5D III Focus Tracking Question - with picture

Hey all, I have a 5D MK3 that I love! I'm trying to improve though. I have been shooting small, FAST birds. See attached. A tuffed tit mouse taking off. I had the dead center focus point with the small square inside the square selected. I locked focus on his eye from about 15 feet away. I then fired as he moved. The focus seemed to lag. So my question is, how can I keep the focus where I want it, i.e. on his eye as it starts to move? Is this impossible?

I was using Case 4 with the tracking sensitivity cracked all the way up. I've tried it with it middle and all the way down too. I seem to just miss... I know there has to be a way though as I see others that seem to nail these shots... help!!! plz

OK... here it goes...

You are SO close and such a shallow DOF and it's a small bird. NOBODY is going to get good keepers consistently. What you are trying to pull off is difficult for any camera.

i wouldn't use spot AF for tracking fast moving birds, the smaller focusing point can take longer to focus than the regular one, as it is less likely to cover a good line of contrast.

And as mentioned above, that situation is a very difficult one for the camera anyway. AI servo is predictive, it learns how fast the subject is moving and tries to focus ahead, so the bird flies into focus as the shutter trips. With a bird taking flight, it hasn't got the time to track and lock on as well. Hamper it with spot AF as well and it is really going to struggle.

Try the center point WITHOUT the little square selected in AIServo. Then the handover to other AF points is enabled.

I would customize the Case as follows:
Tracking sensitivity (-1) - this will force to keep the subject in focus and not change the focus to some intervening object
Accl/Decel tracking (+2)
Auto switch AF points ( +1)

MakisM1 wrote in post #16746960
Try the center point WITHOUT the little square selected in AIServo. Then the handover to other AF points is enabled.

No it's not. You have to enable at least four assist points for any handover to happen.

Note that as long as no more points than one are selected, the last setting (Auto switch AF points) has no meaning.

apersson850 wrote in post #16747231
No it's not. You have to enable at least four assist points for any handover to happen.
Note that as long as no more points than one are selected, the last setting (Auto switch AF points) has no meaning.

Anders, what I see in the viewfinder is the large AF select area and a single large(r) square. If I choose the selection two clicks to the right (small SEL area and a large(r) square, handoff doesn't happen. It doesn't happen with the 4 assist points enabled either.

However, if you pick the large (61 point AF area) and the single large(r) square, it uses up to 4 assist points to determine handover.

EDIT: The 'large(r) point in Canon parlance is called 'Single Point AF'. The large AF select area is '61-point automatic selection AF' p.75 and p.77 of the manual respectively.

No, that's not the way it works.
Assuming you use Servo AF, this however is how it works.

• Single spot AF and single point AF (one box with dot inside and then without): No handover, since there's nothing to hand over to.
  
• Single point AF with four assist points, single point AF with eight assist points and all 61 points (with one box defined as the starting point): Handover will take place if the main point can't track and one or more of the assist points can. The number of assist points in this case is four, eight or 60.
  
• Zone AF: Camera picks starting point according to the same rule as for One Shot AF, then tracks according to Servo AF rules with possible handover inside the zone.
  

That's exactly the way it works in my 5DIII.

All the other cases you just threw in are obfuscating the fact.

However, have it your way... I am not getting into such games... checking out of this thread...

MakisM1 wrote in post #16747496
It doesn't happen with the 4 assist points enabled either.

However, if you pick the large (61 point AF area) and the single large(r) square, it uses up to 4 assist points to determine handover.

These are the two things you've misunderstood.
Handover does occur with four assist points in the first case, and handover occurs to all 60 points as needed in the second.
I just listed the other cases for completeness, not to cover up any fact.

But it's up to you if you want to learn something or not. Perhaps someone else wants to.

Thanks all, I'm reading through and will give these tips a try!!!

There's a lag between the time you press the shutter to enable the continuous focus and the time the camera snaps into focus and starts calculating its tracking algorithm.

Perhaps you are not allowing the camera enough time to do so? May need to start anticipating more and begin focus tracking a little more prior to the intended movement...

Anything up to about half a second helps. After half a second, the camera has all the data it needs, so tracking for longer periods of time usually doesn't add any more benefit.

Is this really an AF issue or a motion blur issue? Sure looks to me like a motion blur...

If no expansion points are being used, Case 3 should provide a faster reaction.