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p.4 #1 · ['NEW Fix' UPDATE!] - MkIII AF still broken | |
Jeff wrote:
Note in the screen grab below that virtually every time the MkIII has an out-of-focus image, it almost ALWAYS exhibits some sort of secondary 'ghost' image, suggestive of some sort of movement (which at 1/8000th, I'd think is unlikely on RG's part). This is very clearly and consistently exhibited on the 'Brooks' logo the runner's blue shirt, since it has a high-contrast area (dark background with white lettering). With the camera in the vertical orientation, the 'Brooks' logo has a ghosted image above it, indicating some sort of movement somewhere in the system (side-to-side in relation to a landscape orientation). This would obviously contribute to an image's overall softness regardless of the actual focal plane, though it appears to me to be consistenly manifested mostly when the camera ALSO has focused either slightly in front of (or more typically) slightly behind the subject. Note that the MkIIn's OOF images do not exhibit this odd characteristic (at least that I could find), suggesting the lens has nothing to do with it.
Whether the cause of this apparent 'movement' in the system is also causing the focus errors becomes the question in my mind (there is also a chicken-and-egg component here). I suppose there is always the slight chance that it could be lens/IS related, but I would doubt that he was using IS for such sequences, and one would expect it would have been duplicated in the MkIIn images. I have no idea what component in the system could be moving, whether it is a result of the new anti-dust mechanism, due to the sensor moving (which seems unlikely), or some sort of overall 'looseness' in the parts of the camera that is exacerbated by the MkIII's extremely fast shooting rate.
Like I said, I have noticed these 'ghosted' secondary images in several of my OOF MkIII images, and as you all have probably seen, there is a fair amount of internet chatter about overall image softness (not the all-over OOF 'misses' that we've seen so much of), though image softness can often be attributable to user error of a variety of sorts.
Hi Jeff,
I just mentioned the following in DavidP's thread, but I think it may be valid here too....
The ghosting is something that I have seen before with my 1DS2 and a 16-35 L II. Would you agree that this is a similar effect?....

At first it looks like motion blur or perhaps a shift in focus, but this was shot AF off, 1/1000 sec, tripod mounted, mirror lockup and shutter delayed. It's not even a corner crop, as it comes from the middle-top of frame.
Now here is a crop from the center of the very same image......

Not a bit of ghosting to be seen and proves that the ghosting above has NOT been created by camera movement.
I ended up thinking that the lens was a dud, as the cam performs flawlessly with all my other lenses.
What does this mean in relation to RG's images? Probably nothing, but it is interesting that a VERY similar effect can be seen in an image where AF tracking and IS was not even involved.
Edited on Dec 22, 2007 at 07:47 AM
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