6D autofocus capabilites: let's bust some myths about it

[Janbo Makimbo]

Will the 6D require somewhat more skill and planning to get the shots you want compared to a 5D MKIII? Yes.

You're talking of focus & recompose skill with thin dof, I guess?

One thing I'm experiencing with my 100L and the 6D and I have "learned" to circumvent by taking more frames is that the 6D sometimes produces actual af misses, i.e. the focus is completely elsewhere even though the camera did an af confirm (red dot) - I practically never experience this with my 6d af, though the 60d more often has "micro misses" while the 6d is either spot-on or lost in the woods.

This.

I've been testing a refurb 6d for a week now. The AF is abominable. AF misses plenty. This is both after focal calibration - twice - and tuning by hand.

I'm now deciding whether to keep the body and get it repaired, or to return it entirely. Still not sure what to do.

Lastly, I'm pretty disappointed at the 6ds sharpness. Images - when accurate- are pretty soft out of camera. Not one image has any of the clarity from my t2i files. I'm not so sure it's the AF entirely, as I've been viewing raw files from around the net and they all show the same soft, oily looking effects.

Perhaps you could look in the 6D Gallery, lots of lovely in focus pictures...either you have a bad copy, bad lens or user error!!

 

[ashmadux]

Will the 6D require somewhat more skill and planning to get the shots you want compared to a 5D MKIII? Yes.

You're talking of focus & recompose skill with thin dof, I guess?

One thing I'm experiencing with my 100L and the 6D and I have "learned" to circumvent by taking more frames is that the 6D sometimes produces actual af misses, i.e. the focus is completely elsewhere even though the camera did an af confirm (red dot) - I practically never experience this with my 6d af, though the 60d more often has "micro misses" while the 6d is either spot-on or lost in the woods.

This.

I've been testing a refurb 6d for a week now. The AF is abominable. AF misses plenty. This is both after focal calibration - twice - and tuning by hand.

I'm now deciding whether to keep the body and get it repaired, or to return it entirely. Still not sure what to do.

Lastly, I'm pretty disappointed at the 6ds sharpness. Images - when accurate- are pretty soft out of camera. Not one image has any of the clarity from my t2i files. I'm not so sure it's the AF entirely, as I've been viewing raw files from around the net and they all show the same soft, oily looking effects.

Perhaps you could look in the 6D Gallery, lots of lovely in focus pictures...either you have a bad copy, bad lens or user error!!

I'm sure the AF problems are working for some out there...but for me it's been a week of WTFs. I always love when canon snds equipment that they barely check...it's happened to me many times before. You don't want to endure what I did with a 7d.

Good lenses, good user, so it's the body. I'll decide by morning, after reviewing some more unprocessed raw files. I'm leaning to send it back.

 

[Marsu42]

I've been testing a refurb 6d for a week now. The AF is abominable. AF misses plenty. This is both after focal calibration - twice - and tuning by hand.

With my f2.8 lens the 6D center af is not great because it sometimes misses, but certainly not that bad - I'd say the real failure rate is 1 in 25-50 shots. Otherwise the center af point is more precise than my 60D in stills shooting, so I'd say there's really something amiss with your copy.

Lastly, I'm pretty disappointed at the 6ds sharpness. Images - when accurate- are pretty soft out of camera. Not one image has any of the clarity from my t2i files. I'm not so sure it's the AF entirely, as I've been viewing raw files from around the net and they all show the same soft, oily looking effects.

In this case it isn't your af. First off, the 6d is tuned for high iso so files at low iso are somewhat less sharp than 5d3 which itself is less sharp than 5d2 - but to a degree that shouldn't matter much in real life shooting.

What you a experiencing is the "ff look" which can be a bit irritating when coming from crop - also the lenses look completely different on ff vs. crop (shallower dof, different bokeh and sharpness). The noisier crop images can be indeed be perceived as "crisp" was also my very first reaction with my new 6d - I got used to it and now use my 60d for macro where the "crop look" seems to be better, next to the deeper depth of field.

