# 5D III focus accuracy with fast primes wide open



## BL (Mar 26, 2012)

I've been rocking a 5DC since launch, and have never been happy about having to manually focus on anything outside of the center cross AF point with pretty much any of my fast primes wide open (e.g. 50L, 85L II, 135L). 

The high precision, MF screen helps and is a life saver, but it's become a crutch as I've come rely on that to validate all focussing. That said, the new 5D III does not have user replaceable screens allowing for proper DOF previews for lenses faster than 2.8

For folks shooting primarily fast primes with their 5D III, how are you coping with this? Is the AF capable enough so that focus points on the edges are accurate down to f1.2?

Focus and recompose is not an option for me. The focal plane is in the millimeters at f1.2 for tighter portraits


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## drmikeinpdx (Mar 26, 2012)

I would also like to see some responses to this question.

I use a 5D classic and have learned to live with poor autofocus results when using primes wide open. I tried manual focus with two special focus screens including a split prism one and did not get repeatable results.

My main reason for considering an upgrade to the Mark III or perhaps another new Canon full frame camera this year is strictly for better autofocus performance.

Mike


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## BL (Mar 27, 2012)

Yeah, I can live with one or the other.

If the AF is crap, at least I can really on focussing with my eyeball MkI, something I had to master in the Canon FD days shooting amateur motorsports with a 300 2.8

But if I can't trust my eyes, I HAVE to believe the outer points will deliver at these extreme apertures.


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## @!ex (Mar 27, 2012)

I've been shooting my 50mm 1.2L wide open for the last few days. I did have to do a +6 micro adjustment but so far it has been very good on about 80% of shots and excellent on about 70% or so. I think a lot of the variance has nothing to do with the AF, but rather a very slight movement on my part after the AF locks. If you even swayed a mm it would be noticeable. I've also had a lot of good luck with off center AF points. Here is a shot I took with an off center AF point (then one over his right eye).

http://www.canonrumors.com/forum/index.php/topic,4864.msg96476.html#msg96476


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## Stephen Melvin (Mar 27, 2012)

My 24 f/1.4L II and 50 f/1.4 are spot on with every cross point sensor even in extremely low light. The difference from the Mk II is amazing.


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## Daniel Flather (Mar 27, 2012)

My 24L mk2, 35L, 85 1.8, and 200/2 are all spot on, my 50 1.2L is performing well too, albeit not quite as well as my other primes, but the 50 1.2L is never perfect. I'm coming from a 50D to add some perspective.

*shooting all wide open of course.


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## wickidwombat (Mar 27, 2012)

Daniel Flather said:


> My 24L mk2, 35L, 85 1.8, and 200/2 are all spot on, my 50 1.2L is performing well too, albeit not quite as well as my other primes, but the 50 1.2L is never perfect. I'm coming from a 50D to add some perspective.
> 
> *shooting all wide open of course.



any chance of posting some samples? raws if possible too


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## Daniel Flather (Mar 27, 2012)

@!ex said:


> http://www.canonrumors.com/forum/index.php/topic,4864.msg96476.html#msg96476



Nice!


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## RLPhoto (Mar 27, 2012)

BL said:


> I've been rocking a 5DC since launch, and have never been happy about having to manually focus on anything outside of the center cross AF point with pretty much any of my fast primes wide open (e.g. 50L, 85L II, 135L).
> 
> The high precision, MF screen helps and is a life saver, but it's become a crutch as I've come rely on that to validate all focussing. That said, the new 5D III does not have user replaceable screens allowing for proper DOF previews for lenses faster than 2.8
> 
> ...



I FEEL YOUR PAIN!

My 5Dc with the EG-S Screen is my Bread and Butter Portrait money maker!!! The New 5D3 doesnt have changeable focus screen's! I may just get a 5D2 because of that reason.

I Love my primes and wouldn't change it for just a new body.


