More 7DII focus problems

[Marsu42]

So, please don't post anymore as it doesn't bring anything.

This is just the reaction desired by trolls, better use the "ignore this user's posts" option in your settings.

Am I hearing it correct that 6D has better focusing ability than the 7D2?

Sure, if a superhero uses it. Superheros always get incredible results even from gear with specs that makes it virtually impossible in the first place . And remember: If something went wrong, you need to check your afma :->

 

[Don Haines]

Am I hearing it correct that 6D has better focusing ability than the 7D2?

The 6D manual has 10 pages for the AF system...
The 7D2 has 111 pages for the AF system.....

The 6D:
11 points
Center: cross-type at f/5.6; vertical line-sensitive at f/2.8.
Upper and lower AF points: vertical line-sensitive AF at f/5.6.
Other AF points: Horizontal line-sensitive AF at f/5.6
Center AF Point: EV -3 to 18
Other AF points: EV +0.5 to 18
AF Point Selection
(1) Automatic selection
(2) Manual selection


The 7D2:
65-points
all cross-type AF
center AF point is a dual cross-type AF point at f/2.8
EV 0-20
AF Point Selection
(1) Single-point Spot AF (Manual selection)
(2) Single-point AF (Manual selection)
(3) AF point expansion (Manual selection, 4 points: Up, down, left, and right)
(4) AF point expansion (Manual selection, surrounding 8 points)
(5) Zone AF (Manual zone selection)
(6) Large Zone AF (Manual zone selection)
(7) Auto Selection 65-point AF


my vote is the 7D2....

 

[Loswr]

Am I hearing it correct that 6D has better focusing ability than the 7D2?

Yes, the 6D is better...but still unusable. Only the T2i and EOS M can accurately autofocus, apparently. At least in the 'right' hands...

 

[sanj]

Am I hearing it correct that 6D has better focusing ability than the 7D2?

Yes, the 6D is better...but still unusable. Only the T2i and EOS M can accurately autofocus, apparently. At least in the 'right' hands...

As they say in American movies: "Houston we have a problem."

 

[Mt Spokane Photography]

Am I hearing it correct that 6D has better focusing ability than the 7D2?

The 6D manual has 10 pages for the AF system...
The 7D2 has 111 pages for the AF system.....

The 6D:
11 points
Center: cross-type at f/5.6; vertical line-sensitive at f/2.8.
Upper and lower AF points: vertical line-sensitive AF at f/5.6.
Other AF points: Horizontal line-sensitive AF at f/5.6
Center AF Point: EV -3 to 18
Other AF points: EV +0.5 to 18
AF Point Selection
(1) Automatic selection
(2) Manual selection


The 7D2:
65-points
all cross-type AF
center AF point is a dual cross-type AF point at f/2.8
EV 0-20
AF Point Selection
(1) Single-point Spot AF (Manual selection)
(2) Single-point AF (Manual selection)
(3) AF point expansion (Manual selection, 4 points: Up, down, left, and right)
(4) AF point expansion (Manual selection, surrounding 8 points)
(5) Zone AF (Manual zone selection)
(6) Large Zone AF (Manual zone selection)
(7) Auto Selection 65-point AF


my vote is the 7D2....

FF bodies have generally had more accurate AF (in terms of inches or mm accuracy) than crop bodies. They need it, because the depth of field on a FF can be a lot less. As I recall, AF accuracy is specified based on 1/3rd the depth of field up to f/2.8.

The number of pages in a manual does not affect AF accuracy, there are no settings for it, its built into the size and spacing of the elements on the AF sensor.

The 7D MK II has a sophisticated AF system, and is much better at tracking subjects, has fast AF speed, and much better when focusing at off center points, but when comparing accuracy on the center point, I'd expect to see the 6D win because in in or cm, 1/3 the depth of field is a much smaller number on FF.