Last not least ff raw files need more postprocessing than crop, they look flat and blurrier than crop - this changes even after a very small degree of tuning, but if you're the sooc type this might be disappointing, in this case get a 70d and better lenses.

 

[gigabellone]

I found this very informative post about the Canon EOS AF system, courtesy of our exceptional fellow forum member Neuroanatomist.

These are the specs of the AF sensor mounted into the 6D (taken here):

AF Points
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.

AF Working Range
Center AF Point: EV -3 to 18 (at 73°F/23°C, ISO 100)

Other AF points: EV +0.5 to 18 (at 73°F/23°C, ISO 100)

While these are the specs of the AF sensor mounted into the 550D/T2i (taken here):

• 9-point CMOS sensor
• F5.6 cross-type at center, extra sensitivity at F2.8
• AF working range: -0.5 to 18 EV (at 23°C, ISO 100)

Comparing the two systems brings to a very disappointing conclusion: the 6D sports an AF sensor which is only marginally better than a 3 years old camera costing 1/4 of its price, and in some ways even less capable of the AF sensor built into an entry level dslr costing 1/3: the 650D sports 9 cross-type points up to f/5.6, sensitivity -0.5 to 18 EV.
I know, that central AF point is really good, but still, i'm not very excited about spending 1400€ (after mail in rebates) on a camera with great AF performance in the center, and the same AF system of my 3 years old entry level dslr on other points.

 

[Marsu42]

Comparing the two systems brings to a very disappointing conclusion: the 6D sports an AF sensor which is only marginally better than a 3 years old camera costing 1/4 of its price, and in some ways even less capable of the AF sensor built into an entry level dslr costing 1/3: the 650D sports 9 cross-type points up to f/5.6, sensitivity -0.5 to 18 EV.

I agree the 6d af system is mediocre esp. for the price, but you're forgetting two major points not in the specs you posted:

* precision: The 6d af is more precise than the 5d2, and way more precise than the older Rebels, meaning if you focus a couple of times on the same target you're more likely to get the same result with the 6d (see lensrentals on this). I know this issue from the 60d and am used to take a couple of shots for safety, but with the 6d the af ends up where it is supposed to be.

* af point size: This is not thanks to Canon, but anyway - the af points vs. sensor size are smaller on the 6d, which means it's easier to focus on small details with the 6d. The one crop camera that addresses this is the 7d with spot af, but alas, this feature has been removed on the 70d again.

 

[Pi]

Comparing the two systems brings to a very disappointing conclusion: the 6D sports an AF sensor which is only marginally better than a 3 years old camera costing 1/4 of its price, and in some ways even less capable of the AF sensor built into an entry level dslr costing 1/3: the 650D sports 9 cross-type points up to f/5.6, sensitivity -0.5 to 18 EV.

* precision: The 6d af is more precise than the 5d2, and way more precise than the older Rebels, meaning if you focus a couple of times on the same target you're more likely to get the same result with the 6d (see lensrentals on this). I know this issue from the 60d and am used to take a couple of shots for safety, but with the 6d the af ends up where it is supposed to be.

+1. Size (format) matters. I still remember when I went from the 50D to the 5D2 years ago. On paper, the 50D had more advanced AF (and I owned two of them). I was amazed how much better the 5D2 was then, and I am still amazed now.

 

[bholliman]

Comparing the two systems brings to a very disappointing conclusion: the 6D sports an AF sensor which is only marginally better than a 3 years old camera costing 1/4 of its price, and in some ways even less capable of the AF sensor built into an entry level dslr costing 1/3: the 650D sports 9 cross-type points up to f/5.6, sensitivity -0.5 to 18 EV.
I know, that central AF point is really good, but still, i'm not very excited about spending 1400€ (after mail in rebates) on a camera with great AF performance in the center, and the same AF system of my 3 years old entry level dslr on other points.

My first DSLR was a 550D and I now have a 6D. The 550D's auto focus does not compare with the 6D's, regardless of how close the specs look on paper. The 6D's AF is faster and more accurate.