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## etto72 (Mar 27, 2012)

The mk III gives new life the 50L and 85L!!
Look over here
http://forums.dpreview.com/forums/readflat.asp?forum=1032&thread=41035032



BL said:


> I've been rocking a 5DC since launch, and have never been happy about having to manually focus on anything outside of the center cross AF point with pretty much any of my fast primes wide open (e.g. 50L, 85L II, 135L).
> 
> The high precision, MF screen helps and is a life saver, but it's become a crutch as I've come rely on that to validate all focussing. That said, the new 5D III does not have user replaceable screens allowing for proper DOF previews for lenses faster than 2.8
> 
> ...


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## wickidwombat (Mar 27, 2012)

RLPhoto said:


> BL said:
> 
> 
> > I've been rocking a 5DC since launch, and have never been happy about having to manually focus on anything outside of the center cross AF point with pretty much any of my fast primes wide open (e.g. 50L, 85L II, 135L).
> ...



the 5Dmk3 viewfinder standard is WAY better than the 5Dmk2 with an EG-S screen for MF it really is super big and bright with fast glass on it


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## Daniel Flather (Mar 27, 2012)

1/4000
f1.2
ef 50mm f1.2 L
Off centre focus point
Hand-held
iso 200






1/60
f1.4
ef 24mm f1.4 L Mrk 2
focus point right over viewer's right eye
Hand-held
iso 800









1/1000
f1.2
ef 50mm f1.2 L
Outer focus point
Hand-held
iso 100

All converted with DPP. Slight adjustments to WB, tiny cropping, a little sharpness. I don't pixel peep much. I know they might not be super photos, but I like them.


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## Stephen Melvin (Mar 27, 2012)

Daniel Flather said:


> 1/1000
> f1.2
> ef 50mm f1.2 L
> Outer focus point
> ...



The links won't work because you posted them as images. You'll need to put the jpegs in the img tags or just remove the tags.


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## blackwind (Mar 27, 2012)

1/1000
f1.2
ef 50mm f1.2 L
Outer focus point
Hand-held
iso 100






1/60
f1.4
ef 24mm f1.4 L Mrk 2
focus point right over viewer's right eye
Hand-held
iso 800






1/4000
f1.2
ef 50mm f1.2 L
Off centre focus point
Hand-held
iso 200


Here fixed


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## wickidwombat (Mar 27, 2012)

Thanks guys, yeah i'm not getting anything remotely that sharp :'(


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## EvilTed (Mar 27, 2012)

Awesome.
I love fast primes.
I wish they'd bundled the 50mm F/1.2 as a kit lens instead of the 24-105 
How's the focus "issues" of the 50 with the new AF of the MK3?

ET


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## dirtcastle (Mar 27, 2012)

I think you posted the same shot twice.


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## JerryKnight (Mar 27, 2012)

wickidwombat said:


> Thanks guys, yeah i'm not getting anything remotely that sharp :'(



I'm a little confused that you can make that assessment from a 640x427 jpeg.. If you really can tell from an image that small, you're doing something wrong or your camera or lens is incredibly broken.

I'm also a little confused by the wording of this thread's subject. Aren't all lenses "wide open" during autofocus? The aperture is only adjusted when the shutter is activated (or the depth-of-field preview is activated).


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## nightbreath (Mar 27, 2012)

JerryKnight said:


> I'm also a little confused by the wording of this thread's subject. Aren't all lenses "wide open" during autofocus? The aperture is only adjusted when the shutter is activated (or the depth-of-field preview is activated).



I believe "wide open" refers to resulted image, not the focusing process. Having a fast prime wide open you can easily notice focusing issues when your DOF is shallow enough.


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## Daniel Flather (Mar 27, 2012)

JerryKnight said:


> wickidwombat said:
> 
> 
> > Thanks guys, yeah i'm not getting anything remotely that sharp :'(
> ...



True, but if their 640*427 jpegs are soft vs. mine, then there is an issue.


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## BL (Mar 27, 2012)

thanks all for the contributions. it all seems very promising!

in hindsight, i realize this question is best answered renting the body and testing it out myself.


