6D MKII Disapointing Focus Points Spread

Started Jun 30, 2017 | Discussions
sssanti Contributing Member • Posts: 608
6D MKII Disapointing Focus Points Spread
21

The dprewiew video: https://www.dpreview.com/videos/4599793823/video-first-look-at-the-canon-eos-6d-mark-ii shows the 6D2 focus points very close to the center of the frame. Scaling an image from this video and comparing to images of the 6D viewfinder, I get the conclusion that the spread of the focus points in the new 6D2 (12.5 mm) is narrower than in the original 6D (14.5 mm).

6D2

6D

Having 45 focus points clustered in the middle of the frame is less useful than having less points, but with a wider spread. Canon must be using the same autofocus module as in the rebels and 80D. Both the spread and the size of the markers is too small for a full frame camera.

Is Canon expecting 6D users to crop all photos with off-center compositions? Was it that expensive to increase the focus points spread to cover more of the full frame sensor?

Reusing the autofocus module from Rebels and the 80D is a very poor design choice.

Canon 6D Mark II Canon EOS 6D
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BlueWolverine02 Forum Member • Posts: 82
Re: 6D MKII Disapointing Focus Points Spread

What does everybody have against live view AF?  Serious question as I have never used it.

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OP sssanti Contributing Member • Posts: 608
Re: 6D MKII Disapointing Focus Points Spread
3

BlueWolverine02 wrote:

What does everybody have against live view AF? Serious question as I have never used it.

I don't have anything against it. Live view AF should be work well with the 6D2 dual pixel sensor and articulated LCD. However, I prefer the optical viewfinder in most cases, unless I use tripod or odd camera positions where it is easier to use the LCD.

apersson850 Senior Member • Posts: 1,402
Re: 6D MKII Disapointing Focus Points Spread
8

sssanti wrote:

Having 45 focus points clustered in the middle of the frame is less useful than having less points, but with a wider spread.

It's exactly the opposite. It's the fact that the points are close together that's good. If you can't have points all over, then better have them tight than far apart.

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Anders

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brightcolours Forum Pro • Posts: 15,590
Really?
10

sssanti wrote:

The dprewiew video: https://www.dpreview.com/videos/4599793823/video-first-look-at-the-canon-eos-6d-mark-ii shows the 6D2 focus points very close to the center of the frame. Scaling an image from this video and comparing to images of the 6D viewfinder, I get the conclusion that the spread of the focus points in the new 6D2 (12.5 mm) is narrower than in the original 6D (14.5 mm).

Wait, you cry over 1 mm difference of the marking of the outer AF point? Which is a whole 2.77% of the image width? Not even taking into account that the 6D mk II shows a bit more of the frame than the 6D does, so your half mm measurements are even less accurate, favouring the 6D?

6D2

6D

Having 45 focus points clustered in the middle of the frame is less useful than having less points, but with a wider spread.

Be serious now.

Canon must be using the same autofocus module as in the rebels and 80D. Both the spread and the size of the markers is too small for a full frame camera.

APS-C and FF cameras have the same usable size for DP AF sensors due to dimension constraints (the submirror has its limits for instance). It has always been this way.

Is Canon expecting 6D users to crop all photos with off-center compositions? Was it that expensive to increase the focus points spread to cover more of the full frame sensor?

Reusing the autofocus module from Rebels and the 80D is a very poor design choice.

mml4 Forum Member • Posts: 73
Re: 6D MKII Disapointing Focus Points Spread

apersson850 wrote:

sssanti wrote:

Having 45 focus points clustered in the middle of the frame is less useful than having less points, but with a wider spread.

It's exactly the opposite. It's the fact that the points are close together that's good. If you can't have points all over, then better have them tight than far apart.

Please explain.

Thanks,

Marc

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Dlee13
Dlee13 Regular Member • Posts: 222
Re: 6D MKII Disapointing Focus Points Spread
3

The spread doesn't bother me. I figure if I'm composing something at the edge of the frame then I can use DPAF which is super accurate with it's tracking.