You really need to try a 6D out yourself to see if it performs to your expectations. If you can't rent one where you live, do you know any other photographers who would loan you theirs for a few hours or days? Is there a local retail store where you could do hands-on comparisons with other bodies?

 

[MLfan3]

many people seem to hate the 6D AF system but it is actually very reliable at least the center point is.
the center AF point of it is more sensitive than any AF point of the 1DX , the 5D3 or my D800E.
I tested my D800E vs my 6D vs my D600 vs rented 5d3 in lowlight , the 6D actually handled extreme lowlight best, no contest here.
the 6D's actually usable ISO6400 combined with the killer lowlight AF make it the best lowlight compact SLR ever from any maker.
that alone makes it worth it and I think it is the best value camera ever made for hybrid photography, I just have to wait ML to come up something amazing for that camera to make it really the hybrid camera.

 

[gigabellone]

My first DSLR was a 550D and I now have a 6D. The 550D's auto focus does not compare with the 6D's, regardless of how close the specs look on paper. The 6D's AF is faster and more accurate.

You really need to try a 6D out yourself to see if it performs to your expectations. If you can't rent one where you live, do you know any other photographers who would loan you theirs for a few hours or days? Is there a local retail store where you could do hands-on comparisons with other bodies?

many people seem to hate the 6D AF system but it is actually very reliable at least the center point is.
the center AF point of it is more sensitive than any AF point of the 1DX , the 5D3 or my D800E.
I tested my D800E vs my 6D vs my D600 vs rented 5d3 in lowlight , the 6D actually handled extreme lowlight best, no contest here.
the 6D's actually usable ISO6400 combined with the killer lowlight AF make it the best lowlight compact SLR ever from any maker.
that alone makes it worth it and I think it is the best value camera ever made for hybrid photography, I just have to wait ML to come up something amazing for that camera to make it really the hybrid camera.

I'm starting to think that focusing on center point and then crop the picture in post-production would be the lesser, and acceptable, of two evil, the other one being spending a 1000€ premium to buy a camera with a very complex autofocus system that i'll never be able to use at 100% of its capabilities. I'll take some more time to think about it, but it's most probable i'll bite the bullet and get the 6D.

 

[Marsu42]

many people seem to hate the 6D AF system but it is actually very reliable at least the center point is.

"Hate" is probably the wrong word, it's about knowing the limitations, try to work around them (or not) and make an educated decision if spending nearly double the amount of money for 5d3 is "worth it" because of the af system.

the center AF point of it is more sensitive than any AF point of the 1DX , the 5D3 or my D800E.
I tested my D800E vs my 6D vs my D600 vs rented 5d3 in lowlight , the 6D actually handled extreme lowlight best, no contest here.

These tests are always interesting, but only if you can give the LV of the scene (iso, shutter, aperture, lens used), i.e. when the 6d starts to outperform the other cameras. That's because the 5d3 is supposed to af up to -2LV which already should cover most situations, so the question is how often you encounter -3LV and when the 6d af starts getting faster even above -2LV than the competition...

 

[thgmuffin]

I found this very informative post about the Canon EOS AF system, courtesy of our exceptional fellow forum member Neuroanatomist.

These are the specs of the AF sensor mounted into the 6D (taken here):

AF Points
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.

AF Working Range
Center AF Point: EV -3 to 18 (at 73°F/23°C, ISO 100)

Other AF points: EV +0.5 to 18 (at 73°F/23°C, ISO 100)

While these are the specs of the AF sensor mounted into the 550D/T2i (taken here):

• 9-point CMOS sensor
• F5.6 cross-type at center, extra sensitivity at F2.8
• AF working range: -0.5 to 18 EV (at 23°C, ISO 100)

Comparing the two systems brings to a very disappointing conclusion: the 6D sports an AF sensor which is only marginally better than a 3 years old camera costing 1/4 of its price, and in some ways even less capable of the AF sensor built into an entry level dslr costing 1/3: the 650D sports 9 cross-type points up to f/5.6, sensitivity -0.5 to 18 EV.
I know, that central AF point is really good, but still, i'm not very excited about spending 1400€ (after mail in rebates) on a camera with great AF performance in the center, and the same AF system of my 3 years old entry level dslr on other points.