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## @!ex (Mar 27, 2012)

So I have a the new 5dmk3 and a 50mm 1.2L. I have been trying to get the micro adjustment on the lens just right, but but I figured out why it had been a bit confusing up to this point. If I use the center point (or any AF point within the metering ring) I get spot on tack sharp AF on like 90% of the shots with 0 MFA. BUT, if I use one of the outer AF spots I get pretty bad back focusing (like +15). I thought maybe it was the body I had, so I just went back to the camera store and exchanged it for another body hoping that I would at least be able to figure out if that was the variable. Turns out this body is exactly the same. This makes me think it is either difficult for the AF to get a good lock due to the aberrations of the glass the closer you get to the edge, or something wrong with the lens itself (it is brand new and date code is uz0909). I'm also just wondering if this is the price you pay with AF on really fast glass. That is where you come in. If you have fast glass (1.2) try checking the AF accuracy on center point and a more lateral point and lets see if we can come to a consensus. I'm especially interested in 50mm 1.2 as thats what I'm working with. I tested my 70-200 2.8 and it's pretty spot on with no MFA, on both center and lateral AF points. I'll post a few test shots of my 50 when I get home later.


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## Daniel Flather (Mar 27, 2012)

@!ex said:


> So I have a the new 5dmk3 and a 50mm 1.2L. I have been trying to get the micro adjustment on the lens just right, but but I figured out why it had been a bit confusing up to this point. If I use the center point (or any AF point within the metering ring) I get spot on tack sharp AF on like 90% of the shots with 0 MFA. BUT, if I use one of the outer AF spots I get pretty bad back focusing (like +15). I thought maybe it was the body I had, so I just went back to the camera store and exchanged it for another body hoping that I would at least be able to figure out if that was the variable. Turns out this body is exactly the same. This makes me think it is either difficult for the AF to get a good lock due to the aberrations of the glass the closer you get to the edge, or something wrong with the lens itself (it is brand new and date code is uz0909). I'm also just wondering if this is the price you pay with AF on really fast glass. That is where you come in. If you have fast glass (1.2) try checking the AF accuracy on center point and a more lateral point and lets see if we can come to a consensus. I'm especially interested in 50mm 1.2 as thats what I'm working with. I tested my 70-200 2.8 and it's pretty spot on with no MFA, on both center and lateral AF points. I'll post a few test shots of my 50 when I get home later.




My 24L and 35L are great using any focus point wide open, the 50L is a tricky lens. It performs well with the centre point, but may vary with using outer focus points. With the 50D the 50L as all over the place. The 5D3 seems to have tamed the 50L some. I'm much happier with the 50L on the 5D3 vs. my (now on eBay) 50D.


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## wickidwombat (Mar 27, 2012)

@!ex said:


> So I have a the new 5dmk3 and a 50mm 1.2L. I have been trying to get the micro adjustment on the lens just right, but but I figured out why it had been a bit confusing up to this point. If I use the center point (or any AF point within the metering ring) I get spot on tack sharp AF on like 90% of the shots with 0 MFA. BUT, if I use one of the outer AF spots I get pretty bad back focusing (like +15). I thought maybe it was the body I had, so I just went back to the camera store and exchanged it for another body hoping that I would at least be able to figure out if that was the variable. Turns out this body is exactly the same. This makes me think it is either difficult for the AF to get a good lock due to the aberrations of the glass the closer you get to the edge, or something wrong with the lens itself (it is brand new and date code is uz0909). I'm also just wondering if this is the price you pay with AF on really fast glass. That is where you come in. If you have fast glass (1.2) try checking the AF accuracy on center point and a more lateral point and lets see if we can come to a consensus. I'm especially interested in 50mm 1.2 as thats what I'm working with. I tested my 70-200 2.8 and it's pretty spot on with no MFA, on both center and lateral AF points. I'll post a few test shots of my 50 when I get home later.


this could explain my wildly varied results too although i was deliberately stopping down to f2 or f2.8 to give it a bit of a chance also images are sharper there.