From TDP http://www.the-digital-picture.com/Photography-Tips/Canon-EOS-DSLR-Autofocus-Explained.aspx

"Precision, invisibility, and other intangibles
As mentioned above with the precision discussion, there's a modified type of AF point called a 'high-precision' point, which focuses within 1/3 of the depth of focus of the lens at max aperture, vs. the normal precision spec of within 1 depth of focus. Usually, the high precision point is the center point, and it operates in high-precision mode with an f/2.8 lens on most bodies, or an f/4 lens on 1-series bodies. The 1D X is an exception in two ways - it has five high-precision points in a central vertical column, instead of just one, and they require f/2.8 unlike previous 1-series bodies. "

 

[takesome1]

Am I hearing it correct that 6D has better focusing ability than the 7D2?

The 6D manual has 10 pages for the AF system...
The 7D2 has 111 pages for the AF system.....

The 6D:
11 points
Center: cross-type at f/5.6; vertical line-sensitive at f/2.8.
Upper and lower AF points: vertical line-sensitive AF at f/5.6.
Other AF points: Horizontal line-sensitive AF at f/5.6
Center AF Point: EV -3 to 18
Other AF points: EV +0.5 to 18
AF Point Selection
(1) Automatic selection
(2) Manual selection


The 7D2:
65-points
all cross-type AF
center AF point is a dual cross-type AF point at f/2.8
EV 0-20
AF Point Selection
(1) Single-point Spot AF (Manual selection)
(2) Single-point AF (Manual selection)
(3) AF point expansion (Manual selection, 4 points: Up, down, left, and right)
(4) AF point expansion (Manual selection, surrounding 8 points)
(5) Zone AF (Manual zone selection)
(6) Large Zone AF (Manual zone selection)
(7) Auto Selection 65-point AF


my vote is the 7D2....

FF bodies have generally had more accurate AF (in terms of inches or mm accuracy) than crop bodies. They need it, because the depth of field on a FF can be a lot less. As I recall, AF accuracy is specified based on 1/3rd the depth of field up to f/2.8.

The number of pages in a manual does not affect AF accuracy, there are no settings for it, its built into the size and spacing of the elements on the AF sensor.

The 7D MK II has a sophisticated AF system, and is much better at tracking subjects, has fast AF speed, and much better when focusing at off center points, but when comparing accuracy on the center point, I'd expect to see the 6D win because in in or cm, 1/3 the depth of field is a much smaller number on FF.

From TDP http://www.the-digital-picture.com/Photography-Tips/Canon-EOS-DSLR-Autofocus-Explained.aspx

"Precision, invisibility, and other intangibles
As mentioned above with the precision discussion, there's a modified type of AF point called a 'high-precision' point, which focuses within 1/3 of the depth of focus of the lens at max aperture, vs. the normal precision spec of within 1 depth of focus. Usually, the high precision point is the center point, and it operates in high-precision mode with an f/2.8 lens on most bodies, or an f/4 lens on 1-series bodies. The 1D X is an exception in two ways - it has five high-precision points in a central vertical column, instead of just one, and they require f/2.8 unlike previous 1-series bodies. "

That is the real problem with the 7D II AF system, it is salesman hype and bloated specs. 65 points sure makes it sound like it is on par with a 1D x, but lost in the text is the 5 precision points versus 1.

Does the 7D II really need 65 points? Probably for sales but I have a suspension that it could have been designed to perform just as we'll with far fewer.

 

[Marsu42]

Does the 7D II really need 65 points? Probably for sales but I have a suspension that it could have been designed to perform just as we'll with far fewer.

I don't know how the 7d2 performs with single af points in real life, but having a high point density isn't only good for multi-point af tracking, but for shooting w/o recompose.

If you can have the af point exactly where you want it given the current picture composition, you get the maximum resolution (as you don't have to crop w/o recompose) or loose precision (because of recompose). Esp. if your af target is off the center, this is an advantage to ff cameras with all af points clustered.

