I believe it. It's possible to get shots in focus in both modes.

Canon's AF guide specifically recommends not using "Main point focus priority" when you'll have things moving in front of your subject or near the subject. However, if you can keep this from happening then both modes will work more or less the same.

My problem is that I can't do this in basketball. My subject will almost always be surrounded with other focus targets closer to the camera.

 

[Scott Larson]

Tests are nice but I looked around for experienced photographer's settings when I received my 1D4 a year ago and began by using Miller's settings shooting aircraft, birds and sports. 4:1 produced erratic results, while Miller's suggested 4:0 worked well in spite of the apparent conflict of setting descriptions.

And can you explain why "Continuous focus point priority" caused "erratic results"?

My experience is that using point expansion will cause the AF to act strangely from time to time. That's why I switched back to using a single point. Now the AF doesn't shoot off into the foreground or background like it did with expansion points.

It's possible that "Main focus point priority" causes less erratic behavior with expansion points but it still will want to focus on whatever is closest to the camera whether you want it to or not.

 

[Blake Cook]

Tests are nice but I looked around for experienced photographer's settings when I received my 1D4 a year ago and began by using Miller's settings shooting aircraft, birds and sports. 4:1 produced erratic results, while Miller's suggested 4:0 worked well in spite of the apparent conflict of setting descriptions.

And can you explain why "Continuous focus point priority" caused "erratic results"?

My experience is that using point expansion will cause the AF to act strangely from time to time. That's why I switched back to using a single point. Now the AF doesn't shoot off into the foreground or background like it did with expansion points.

It's possible that "Main focus point priority" causes less erratic behavior with expansion points but it still will want to focus on whatever is closest to the camera whether you want it to or not

The erratic behavior found was with initial focus. Occasionally it would not lock on as readily as 4:0. Since this occurred during the first few weeks I had the camera user error is a disctinct possibility, but that all but dissappeared when I adopted Miller's settings.

--
Blake in Vancouver
Panasonic Stuff, Canon Stuff. Mac Stuff & annoying PC & Windows stuff.

 

[Scott Larson]

The erratic behavior found was with initial focus. Occasionally it would not lock on as readily as 4:0. Since this occurred during the first few weeks I had the camera user error is a disctinct possibility, but that all but dissappeared when I adopted Miller's settings.

But you don't know why?

 

[Blake Cook]

The erratic behavior found was with initial focus. Occasionally it would not lock on as readily as 4:0. Since this occurred during the first few weeks I had the camera user error is a disctinct possibility, but that all but dissappeared when I adopted Miller's settings.

But you don't know why?

If I had to guess I probably was shooting before focus was locked. Yesterday I took some photos using c.Fn4:1 without any AF problems at all.

--
Blake in Vancouver
Panasonic Stuff, Canon Stuff. Mac Stuff & annoying PC & Windows stuff.

 

[riknash]

My experience is that using point expansion will cause the AF to act strangely from time to time. That's why I switched back to using a single point. Now the AF doesn't shoot off into the foreground or background like it did with expansion points.

I've read others who have simply gone to a single point. This leaves me wondering what beneficial usefulness of the 1D MkIV's advanced AF features are you enjoying?