The 6D AF feels worlds ahead from my T2i!

 

[CarlTN]

I've had the Mk III since it launched and received a 6D on Friday. I took it on a hike yesterday with the Sigma 35 and Canon 50 1.2. I used both the center point focus recompose technique and the farthest outside point. We got in late last night and I only glanced through the images after importing, but my initial impression was that focus accuracy was fine. I didn't bring the Mk III or do a side-by-side comparison though.

I will comment that I am surprised by how much lighter and more compact the 6D feels. It feels like more of a joy to take out and shoot than the Mk III which sometimes seems like a burden. I plan to sell the Mk III.

I'll do some editing tonight and post some of the images.

Don't you realize that if you admit this, in the eyes of most 5D3 lovers, suddenly you're not a real photographer anymore?

 

[CarlTN]

Will the 6D require somewhat more skill and planning to get the shots you want compared to a 5D MKIII? Yes.

You're talking of focus & recompose skill with thin dof, I guess?

One thing I'm experiencing with my 100L and the 6D and I have "learned" to circumvent by taking more frames is that the 6D sometimes produces actual af misses, i.e. the focus is completely elsewhere even though the camera did an af confirm (red dot) - I practically never experience this with my 6d af, though the 60d more often has "micro misses" while the 6d is either spot-on or lost in the woods.

This.

I've been testing a refurb 6d for a week now. The AF is abominable. AF misses plenty. This is both after focal calibration - twice - and tuning by hand.

I'm now deciding whether to keep the body and get it repaired, or to return it entirely. Still not sure what to do.

Lastly, I'm pretty disappointed at the 6ds sharpness. Images - when accurate- are pretty soft out of camera. Not one image has any of the clarity from my t2i files. I'm not so sure it's the AF entirely, as I've been viewing raw files from around the net and they all show the same soft, oily looking effects.

It's pretty well documented on here that many early 6D's had an AF sensor that would malfunction, for whatever reason. It's very likely your refurb unit is one of these. The 6D can't be judged by the quality of its refurbs.

 

[CarlTN]

My only worry is related to its outer AF points. Is it really that bad?Thanks for the feedback. What about the outer AF points? Have you tried to use them with a fast prime? Are they really that bad?

One slightly "bad" thing about the outer af points is that they only have f5.6 precision, so the faster your lens is the more slightly out of focus images you'll get - but with a really fast prime that probably also happen with the f2.8 center point so you should know something about manual focus. How much this hurts is very depending on what you do.

Two really "bad" things about the outer points are more severe though since you cannot work around these: They only work up to 0.5LV (like my 60d, and this means dim light = no more or incredibly slow af) and they are not cross so they'll often fail to focus on low-contrast surfaces, you still have to focus & recompose on something they can lock on - an then you can simply use the center point to begin with. In good light this often won't be a problem, but in dim light it adds up and the 6d is essentially a one point af camera.

Agreed.

 

[CarlTN]

many people seem to hate the 6D AF system but it is actually very reliable at least the center point is.

"Hate" is probably the wrong word, it's about knowing the limitations, try to work around them (or not) and make an educated decision if spending nearly double the amount of money for 5d3 is "worth it" because of the af system.

the center AF point of it is more sensitive than any AF point of the 1DX , the 5D3 or my D800E.
I tested my D800E vs my 6D vs my D600 vs rented 5d3 in lowlight , the 6D actually handled extreme lowlight best, no contest here.

These tests are always interesting, but only if you can give the LV of the scene (iso, shutter, aperture, lens used), i.e. when the 6d starts to outperform the other cameras. That's because the 5d3 is supposed to af up to -2LV which already should cover most situations, so the question is how often you encounter -3LV and when the 6d af starts getting faster even above -2LV than the competition...

