Was in AI Servo mode with my Mark 3, f/4, 1/1250, ISO 400, L JPG mode, using my 70-200 2.8 IS. I was tracking them coming down the road and fired off about 3 shots quickly, and this was the worst of the 3, the other two weren't in focus either.
It's clearly back-focusing, the grass along the other side of the road is VERY sharp. I was getting quite a few like this, but I thought the issue was the Mark 3 FRONT focusing, not back focusing..? I had the red square right in the middle, right about on the horse's lower butt, should have been easy to get focus. And like I said, I got quite a few others like this in different lighting situations but again, trees and grass in the background are razor sharp. I did however get enough keepers, this just seems awfully "wrong" for the camera to be focusing like this. I've got a blue dot Mk3 that is also outside the serial number range.
Should I be considering issues like this "normal," do I need to change my technique, change some settings in the camera, or send it in?
Clearly...yours is also one of the troubled ones, Will, if all 3 in a burst of 3 didn't lock focus on the horse's butt.
Yea, there's plenty threads, am sure you know about them already. I know someone with a "blue" dot MkIII and his "back focusses" just like yours. No1 is immune from the "mark 3 curse". sorry !
PS: With so many folks selling their MarkIII's on B&S, it's becoming obvious to me "no one will sell his properly focussing mkIII to ANYONE". I would rather try and buy it from some1 who IS NOT ready to sell his camera at all (for some premium price) :-).
Imagine Gary Peterson putting up his "mark 3" for sale on B&S? No sir, he won't !!!
Edited by LCollector on Aug 21, 2008 at 03:57 AM GMT
LCollector wrote:
Clearly...yours is also one of the troubled ones, Will, if all 3 in a burst of 3 didn't lock focus on the horse's butt.
Yea, there's plenty threads, am sure you know about them already. I know someone with a "blue" dot MkIII and his "back focusses" just like yours. No1 is immune from the "mark 3 curse". sorry !
PS: With so many folks selling their MarkIII's on B&S, it's becoming obvious to me "no one will sell his properly focussing mkIII to ANYONE". I would rather try and buy it from some1 who IS NOT ready to sell his camera at all (for some premium price) :-).
Imagine Gary Peterson putting up his "mark 3" for sale on B&S? No sir, he won't !!!
Edited by LCollector on Aug 21, 2008 at 03:57 AM GMT...Show more →
I am one of those guys who won't part with his MkIII and, Will, you definitely are having issues. There is certainly something amiss if all three of your images failed to capture a single sharp image. Does this happen with any of your other lenses or is it limited to the 70-200? Also, which AF points were you using?
David Israel wrote:
I am one of those guys who won't part with his MkIII and, Will, you definitely are having issues. There is certainly something amiss if all three of your images failed to capture a single sharp image. Does this happen with any of your other lenses or is it limited to the 70-200? Also, which AF points were you using?
I was only using the center focus point, and to be honest I do not notice this on any other lens than my 70-200.
Oh well, I still love the camera and to me is much better than my Mark II was, so I'm going to keep it of course but I was just curious if this was part of that "issue." I thought it only pertained to front focusing, and more often in high temps, and with someone running directly at the camera.
I don't know about the MkIII because I don't own one and probably never will.
However, looking at your target type (i.e., size, contrasts, dynamics) I'd say that if my old 300D in the "sports mode" failed to focus properly on that target more than 1 out of 5 shots in a sequence, I'd consider it defective.
Looks normal for a 1D III. I think Canon introduced a randomness into the 1D III AF to add a dose of excitement back into photography - what's the fun in getting focused shots all the time. This keeps you on your toes; it's a thinking mans camera.
"I had the red square right in the middle, right about on the horse's lower butt, should have been easy to get focus."
#1 Why do you think this is true? (Seriously I am asking.) That would have been the last place I would have chosen to try and get a focus lock. It's pretty lacking in contrast isn't it - and there a nice nearly blown hi-light area right on the horses a$$
#2 In AI Servo mode isn't it better to use more points and let the predictive AF do its job?
RGS65 wrote:
"I had the red square right in the middle, right about on the horse's lower butt, should have been easy to get focus."
#1 Why do you think this is true? (Seriously I am asking.) That would have been the last place I would have chosen to try and get a focus lock. It's pretty lacking in contrast isn't it - and there a nice nearly blown hi-light area right on the horses a$$
#2 In AI Servo mode isn't it better to use more points and let the predictive AF do its job?
The picture is just an example. I could post a lot more from the day, all under similar yet different conditions.
It's definitely something that many of us have seen randomly. I attribute it to contrast and the AF system. The MKIII likes edges... Often, if you don't focus on an edge and rather a large uniform low contrast area it'll hunt and find something else in the frame (EVEN THOUGH IT IS NO WHERE NEAR THE AF POINT). The fact that it likes edges (and most AF systems do), is not near as big a problem for me as the fact that when it cant grab the spot chosen, it arbitrarily finds something random in the frame. It's almost like it forgets that you are in SINGLE AF POINT mode. And I do realize that several of the Custom Functions seem to address this...However, none of them have completely solved the problem for me. With everything set in a way that it should not do anything but lock on a single point, I will still on occasion get something exactly like pictured here. But for me, it's typically Front focused...And GRASS seems to be what it likes the most. It's nuts.
That would have been the last place I would have chosen to try and get a focus lock. It's pretty lacking in contrast isn't it - and there a nice nearly blown hi-light area right on the horses a$$ 