? about MK3

Discussion in 'Other Cool Gear, Camera Bags, Camera Straps' started by cwilt, Jul 10, 2007.

  1. cwilt

    cwilt

    Apr 24, 2005
    Denver, CO
    I have been watching the DPR about the focus issues with the MK3. This morning I find THIS thread.

    A few observations....

    If Nikon came out with a body with micro AF adjustment the first thing I would do is test and adjust the most commonly used lenses. From the DPR I get the feeling that they do not want to, or feel there should be no need to. They keep comparing it to other C bodies. It seems to me that the AF in the MK3 is a different animal and must be treated as such.

    After reading that first post I am left with a question. Does the MK3 not have an AF-ON button?:confused:
     
  2. GBRandy

    GBRandy

    Feb 28, 2006
    Green Bay, WI
    The MKIII, like the MKII has an AF-ON button. In fact it has 4. Two in the portrait position and two in the landscape. On the MKIIn I have one dedicated to the center focus point and the other to whatever AF point I program in.....That way I can dead center up on an object or slide my thumb to the right and select the pre-selected alternate AF point or ring....it is great for fast moving sports.

    I know the MKIII has the same capability as it is a feature I have grown to love and would be disappointed if it was not available....but it is.

    I suspect the issue is the result of yet another DPReviewer not RTFM :)

    EDIT...Page 17 of the manual has a picture........ Canon USA MKIII
     
  3. cwilt

    cwilt

    Apr 24, 2005
    Denver, CO
    Randy,

    I see it often in the MK3 threads. They talk about using the shutter release for AF. Never saw it mentioned to try AF-ON. Seems odd to me.

    I don't think its just a DPR thing.
     
  4. GBRandy

    GBRandy

    Feb 28, 2006
    Green Bay, WI
    Dunno...I see more mis-information on the DPReview site than anywhere else so I jump to conclusions.

    I need to research this guys claim that the MKIII AF only uses the closest subject for selection. The group focus of the Canon 1 series is a big AF feature and for Canon to dump it seems odd. I suspect there is a Custom Function that selects that as an option....but I am not 100% sure yet....need to read up before I call him on that one.

    As for the AF-ON...it exists in a big way....I guess Canon shooters just don't know how to use it! :tongue:
     
  5. There seem to be an awful lot of people over at DPR picking up a 1D3 who have little idea how to use any DSLR, let alone one of this complexity.
     
  6. adrianaitken

    adrianaitken Guest

    It's a new bragging rights toy - look how many x thousands I've just spent on something that might not work / is too complex for me to use :biggrin:
    Same happens with every release of Windows - people complain they don't know how to do things so the operating system must be at fault, Mac/Linux users claim theirs is still better. No different here.

    A funny thing though... when people starting complaining about the D2H meter not working, people didn't start burning cars in the streets in protest (or other flame wars!!!!) but as soon as people complain about AF not working it's all out hostility. Can't people see that things are out of focus anymore (am I that old I still remember manual focus?) before hitting the shutter release ?
     
    Last edited by a moderator: Jul 11, 2007
  7. cwilt

    cwilt

    Apr 24, 2005
    Denver, CO
    Can you see the plane of focus at 11 fps with mirror blackout?

    Just to be clear. I have no interest in the Canons and I am not bashing them or their users.

    Well.... maybe Randy.:wink:

    I just find some of thier suggested work arounds interesting. Sometimes I wonder if they have read the manual.
     
  8. GBRandy

    GBRandy

    Feb 28, 2006
    Green Bay, WI
    I can live with that.....BTW it's 10 FPS....that's in the manual too :tongue:
     
  9. cwilt

    cwilt

    Apr 24, 2005
    Denver, CO
    I thought you could.:wink:

    Is there a big difference between 8 and 10 fps photographicly speaking? Whats the VF blackout time for the MK3?
     
  10. GBRandy

    GBRandy

    Feb 28, 2006
    Green Bay, WI
    I do see a difference photographically. But I shoot sports. A gymnast making a tumbling run is tough to catch in the apex of a move....with 10 FPS versus 8 I have a 25% better chance of getting the very height of a leap or flip. Similar argument for football and baseball defensive action. Baseball batting is another matter all together as I am sure you know. Let me quickly add that knowledge of the event and being prepared for a shot are considerably more important than just the "Spray & Pray" method advocated by some....I rarely fire more than 5 shots in any given sequence...usually two to four.

    VF Blackout? Not sure, but as long as I can see enough to keep th subject on the selected AF point, I am good to go...so far in the MKIIn I have plenty of time to do just that. Not sure about the MKIII....but i would suspect i will have similar between frame times to adjust the camera for AF points...

    What were you thinking in regards to the VF blackout rate? Do you see that as a concern?
     
