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Author Topic: 5DMKIII Autofocus help required  (Read 4633 times)

bdunbar79

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Re: 5DMKIII Autofocus help required
« Reply #15 on: June 18, 2012, 03:15:35 PM »
  I think the 5D Mark III can do spot metering everywhere (all 61 points) in single shot mode can't it?  I can't remember.  AI Servo is different.
I was wondering about this. Sure it has the 61 point AF, and I can select any of those points, but is the one I select
also used for metering? In the book it says something about a central area about 1.5% of the total area for spot.
So who knows this for certain?
Cheers Brian

If you're using evaluative metering, weighting is given to the region around the selected AF point.  Spot metering on the 5DIII is in the center only, not linked to the AF point selected.  AF point-linked spot metering is currently a 1-series only feature.

Thank you thank you.  I was thinking of my 1D Mark IV.  Good thing I didn't go out and try this.  Maybe I shouldn't have two cameras :)
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Re: 5DMKIII Autofocus help required
« Reply #15 on: June 18, 2012, 03:15:35 PM »

hoghavemercy

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Re: 5DMKIII Autofocus help required
« Reply #16 on: June 18, 2012, 05:15:21 PM »
  I think the 5D Mark III can do spot metering everywhere (all 61 points) in single shot mode can't it?  I can't remember.  AI Servo is different.
I was wondering about this. Sure it has the 61 point AF, and I can select any of those points, but is the one I select
also used for metering? In the book it says something about a central area about 1.5% of the total area for spot.
So who knows this for certain?
Cheers Brian

If you're using evaluative metering, weighting is given to the region around the selected AF point.  Spot metering on the 5DIII is in the center only, not linked to the AF point selected.  AF point-linked spot metering is currently a 1-series only feature.

Is that possible with a firmware update on the 5DIII??

neuroanatomist

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Re: 5DMKIII Autofocus help required
« Reply #17 on: June 18, 2012, 06:09:34 PM »
  I think the 5D Mark III can do spot metering everywhere (all 61 points) in single shot mode can't it?  I can't remember.  AI Servo is different.
I was wondering about this. Sure it has the 61 point AF, and I can select any of those points, but is the one I select
also used for metering? In the book it says something about a central area about 1.5% of the total area for spot.
So who knows this for certain?
Cheers Brian

If you're using evaluative metering, weighting is given to the region around the selected AF point.  Spot metering on the 5DIII is in the center only, not linked to the AF point selected.  AF point-linked spot metering is currently a 1-series only feature.

Is that possible with a firmware update on the 5DIII??

In theory, yes. Might be a slight technical challenge due to the very tightly-packed 61 AF points, but previous 1-series bodies managed it with pretty tightly-packed 39 AF points and the same 63-zone metering found in the 5DIII.  But, practically...based on Canon's history, I really doubt it'll happen.
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bjd

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Re: 5DMKIII Autofocus help required
« Reply #18 on: June 28, 2012, 02:42:43 AM »
Getting there (I think).
I found the feature that allows me to display the focus points when viewing the picture
and generally its now spot on. I think one problem is trying to shoot very fast moving
subjects at too low a shutter speed. I suspect that was more the problem than incorrect
focus.
Certainly this example seems to be well focussed, DOF is low due to aperture, certainly no
complaints with the equipment anymore. 
PEBC = Problem exists behind Camera

5DMK3 F6.7, 1/1000 ISO1600 Canon 70-200 F4 IS at 200mm, 2m to subject.

Cheers 

bjd

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Re: 5DMKIII Autofocus help required
« Reply #19 on: July 22, 2012, 01:25:13 PM »
So I've got stationary objects sorted I think, and have been playing the last two days with the AF setting
trying to capture birds in flight. I guess I have two use cases I'm trying to master:
1. Already focussed on a bird, and want the AF to follow it when it takes off and flies (more or less)
towards me.
2. Set up the camera so a bird will fly from the left into frame as it lands at the right of the frame.

I have read the 1dX Autofocus guide, but still dont have the focus tracking the way I think it should.
Are there any showstoppers (e.g. aperture) that I should know about that may interfere?
Would anyone be prepared to say which settings they would use?

As I'm mainly trying to shoot small birds, are they maybe too small for the AF? Too fast?

I'm primarily using the 70-200 1:4 L IS zoom.

Also, I didn't find a way to get the actually used AF points to be displayed in ACR or PS (I can see
them on the camera when I review the  shots), is that at all possible?

Thanks in advance.











bjd

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Re: 5DMKIII Autofocus help required
« Reply #20 on: July 29, 2012, 09:05:33 AM »
Just bumping this up to see if anyone has any ideas?
Trying to capture birds in flight. I guess I have two use cases I'm trying to master:
Q1. Already focussed on a bird, and want the AF to follow it when it takes off and flies (more or less) towards me.
A1. I guess that AI Servo is correct here. I have also set the AF so that all focus points are used.
When the bird takes off towards me then the camera AF just does not follow it, in fact it makes no attempt.
The selected AF points (the ones in focus) just stay where they were in the background.
I have tried all AF cases and they dont seem to make a difference.
My conclusion is just that the bird is too small, and therefore does not register.
 
Q2. Set up the camera so a bird will fly from the left into frame as it lands at the right of the frame.
In this case the bird is a lot nearer and therefore fills out a lot more of the frame. Also tried using my
24-105 at around 50mm instead of the 70-200 so that the amount of time the bird is crossing the AF points is longer.
A2.Still, I cant see the AF trying to follow the bird, not matter what case is used, using AF Focus.

I have read the 1dX Autofocus guide, but still dont have the focus tracking the way I had hoped it would!!.
Are there any showstoppers (e.g. aperture) that I should know about that may interfere?
Would anyone be prepared to say which settings they would use?
As I'm mainly trying to shoot small birds, are they maybe too small for the AF? Too fast?
With AI Servo, taking a fairly large object, get it in focus, slowly move the camera then the AF points
try to stay on the object, so it doesn't seem to be totally broken.

Just found this:
Canon EOS 5D Mark III - Tutorial AF Area Selection 1/14
It talks about "Large and rapidly moving objects", not small birds I guess.



Thanks in advance.
« Last Edit: July 29, 2012, 09:26:11 AM by bjd »

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Re: 5DMKIII Autofocus help required
« Reply #20 on: July 29, 2012, 09:05:33 AM »