 

[Don Haines]

Am I hearing it correct that 6D has better focusing ability than the 7D2?

The 6D manual has 10 pages for the AF system...
The 7D2 has 111 pages for the AF system.....

The 6D:
11 points
Center: cross-type at f/5.6; vertical line-sensitive at f/2.8.
Upper and lower AF points: vertical line-sensitive AF at f/5.6.
Other AF points: Horizontal line-sensitive AF at f/5.6
Center AF Point: EV -3 to 18
Other AF points: EV +0.5 to 18
AF Point Selection
(1) Automatic selection
(2) Manual selection


The 7D2:
65-points
all cross-type AF
center AF point is a dual cross-type AF point at f/2.8
EV 0-20
AF Point Selection
(1) Single-point Spot AF (Manual selection)
(2) Single-point AF (Manual selection)
(3) AF point expansion (Manual selection, 4 points: Up, down, left, and right)
(4) AF point expansion (Manual selection, surrounding 8 points)
(5) Zone AF (Manual zone selection)
(6) Large Zone AF (Manual zone selection)
(7) Auto Selection 65-point AF


my vote is the 7D2....

FF bodies have generally had more accurate AF (in terms of inches or mm accuracy) than crop bodies. They need it, because the depth of field on a FF can be a lot less. As I recall, AF accuracy is specified based on 1/3rd the depth of field up to f/2.8.

The number of pages in a manual does not affect AF accuracy, there are no settings for it, its built into the size and spacing of the elements on the AF sensor.

The 7D MK II has a sophisticated AF system, and is much better at tracking subjects, has fast AF speed, and much better when focusing at off center points, but when comparing accuracy on the center point, I'd expect to see the 6D win because in in or cm, 1/3 the depth of field is a much smaller number on FF.

From TDP http://www.the-digital-picture.com/Photography-Tips/Canon-EOS-DSLR-Autofocus-Explained.aspx

"Precision, invisibility, and other intangibles
As mentioned above with the precision discussion, there's a modified type of AF point called a 'high-precision' point, which focuses within 1/3 of the depth of focus of the lens at max aperture, vs. the normal precision spec of within 1 depth of focus. Usually, the high precision point is the center point, and it operates in high-precision mode with an f/2.8 lens on most bodies, or an f/4 lens on 1-series bodies. The 1D X is an exception in two ways - it has five high-precision points in a central vertical column, instead of just one, and they require f/2.8 unlike previous 1-series bodies. "

Although the center point of the 7D2 is a dual cross point, not a single cross like the 6D

 

[luckydude]

Hi the guy who started this thread here. Sorry I've been absent, been sick as a dog, you just don't want to know. Coming out of both ends, nuf said, bokay?

Some more info/thoughts. First I have a 5DIII, not II, not that that would matter in this case. Second, the reason I took the 7DII and the 35mm is I knew that I wanted about a 50mm lens and I had loaned out my 50mm f1.4. So either it was too wide with the 35mm (in your face) or 85mm 1.8 (too long), or the 24-105 (too dark). I'd heard good things about the 7DII at high ISO so I went with that. (As an aside, I'm inclined to send the 35 f2 back and get the Sigma, bokeh is less of an issue for me, low light is a big issue. YMMV.)

As for flash, I wasn't a pro, I was an invited guest. I hate flash, it's annoying, I like candid shots. So no flash for me.

As for Tv, AiServo, half of that is my bad. I'm reasonably good at shooting sports, there it is center point, spot metering, Ai Servo, Tv. I use that because I need a certain shutter speed to capture the action, I float aperture rather than ISO because the 5D floats it into a bad space.

But yeah, I shouldn't have been on Ai Servo. Did I mention there was booze at this party?

All that said, I don't own a 1Dx, what I've heard is that the 7DII has the 1Dx AF system. Maybe I'm naive but I expected more. So am I to take away that the only place you use all 61 AF points is BIF?

