Investing in a 6D or 5D Mark III

Started Mar 13, 2014 | Discussions thread
bhollis Veteran Member • Posts: 3,801
Re: Investing in a 6D or 5D Mark III

billythek wrote:

abolit66 wrote:

the center AF point of 6D is not better , it's more sensitive. 5DIII has , if I'm not mistaken, 4 or 5 double cross-type points at the center area where as 6D - only one cross-type(not double).

Keith Z Leonard wrote:

Jovits wrote:

The center AF point of the 6D is actually slightly better than that of the 5D3

What you say is correct and completely irrelevant to my statement, I did not say the center group or portion of the AF area is better, I stated the the 6D's center AF point is slightly better. Anyone evaluating these two cameras in single shot, single point AF using the center points will have better results in low light with the 6D, and nearly equal results under normal to good lighting conditions. They perform very similarly except in an edge case where the 6D will out perform the 5D3, that ranks a "slightly better" qualifier to me. This seems a reasonable and perfectly valid estimation of the relative abilities of the individual center AF points of the two cameras.

I did not say that the 6D AF system is better than the 5D3's, that would be silly. If it makes you feel better, I own and operate a 5D3 and think it's fantastic. I am also not threatened in any way by the simple fact that the 6D center AF point can do things that the 5D3's center AF point cannot. Please feel free to continue a pointless semantic argument if you so desire, but I will not.

Here is an article laying out the 5D3 AF module, interesting but has no relevance in a direct comparison of the single center AF point only. Thus a focus/recompose shooter using only the center AF point will likely not care about the performance of the other 60 AF points from the 5D3. This isn't how I shoot, but it is how a lot of people shoot.

5 center most AF points are high precision cross type

21 are cross type at f5.6

41 total cross type at f4

The center point on the 6D will operate in lower light than the center point of the 5D3. However, the center points of the 5D3 are high precision double cross points.

What that means is, provided you are using a lens that is f/2.8 or wider, the focus will be more precise using the 5D3 when using the center point. This means more to some people than being able to function in extremely low light. Of course, others might not even notice.

The way phase detection works is the camera iterates using the normal focus points until it detects focus within a certain tolerance. In fact the focus is usually at the end of that tolerance. If a camera has high precision points (and you are using an f/2.8 or faster lens), the high precision points then take over and drive focus to a tighter tolerance.

So it is not just semantics, it can make a big difference to some people. But to others, granted, not so much.
- Bill

Discussion of 6D center point AF accuracy.

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