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RedFox88 Forum Pro • Posts: 28,612
Re: 6D MKII Disapointing Focus Points Spread
3

sssanti wrote:

The dprewiew video: https://www.dpreview.com/videos/4599793823/video-first-look-at-the-canon-eos-6d-mark-ii shows the 6D2 focus points very close to the center of the frame. Scaling an image from this video and comparing to images of the 6D viewfinder, I get the conclusion that the spread of the focus points in the new 6D2 (12.5 mm) is narrower than in the original 6D (14.5 mm).

NO it's  the same width

6D2

6D

Having 45 focus points clustered in the middle of the frame is less useful than having less points, but with a wider spread. Canon must be using the same autofocus module as in the rebels and 80D. Both the spread and the size of the markers is too small for a full frame camera.

Is Canon expecting 6D users to crop all photos with off-center compositions? Was it that expensive to increase the focus points spread to cover more of the full frame sensor?

Reusing the autofocus module from Rebels and the 80D is a very poor design choice.

no, it's one design that just looks better in aps-c due to cropped viewfinder

noggin2k1
noggin2k1 Senior Member • Posts: 2,067
Re: 6D MKII Disapointing Focus Points Spread
4

Any photographer worth their salt with focus and recompose. If this is a problem because of trying to focus on a moving object - you need to realise this isn't what the camera is designed for.

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Steve Balcombe Forum Pro • Posts: 13,090
Re: 6D MKII Disapointing Focus Points Spread
28

As usual the people who will react to any critical comment as if it was a personal attack on their firstborn have jumped straight in. When people are quibbling about whether it's a tiny bit more or a tiny bit less than the Mk I you know you have struck a nerve. However the objective fact is you are right - the area covered is unusually small, and many will be disappointed, with some justification.

I've looked for official information from Canon but I don't think there is any, so the dpreview image is probably the best we have. (BTW see Canon's Rudy Winston video: https://www.youtube.com/watch?v=whntis9ogZ4 at 2:25 - it looks like Canon have cropped the image to give a false impression of the coverage. Very sly.)

I did find some useful figures on Imaging Resource's early review at http://www.imaging-resource.com/PRODS/canon-6d-mark-ii/canon-6d-mark-iiA.HTM - scroll down to the paragraph headed "Borrowed from the 80D" which gives the percentage coverage on an APS-C sensor as 62% horizontal and 48% vertical. Dividing by 1.6 the coverage on the 6D2's full frame sensor is a paltry 39% horizontal and 30% vertical. Given that the vertical coverage is even less on the left and right, that doesn't even reach the 'rule of thirds' points.

Yes, Live View AF is an option in some situations - I sometimes use it myself when working on a tripod - but that isn't really the point.

Overall the 6D2 is an excellent package, and for many users this won't be an issue, but it really is a weak point in the spec.

Steve Balcombe Forum Pro • Posts: 13,090
Re: 6D MKII Disapointing Focus Points Spread

noggin2k1 wrote:

Any photographer worth their salt with focus and recompose. If this is a problem because of trying to focus on a moving object - you need to realise this isn't what the camera is designed for.

If you're saying this camera is not designed for moving subjects, I don't think Canon would agree!

But also there's another area where focus/recompose is problematic, and it's one which is squarely in the 6D2's remit - using wide angle lenses. The very large angular movement needed combined with the non-spherical 'plane' of focus mean focus/recompose is difficult and maybe impossible to use.

Mako2011
MOD Mako2011 Forum Pro • Posts: 25,048
Same
2

sssanti wrote:

The dprewiew video: https://www.dpreview.com/videos/4599793823/video-first-look-at-the-canon-eos-6d-mark-ii shows the 6D2 focus points very close to the center of the frame. Scaling an image from this video and comparing to images of the 6D viewfinder, I get the conclusion that the spread of the focus points in the new 6D2 (12.5 mm) is narrower than in the original 6D (14.5 mm).