Seems to me that most point and shoots make better choices than the 7DII did. Did you see that one where it had my wife front and center and focussed on the background? I can go through the non keepers and find a ton more like that. If Ai Servo is the culprit, yeah, ok, my bad. But I'm skeptical.

I'm inclined to repeat some low light tests with the 7DII and 5DIII. Right now my kids are wondering why I'm talking to you instead of watching a Christmas movie with them. Silly kids.

 

[sanj]

Am I hearing it correct that 6D has better focusing ability than the 7D2?

The 6D manual has 10 pages for the AF system...
The 7D2 has 111 pages for the AF system.....

The 6D:
11 points
Center: cross-type at f/5.6; vertical line-sensitive at f/2.8.
Upper and lower AF points: vertical line-sensitive AF at f/5.6.
Other AF points: Horizontal line-sensitive AF at f/5.6
Center AF Point: EV -3 to 18
Other AF points: EV +0.5 to 18
AF Point Selection
(1) Automatic selection
(2) Manual selection


The 7D2:
65-points
all cross-type AF
center AF point is a dual cross-type AF point at f/2.8
EV 0-20
AF Point Selection
(1) Single-point Spot AF (Manual selection)
(2) Single-point AF (Manual selection)
(3) AF point expansion (Manual selection, 4 points: Up, down, left, and right)
(4) AF point expansion (Manual selection, surrounding 8 points)
(5) Zone AF (Manual zone selection)
(6) Large Zone AF (Manual zone selection)
(7) Auto Selection 65-point AF


my vote is the 7D2....

FF bodies have generally had more accurate AF (in terms of inches or mm accuracy) than crop bodies. They need it, because the depth of field on a FF can be a lot less. As I recall, AF accuracy is specified based on 1/3rd the depth of field up to f/2.8.

The number of pages in a manual does not affect AF accuracy, there are no settings for it, its built into the size and spacing of the elements on the AF sensor.

The 7D MK II has a sophisticated AF system, and is much better at tracking subjects, has fast AF speed, and much better when focusing at off center points, but when comparing accuracy on the center point, I'd expect to see the 6D win because in in or cm, 1/3 the depth of field is a much smaller number on FF.

From TDP http://www.the-digital-picture.com/Photography-Tips/Canon-EOS-DSLR-Autofocus-Explained.aspx

"Precision, invisibility, and other intangibles
As mentioned above with the precision discussion, there's a modified type of AF point called a 'high-precision' point, which focuses within 1/3 of the depth of focus of the lens at max aperture, vs. the normal precision spec of within 1 depth of focus. Usually, the high precision point is the center point, and it operates in high-precision mode with an f/2.8 lens on most bodies, or an f/4 lens on 1-series bodies. The 1D X is an exception in two ways - it has five high-precision points in a central vertical column, instead of just one, and they require f/2.8 unlike previous 1-series bodies. "

Is this had or have? And any links where I could read further on this pls?

 

[FEBS]

Hi the guy who started this thread here. Sorry I've been absent, been sick as a dog, you just don't want to know. Coming out of both ends, nuf said, bokay?

Some more info/thoughts. First I have a 5DIII, not II, not that that would matter in this case. Second, the reason I took the 7DII and the 35mm is I knew that I wanted about a 50mm lens and I had loaned out my 50mm f1.4. So either it was too wide with the 35mm (in your face) or 85mm 1.8 (too long), or the 24-105 (too dark). I'd heard good things about the 7DII at high ISO so I went with that. (As an aside, I'm inclined to send the 35 f2 back and get the Sigma, bokeh is less of an issue for me, low light is a big issue. YMMV.)

As for flash, I wasn't a pro, I was an invited guest. I hate flash, it's annoying, I like candid shots. So no flash for me.

