Curious..

While the Canon 5D MKII, 5D MKIII and 6D each have a varying number of focus points, if you only use the center AF point is the AF performance of these three cameras fairly much equal?

I thought I read that the 6D's center point will be more sensitive than the two 5Ds.

coppertop wrote:
... if you only use the center AF point is the AF performance of these three cameras fairly much equal

Equal in good light.
6D supposedly better in low light.

Note the new focus points (5d3, 6d we assume, 1dx) are more accurate with the new lenses (mkII superteles, 40stm, 24/28Is, 70-300L etc.

Even the center focus point can be different, there is the ordinary 'cross-type', 'dual-cross-type' (better), and so on.

Access wrote:
Even the center focus point can be different, there is the ordinary 'cross-type', 'dual-cross-type' (better), and so on.

I thought all three had cross-type center focus point... guess I gotta do some more reading.

Thanks for the help everyone

Here's the exact details:

5d3 - Dual cross type for f/2.8 and wider. Cross type for f/5.6 and wider lenses.
5d2 - High-precision cross type for f/2.8 and wider lenses. Cross type for f/5.6 or wider lenses.
6d - Cross type, unknown (most likely similar to 5d2).

coppertop wrote:
Access wrote:
Even the center focus point can be different, there is the ordinary 'cross-type', 'dual-cross-type' (better), and so on.

I thought all three had cross-type center focus point... guess I gotta do some more reading.

Thanks for the help everyone


Read Roger's article in his blog at LensRentals site about Canon AF reality. He has some extremely valuable info up there, backed up by his work with Imatest.

http://www.lensrentals.com/blog/2012/08/autofocus-reality-part-3b-canon-cameras

I love it when Roger gets his geek on. It's a nerd crush.

Access wrote:
Here's the exact details:

5d3 - Dual cross type for f/2.8 and wider. Cross type for f/5.6 and wider lenses.
5d2 - High-precision cross type for f/2.8 and wider lenses. Cross type for f/5.6 or wider lenses.
6d - Cross type, unknown (most likely similar to 5d2).

The 6D AF chip, for those interested can be seen here:
http://www.learn.usa.canon.com/resources/photos/products/cameras/eos_6d/eos_6d_af.shtml

Even though AF performance depends on both HW and SW (in body and lens) some observation can be made in regards to the new chip:
- Very similar in AF-point array layout to the 5Dc and 5DII and thus inherits the same AF point directional sensitivity
- All AF-arrays appear to have been widened (thus improved sensitivity)
- F2.8 baseline horizontal array now double line, staggered configuration (improved accuracy)
- Only center point arrays are double row configuration and hence likely more accurate than outer points

~ hans ~