You're wrong about the 6D

I recently posted questions regarding the 6D, mostly asking for comparisons to the 5D2.
Most of those who kindly contributed mentioned that the 6D does as well throughout as the 5D2. Specifically when it comes to noise, in which case many claimed it does slightly better, but not as good as the 5D3. For focus accuracy and speed (using the center point only) all stated it should be just as fast and accurate as the 5D2. After real world testing both of these aspects, I quickly notice the 6d is significantly inferior. At 2000 you see very unappealing noise, and while shooting people moving in dim environments, even with flash assist, the focusing speed was over 50% slower than the 5D2. Just thought I'd clarify this for others who may be thinking of purchasing a 6D. It's definitely not on par with the 4 year older 5d2, and certainly not better where it matters most.
Let me know if you've experienced differently, perhaps my new camera is a lemon.

how do you measure something as temporal and brief as AF speed, to derive the '50% slower' assessment?

Badly exposed image will bring more noise no matter how low the ISO is, you have to account for user error.

If you are getting unappealing noise at ISO 2000 with a 6D you are exposing poorly or you have a lemon......

I am a hobbyist grandma and not a professional at all. But I went from the 5D II to the 6D for better ISO performance three years ago and I have yet to be disappointed. At the time, 6d was a tad better than the 5D III for noise performance. Notice the word "tad" but the threads of both 5D III and 6d owners were mostly in agreement of this at that time.

I will be the first to admit that it was probably user error when I had the 5D II more than the camera itself. I went from a newbie with a T1i to a 5D II probably before I was ready to. The biggest reason I switched was the 6D was a bit lighter and a bit easier for me to handle. However, never have I been disappointed with high ISO and noise with the 6D, never. It takes fantastic pictures. The camera is what 5 years (?) newer than the 5d, where technology and newer sensor do help out a lot.

Recently I purchased the T6i for back-up, lightweight and zoom lens and the 6D is leaps ahead with the ISO performance. I don't pretend to know more than I do, but all things equal, I would think the 6D would be as good, if not better, than your 5D II.

But that is my experience with the two.

Post some side by side pics. Well planned tests shots, not snapshots taken hours or days apart under different conditions with different lenses. There are plenty of examples out there that show the contrary.

If you have a lemon you will want the strong evidence of testing anyway.

I don't know about the image quality between the two at high ISO...but the 5D2 had some hidden focus points around the center that really helped out focusing which I believe the 6D does not have. This most likely is contributing to the difference in focus speed.

I had a 5Dc (same AF system as 5D2) and my 6D at the same time. My experience is the exact opposite of yours. Using only the center AF point, my 6D is BETTER at tracking, and switching targets quickly, than my 7D was. I had peripheral points on the 5D totally fail in broad daylight. The 6D is better, but I don't use the peripheral points anymore. The 6D can also focus in light low enough the 5D quits trying entirely.

I can't compare noise, because I never had a 5D2. As far as the 6D goes, if you are getting un-resolvable noise at ISO 6400, either your camera is broken, or you are doing something wrong. I've taken well-controlled test shots with my 6D at ISO 102,400 that have little to no noticeable noise, even in the shadows. The 5D2's upper ISO limit is 25,600. I can shoot my 6D JPG at that level and get decent results.

I made the mistake of giving a specific number when I actually don't know of course, like you said, it's too hard to come up with, but for that reason I didn't anyone would take it literally. I said over 50% simply because I could take about 2 photos in the time I took 1 with the 6d. That's technically 100% slower, but I rather be under than over the fact. I could be doing something wrong, though.

But I only use the center focusing point at all times....

I will admit that it was in improperly exposed images that I noticed this difference. When looking at properly exposed I can't find a differece at 2000 iso... but if one camera is better than the other I would assume that would apply across the board. I'll have to do controlled test shots and post them here when I get a chance. Probably of high ISO proper exposure and the 2000 iso poor exposure and show both scenarios.

I will do so, hopefully tomorrow if I get a chance. The photos I was comparing were not most accurately exposed I should have noted. when looking at properly exposed I can't find a differece at 2000 iso... but if one camera is better than the other I would presume that would apply across the board.

Bassat wrote in post #18259014
I had a 5Dc (same AF system as 5D2) and my 6D at the same time. My experience is the exact opposite of yours. Using only the center AF point, my 6D is BETTER at tracking, and switching targets quickly, than my 7D was. I had peripheral points on the 5D totally fail in broad daylight. The 6D is better, but I don't use the peripheral points anymore. The 6D can also focus in light low enough the 5D quits trying entirely.

I can't compare noise, because I never had a 5D2. As far as the 6D goes, if you are getting un-resolvable noise at ISO 6400, either your camera is broken, or you are doing something wrong. I've taken well-controlled test shots with my 6D at ISO 102,400 that have little to no noticeable noise, even in the shadows. The 5D2's upper ISO limit is 25,600. I can shoot my 6D JPG at that level and get decent results.

Are you really sure the AF system is the same between the two cameras? Does the 6D have the 6 hidden assist AF points around the center for helping track focus?

I've never used the 6D...but everything I read about it indicated the AF is not up to the level of the 5D2, but the image quality is better, especially at higher ISO.

The 6D, shot in JPG, @ ISO 102400, as shot and ~100% crop. The only adjustment in LR was -1EC exposure correction. No noise reduction AT ALL. I see next to no noise in the original on a 22" monitor @ 100%. Try this with a 5D2.

Hogloff wrote in post #18259050
Are you really sure the AF system is the same between the two cameras? Does the 6D have the 6 hidden assist AF points around the center for helping track focus?

I've never used the 6D...but everything I read about it indicated the AF is not up to the level of the 5D2, but the image quality is better, especially at higher ISO.

The 5Dc and 5D2 have the same AF system. The AF system on the 6D is about 10 years newer. The 6D does not have any hidden AF points. It is my considered opinion, having used both 5D and 6D AF systems, that the 5D does not even come close to the 6D. The 6D will snap focus in -3EV light. The 5D stops even trying at 0EV. The 6D's AF is configurable for AI-SERVO tracking, or switching targets. The 5D/5D2 has no such feature. A 6D would have to be broken to perform down to the level of a 5D/5D2. And that is just the auto-focus systems.

I've never owned a 5D2, but my post above at ISO 102400 (says 51200, rest assured it was shot at 102,400) give a hint of what the 6D can do in JPG. I suppose it would be better if I shot raw and processed. With JPG files this good, I don't see any reason whatsoever to shoot raw.

EDIT: Apologies to Hogloff. I though I was replying to OP.

EDIT:
LR screenshot added to verify 102,400 ISO>