As for Tv, AiServo, half of that is my bad. I'm reasonably good at shooting sports, there it is center point, spot metering, Ai Servo, Tv. I use that because I need a certain shutter speed to capture the action, I float aperture rather than ISO because the 5D floats it into a bad space.

But yeah, I shouldn't have been on Ai Servo. Did I mention there was booze at this party?

All that said, I don't own a 1Dx, what I've heard is that the 7DII has the 1Dx AF system. Maybe I'm naive but I expected more. So am I to take away that the only place you use all 61 AF points is BIF?

Seems to me that most point and shoots make better choices than the 7DII did. Did you see that one where it had my wife front and center and focussed on the background? I can go through the non keepers and find a ton more like that. If Ai Servo is the culprit, yeah, ok, my bad. But I'm skeptical.

I'm inclined to repeat some low light tests with the 7DII and 5DIII. Right now my kids are wondering why I'm talking to you instead of watching a Christmas movie with them. Silly kids.

OK. Thanks for your feedback. Glad to hear you are better right now, and can further follow on this thread.

But it does matter if you own a 5Diii. The high iso of the 5Diii is better and also the AF is better compared to the 5Dii. In that case I would never have taken the 7D2. FF is so much better for high iso. The 7D2 can't being compared to the 7D, but it is an APS-C. That means more noise compared to the FF, as the pixels are much smaller.

Even on a 5Diii I will not allow my ISO to go up till 12800. You must go really max to 6400. The shutterspeed might have been a little lower. The IS inside must hep you to reduce your shutterspeed to 1/60 or even 1/30. Using the 7D2 on iso 12800 is not an option for me. I really don't expect hardly a keeper at that moment. I will have more keepers with a lens with a good IS and a lower shutterspeed in combination on a 7D2 with max 1600 till 3200ISO.

To be honest, as already mentioned before, I would use flash. I can accept that it is not your choice, but then you should keep ISO moderate and not as high as 12800, because all your photos will otherwise soft.

 

[luckydude]

OK. Thanks for your feedback. Glad to hear you are better right now, and can further follow on this thread.

But it does matter if you own a 5Diii. The high iso of the 5Diii is better.

The problem with the 5D was that I didn't have an appropriate lens, I had loaned out my 50mm f1.4. I agree that the 5D is the tool for the job given the right lens.

The issue I have with the 7D in all AF points mode is what it locks onto. There are number of pictures where it made the wrong choice. Like that one of my wife in the kitchen, why did it choose the background? I'll bet you a beer that a cheap point and shoot would get that AF right every time, why does the 7DII get it wrong?

And here, where is the focus?

http://www.mcvoy.com/lm/yunah-bad/10.html
http://www.mcvoy.com/lm/yunah-bad/11.html
http://www.mcvoy.com/lm/yunah-bad/22.html

These are the real weird ones, the camera is ignoring the obvious focus choice and grabbing the back of someone's head:

http://www.mcvoy.com/lm/yunah-bad/24.html
http://www.mcvoy.com/lm/yunah-bad/68.html
http://www.mcvoy.com/lm/yunah-bad/69.html

Those seem pretty bad to me, yeah, the camera picked something to track but don't you see how it clearly picked the wrong thing in those last 3? Seems like the alg is to pick the closest thing, which maybe makes sense but then how do you explain it picking the background on my wife?

 

[Loswr]

The issue I have with the 7D in all AF points mode is what it locks onto. There are number of pictures where it made the wrong choice. Like that one of my wife in the kitchen, why did it choose the background? I'll bet you a beer that a cheap point and shoot would get that AF right every time, why does the 7DII get it wrong?

The issue with your 7D is wetware - you. The camera's auto AF point selection operates on a defined set of parameters, which do not include reading your mind or correctly guessing what you think should be the subject of the image.

