EOS 1D MkIV AF problem

[Ken Watkins]

I have had a slight problem with AF of late, I only use a 500mm F4with this body.

I am sometimes losing AF when moving the AF point from the main body of the subject to the head or eye.

My settings are mainly those in Artie's PDF.

Has anybody else had this problem?

[Ken Watkins]

Peter,

I have tried almost everything, turning everything off to one shot rather than A1 Servo, I even cleaned the contacts on lens and body

My problem is the fact that it is intermittent, a fine example would be some images of Darters I took at Kariba, AF worked when I used the centre point on the main body, when I move the AF upwards to the head AF failed totally.

Cheers

Ken

[Christopher C.M. Cooke]

My problem is the fact that it is intermittent, a fine example would be some images of Darters I took at Kariba, AF worked when I used the centre point on the main body, when I move the AF upwards to the head AF failed totally.

Ken I have the same problem with my MKIII and it went back twice to Canon who insisted it was fine, I have since learned to live with it by moving the focus point around to compensate, this becomes easier the more you do it.

[Ken Watkins]

Christopher,

It is a relief to find that someone has had a similar problem, albeit with a different body (I do not remember having this on My MkIII).

The problem arises when I move the camera and/or the AF point.

Do you think I should change my AF settings?

Any suggestions as to set up wouldbe greatly appreciated.

Cheers

Ken

[Christopher C.M. Cooke]

Ken I only use one focus point and I note that when I move the point to say the eye it drops focus so rather than concentrate on the focus point I work within the area around the focus point and set my focus search to slow and it seems to work for me but it did really pi** me off for a while with Canon telling me it was all in my mind, if your MKIV is new I would take it back.

Breeze Browser is a great program to use with this problem as it shows the focus point against the image and I took screen shots of this to Canon to illustrate my to to no avail.

Keep trying and weather permitting I will take my MKIII for a spin and get back to you.

The more I use my 7D the less I use the MKIII, Artie's paper on setting up both the MKIII and 7D are invaluable tools.

[Jim Neiger]

Try letting off the focus button, then move to put the focus point to the desired location, then press the focus button again. After you have focused on the desired spot, you can lock the focus, recompose, and shoot. All of this assumes you are using the center point only and AI Servo AF.

[Christopher C.M. Cooke]

Good idea Jim but difficult to do with a moving subject.

[Roger Clark]

I agree with Jim. That is what I do. The more you practice, the easier it gets, as with many things.

Roger

[Jim Neiger]

Good idea Jim but difficult to do with a moving subject.

For moving subjects I try to do it very quickly or, if the subject is moving too quickly, I will try to focus on part of the subject that is in the same plane with the eye and allows a good comp. Sometimes a good comp is not possible in camera. In that case I would back up a bit and use cropping to get the comp I want.

[Christopher C.M. Cooke]

The advice here has no got to a point that I bought a 10 inch solid state hard drive laptop and am in the process of setting it up with a variety of everyone's suggestions by Camera, Situations, Problems so that in the field when I hit the wall I can cross reference the problem to suggestions and make comments as to how they work in any given situation.

This will no doubt either work OR I will book myself into therapy. :)

[Ken Watkins]

Thanks to everbody for their suggestions, but I am a little confused by Jim's comments as my most notable failure was when the AF worked perfectly well on the main body but not on the head. Perhaps I should not have moved the AF point up to the eye?

[David Pugsley]

I'm not sure I'm following exactly what the problem is. I have a MkIII and may be able to help. Can you tell us exactly what you are doing sequentially and what your AF settings are?

[Jim Neiger]

I think the solution must be found in a either what Jim is saying, release AF and re-acquire on the head, or experimenting with C.FnIII-2, tracking sensitivity.

It's possible that the tracking sensitivity delay is causing what appears to be no focus. By letting off and refocusing (bumping the focus) you override the tracking sensitivity delay and the camera will focus instantly. There is a need to be careful with using settings for a specific situation that are not good settings for other situations. Things can change quickly, and if you have to change the settings inbetween situations, you will often miss the most important opportunities. I try to use settings that allow me to capture the desired images in any situation. That way the only adjustments I need to make on the fly are exposure adjustments which may or may not be needed. By doing this I remain ready for action and changes in the situation at all times.

[Ken Watkins]

Thanks for the further assistance, just for info I have my Auto Focus tracking sensitivity set to one up from slow,is this OK.

As I am now understanding that the solution is this, when moving the AF from the centre point I should release the shutter button and then press again to iniate focus, is this correct.

I certainly would not wish to mess about with different settings for different situations, it is complicated enough as it is:D

[Jim Neiger]

Thanks for the further assistance, just for info I have my Auto Focus tracking sensitivity set to one up from slow,is this OK.

As I am now understanding that the solution is this, when moving the AF from the centre point I should release the shutter button and then press again to iniate focus, is this correct.

I certainly would not wish to mess about with different settings for different situations, it is complicated enough as it is:D

I think you've got it as long as you are using the center point only and not multiple af points.

[Gerald Kelberg]

Interesting thread. I have one observation and one question.

First the observation - Ken, you ask if you should "release the shutter button and press again to initiate focus". On an IPT earlier this year, I was converted away from using the shutter button for focus - using the AF-ON button instead (CFnIV 1, 2 on the Mk III). Before I was having trouble, kept loosing the AF on the head of practically any moving target. Surprising how easy it is to switch the habit.

The question - Does the AF expansion work on any selected AF point or only on the centre point?

Regards,

Gerald

[Ken Watkins]

Gerald,

Thanks for the tip I will try this.

I just found this but have not read it thoroughly yet

http://www.usa.canon.com/dlc/control...articleID=3107