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

[ashmadux]

Not to cut into the AF conversation, but ive finally gotten a chance to take some test shots with a replacement 6d. The first ones AF/sharpness was atrocious. Much better, but its not 'there' yet. I havent AFMA'd though.

The screen is a 1:1 screen shot, non- developed, adobe bridge 100% raw file preview. Reference 24-105.

 

[Skirball]

The screen is a 1:1 screen shot, non- developed, adobe bridge 100% raw file preview. Reference 24-105.

So, you're allowed to litter any time other than 8:30 - 10:00 on Mondays?

 

[Chuck Alaimo]

The screen is a 1:1 screen shot, non- developed, adobe bridge 100% raw file preview. Reference 24-105.

So, you're allowed to litter any time other than 8:30 - 10:00?

LOL!!!!

 

[Tonywintn]

I went to a college women's basketball game yesterday and got a number of nice shots using my 6D. This was my first time shooting a sporting event since the early 1980s. Some background: I used to shoot sports when I was in college in the 1970s for the local newspaper. I freelanced college and high school football and basketball games going wherever the Sports Editor sent me. I earned much needed cash doing that. I used my 35mm camera with a 50mm f/1.4 lens back then for most shots and push processed to ASA1000 in order to use available light. Flash wasn't allowed at most sporting events. Fast forward to yesterday: My Canon 6D with 50mm f/1.4 lens (just like the old days) set on AI Focus. A momentary lag on each shot as I pressed the button so that the camera could focus. I got a number of nice action shots and in focus. A couple focused on players behind the action. All and all, not bad. I switched to AI Servo and multi-shot mode. Now we're talkin'. Focus hit on nearly every shot. I have a few that focused on the bleachers or on the wrong players; but 90% dead on. I used 1/250 and f/2.8 with the 50mm and stayed with 1/250 but shot wide open with my 70-300mmL at f/5.6. ISO was between 2000 and 6400. So pretty good lighting on the floor. The shots with both lenses were excellent. My experience compared to the 70s is what a difference technology makes. I used to go through a lot of B&W film to bag a few great shots. My keeper rate was way higher with today's technology. I was also glad to see I still have the knack. btw- would I get in trouble posting a few of these pix from a public sporting event? Do we need released to do that? What are the rules?

 

[ashmadux]

If you can't get decent pictures out of a 6D then there is some serious wrong with you as a photographer!!

+1, and I'd even expand on that: you can't get decent pictures out of any *Rebel* then there is something seriously wrong with you as a photographer.

Post like this are ridiculous. Also considering that my rebels have been super reliable, yet 7d/6d have been nothing but trouble in the Af department. My Xsi focus put these higher level bodies to shame...and im ashamed to have to say that.

 

[Tonywintn]

Well, I wanted to share these. The first shot is with my 50mm and the 2nd shot with the 70-300mm. I liked AI Servo mode which worked very well for me focusing on the players. Out of about 150 shots- not all were keepers from an action standpoint; but only three or four pix I found to be out of focus- or really just not focused on the subject that I wanted.

 

[kozakm]

I tested 6D a year ago. I did some shooting in very dark club (ISO 12 800, F2,8, 1/60 s) and on the evening street and was quite happy with the AF performance. Most of the time I used central point, outer points were significantly slower, but still accurate. As a 1D Mark IV owner (at that time) I was really positively surprised as one shots AF was noticeable better.

As a sport photographer I also give it a try in indoor cycling under the poor lighting conditions (ISO 6400, F2,8, 1/320 s). Central point was working acceptably well and was able to focus on moving cyclist. Outer points were no use at all. 1D Mark IV performed significantly better under these really hard conditions.

For me only shame was a lack of dual memory slot, otherwise it'd be perfect second body for weddings, parties, proms etc.

 

[CarlTN]

I tested 6D a year ago. I did some shooting in very dark club (ISO 12 800, F2,8, 1/60 s) and on the evening street and was quite happy with the AF performance. Most of the time I used central point, outer points were significantly slower, but still accurate. As a 1D Mark IV owner (at that time) I was really positively surprised as one shots AF was noticeable better.

As a sport photographer I also give it a try in indoor cycling under the poor lighting conditions (ISO 6400, F2,8, 1/320 s). Central point was working acceptably well and was able to focus on moving cyclist. Outer points were no use at all. 1D Mark IV performed significantly better under these really hard conditions.

For me only shame was a lack of dual memory slot, otherwise it'd be perfect second body for weddings, parties, proms etc.

Nice highlight bokeh effect!