The cheap P&S could pick something totally random and in most cases (including 'typical' indoor scenes like those you've posted), pretty much everything in the frame is within the DoF due to the very narrow effective aperture of the lens. The larger effective aperture(s) of the lens(es) used on an APS-S or FF mean shallower DoF which makes proper focusing much more important. I suppose you could continue using auto point selection in your dSLR and just stop your lenses down to f/22...that way, you'd have a much better chance of getting the subject you want in focus with your very large/heavy/expensive P&S.

 

[takesome1]

OK. Thanks for your feedback. Glad to hear you are better right now, and can further follow on this thread.

But it does matter if you own a 5Diii. The high iso of the 5Diii is better.

The problem with the 5D was that I didn't have an appropriate lens, I had loaned out my 50mm f1.4. I agree that the 5D is the tool for the job given the right lens.

The issue I have with the 7D in all AF points mode is what it locks onto. There are number of pictures where it made the wrong choice. Like that one of my wife in the kitchen, why did it choose the background? I'll bet you a beer that a cheap point and shoot would get that AF right every time, why does the 7DII get it wrong?

And here, where is the focus?

http://www.mcvoy.com/lm/yunah-bad/10.html
http://www.mcvoy.com/lm/yunah-bad/11.html
http://www.mcvoy.com/lm/yunah-bad/22.html

These are the real weird ones, the camera is ignoring the obvious focus choice and grabbing the back of someone's head:

http://www.mcvoy.com/lm/yunah-bad/24.html
http://www.mcvoy.com/lm/yunah-bad/68.html
http://www.mcvoy.com/lm/yunah-bad/69.html

Those seem pretty bad to me, yeah, the camera picked something to track but don't you see how it clearly picked the wrong thing in those last 3? Seems like the alg is to pick the closest thing, which maybe makes sense but then how do you explain it picking the background on my wife?

I don't want to beat the horse to death, but all those examples I would have been using single shot single point focus. Focus and recompose, since it is faster than shuffling around fro the right point. Not using AI servo and Not all points.

Now if those shots are in that mode then maybe you have problems.

 

[FEBS]

OK. Thanks for your feedback. Glad to hear you are better right now, and can further follow on this thread.

But it does matter if you own a 5Diii. The high iso of the 5Diii is better.

The problem with the 5D was that I didn't have an appropriate lens, I had loaned out my 50mm f1.4. I agree that the 5D is the tool for the job given the right lens.

The issue I have with the 7D in all AF points mode is what it locks onto. There are number of pictures where it made the wrong choice. Like that one of my wife in the kitchen, why did it choose the background? I'll bet you a beer that a cheap point and shoot would get that AF right every time, why does the 7DII get it wrong?

And here, where is the focus?

http://www.mcvoy.com/lm/yunah-bad/10.html
http://www.mcvoy.com/lm/yunah-bad/11.html
http://www.mcvoy.com/lm/yunah-bad/22.html

These are the real weird ones, the camera is ignoring the obvious focus choice and grabbing the back of someone's head:

http://www.mcvoy.com/lm/yunah-bad/24.html
http://www.mcvoy.com/lm/yunah-bad/68.html
http://www.mcvoy.com/lm/yunah-bad/69.html

Those seem pretty bad to me, yeah, the camera picked something to track but don't you see how it clearly picked the wrong thing in those last 3? Seems like the alg is to pick the closest thing, which maybe makes sense but then how do you explain it picking the background on my wife?

Please do read the 7d2 AF guide carefully for using all 65 points. There is mentioned in that guide that if one-shot is choosen the closest point of the 65 points will be used. In ai-servo mode however, focus starts with the manual selected af point And will then follow that point over the 65 different positions, dependentie on Itr additionele tracking info. Both methodes are very usefull, however they different ferm the current p&s that have auto face recognition which the 7d2 does NOT have. The 7d2 Has a color And face tracking system, but that's different from p&s

 

[luckydude]

The issue I have with the 7D in all AF points mode is what it locks onto. There are number of pictures where it made the wrong choice. Like that one of my wife in the kitchen, why did it choose the background? I'll bet you a beer that a cheap point and shoot would get that AF right every time, why does the 7DII get it wrong?

