Alistair Watson
Offline
• • • • •
Upload & Sell: Off
|
 p.3 #2 · Does your MkIII have AF issues? | |
I have gone about as far as I am prepared to go with my Mark 3. I have confirmed with the dealer that I will return it for a full refund as soon as I can get to the store.
My Mark 3 arrived on the 1st June, today - the 21st June, is the last time this Mark 3 will be used by me. Apparently there is no stock of Mark 3's in the UK so exchange is out of the question unless I am prepared to wait quite some time. Return really does seem the best option at this point.
90% of my photography is based on shooting moving objects; wildlife, military airshows and motorsport. I have racked up about 3000 shots during the time I have had the Mark 3. At the beginning I just had a feeling, that the camera wasn't able to maintain a focus lock while tracking a moving object (bird/aircraft/racecar) but I initially put this down to user error, lack of familiarity with a new body. After multiple outings with the body I am now convinced that it is the body and not user error. I have experimented with all the custom settings, believe it or not, I found the defaults to work the best, slowing the focus tracking down made the focus sluggish, speeding it up, made the focus even more hyper.
Today I was at Silverstone shooting the final day of Formula 1 testing. I took my Mark 3 and trusty 300/2.8 IS lens. F1 is always a good test of how well a camera focusses since the cars accelerate to high speeds in no time at all making panning shots a real challenge and change direction quickly without warning. I took over a 1000 shots today, panning shots with the car entering from the frame from right to left and many many head on shots. My standard settings for this are centre point AF and servo mode.
Imagine this scenario - over and over again. You hear the car down shifting coming to the end of the straight, you are already in position, the car emerges into view and you lock onto it, tracking the car smoothly (giving the IS time to settle down and AI servo time to lock on) through 2 low speed bends before it arrives fully in front of you. As it begins to turn, your focus point is pretty much static on the drivers head and you shoot a burst of frames, 5 to 7 normally. On to the next car, and the next. The only trend I saw today is that the very first frame is ALWAYS in focus, deadly sharp in fact. Frames 2 to 6 are either sharp or unfocussed with no pattern, and yes, sometimes there is a focus placement problem on my part where the car jinks or something and the focus point ends up over the engine cowling, though this is easy to see. What is not at all clear is why so many frames are unfocussed, ever so slightly but enough to make the images useless. They are not front focussed or back focussed, no point in the image is focussed. It almost feelings like there is some multi-tasking problem within the camera ie as soon as you shoot a burst of frames and the buffer begins to fill and then write to the card (I always use Extreme 4 4gb CFs btw) that the camera suddenly is not able to focus properly. This is my feeling and I have nothing technical to back this up other than if I repeat the exercise in single shot drive mode but still using AI Servo focussing, nearly all the images are deadly sharp so in my opinion, and I am no professional, the problem seems only to occur in AI servo mode AND when shooting bursts of frames.
I hope people find this useful, or perhaps can use this information to go off and test their Mark 3's.
Photography is not my primary income and thus I can no longer justify a £3000 investment in a body which offers no better focus accuracy than my 1D2N, in the ways I have mentioned I feel it is worse. Other than this, the Mark 3 is perfect, at least for the type of shooting I do. High ISO capability is wonderful, as is how easy it is to control and customise functions you regularly use. For now, until these issues are fixed one way or the other, I will part company with the Mark 3 and go back to my well used 1D2N, and be happy that the camera won't miss so many shots, but a little sad that the 1D3 in it's current state is not the camera I had so hoped for. 
Alistair
|
