Nikon focus lock-on setting advice

Deckard

Deckard

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Ben
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After a bit of advice from those in the know.

I've recently crossed the great divide, having previously been using a Canon 450D + 70-210 USM lens for shooting tennis and football with good results.

Now I've moved to a D2x with a Sigma 70-200 f/2.8 EX HSM and found a pretty poor keeper rate yesterday shooting one of my lad's football matches.

I'd got the camera set to AF-C, Ch frame rate mostly using high speed crop, shutter speed held around 1/640-1/1250, aperture f/4 and ISO 400, group dynamic pattern 1 with centre focus, release priority.

Sadly I found I'd missed focus a lot of the time [much more than the Canon]. I'd happily shot some family pics sledging and out for a walk with the lens with accurate focus and tested it to ensure it wasn't front/back focussing after the match [it wasn't].

My suspicion has begun to fall on the a4 setting for focus tracking with lock-on which was set to normal, I wonder if the camera was locking on to detail slightly further away and not refocusing quickly enough?

How do other Nikon users set this? Any other suggestions?
 
I always work with this switched off.
My understanding is that with it switched on, the focus will be less liable to be taken away from your subject by something briefly passing in front.
However the result is that while tracking a moving subject, the focus will adjust in steps rather than continually adjusting, and so will be out of focus more of the time.

When I switched to Nikon I found this video tutorial useful, though no doubt others will find points in it to disagree with.
 
duncolm said:
My understanding is that with it switched on, the focus will be less liable to be taken away from your subject by something briefly passing in front.
However the result is that while tracking a moving subject, the focus will adjust in steps rather than continually adjusting, and so will be out of focus more of the time.
Click to expand...

you're right in that it controls the amount of time before AF switches to a new subject - to allow, as you say, for objects passing in front of the camera, but this shouldn't cause a step wise focus adjustment on the subject itself though
 
Thanks guys!

Yeah, focus priority is one thing to try, but the Canon equivalent to release priority [AI Servo] never caused me problems like this, that's why I think the camera is "holding" onto focus longer than it should. Focus priority may not help, as the camera may still think it's focussed [even if it's on the wrong spot] but next time out I'll try it and leave a4 set to off.
 
Mmmm, looks like it's the lens at fault.

I used my 180mm f/2.8 as well yesterday and it coped fine, despite being an older screw drive design it kept focus nearly all the time.

The Sigma on the other hand still appeared to focus behind a lot of the time. It can focus cleanly on still objects but looks like it's struggling with moving targets, maybe the HSM motor is poorly? It's going back to Sigma today for a once over.
 
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