6D2

6D

Having 45 focus points clustered in the middle of the frame is less useful than having less points, but with a wider spread. Canon must be using the same autofocus module as in the rebels and 80D. Both the spread and the size of the markers is too small for a full frame camera.

Is Canon expecting 6D users to crop all photos with off-center compositions? Was it that expensive to increase the focus points spread to cover more of the full frame sensor?

Reusing the autofocus module from Rebels and the 80D is a very poor design choice.

I think your scaling isn't right.  The AF Array spread seems to actually be near Identical from what I have seen.  Don't forget that the boxes are just boxes and don't actually represent the AF array true coverage.   Total FoV of the new PDAF array is likely significantly increased in area over the older unit...and near same in terms of vertical/horizontal dimensions.  Limiting factor is really mirror box/flange distance/dimensions and how it relates to the FF image circle.

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brightcolours Forum Pro • Posts: 15,590
Re: 6D MKII Disapointing Focus Points Spread

Steve Balcombe wrote:

noggin2k1 wrote:

Any photographer worth their salt with focus and recompose. If this is a problem because of trying to focus on a moving object - you need to realise this isn't what the camera is designed for.

If you're saying this camera is not designed for moving subjects, I don't think Canon would agree!

But also there's another area where focus/recompose is problematic, and it's one which is squarely in the 6D2's remit - using wide angle lenses. The very large angular movement needed combined with the non-spherical 'plane' of focus mean focus/recompose is difficult and maybe impossible to use.

Uhmm, are you sure? The distance usually is quite big, and the DOF is also large. Do some math?

The only issue with focus and recompose is when you have a lens with a big field curvature.

noggin2k1
noggin2k1 Senior Member • Posts: 2,067
Re: 6D MKII Disapointing Focus Points Spread

Steve Balcombe wrote:

noggin2k1 wrote:

Any photographer worth their salt with focus and recompose. If this is a problem because of trying to focus on a moving object - you need to realise this isn't what the camera is designed for.

If you're saying this camera is not designed for moving subjects, I don't think Canon would agree!

But also there's another area where focus/recompose is problematic, and it's one which is squarely in the 6D2's remit - using wide angle lenses. The very large angular movement needed combined with the non-spherical 'plane' of focus mean focus/recompose is difficult and maybe impossible to use.

Apologies, probably wasn't clear enough;

Moving subjects - yes. Out and out sports photograph - no.

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Steve Balcombe Forum Pro • Posts: 13,090
Re: 6D MKII Disapointing Focus Points Spread
5

brightcolours wrote:

Steve Balcombe wrote:

noggin2k1 wrote:

Any photographer worth their salt with focus and recompose. If this is a problem because of trying to focus on a moving object - you need to realise this isn't what the camera is designed for.

If you're saying this camera is not designed for moving subjects, I don't think Canon would agree!

But also there's another area where focus/recompose is problematic, and it's one which is squarely in the 6D2's remit - using wide angle lenses. The very large angular movement needed combined with the non-spherical 'plane' of focus mean focus/recompose is difficult and maybe impossible to use.

Uhmm, are you sure? The distance usually is quite big, and the DOF is also large. Do some math?

Absolutely sure yes. Not a big deal for many landscapes, as you say the depth of field is big, but a huge deal for portraits at large apertures, and for close-up subjects.

No need to repeat any calculations, there are references online if you want them but it's well known, doesn't really need checking.

The only issue with focus and recompose is when you have a lens with a big field curvature.

Actually that's not right. If the field curvature is spherical it's not an issue, but if it's flat then focus/recompose results in front focus. Field curvature is typically neither of these of course.

Another practical issue is that if you're working with a very thin depth of field, any slight camera movement while recomposing can throw focus off.

brightcolours Forum Pro • Posts: 15,590
Re: 6D MKII Disapointing Focus Points Spread

Steve Balcombe wrote:

brightcolours wrote:

Steve Balcombe wrote:

noggin2k1 wrote:

Any photographer worth their salt with focus and recompose. If this is a problem because of trying to focus on a moving object - you need to realise this isn't what the camera is designed for.