 

[Marsu42]

As a 1D Mark IV owner (at that time) I was really positively surprised as one shots AF was noticeable better.

Interesting - was the 1d4 less prices, slower, ... or ? At least you can use af point expansion(?) on the 1d which is missing on the 6d so you're really nailed to one single af point.

For me only shame was a lack of dual memory slot, otherwise it'd be perfect second body for weddings, parties, proms etc.

Not that I'm defending Canon's decision which is clearly made to differentiate the 6d from "pro" 1d and "semi-pro" 5d3, but I recon you can set up the wifi to instantly transmit the shots to a smartphone or similar to keep them safe in case of card failure ... and this option is even better if your camera gets eaten by a Grue

 

[grahamclarkphoto]

I'm about to spend a significant (for my finances) amount of money on a new Canon full frame body, it is going to be either a 6D or a 5D3. The plan is to get the camera body and 2 very fast primes: Sigma 35/1.4 and Canon 85/1.2. The 6D has got what i want and costs about 1000€ less than the 5D3, but given the fact that the DoF with fast primes is going to be tiny to say the least, how is the supposedly "simplistic" 6D AF system going to perform? The main fields of application will be travel and street photography, family portraits, some landscapes, the occasional event, and everything will happen just for the sake of it, i'm not trying to make a living out of my hobby (or else i wouldn't have such quantity of money to squander on gear ). I just don't want to spend a significant amount of money and be disappointed by a quirky AF behavior. I would like to hear from owners of these cameras and lenses, lots of online researches and reading still aren't enough to make up my mind.

It's easy to run around in circles on this one.. but to simplify it:

- The 6D's simple AF system with few number of AF points may not cut it if you shoot fast action 80% of the time or more
- The 6D's -3 EV lowlight sensitivity is currently unmatched by any DSLR on the market

If you shoot lowlight, sunsets, night photography or landscape photography the lowlight AF performance on the 6D wins.

Video review of the 6D: http://www.canonrumors.com/forum/index.php?topic=19066

Graham

 

[AbsN]

Having read through this and other threads about the 6Ds AF performance I'm still not sure what conclusions to draw, especially regarding accuracy with wide apertures.

Is the 6D's center AF point capable of accurately and reliably focusing the Canon 50 1.2, 35 1.4 and 85 1.2 - all at their widest apertures for static/posed single shot portraits at fairly close range (say 2 meters)?

 

[Max ☢]

Is the 6D's center AF point capable of accurately and reliably focusing the Canon 50 1.2, 35 1.4 and 85 1.2 - all at their widest apertures for static/posed single shot portraits at fairly close range (say 2 meters)?

I cannot comment on the 35/1.4L, but having the 85/1.2LII and the 50/1.2L my observations are:

- 85/1.2LII: I acquired this lens more than half a year ago and so far I am very happy with the 6D operation with this lens. Overall I manage to get a lot of keepers in the batchs I shoot at evening parties (mostly close-up portraits) and I usually find only a few misfocused images. Getting properly focused images with this lens requires some AFMA and a lot of practice and exercise but when the proper way of working is found, the 6D and 85/1.2LII combination is then a real pleasure to use and delivers outstanding results.
Nevertheless, I do see some slight variations in the focusing precision from the 6D, but not to a point of being an issue with the 85/1.2LII as far as I am concerned.

- 50/1.2L: I got this lens much more recently (three days ago!) and I find that the 6D autofocus ability becomes quite problematic under certain situations such as in low light environments and/or with low-contrast subjects. After AFMA and using the central AF point I rarely get a spot-on image focus under these critical conditions. The problem is not a bias in the 6D AF since it is not solved by AFMA, but rather due to a too large spread in the focused position relative to the desired point. The resulting focus inaccuracy is quite a shame because this lens delivers a phenomenal rendering when the image focus is properly nailed. The paper-thin DoF of the 50/1.2L (especially at close subject distances) combined with its very pronounced spherochromatic aberrations result in the need for very, very tight AF tolerances, which are clearly not met by the AF system of the 6D under low light and/or low contrast conditions.
On this subject there is an interesting article from Lens Rentals (Roger Cicala) which you can find here and whose data can be compared to those from there. In short, it is found that the AF accuracy of the 6D is nearly identical to that from the 5D mkII, but around twice worse than that from the 5D mkIII and 1Dx. Interestingly, when I dug into the 50/1.2L reviews over the internet I did find a few comments that the focusing with this lens was always spot-on with the 5D3 and 1Dx, which is quite consistent with a more accurate AF from those bodies. I think this is also an indication that all the “backfocusing” issues reported all over the net has more to do with challenged AF systems operated beyond their tolerances than an improperly designed lens...