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## Drizzt321 (Mar 28, 2012)

Daniel Flather said:


> @!ex said:
> 
> 
> > So I have a the new 5dmk3 and a 50mm 1.2L. I have been trying to get the micro adjustment on the lens just right, but but I figured out why it had been a bit confusing up to this point. If I use the center point (or any AF point within the metering ring) I get spot on tack sharp AF on like 90% of the shots with 0 MFA. BUT, if I use one of the outer AF spots I get pretty bad back focusing (like +15). I thought maybe it was the body I had, so I just went back to the camera store and exchanged it for another body hoping that I would at least be able to figure out if that was the variable. Turns out this body is exactly the same. This makes me think it is either difficult for the AF to get a good lock due to the aberrations of the glass the closer you get to the edge, or something wrong with the lens itself (it is brand new and date code is uz0909). I'm also just wondering if this is the price you pay with AF on really fast glass. That is where you come in. If you have fast glass (1.2) try checking the AF accuracy on center point and a more lateral point and lets see if we can come to a consensus. I'm especially interested in 50mm 1.2 as thats what I'm working with. I tested my 70-200 2.8 and it's pretty spot on with no MFA, on both center and lateral AF points. I'll post a few test shots of my 50 when I get home later.
> ...



I remember reading from a link posted somewhere in this forum on autofocus with lenses, and how it won't always work properly when further from the center. Perhaps that's what's going on with your 50 1.2.


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## wickidwombat (Mar 28, 2012)

JerryKnight said:


> wickidwombat said:
> 
> 
> > Thanks guys, yeah i'm not getting anything remotely that sharp :'(
> ...


true I was just feeling sorry for myself yesterday so i spend most of last night doing detailed testing i posted all the raws this morning


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## mrmarks (Mar 28, 2012)

@!ex said:


> So I have a the new 5dmk3 and a 50mm 1.2L. I have been trying to get the micro adjustment on the lens just right, but but I figured out why it had been a bit confusing up to this point. If I use the center point (or any AF point within the metering ring) I get spot on tack sharp AF on like 90% of the shots with 0 MFA. BUT, if I use one of the outer AF spots I get pretty bad back focusing (like +15). I thought maybe it was the body I had, so I just went back to the camera store and exchanged it for another body hoping that I would at least be able to figure out if that was the variable. Turns out this body is exactly the same. This makes me think it is either difficult for the AF to get a good lock due to the aberrations of the glass the closer you get to the edge, or something wrong with the lens itself (it is brand new and date code is uz0909). I'm also just wondering if this is the price you pay with AF on really fast glass. That is where you come in. If you have fast glass (1.2) try checking the AF accuracy on center point and a more lateral point and lets see if we can come to a consensus. I'm especially interested in 50mm 1.2 as thats what I'm working with. I tested my 70-200 2.8 and it's pretty spot on with no MFA, on both center and lateral AF points. I'll post a few test shots of my 50 when I get home later.



All AF points should work the same. Canon should look into this issue as well.


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## Drizzt321 (Mar 28, 2012)

mrmarks said:


> @!ex said:
> 
> 
> > So I have a the new 5dmk3 and a 50mm 1.2L. I have been trying to get the micro adjustment on the lens just right, but but I figured out why it had been a bit confusing up to this point. If I use the center point (or any AF point within the metering ring) I get spot on tack sharp AF on like 90% of the shots with 0 MFA. BUT, if I use one of the outer AF spots I get pretty bad back focusing (like +15). I thought maybe it was the body I had, so I just went back to the camera store and exchanged it for another body hoping that I would at least be able to figure out if that was the variable. Turns out this body is exactly the same. This makes me think it is either difficult for the AF to get a good lock due to the aberrations of the glass the closer you get to the edge, or something wrong with the lens itself (it is brand new and date code is uz0909). I'm also just wondering if this is the price you pay with AF on really fast glass. That is where you come in. If you have fast glass (1.2) try checking the AF accuracy on center point and a more lateral point and lets see if we can come to a consensus. I'm especially interested in 50mm 1.2 as thats what I'm working with. I tested my 70-200 2.8 and it's pretty spot on with no MFA, on both center and lateral AF points. I'll post a few test shots of my 50 when I get home later.
> ...



There's certain physics on the path light takes that causes it to come in at different angles towards the edges versus near the center. Theoretically Canon could probably make a sensor that works much better, but it'd probably be physically larger/different, and probably much more expensive.


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## jm345 (Mar 28, 2012)

My 5DIII is working great with the 35L 1.4 wide open. Accurate focussing in low light in the center and extreme left and right focus points. And ISO 3200 is amazing.


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