1D Mark 2 N Problem With Focus

[graemeo_bolton]

I got my 1D Mark2 N in november moving from a 20D last month

i got a replacement 1D as the aiservo was way off but I have

problems with my 70-200L IS which doesnt seem t focus at correctly

in aiservo or oneshot but oneshot is alot better, I swapped to

my old Sigma 100-300EX F4 on Saturday for a local football match

(soccer) and got alot better photos, Would anyone know what the

problem most likely is the camera or lens and i can e-mail some

photos of the problem if anyone can help me

 

Thanks

 

Graeme Bolton (N, Ireland)

[g.richardson]

Some examples would be useful but here's a couple of things...

 

a) Are you using the centre focusing point, or are you letting the camera choose? Are you sure the cameras not just focusing in the wrong place?

 

b) Are you making sure the camera has achieved focus before firing off shots? The Canon EOS 1 series cameras in AI Servo will fire whenever the photographer presses the shutter release, whether focused or not.

 

c) Well ok, three things... When you track a player using the AI servo mode, do you keep the shutter release pressed down halfway, or do you "pulse" it? It's best to keep your finger halfway pressed on the button, and just release it when you want to stop the AF tracking i.e. when someone walks in the way. There is also an option to use one of the custom buttons to stop the AF, that�s in the manual.

 

From my experience, you cant just point and blast away with AI-Servo, it takes some thought to know when it will lock on and when it's going to lose it. Just watch how the camera focuses, try tracking players without taking any shots.

[graemeo_bolton]

http://www.pbase.com/graemebo/1d_mk2_n_test

 

Some samples I sort of think its the lens but i aint sure

[derek_simpson]

Graeme - I was shooting footie on Saturday a few miles north of you and conditions varied a lot through the day from blazing sun to murk. From these samples it seems your 70-200 was shooting at f2.8 which limits the DOF to a point where there is no leeway - the 100-300 shots are all reading smaller aperture and therefore greater depth of field - they also look as though they are doing so because there is more light and crucially contrast - greater contrast makes all AF lenses more perky - I've noticed on occasion that even in crap floodlit situations shooting at 3200 & underexposed the contrast can actually make focussing easier than a typical Northern Ireland Sunday afternoon. This doesn't mean there isn't something amiss - I am less than deliriated with my MkII and the shots look rather similar to yours. It's not easy to set up real comparisons with condiions constantly changing and there's no artificial repeatable situation I can think of for an objective test - but just because a conclusion is subjective doesn't make it wrong. On another thread on another board a current discussion on the MkII's focussing is edging toward the notion that both the 1D and MkIIN are better - subjectively.