Back to the original question, I nevertheless do find that under properly lit conditions and with high-contrast subjects the 6D AF works properly and shows quite a good AF accuracy and consistency, delivering the expected image quality (sharp subject at the center and lowest amount of spherochromatic aberrations). The best AF mode I found is the “One shot” setting as it prevents the camera’s AF system from hunting around too long before locking on the subject.
However, these ideal conditions are rarely met in real situations and when I sense that the AF struggles I then manually focus the lens using the autofocus confirmation. I found that focusing by starting from a point in front of the subject rather than behind consistently delivers properly focused images, even of subjects having a very poor contrast. Soon I will replace the 6D focusing screen by Canon’s EG-S screen in order to improve my ability to manually focus this 50/1.2L and spot misfocused images before I take them (this will help also with the 85/1.2LII although I never had to revert to manual focus with it).
So, overall the 6D-50/1.2L combo does not come without its lot of frustrations and there is definitely a steep learning path to be followed in order to get the best out of this system – but it is well worth the effort in the end and I am becoming satisfied with it as I am getting to understand how to use this piece of glass. The lack of proper AF ability under low light and low contrast conditions is of course quite a pity, but I don't mind having to find a way around this issue as long as I get the shots I want. If for you a good AF accuracy under all ciscumstances is a must and you don’t want to manually focus your lens, then forget the 6D-50/1.2L combo and go for the 5DIII-50/1.2L which according some reviews should faultlessly deliver the goods. As far as I am concerned, I keep the 6D and the lens, I will work with manual focus until I upgrade the body or the lens in 4-5 years from now. Hopefully there will be a 6D-mkII or mkIII with a mirrorless configuration and dual pixel sensor which will enable a spot-on autofocus under all circumstances 8)

 

[Dick]

still not sure what conclusions to draw, especially regarding accuracy with wide apertures.

It is actually quite simple. You can only use the middle AF point and then recompose = getting an OOF photo. Servo tracking may work for the center of the frame but a person's face usually is not in that spot so it's useless to track people that way.

 

[mnclayshooter]

It's easy to run around in circles on this one.. but to simplify it:

- The 6D's simple AF system with few number of AF points may not cut it if you shoot fast action 80% of the time or more
- The 6D's -3 EV lowlight sensitivity is currently unmatched by any DSLR on the market

If you shoot lowlight, sunsets, night photography or landscape photography the lowlight AF performance on the 6D wins.

I'll second this... with one exception. I haven't had really any issues with "fast action" other than when I was moving quickly (passenger in a vehicle) trying to take a picture of a deer running. I got maybe 2 out 6 shots that were out of focus beyond usable. Use your Av control or Tv controls to your advantage. Make the camera do what YOU want it to do, not rely on it to be smarter than you, and you'll be happier.

I'll also add this one note... I tested the "dot-tune" method for AF Micro Adjustment with my lenses, basically knowing that I could just undo it if I wanted to... it made a BIG difference on my long zooms for both AF accuracy and speed - especially when using only the center point, and a subtle difference on my 100mm macro (which was already pretty darn good). Might be worth a try if you're having troubles. I followed the generally recommended method of using 50x the focal length of the lens (for zooms, 50x each end of the zoom extremes). Some lenses were pretty spot on (as I would hope) others were in the +4 or 5 range which made a huge difference.

Not trying to spark a debate about AMFA. Just posting on my experience with the 6D, autofocus accuracy/speed and what I've seen as ways to improve on what actually isn't nearly as bad as some might make it out to seem.

I'd wager that many of the "6D is too slow" posts are by people who are only reading spec pages and not actually handling the camera body itself.

Is it as accurate or fast or flexible as a 5DIII - probably not, but it's also half the price - and in my humble opinion, a better all-around value for the VAST MAJORITY of casual/hobby photog's. Just my 2 cents.

 

[neuroanatomist]

- The 6D's -3 EV lowlight sensitivity is currently unmatched by any DSLR on the market

If you shoot lowlight, sunsets, night photography or landscape photography the lowlight AF performance on the 6D wins.

As I pointed out a few pages ago in this thread:

How do you define 'low light'? For example, the difference between shooting at -2 EV and-3 EV could mean 1/15 s, f/2.8, ISO 51200 vs. 102400. Neither is very usable from an IQ standpoint. What most people call 'low light' is generally substantially brighter than either spec.

