September 02, 2014, 11:41:44 AM

Author Topic: AF problems with 70D and fast lenses  (Read 9017 times)

ashmadux

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Re: AF problems with 70D and fast lenses
« Reply #15 on: February 20, 2014, 01:44:01 PM »
@ OP

You should refer to the review here of the 24 1.4. He does mention focus issues, but even i didn't really notice that line until after I tried it myself. I rented this last summer, trying to somewhat replicate my great experience with the EOS - M's 22/f2 (love it!) on a full sized body.

Spoiler: it didnt go well. I had problems focusing on pretty much anything in the most amateur of shooting situations. And I mean anything- people, places, and things. It was all over the place. OOF 99% of the time- i couldnt even get a bridge in focus- not kidding.

I can only talk about my experience, but im guessing that this is pretty well known. Maybe.
« Last Edit: February 20, 2014, 01:45:51 PM by ashmadux »
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Re: AF problems with 70D and fast lenses
« Reply #15 on: February 20, 2014, 01:44:01 PM »

MYB

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Re: AF problems with 70D and fast lenses
« Reply #16 on: March 15, 2014, 12:01:08 PM »
I'm not sure but i have this problem too imo. I have 70D with sigma 17-70mm f/2.8-4. There is a focus problem at wide angles (17-20mm). Maybe because of the lens but i have only one, couldn't try with another. AFMA didn't solve it. I'm using in aiservo mode with all 19 points, best i can for now.
New in DSLR. Canon 70D.

drjlo

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Re: AF problems with 70D and fast lenses
« Reply #17 on: March 15, 2014, 12:27:50 PM »

I have similar issues with the 5d3.  I discovered some things

1. The 24mm and in fact many lenses have quite a different afma depending on focus distance.
2. Focal is not very reliable.  I have never obtained consistent results using my 5diii or 7d with 10 different lens combinations.
3.  Fast lenses have a very thin dof so any error is more apparent.  You can try the lenses at f4 and see if your curves stabilize.

I ended up having to manually verify focal with a Spyder lenscal and ended up just not using focal as i got better results doing it manually.

I have similar issues with 5D III with its "Advanced 61 AF points", something I'm sure is prevalent with all phase-detect/mirrored bodies out there.  There is good reason live view with magnification is recommended for critical focus.  The problem is current DSLR's are slow as molasses to AF in live view. 

I do think the future is mirrorless bodies with advanced AF, not having to go through the mirrorbox mechanism, such as the upcoming Sony A6000.  Having tried the Sony A7R, I do look forward to the day the A6000 AF system is implemented on that A7R sensor.   


East Wind Photography

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Re: AF problems with 70D and fast lenses
« Reply #18 on: March 16, 2014, 10:15:02 AM »

I have similar issues with the 5d3.  I discovered some things

1. The 24mm and in fact many lenses have quite a different afma depending on focus distance.
2. Focal is not very reliable.  I have never obtained consistent results using my 5diii or 7d with 10 different lens combinations.
3.  Fast lenses have a very thin dof so any error is more apparent.  You can try the lenses at f4 and see if your curves stabilize.

I ended up having to manually verify focal with a Spyder lenscal and ended up just not using focal as i got better results doing it manually.

I have similar issues with 5D III with its "Advanced 61 AF points", something I'm sure is prevalent with all phase-detect/mirrored bodies out there.  There is good reason live view with magnification is recommended for critical focus.  The problem is current DSLR's are slow as molasses to AF in live view. 

I do think the future is mirrorless bodies with advanced AF, not having to go through the mirrorbox mechanism, such as the upcoming Sony A6000.  Having tried the Sony A7R, I do look forward to the day the A6000 AF system is implemented on that A7R sensor.

I agree.  Future of af is to do it in the sensor where the image is obtained.  Need to speed up af times, faster than phase detect, and do it with an accurate viewfinder for object tracking.  7dii may try to address these issues but i doubt the af speed will improve much....which is why it will first be marketed for video use.

As far as fast lenses go its best to afma them at the focus distance you expect to use the lenses the most.  Outside of that, use manual or live view focus, or use a higher f stop to increase dof.  Id like to see afma tweaked to allow for afma at distance and minimum focus distance then extrapolate between the two.  Similar to what they do now with zoom lenses at wide and tele.  That should help considerably.


Lightmaster

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Re: AF problems with 70D and fast lenses
« Reply #19 on: March 20, 2014, 06:32:46 PM »
so what will waiting a few hours change on the center AF point?

that is something relates to light (it is also your user name).  i stopped watching video at 10:45 after clearly identified:

1. focus object,
2. direction of light,
3. position where he stood and camera focus angle,
4. and some other, but the top 3 are much much important...

well, this is my own guess according to my understanding.  but i would love to see second video demonstrated like i have described if i can...

sorry but you missed the point entirely.

as i wrote a few times:  the camera focuses fine with any other focus point then the center AF point.... under the SAME light situation.

there goes your theory...

IF your theory would hold it´s water then all AF points should be affected... you agree?
« Last Edit: March 20, 2014, 06:36:57 PM by Lightmaster »

Scoobertdoo

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Re: AF problems with 70D and fast lenses
« Reply #20 on: March 30, 2014, 11:00:13 PM »
I found this site by google searching 70D focus issues. Mine has the same exact problem as the German ones. With a 50 /1.4, 85/1.8 or tamron 28-75 /2.8 on the body and wide open and using the center focus point. The focus is all over the place. 1 out of 10 MIGHT get focus nailed, MIGHT.

Canon stays in full denial over the whole thing, as you would expect.


MYB

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Re: AF problems with 70D and fast lenses
« Reply #21 on: May 28, 2014, 04:02:30 PM »
Hi,
I could try with different lenses. Tamron 17-50mm F/2.8 ( i can't call it test, just a few photos ) no mistake. Canon 70-200mm F/2.8 II ( a lot of photos with different combination ) first not good but after microadjustment it's perfect. Than i retuned my Sigma 17-70mm F/2.8-4 C and tried microadjustment again. Not perfect but better. Maybe AFMA works not very well with third party lenses or i couldn't do it properly.
I figured that with my camera, single ( center ) point af works very good, all 19 point also nice but zone af not sharp. I'm not saying it can't focusing but it doesn't as sharp as center point. AF sensor is same with 7D but maybe system is different and it can't perform like the 7D. Or i'm just new with DSLR :)
My opinion, I'm sure my camera is not effected.

I'm not good at English, i'm from Türkiye. Sorry if i said something wrong.
« Last Edit: May 28, 2014, 04:15:25 PM by MYB »
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Re: AF problems with 70D and fast lenses
« Reply #21 on: May 28, 2014, 04:02:30 PM »

felipy2k

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Re: AF problems with 70D and fast lenses
« Reply #22 on: July 29, 2014, 01:04:48 PM »
after read billions of users around the world, complaining about the same thing, i'm 100% sure that is a hardware fault and i have no hope of a salvation firmware. I've been testing with 50mm 1.8 and 17-55 2.8 since a got the first soft shot and i notice that even from liveview, if you using quick mode you got even worse results than from the viewfinder. I'm about to sell the body and the 17-55 and buy a 6D with 24-105. Some rumors says, that 7D MK II was delayed to fix this  issue!

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Re: AF problems with 70D and fast lenses
« Reply #22 on: July 29, 2014, 01:04:48 PM »