If you're saying this camera is not designed for moving subjects, I don't think Canon would agree!

But also there's another area where focus/recompose is problematic, and it's one which is squarely in the 6D2's remit - using wide angle lenses. The very large angular movement needed combined with the non-spherical 'plane' of focus mean focus/recompose is difficult and maybe impossible to use.

Uhmm, are you sure? The distance usually is quite big, and the DOF is also large. Do some math?

Absolutely sure yes. Not a big deal for many landscapes, as you say the depth of field is big, but a huge deal for portraits at large apertures,

Oh my. Now it is about portraits and big apertures? It was about wide angles just a moment ago.

and for close-up subjects.

No need to repeat any calculations, there are references online if you want them

There are?

but it's well known, doesn't really need checking.

It is often repeated, along with no real math and only the idea that it has to be an issue, without any actual reference.

The only issue with focus and recompose is when you have a lens with a big field curvature.

Actually that's not right. If the field curvature is spherical it's not an issue, but if it's flat then focus/recompose results in front focus.

No. With wide angle lenses DOF is big. Yet the shift in focus distance due to recomposing is very small. With normal/portrait lenses DOF may be small, but the shift in focus distance due to recomposing is even smaller. This issue gets often repeated, but no one ever does the math.

Field curvature is typically neither of these of course.

Another practical issue is that if you're working with a very thin depth of field, any slight camera movement while recomposing can throw focus off.

In macro photography, this indeed can be an issue.

Mako2011
MOD Mako2011 Forum Pro • Posts: 25,048
Not really
5

brightcolours wrote:

Steve Balcombe wrote:No need to repeat any calculations, there are references online if you want them

There are?

A number of them actually

but it's well known, doesn't really need checking.

It is often repeated, along with no real math and only the idea that it has to be an issue, without any actual reference.

Not so...?

https://www.google.com/search?q=focus+and+recompse+isses&ie=utf-8&oe=utf-8

The only issue with focus and recompose is when you have a lens with a big field curvature.

Actually that's not right. If the field curvature is spherical it's not an issue, but if it's flat then focus/recompose results in front focus.

No. With wide angle lenses DOF is big. Yet the shift in focus distance due to recomposing is very small. With normal/portrait lenses DOF may be small, but the shift in focus distance due to recomposing is even smaller. This issue gets often repeated, but no one ever does the math.

Can be a player in some cases

http://www.clickinmoms.com/blog/focus-and-recompose-the-good-the-bad-and-the-ugly/

And a few real life examples to further illustrate the point. The following images were all shot with a 28mm lens at f1.8 with the exact same distance to subject. In the first image, I focused using the center focal point and took the image.

In this image, I used the same center focal point but shifted the subject to the bottom of the frame (keeping the same position horizontally but changing my angle in the vertical direction).

And finally, I used the same center focal point but shifted both horizontally and vertically, moving my subject to the bottom right-hand corner of the image.

It can be hard to see the difference in a web-sized image so I have cropped each image to 100% on the eye (which I used to focus) so that you can see the loss in sharpness on the second and third images.

Another practical issue is that if you're working with a very thin depth of field, any slight camera movement while recomposing can throw focus off.

In macro photography, this indeed can be an issue.

And in some portraiture cases as well. Easy to mitigate though. Lots of ways to do that

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dpr4bb Senior Member • Posts: 1,294
Re: 6D MKII Disapointing Focus Points Spread
2

sssanti wrote:

The dprewiew video: https://www.dpreview.com/videos/4599793823/video-first-look-at-the-canon-eos-6d-mark-ii shows the 6D2 focus points very close to the center of the frame. Scaling an image from this video and comparing to images of the 6D viewfinder, I get the conclusion that the spread of the focus points in the new 6D2 (12.5 mm) is narrower than in the original 6D (14.5 mm).