The issue with your 7D is wetware - you. The camera's auto AF point selection operates on a defined set of parameters, which do not include reading your mind or correctly guessing what you think should be the subject of the image.

The cheap P&S could pick something totally random and in most cases (including 'typical' indoor scenes like those you've posted), pretty much everything in the frame is within the DoF due to the very narrow effective aperture of the lens. The larger effective aperture(s) of the lens(es) used on an APS-S or FF mean shallower DoF which makes proper focusing much more important. I suppose you could continue using auto point selection in your dSLR and just stop your lenses down to f/22...that way, you'd have a much better chance of getting the subject you want in focus with your very large/heavy/expensive P&S.

Hey, ease up a bit, I'm just trying to learn here. And I'm not quite the idiot you think I am, I shoot sports and it's almost always center point only, I get good shots, as good as the pros at the tournaments I've gone to.

Perhaps you can explain how these defined set of parameters choose what they choose. Why does it sometimes choose what is the background, ignoring a decent foreground? Why does it sometimes choose stuff off to the side and other times not?

Did you look at those pictures and can you explain why it choose what it did?

Am I the only one scratching my head over that? For the record, the 5DIII does not do that, the 7DI did not do that, my 20D and 40D and T4i did not do that. But I'm sure the problem is me and the camera is perfect and all those other bodies just happened to do a better job.

 

[luckydude]

Please do read the 7d2 AF guide carefully for using all 65 points. There is mentioned in that guide that if one-shot is choosen the closest point of the 65 points will be used. In ai-servo mode however, focus starts with the manual selected af point And will then follow that point over the 65 different positions, dependentie on Itr additionele tracking info. Both methodes are very usefull, however they different ferm the current p&s that have auto face recognition which the 7d2 does NOT have. The 7d2 Has a color And face tracking system, but that's different from p&s

Thanks, will do. Is the all points mode in the 7DII a departure from the 5DIII and other earlier bodies?

I remember discussions here about how the camera will decide where to start and there is supposedly logic in there to prevent (as was shown) an fencepost grabbing the focus when the main picture is beyond that.

 

[Keith_Reeder]

That is the real problem with the 7D II AF system, it is salesman hype and bloated specs. 65 points sure makes it sound like it is on par with a 1D x, but lost in the text is the 5 precision points versus 1.

There is no "problem" with the 7D Mk II's AF. There may be a problem with some 7D Mk II users.

As to the "5 precisions points vs. 1" detail - can you tell me when that's ever likely actually to matter?

Here's a far more useful page from TDP:
http://www.the-digital-picture.com/Comparisons/Canon-EOS-7D-II-1D-X-5D-III-AF-Comparison.aspx

Of particular Real World significance:

"However, all 65 AF points on the EOS 7D Mark II are standard precision cross-type points, versus 21 standard precision cross-type points on the EOS- 1D X and EOS 5D Mark III. For EF lenses with maximum apertures equal to or larger than f/5.6, the EOS 7D Mark II has an advantage, especially when considered in combination with the larger coverage area described earlier. Advantage: EOS 7D Mark II"

I know from hands-on experience that in the vast majority of cases, that's going to get me more in-focus shots than four more high precision AF points in a vertical line in the middle of the AF array.

 

[Keith_Reeder]

I don't know how the 7d2 performs with single af points in real life, but having a high point density isn't only good for multi-point af tracking, but for shooting w/o recompose.

Correct - and as a bird 'tog I get more benefit from these additional AF points compositionally than I do from the benefit they deliver in AF terms.

I'm shooting a car rally tomorrow - I'll be all over the AF array for compostional purposes there, too.

 

[Keith_Reeder]

there is supposedly logic in there to prevent (as was shown) an fencepost grabbing the focus when the main picture is beyond that.

No camera's that clever - that's our job.