Long exposure night photograpy might benefit from that extra stop of AF capability (but in that situation, you are on a triod and probably using Live View to focus anyway). Sunsets, landscapes and general shooting have plenty of light relative to the AF sensitivity of even lower end dSLRs.

I think the -3 EV spec of the 6D is Canon saying 'we did it because we can, and to throw a bone after otherwise limiting AF functionality of this body' - it looks good on paper, but is of little practical benefit in the vast majority of shooting situations.

 

[MichaelHodges]

I had the pleasure of shooting a 6D for several months in the Bob Marshall Wilderness complex and other wilderness areas in Montana, Washington, and Oregon. I shot a variety of subjects, from bighorns to golden eagles to beaches.

The 6D lowlight focus is the best I've ever used on any camera.

 

[CarlTN]

It's easy to run around in circles on this one.. but to simplify it:

- The 6D's simple AF system with few number of AF points may not cut it if you shoot fast action 80% of the time or more
- The 6D's -3 EV lowlight sensitivity is currently unmatched by any DSLR on the market

If you shoot lowlight, sunsets, night photography or landscape photography the lowlight AF performance on the 6D wins.

I'll second this... with one exception. I haven't had really any issues with "fast action" other than when I was moving quickly (passenger in a vehicle) trying to take a picture of a deer running. I got maybe 2 out 6 shots that were out of focus beyond usable. Use your Av control or Tv controls to your advantage. Make the camera do what YOU want it to do, not rely on it to be smarter than you, and you'll be happier.

I'll also add this one note... I tested the "dot-tune" method for AF Micro Adjustment with my lenses, basically knowing that I could just undo it if I wanted to... it made a BIG difference on my long zooms for both AF accuracy and speed - especially when using only the center point, and a subtle difference on my 100mm macro (which was already pretty darn good). Might be worth a try if you're having troubles. I followed the generally recommended method of using 50x the focal length of the lens (for zooms, 50x each end of the zoom extremes). Some lenses were pretty spot on (as I would hope) others were in the +4 or 5 range which made a huge difference.

Not trying to spark a debate about AMFA. Just posting on my experience with the 6D, autofocus accuracy/speed and what I've seen as ways to improve on what actually isn't nearly as bad as some might make it out to seem.

I'd wager that many of the "6D is too slow" posts are by people who are only reading spec pages and not actually handling the camera body itself.

Is it as accurate or fast or flexible as a 5DIII - probably not, but it's also half the price - and in my humble opinion, a better all-around value for the VAST MAJORITY of casual/hobby photog's. Just my 2 cents.

I agree completely. However, to a few on here, it just doesn't matter what you say. The 6D is only a sensor, and not a camera, to them.

 

[CarlTN]

- The 6D's -3 EV lowlight sensitivity is currently unmatched by any DSLR on the market

If you shoot lowlight, sunsets, night photography or landscape photography the lowlight AF performance on the 6D wins.

As I pointed out a few pages ago in this thread:

How do you define 'low light'? For example, the difference between shooting at -2 EV and-3 EV could mean 1/15 s, f/2.8, ISO 51200 vs. 102400. Neither is very usable from an IQ standpoint. What most people call 'low light' is generally substantially brighter than either spec.

Long exposure night photograpy might benefit from that extra stop of AF capability (but in that situation, you are on a triod and probably using Live View to focus anyway). Sunsets, landscapes and general shooting have plenty of light relative to the AF sensitivity of even lower end dSLRs.

I think the -3 EV spec of the 6D is Canon saying 'we did it because we can, and to throw a bone after otherwise limiting AF functionality of this body' - it looks good on paper, but is of little practical benefit in the vast majority of shooting situations.

As I've said many times, due to the low noise of the 6D, the low light sensitivity of the center AF point, can be very useful in the majority of situations where you are shooting wildlife (or people) around, before, or after sunset. Or else if you are shooting landscape hand-held, with an IS lens, up to an hour after sunset...or during a full moon. Or if you are shooting inside a club, or outside on a dimly lit city street at night, that -3EV capability is very useful.

ISO 6400 is extremely usable for professional prints via the 6D (with a bit of post processing), and ISO's a bit above that are still useful.

As for bashing the other AF points on the 6D, you need to bash the 5D2's as well, because they were no better. It might not still be on sale, but plenty of forum readers still own and use the 5D2.

For anyone shooting with strobes, or shooting fast sports action in well lit areas, the 5D3 or 1DX is the camera you need (or perhaps a D800 at low ISO).