  11. cwilt

    cwilt

    Apr 24, 2005
    Denver, CO
    Thats a fair answer. I don't shoot sports or BIF so it was an honest question

    Correct me if I am wrong but the AF sensors only receive light when the mirror is down. That blackout time takes away from time for the AF to work. Perhaps the tracking algorithm doesn't have enough time to calculate subject movement at that frame rate. That could explain some of the series shots I have seen posted. I assume you can turn the speed down and think it would be an interesting test. Have a sprinter on a sunny day. Compare focus between bursts at 10fps and at 5fps.

    Just an idea.
     
  12. I just checked the 1DIII manual (not I don't have the camera) and you get two choices: 10 or 3 FPS.

    Granted it is possible, I'd bet on them offering 5 or 8 or something like that.

    Time wise, I would imagine they can make 10 FPS work. Probably just bugs in their firmware. It would be a real pain if they were exceeding the limits of the hardware at 10 FPS.
     
  13. cwilt

    cwilt

    Apr 24, 2005
    Denver, CO
    Thanks for looking that up. I thought there would have been more choices from such a high end camera.

    My guess is just a stab in the dark. Trying to look at the issue from a different angle.:smile:
     
  14. GBRandy

    GBRandy

    Feb 28, 2006
    Green Bay, WI
    Actually, as I understand it, the MKIIn & MKIII firing at 8.5 or 10 FPS respectively do NOT use the AF sensor on each sequential shot to acquire focus. Instead there is a built in calculation that "predicts" the focus point based on the speed the camera sees the object moving. This works great for constant speed direct head on or direct moving away objects.

    I have had "issues" in gymnastics when girls tumble past at a quartering angle with every other shot not 100% crisp, so my guess is the AF on my MKIIN is adjusted on alternating shots and the predictive AF is used on the other shots.

    The shear speed it would take at 8.5 or 10 FPS to acquire the object and adjust the lens...in between the mirror going back up... would seem to be impossible in each and every sequence....

    Having said all of that, I have not really studied the intricacies of the AF system as I can not really adjust it short of what I am doing....so my analysis may be more speculation than fact.
     
  15. cwilt

    cwilt

    Apr 24, 2005
    Denver, CO

    Very interesting if that is indeed the way it works. Have any links where this is discussed so that I may read up on it? I would hope it would not rely completely on the predictive algorithm and at least check its prediction by looking for a contrast change.

    It seems that the newer camera's struggle with focus at the fast frame rate that they can now do.

    I have no idea why this issue interests me.:confused:

    Glad I only shoot kids.:smile:
     
  16. I knew I had read info concerning this topic before and it took me awhile to locate it.

    Posted by LesZ in that 40-something page thread at Naturescapes. Their forum software doesn't allow displaying a single message to get the url so if you want to read it in context, it's on page 17.

    I'd find it hard to believe that they'd only offer 2 speeds on a camera of that level as I thought even the 30D offered the ability to set the frame rate.
     
  17. The camera would have to test the focus more than once in order to do anything predictive.
     
  18. cwilt

    cwilt

    Apr 24, 2005
    Denver, CO
    I know this isn't a typical Cafe discussion. However, it is interesting to examine what is wrong and to see what it takes to cure it. Perhaps learning a new way to do things with your system of choice along the way.

    Back to the topic....

    I just saw a post on the DPR where the MK3 had a similar issue even on a static subject. That shoots my idea in the foot.
     
  19. And how, pray tell, does Nikon handle this problem, predictive focus that is?

    Thanks to Digital Darrel and his great Multi-Cam 2000 article, this is pretty standard across manufacturers, at least Canon and Nikon. I don't know about the rest of you, but I can sure see this at times in sequences I shoot of "moving bodies", be they birds, dogs, other animals or people. The "perfect AF" system has yet to be produced.

    I have also heard, and if someone could confirm this with a link I'd be much appreciative, that one difference between Nikon and Canon is that after the Nikon first aquires focus, there is a "feedback loop" where it checks once again. As I was told, this is why Canon will often aquire more quickly, but that Nikon will often be more "in focus" on the first shot.

    I suspect that a percentage of folks are just experiencing the "differences" in the new camera, although the specific issues noted by Rob Galbraith sure seem to point to a problem under specific conditions. Perhaps we are seeing the same as with the D200 "banding". Don't shoot at lights at you won't get it :wink: So, for the MkIII, just don't shoot on sunny and hot days :biggrin::biggrin::biggrin: For us here in Washington State, that would indicate a problem for only about 3 days a year ...... :wink::wink:
     
  20. cwilt

    cwilt

    Apr 24, 2005
    Denver, CO
    That could be an interesting discussion.

    I have read his article and my settings for what I do are very different than what he suggests. We all have our own way of getting the job done. I doubt that there will ever be an AF system that we will ever be happy with.

    I would like to see that too.

    I believe some of it may be user error on a new system but there are a lot of reports for that to be the only problem. Problem is that it appears to be happening even on indoor static test shots. I know that my D2x focuses better with AF-D lenses compared to AF-S. The AF-S lenses never seem to be as accurate on that body. Yet I can take those same lenses and put them on the S5 and see very little difference. Every system would seem to have its quirks.:wink:
     
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