70D AF Points

I wasn't sure where to post this question, but my question is, what are the best AF points to use when shooting action/moving subjects such as birding or sports?
I have been trying to search and am getting mixed reviews. Some are saying use all Focus points and others say to use center.
Tips or suggestions would be greatly appreciated

Don't use AUTO AF point selection. It will automatically (DUH!) pick the closest high contrast thing in the VF-point array. The chance of that being your intended target is exceedingly small. I would start with the center ZONE and see how that works for you. Adjust as necessary.

Center zone is a good bet.
But the 19-point mode may work too in AI Servo mode. It lets you select the initial AF point (you place that on your subject) then the camera tracks the subject across the 19 points. It does work, although it has its limitations too. (NOTE: this 19-point AF mode works differently in One Shot mode. It will automatically make a decision based on the closest subject with good contrast.)

Start off using the center auto focus point. If you can't lock on to your subject next try AF point expansion with the center point active. You could also try Zone AF. I generally shoot with the center point, but for very fast eradic subjects such as Terns, I some times get better results with AF point expansion.

http://www.the-digital-picture.com/Reviews/Ca​non-EOS-70D.aspx

sliceotime wrote in post #16302436
Start off using the center auto focus point. If you can't lock on to your subject next try AF point expansion with the center point active. You could also try Zone AF. I generally shoot with the center point, but for very fast eradic subjects such as Terns, I some times get better results with AF point expansion.

http://www.the-digital-picture.com/Reviews/Ca​non-EOS-70D.aspx

The 70D doesn't have AF point expansion. That's a feature that the 7D has but which the 70D lacks.

The area covered by a single point may be large enough to make single-point tracking reasonable. You can also choose zones to track within, and that may be enough as well (depends on your needs).


While the 70D's autofocus system isn't as featureful as the 7D's, it looks to be pretty darned close in terms of end result capability, and might actually do tracking better than the 7D (you'll have to wait for head-to-head tracking comparisons to emerge to know that).

As much as I think the 7D is currently more camera for the money, that's only because they're available on the used/refurbished market. The 70D is serious camera for the money regardless, and I think people who buy it are going to be incredibly happy with it.

For those who want that tiny bit more camera for traditional (through the viewfinder) still shots, there's always the 7D.

Does anybody know if they designed the 70D to have a dedicated AF processor as well, just like the 7D has? Admittedly, the 70D has a slightly lower frame rate, thus a litte more time between shots for the focusing to do its calculations, but the difference isn't large as far as frame rate goes.
Thus ample computing power is critical to keep up AF tracking even when the camera rattles away at max continuous shooting speed.

apersson850 wrote in post #16302874
Does anybody know if they designed the 70D to have a dedicated AF processor as well, just like the 7D has? Admittedly, the 70D has a slightly lower frame rate, thus a litte more time between shots for the focusing to do its calculations, but the difference isn't large as far as frame rate goes.
Thus ample computing power is critical to keep up AF tracking even when the camera rattles away at max continuous shooting speed.

I don't think it needs it. The Digic5+ is 17 times faster than the Digic4. The 7D has 2-Digic4 chips and a dedicated AF chip. The Digic5+ can handle what all 3 chips on the 7D do, with processing power to spare.

YashicaFX2 wrote in post #16303091
I don't think it needs it. The Digic5+ is 17 times faster than the Digic4. The 7D has 2-Digic4 chips and a dedicated AF chip. The Digic5+ can handle what all 3 chips on the 7D do, with processing power to spare.

Wow, great infos, thanks

YashicaFX2 wrote in post #16303091
I don't think it needs it. The Digic5+ is 17 times faster than the Digic4. The 7D has 2-Digic4 chips and a dedicated AF chip. The Digic5+ can handle what all 3 chips on the 7D do, with processing power to spare.

Which is why the 5DMkIII doesn't have a dedicated AF chip. Oh, wait a moment - yes it does!

Frank,
I was just going to search for that info. Where did you find that?

From TDP 5DIII review:
(5D III has a single DIGIC 5+ processor and a non-specified AF-dedicated processor)

More searching yields info that confirms your statement. AF system of 5DIII is inherited from 1Dx. AF system of 1Dx is managed by a dedicated Digic4 chip. 1Dx has dual Digic5+ image processors to handle 12(14) fps. 5DIII had one Digic5+, but also the dedicated DIgic4 AF chip. The last question is: Does the 70D have a dedicated AF chip? Comparing to the 5DIII suggests that it does.

YashicaFX2 wrote in post #16303091
I don't think it needs it. The Digic5+ is 17 times faster than the Digic4. The 7D has 2-Digic4 chips and a dedicated AF chip. The Digic5+ can handle what all 3 chips on the 7D do, with processing power to spare.

Is this data validated?

Lone Rider wrote in post #16303101
Is this data validated?

No. I retract that statement. See posts 9 & 10, I believe.

YashicaFX2 wrote in post #16303115
No. I retract that statement. See posts 9 & 10, I believe.

Thanks...we had some cross posts

I've written this many times before, but again, then.
From what you can dechiper from Canon's information, it's like this.

Cameras have a Digic something CPU, or two of them (depending upon frame rate) to do the following:
Image processing from sensor.
Memory card and buffer memory control.
Rear LCD control.
Contrast detection and face recognition AF in live view.
Lighting type evaluation (5D Mark II & 50D).

Then there's a sequence control CPU, rsponsible for everything else. This is a RISC-based processor at about 40 MHz, of a different kind than the Digic chips, optimized for image processing as they are. This CPU takes care of the following:
Handling buttons and dials.
Shutter and mirror control.
Exposure metering and calculations.
AF metering and calculations.

Then some high end cameras, like the 7D, 1D Mark III, 1DX, 5D Mark III and some more, have a dedicated AF processor. This is also a RISC-based CPU, not Digic type, running at around 40 MHz.

The 1DX is the first one having a dedicated processor also for exposure metering. In this case it's a Digic type CPU, but that's becuase it also has to do image analysis, finding and tracking faces in the image etc.

Thus cameras with the "normal" dual Digic configuration (7D, 1DX etc.) don't use these for normal AF and other such stuff, but they are dedicated to image processing.

hollis_f wrote in post #16303097
Which is why the 5DMkIII doesn't have a dedicated AF chip. Oh, wait a moment - yes it does!

good thing 5DIII doesn't have far superior and more sophisticated AF.

Oh, wait a moment - yes it does!

give 70D a break, as it is a good performer and people who own 7D and 70D claim that the latter even has better AF performance - focus lock. all you do is bash the hell out of it.