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Archive 2012 · Need Help with Auto-Focus Servo jumping focus (1D Mk IV w...
  
 
iamcdn
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p.1 #1 · Need Help with Auto-Focus Servo jumping focus (1D Mk IV with 300 2.8 USM)


Here is the gear in question

Canon 1D Mark IV - (45 point AF enabled)
Canon 300 2.8 USM (version 1)

Here is the issue

Recently I bought the 300 2.8, prior to that I would shoot sports with a 100-400 5.6. With the 100-400 I set a single auto focus spot on the 1D and would put my action on the spot and get about 90% of my shots in focus.

On the weekend I used my 300 2.8 for the first time for a football game, and the auto focus spot would jump all over the place, grabbing new focus points throughout a play. basically I would have my shot set, press the shutter and get the first couple images in focus, then someone else in frame would steal the focus and the next several shots are OOF. Actually about 50% of my images are now OOF.

I suspect that the 1D deals with a 2.8's fast focus differently and that it doesn't do it with my 5.6.

I tried changing a bunch of my settings, but nothing would stop the auto focus from jumping around in my viewfinder.

Can anyone suggest a solution that can get me back on track.

Thanks
Doug



Oct 01, 2012 at 04:16 PM
BrianO
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p.1 #2 · Need Help with Auto-Focus Servo jumping focus (1D Mk IV with 300 2.8 USM)


iamcdn wrote:
...With the 100-400 I set a single auto focus spot on the 1D and would put my action on the spot and get about 90% of my shots in focus. ...On the weekend I used my 300 2.8 for the first time for a football game, and the auto focus spot would jump all over the place, grabbing new focus points throughout a play.


If you're shooting at wider apertures now -- and that's the benefit of a 2.8 aperture -- you may be dealing with a narrrower depth of field than you were before, and so changing of focus points is happening more than it would have before.

One solution is to take the camera off Automatic AF Point Selection and always pick the focus point manually.

You can use the center point only or you can pick a different point, and then just follow the action so that the subject stays under the same focus point. In Servo AF the camera will then keep changing the focus distance as the subject moves back and forth in the frame under that spot.

In case your Manual isn't handy, here's a shot of the relevant page:









Oct 01, 2012 at 11:39 PM
mrfozibear
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p.1 #3 · Need Help with Auto-Focus Servo jumping focus (1D Mk IV with 300 2.8 USM)


Take a look at this http://cpn.canon-europe.com/files/product/cameras/eos1d_mark_iv/1D_Mark_IV_guide_en.pdf and this http://www.sportsshooter.com/news/2371. These are good starting points.

Chris



Oct 02, 2012 at 01:37 AM
JimN
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p.1 #4 · Need Help with Auto-Focus Servo jumping focus (1D Mk IV with 300 2.8 USM)


Try using the center af point with surrounding af expansion and set the tracking cf to slow. Good luck


Oct 02, 2012 at 02:37 AM
iamcdn
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p.1 #5 · Need Help with Auto-Focus Servo jumping focus (1D Mk IV with 300 2.8 USM)


I do use a manual point, which is why I am confused. I pick a single point and it stay static with every lens I own except the 300 2.8, with that one it will jump around to adjacent points.




Oct 02, 2012 at 01:53 PM
Bruce Sawle
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p.1 #6 · Need Help with Auto-Focus Servo jumping focus (1D Mk IV with 300 2.8 USM)


If I understand correctly your focus point is not actually changing but it is selecting a new target that entered the play correct. If so the 100-400 at f5.6 may of had enough depth of field to hide this shift. With the 300 at f2.8 if it picks up a new target your original subject would fall outside the depth of field and not be sharp. This is not a lens issue. The body your using needs to be set to a slower tracking setting this would help prevent the lens from leaving your intended subject so quickly.

If your focus point is jumping around do you have all 45 points active. This setting will allow tounto pick the initial point but will then change the focus point to track what everit wants. If so this may be why your point is jumping around.



Oct 02, 2012 at 02:11 PM
iamcdn
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p.1 #7 · Need Help with Auto-Focus Servo jumping focus (1D Mk IV with 300 2.8 USM)


The red point indicator moves from one point to another. I can watch it dance around when i depress the shutter 1/2 way, so it is not a issue of DoF.

Yes, I am set to 45 points, so if that is the issue I will try turning it to something else and see if that helps

thanks



Oct 02, 2012 at 02:58 PM
JimN
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p.1 #8 · Need Help with Auto-Focus Servo jumping focus (1D Mk IV with 300 2.8 USM)


iamcdn wrote:
The red point indicator moves from one point to another. I can watch it dance around when i depress the shutter 1/2 way, so it is not a issue of DoF.

Yes, I am set to 45 points, so if that is the issue I will try turning it to something else and see if that helps

thanks


The best way to precisely control focus using AF is to use one focus point only and no expansion. If you set the tracking sensitivity to slow, it will stay with your subject longer when you wander off of the subject. If you focus on an unintended subject, you can override the tracking delay by letting off focus and re-focusing quickly (I call this bumping the focus) to return focus to the intended subject.



Oct 02, 2012 at 03:39 PM
iamcdn
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p.1 #9 · Need Help with Auto-Focus Servo jumping focus (1D Mk IV with 300 2.8 USM)


Thanks Jim,

I will give that a try tonight. will dig up my manual and find the right cFN code to change



Oct 02, 2012 at 04:44 PM
3iron
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p.1 #10 · Need Help with Auto-Focus Servo jumping focus (1D Mk IV with 300 2.8 USM)


Very good advice here; also suggest you look at the bird forum and check on how they set their cameras up. Some most helpful suggestions there.


