This is the first time I have had an issue with my MkIII since I got it weeks ago. I have used my 17-40L, Sigma 70-200, Canon 70-200 2.8L, Canon 85 1.8 and this afternoon my Sigma 100-300 f/4. I have shot night football and soccer, day soccer and field hockey with no issues whatsoever. Yesterday I shot a bicycle race with my MkIII and 85 1.8 and 17-40L with bikes coming at me and the camera/lens performed as I expected. I don't know what to make of these shots. Now I know I used a slow shutter speed (1/250 at f/4) but I was quite close to the tree with the woodpecker on it. Look at the suet feeder and the bird. The suet feeder is sharp but the bird looks horrible. The second one is even worse and I shot it at 1/400 with the focus point on the middle of the feeder. I took about 30 shots using single shot and they all look like this. Is this the dreaded AF issue or could it be the lens/body combo? I am using the middle focus point with C.FnIII 8-2 (Enable, surrounding point assist) and 9-4 (Inner 9-points). Help?
I added one more to show how horrific the focusing is. Shot at 1/800 at f/4. Seems very bad if you ask me.
as long bright details like the feeder is within the focus point area it is likely to shift focus to that area. You will see that with any camera. You need to get much closer
The blue-jay shot seems sharp to me - at least the feeder. Problem is that the feeder is very contrasty - and as long it is that close to or within the focus point is likely to shift to the feeder. It will be a hit and miss situation IMO
But if all your shots are oof you better get it checked. For perched birds I never get oof shots with mine.
BTW, always use center-point(or single af-point). I don't find extension much useful. On the contrary it will shift focus much more. Only situation extension might be useful is flying bird against sky
A VERY typical 1D III AF problem from my experience shooting wildlife with the various 1D Mk III bodies I have owned. In general, the camera works fantastically well in almost all situations for One-shot AF (as everyone knows, the Al Servo is a different issue altogether), but it has at least one serious flaw in it that causes front focusing and I'm pretty sure Canon still has no clue what's causing it. I find it occurs most in subjects that are black and white in a coloured setting, for instance, a badger in a sunny green field.
I have put in a long and detailed research request to Canon and Canon research development here in Calgary, Alberta and am waiting for their analysis of my shots and my findings.
There are two ways to try to mitigate the AF problems in these types of situations. One, just use center point AF (I rarely use surrounding assist points unless it's an action sequence) and two, if you suspect your camera is not focusing properly, focus and refocus continually and take shots the whole time. This helps ensure that you get one or two sharp shots out of the series. It's not ideal, but then again, neither is the 1D III as it currently is.
kjetils wrote:
The blue-jay shot seems sharp to me - at least the feeder. Problem is that the feeder is very contrasty - and as long it is that close to or within the focus point is likely to shift to the feeder. It will be a hit and miss situation IMO
But if all your shots are oof you better get it checked. For perched birds I never get oof shots with mine.
all the best
K
I am coming from a MkIIn and I have never really missed birds perched on feeders either. My 30D and 70-200 2.8L and even my 300 f/4 IS (turned off) produced super results. I have a 30D coming Wednesday so I will test the lens out on that body as well. Oh yeah, with the MkIII I always select the middle focus point.
Again If you have this problem I would send it back. The mkIII performs much better than my old mkII in AI-servo(not to mention the 30D). In all conditions of light (at least after the latest firmware)
I would say the AF assist is causing your problem. In some situations it is very useful but if your central (or other) point loses AF lock then the assist will activate, simple.
Alistair Watson wrote:
I would say the AF assist is causing your problem. In some situations it is very useful but if your central (or other) point loses AF lock then the assist will activate, simple.
I would like to blame it on that but it's hard to especially since I have shot so many games of soccer and field hockey and not had a single problem. When my 30D arrives tomorrow I will test the lens out on that body.
My MkIII has performed flawlessly in AI SERVO. I shot a h.s. football game in the pouring rain and I only had 1 OOF shot due to someone cutting in front of me and the camera just grabbed that player instead of the player I was attempting to aim for. However.....later on I was in single shot mode and I was quite surprised at the number of OOF shots I got while shooting kids coming at me and by me while learning to ice skate. I was at F/4 at about 1/500 and they were moving pretty slow. Should I just not use single shot mode?!?!
The third shot makes me think the lens is back focusing. Take a shot of a wall at an angle, use center point af, and see if the wall is sharp in the center. Shoot wide open too.
Just to add my two-cents worth...While I don't own a Mark III, I have had plenty of Sigma lenses over the years and the one thing I can say is they have all had more inconsistent focus when compared to my Canon lenses. I am down to just one last Sigma lens, a 28-70 f/2.8. While it focuses perfectly most of the time, I can not get it to focus properly under certain daylight conditions. I know many people will extoll the virtues of Sigma lenses, however, my experience (when compared to comparable Canon lenses) is that they have a greater OOF tendency.