I was able to get mine to AF in light so dark that I couldn't really see what I was aiming at through the viewfinder, with my 120-400mm lens...at 400mm at f/5.6...at ISO 102k. (I had a little trouble with just my naked eye, but the viewfinder is a lot darker than the naked eye). The amount of light was, I don't know...there was no moon...it was 40 minutes or so after sunset. It was very late "blue hour", and I would say was about equal to midnight with a quarter moon showing, and clear skies. The target AF subject was the white belly fur of some deer...which was obviously facing the dark ground...but that fur was all I could see with the naked eye.

Needless to say the images sucked but it focused ok (took about a second to achieve lock). I shot them as lower resolution jpegs, and the noise is still not what I would call clean, haha. To make matters worse...in such dark conditions, you have to compensate exposure by +1 1/3, and even then it's still underexposed...at a slow shutterspeed with "OS" switched on.

Certainly that center point can focus in a lot darker light than is practical to take pictures that are worth looking at, even as an experiment.

But...what does this say about future cameras with future AF points? Seems like things will continue to improve. We all need to be saving for that 2014 1 series, don't we?

 

[Marsu42]

Needless to say the images sucked but it focused ok

Indeed :-> ... and that's why -2LV is probably enough for available light shooting, -3LV imho only makes sense if you want to flash something but don't want to use the af assist (or don't have the flash on camera).

The one thing that might be interesting if a -3LV camera is faster at focusing @-2LV than one onle rated for -2LV peak - but I haven't read anything conclusive on this yet, just quick/subjective tests.

For simple "shoot in the dark" on tripod there are alternative solutions like Magic Lantern which can boost your LV to work as a night mode, then you can contrast af or just use focus peaking.

 

[CarlTN]

Needless to say the images sucked but it focused ok

Indeed :-> ... and that's why -2LV is probably enough for available light shooting, -3LV imho only makes sense if you want to flash something but don't want to use the af assist (or don't have the flash on camera).

The one thing that might be interesting if a -3LV camera is faster at focusing @-2LV than one onle rated for -2LV peak - but I haven't read anything conclusive on this yet, just quick/subjective tests.

For simple "shoot in the dark" on tripod there are alternative solutions like Magic Lantern which can boost your LV to work as a night mode, then you can contrast af or just use focus peaking.

I did a few more this evening. Some of them actually don't suck, but I guess it's all relative. I disagree that -2LV is "enough", though.

 

[Marsu42]

I disagree that -2LV is "enough", though.

I think we agree this is not about agreement, but just about if some shooting styles requires it or not...

If I understand it correctly, -2LV means @f2.8 (the fastest speed you'd expect the af to work flawlessly and not require mf tricks) and iso12800 (arguably the fastest speed that makes a residual sense) ... 1/4s. Personally, I'm unlikely to shoot with 1/4s handheld requiring phase af, let alone 1/2s of -3LV.

The one situation where -3LV might make sense for me is with a IS prime which axes up to 4 stops from non-IS handheld, and @24mm you just might be able to handhold 1/2s if you've got low blood pressure... but I don't have such a lens, so it's not necessary for me, I'm more interested in *fast* phase af at lower light levels.

 

[Loswr]

The one situation where -3LV might make sense for me is with a IS prime which axes up to 4 stops from non-IS handheld, and @24mm you just might be able to handhold 1/2s if you've got low blood pressure...

This was handheld (free standing, not braced) at 95mm for a 0.5 s exposure…


EOS 5D Mark II, EF 70-200mm f/2.8L IS II USM @ 95mm, 1/2 s, f/5.6, ISO 100

 

[Marsu42]

This was handheld (free standing, not braced) at 95mm for a 0.5 s exposure…

Ok, ok, I give in ... if you're shooting for a keychain-holder print size it even -5LV does make sense because no one will ever see the shake - and with the newest PS CC shake reductions algorithms you can even remove a lot of this.

My reference was 100% crop and more than 1:10 chance of getting an ok iq, but yes, if the af works you can have at least give it a try while if your af refuses to work at all (I'm experiencing this a lot on the 0.5LV 60d) you're completely lost.