If you're shooting portraits with an f/1.4 lens, wide open at f/1.4, and require peripheral AF points to be used (for focusing on eyes, etc.), then yes the 6D will not give consistent results. But then the 1DX and 5D3 don't fare much better in that situation, which is why serious portrait photogs who shoot this way, either manually focus, or use live view. Of course most of them are closing that fast lens down quite a bit, in which case there is more wiggle room for AF inaccuracies.

And besides, in that peripheral area of these lenses (other than the Zeiss Otus)...those eyes that you claim are so razor sharp...actually are not, and are suffering from coma and astigmatism. It's unavoidable...especially with such lenses as the 50L and 85L.

 

[CarlTN]

- 85/1.2LII: I acquired this lens more than half a year ago and so far I am very happy with the 6D operation with this lens. Overall I manage to get a lot of keepers in the batchs I shoot at evening parties (mostly close-up portraits) and I usually find only a few misfocused images. Getting properly focused images with this lens requires some AFMA and a lot of practice and exercise but when the proper way of working is found, the 6D and 85/1.2LII combination is then a real pleasure to use and delivers outstanding results.
Nevertheless, I do see some slight variations in the focusing precision from the 6D, but not to a point of being an issue with the 85/1.2LII as far as I am concerned.

I find this very interesting indeed. If I had said it, I would have to defend it from hostile blowhard 6D bashers. Lucky for me that I don't currently own the 85L, or I might be agreeing with you! Can I see some of these shots?

 

[neuroanatomist]

As I've said many times, due to the low noise of the 6D, the low light sensitivity of the center AF point, can be very useful in the majority of situations where you are shooting wildlife (or people) around, before, or after sunset. Or else if you are shooting landscape hand-held, with an IS lens, up to an hour after sunset...or during a full moon. Or if you are shooting inside a club, or outside on a dimly lit city street at night, that -3EV capability is very useful.

ISO 6400 is extremely usable for professional prints via the 6D (with a bit of post processing), and ISO's a bit above that are still useful.

ISO 6400 at -3 EV would be 1/4 s at f/1.4, 1 s at f/2.8. Are you actually suggesting that such settings are, "useful in the majority of situations where you are shooting wildlife (or people) around, before, or after sunset??" In that case, I would expect you'll have plenty of examples of wildlife that you shot at 1 s or longer exposures (unless you shoot a lot of wildlife with f/1.4 lenses) and people that you've shot at exposures of 1/4 s or longer, and you should be able to share several of them to support your contention.

Assuming 1/FL, a 24-28mm lens with 4-stop IS could be handheld at ~1/4 s (a conservative assumption, as with today's sensors 1/2xFL is more realistic). That means your handheld landscape at -3 EV ISO 6400 would be at f/2.8 (and there are a few wide angle f/2.8 lenses with 4-stop IS/VC). I'd be interested in seeing some examples of your landscapes shot at those settings, too, assuming you have any.

I've personally never shot landscapes/cityscapes at -3 EV unless on a tripod. The shot below with the swan at the Palace of Fine Arts in San Francisco is the closest I've come to that handheld, it's 1/25 s, f/3.2 and ISO 12800, which is -1.3 EV. There are issues with the shot - the DoF is too shallow so the structure is OOF, and the shutter speed wasn't quite fast enough to freeze the motion of the swimming swan; IS would not have helped (and at 17mm on a FF camera, IS isn't even a possibility). The second shot below is an example of -3 EV - the only light sources in the room were the fireplace and the jack-o-lanterns, the settings were 1/15 s, f/2.8, ISO 102400. In fact, I focused that shot through the viewfinder (although I could barely see), meaning the 1D X's AF was actually able to focus at -3 EV (although that's for the whole scene, the AF point was seeing more light than that). Still, there's motion blur and lots of noise, and image is no more than a snapshot (albeit one not possible with most cameras).

Considering the examples above, I would suggest that anyone arguing the -3 EV sensitivity of the 6D's AF system is an advantage over the -2 EV of the 5DIII or 1D X, or even the -0.5 EV sensitivity of most other bodies, in many situations, much less a majority of situations, doesn't know what they're talking about.

As I stated, the majority of situations which people call "low light" really offer plenty of light for the AF systems of even low-end dSLRs. The extra one stop of sensitivity that the 6D has is an advantage only in very rare situations, so rare that many 6D users probably have not ever experienced them.

As for bashing the other AF points on the 6D, you need to bash the 5D2's as well, because they were no better. It might not still be on sale, but plenty of forum readers still own and use the 5D2.

I agree, the outer AF points of the 5DII were not very useful, much like those of the 6D. They did ok with high contrast subjects in bright light, but were lousy in dimmer light or for Servo tracking.