Oct 02, 2012 at 04:46 PM
 

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JimN
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p.1 #11 · Need Help with Auto-Focus Servo jumping focus (1D Mk IV with 300 2.8 USM)


3iron wrote:
Very good advice here; also suggest you look at the bird forum and check on how they set their cameras up. Some most helpful suggestions there.


Here is a link to a thread I started in another forum that gives my 1D4 settings and reasons for using them. I also discuss some of the techniques I use.

http://www.naturescapes.net/phpBB3/viewtopic.php?f=57&t=172108&p=1699747&hilit=Mark+IV+bif#p1699747



Oct 02, 2012 at 05:40 PM
BrianO
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p.1 #12 · Need Help with Auto-Focus Servo jumping focus (1D Mk IV with 300 2.8 USM)


iamcdn wrote:
I do use a manual point, which is why I am confused. I pick a single point and it stay static with every lens I own except the 300 2.8, with that one it will jump around to adjacent points.


I'm confused, too; that shouldn't happen. AF Mode isn't lens specific. Could it be that you were accidentally pushing in the Multi-Controller (joy stick) without meaning to while mounting the 300? (A double push will switch the AF Mode to automatic.)

Have you changed lenses and then changed back, and it's still happening?



Oct 02, 2012 at 06:27 PM
JimN
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p.1 #13 · Need Help with Auto-Focus Servo jumping focus (1D Mk IV with 300 2.8 USM)


BrianO wrote:
I'm confused, too; that shouldn't happen. AF Mode isn't lens specific. Could it be that you were accidentally pushing in the Multi-Controller (joy stick) without meaning to while mounting the 300? (A double push will switch the AF Mode to automatic.)

Have you changed lenses and then changed back, and it's still happening?


You may have a single point set with 45 point AF expansion on. Turning off the AF expansion will keep the focus on the center point only.



Oct 02, 2012 at 06:43 PM
OntheRez
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p.1 #14 · Need Help with Auto-Focus Servo jumping focus (1D Mk IV with 300 2.8 USM)


Doug,
What you're describing is a bit odd sounding. One thing for sure, moving from f/5.6 to f/2.8 IS going to seriously effect where focus lands. Fact of life with a bigger aperture.

Like others have suggested, I (on my 1DIV) set AF point to center only (also metering to spot), no assist. I've played with C.FnIII (2) trying slow to middle and can't seem to tell for sure. All the way to slow is worse, but the other settings don't make a significant difference. (I've never gone above middle.) I also keep C.FnIII (3)=0, C.FnIII (4)=1, C.FnIII (5)=1, C.FnIII (8)=1. I do fairly well shooting FB on a very dark field and attribute most OOF to idiot (user) error, though admittedly in the dark focus acquisition is always a challenge.

Dig into the manual and experiement.

BrianO, do you really have the presence of mind, manual dexterity to switch AF points while a play is developing? I'm impressed. How do you do it?

Robert



Oct 02, 2012 at 07:12 PM
iamcdn
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p.1 #15 · Need Help with Auto-Focus Servo jumping focus (1D Mk IV with 300 2.8 USM)


I know it is not a 2.8 DoF thing since I shoot a 24-70 and 70-200 2.8 on the same body or my backup body, and the AF SEL point does not jump, and I am used to the DoF.

Myself I won't use the Center Point only because I never frame the center point, I offset it as described by BrianO. I am very used to this as I set it prior to the play based on what I believe will happen, and where the play will be. Sometimes I have it wrong, but mostly I have the right point.

I think the issue might be as BrianO indicated, I may have double-pushed the controller and went to Auto, or as JimN identified that I have to turn off 45 point expansion. I will check both tonight to verify.

Thanks all for your very helpful suggestions so far.



Oct 02, 2012 at 08:17 PM
iamcdn
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p.1 #16 · Need Help with Auto-Focus Servo jumping focus (1D Mk IV with 300 2.8 USM)


DING DING DING - we have a winner. Thanks JimN

It turns out c.FN III #8 AF Expansion was set to 3 - all 45 points. so it was grabbing anything new that come into frame. I turned it off ( 0 ), and I am golden. I will likely try Left-Right (1) to see how that works but for now with it off my 300 2.8 works like all my other lenses.

Thanks again for the help folks



Oct 02, 2012 at 10:21 PM
JimN
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p.1 #17 · Need Help with Auto-Focus Servo jumping focus (1D Mk IV with 300 2.8 USM)


iamcdn wrote:
DING DING DING - we have a winner. Thanks JimN

It turns out c.FN III #8 AF Expansion was set to 3 - all 45 points. so it was grabbing anything new that come into frame. I turned it off ( 0 ), and I am golden. I will likely try Left-Right (1) to see how that works but for now with it off my 300 2.8 works like all my other lenses.

Thanks again for the help folks


I'm glad the problem is solved.



Oct 02, 2012 at 11:18 PM
Caleb Williams
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p.1 #18 · Need Help with Auto-Focus Servo jumping focus (1D Mk IV with 300 2.8 USM)


I have to see if this what my IIn is doing...hmm. I didn't see the focus poitn moving all over the place though. But have to wait an hour until I'm home to check.


Oct 02, 2012 at 11:22 PM
BrianO
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p.1 #19 · Need Help with Auto-Focus Servo jumping focus (1D Mk IV with 300 2.8 USM)


OntheRez wrote:
...BrianO, do you really have the presence of mind, manual dexterity to switch AF points while a play is developing?


Only in baseball or golf.

No, usually I pick a focus point in advance and stick with it. That's why I wrote, "follow the action so that the subject stays under the same focus point."



Oct 03, 2012 at 01:58 AM





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