6D2

6D

Having 45 focus points clustered in the middle of the frame is less useful than having less points, but with a wider spread. Canon must be using the same autofocus module as in the rebels and 80D. Both the spread and the size of the markers is too small for a full frame camera.

Is Canon expecting 6D users to crop all photos with off-center compositions? Was it that expensive to increase the focus points spread to cover more of the full frame sensor?

Reusing the autofocus module from Rebels and the 80D is a very poor design choice.

The one glaring shortcoming of the 6D remains unsolved with the 6DII. If you don't want to focus and recompose constantly, you have to carry the big heavy brick that is the 5DIV. Pathetic...

Battersea Contributing Member • Posts: 667
Re: 6D MKII Disapointing Focus Points Spread
4

It's definitely my biggest disappointment with the 6DMII. Density is good but that spread is just too small. Everything else is great for me. I hope IQ gets a nice boost both with high ISO noise and DR. That will help alleviate some of my focus spread disappointment.

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Steve Balcombe Forum Pro • Posts: 13,090
Re: 6D MKII Disapointing Focus Points Spread
5

brightcolours wrote:

Steve Balcombe wrote:

brightcolours wrote:

Steve Balcombe wrote:

noggin2k1 wrote:

Any photographer worth their salt with focus and recompose. If this is a problem because of trying to focus on a moving object - you need to realise this isn't what the camera is designed for.

If you're saying this camera is not designed for moving subjects, I don't think Canon would agree!

But also there's another area where focus/recompose is problematic, and it's one which is squarely in the 6D2's remit - using wide angle lenses. The very large angular movement needed combined with the non-spherical 'plane' of focus mean focus/recompose is difficult and maybe impossible to use.

Uhmm, are you sure? The distance usually is quite big, and the DOF is also large. Do some math?

Absolutely sure yes. Not a big deal for many landscapes, as you say the depth of field is big, but a huge deal for portraits at large apertures,

Oh my. Now it is about portraits and big apertures? It was about wide angles just a moment ago.

I can't write a comprehensive essay, this is about a range of situations. 35 mm f/1.4 is wide angle combined with shallow depth of field, and a great choice for some portraits.

If you were genuinely interested in the issues instead of just trying to trip people up and pick holes in what they say, I'm sure you could have made a more useful contribution.

and for close-up subjects.

No need to repeat any calculations, there are references online if you want them

There are?

but it's well known, doesn't really need checking.

It is often repeated, along with no real math and only the idea that it has to be an issue, without any actual reference.

The only issue with focus and recompose is when you have a lens with a big field curvature.

Actually that's not right. If the field curvature is spherical it's not an issue, but if it's flat then focus/recompose results in front focus.

(Correction - I should have said back focus. Brain f@rt.)

No. With wide angle lenses DOF is big. Yet the shift in focus distance due to recomposing is very small. With normal/portrait lenses DOF may be small, but the shift in focus distance due to recomposing is even smaller. This issue gets often repeated, but no one ever does the math.

It has been done countless times, but allow me:

35 mm on full frame. Horizontal half-angle is 27 deg but to be realistic let's use only part of that, say 20 deg. Subject distance when focusing let's say 6 feet. Subject distance after recomposing is the long side of the right-angled triangle so it's 6/cos(20) = 6.385 feet.

Depth of field at f/1.4 as per http://www.dofmaster.com/dofjs.html - far limit is 6.4 feet, so we are right on the limit of "acceptable" according to a standard depth of field calculation. For critical focus we are way out.

It's worse when you get closer. Shooting at 4 feet (yes, I know, big noses etc., but some people are creative enough to take great shots from 4 feet) gives us a distance after recomposing of 4/cos(20) = 4.257 feet. DoF calc gives far limit of 4.17 feet - we are now firmly outside the calculated depth of field.

Once again this is using the standard DoF calculation which assumes very conservative viewing conditions - a 10x8 print at arm's length. We tend to be more critical these days so the potential problem is actually greater than these numbers suggest.

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