Canon 1D MKIII Autofocus- Interactive Review

Canon 1D MKIII Autofocus Problems- Interactive Review

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Your means of presenting the images poses some challenges to viewing them all, but what I see in the f/2.8 shots is a paper-thin DOF, and many of the shots out of focus. Notably both sets have the initial shots are out of focus. Do you know whether the shooter held the shutter button down for any length of time before firing the first frame?

It's been implied by others that the earlier 1D models would lock and stay locked on such subject material, when set up similarly.

Is this true? Could earlier 1D cameras track the wrinkles in a white tee shirt with enough accuracy to maintain focus on a runner heading straight into the camera? Can the Mark III track in this very same situation when the camera is at a lower temperature?

Any way you can cool the camera down and run the test again with the same clothing in the same light?

-Noel

I did a litte analysis of the second sequence, the one with the shorter DOF.

Just looking at the images, I assigned numbers -3 through +3 for focus accuracy, where -3 is completely back focused, -2 is back shoe in focus, -1 is almost in focus, 0 is dead-on, +1 is slightly front focused, +2 is front focused on front hand, and +3 is completely out of focus.

I'd say a shot that is either 0 or +1 may be usable.

For the most part the camera seemed to be behind, save for a few hard jumps ahead. Drew, did you center the focus of the body with this particular lens? Just a slight shift to front focus overall would have yielded up to 19 more keepers out of 60 shots.

-Noel

Attached Images

 

Hi Noel,

Thanks for the analysis. I will upload another sequence for you to take a look at and analyze if you would be so kind. However, this whole line gets us a bit off track from testing the two main variables. The aperture issue is really a whole other set of tests.

Between the two different days of running at the camera (well over 3000 frames; probably at least 50 trials (runs at the camera)) I am seeing almost the exact same results. F/5.6 perfectly usable, f/2.8 a disaster. After the first day I thought it might have had to do with motion blur and shutter speed. But, it does not.

As you point out; what is lacking is a direct comparison to the MKII and/ or other cameras in the same conditions. Can the MKII handle this razor thin dof under these extreme shooting conditions any better? What about a 5D or a 10D even? I hope to find out today.

Probably the most disturbing thing about the results was the fact that stationary objects at f/2.8 showed the exact same problem. Stationary objects at f/5.6 were perfectly fine across a long series of frames at 10fps. And yes, the shooter made sure to lock focus before the start of every run.

As I mentioned, the amount of data to go through now is quite large. Probably about 7000 frames. It is hard enough to get through it all on a local drive on a fast machine. Just uploading those two photo series and getting them into the story takes 2-3 hours. I played around with creating pdfs and an album previewing software we have for presenting the images. Neither method works well. One is too large and the other does not show enough detail.

I am not prepared to officially write up any conclusions into the article at this point. But, I will at least address the question of how we missed this the first time. Quite simple, in the 24 hours that I had the camera we only shot a few long action sequences. The primary one being the baseball game. These were all fine. However, if you go back and look at those samples you will see that they were all shot at a higher aperture (f/4 or f/5).

So, can the MKII or another camera do better in the same conditions? That is the pressing question at the moment. I intend to do a more thorough write up and provide more proof of the entire process. For now I am trying to just find out what I can about this specific issue.

Day 3 Added.

I'm finding the navigation of this report to be something of a challenge, figuring out how to go from one day to the next, with the posts sprinkled in between. Maybe I'm just slow this morning...

Nill

I have forced the images to 2 on a line now. On firefox it wraps the images properly. IE does not.

Should be easier to view now.

Day 4 Added.