Miss Focus With Canon 50mm 1.8


Jun 15, 2010
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Singapore
miltontan.com
#1
Hey guys. So when shooting portraits with my Canon 50mm 1.8 II the focus tend to miss sometimes and be a little off focus.

I wonder if this has got to do with the extreme shallow DoF or the focusing mechanism in the lens? I'm using a 7D, so the focus shouldn't be all that bad right?

I'm sure the subject and me are perfectly still when the shots are taken, and I don't focus and recompose. I also make sure to put the focus point on an area with contrast (usually the eye). So is it a fault with the lens? Do any of you guys experience this too?

Also, I'm wondering if getting a 50 1.4 will help me solve this issue since it uses USM focusing.

Thanks.
 

Irvine

Senior Member
Jan 1, 2010
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#2
in the meantime, why dun u search for a focus test chart in google and test for front/back focus with the 50 f/1.8?
 

Dec 12, 2009
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#3
Not sure...but I don't face the problem with my copy in general. The main drawback is only the noisy and abit slow focusing speed due to its cheap motor. Why not test on other objects? Again what type of focusing are you using in 7D? Centre pt af? Try centre pt af on other objects to see if the same thing occurs.
 

Jun 15, 2010
328
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Singapore
miltontan.com
#5
in the meantime, why dun u search for a focus test chart in google and test for front/back focus with the 50 f/1.8?
Did that, the focus seems to be spot on.


Not sure...but I don't face the problem with my copy in general. The main drawback is only the noisy and abit slow focusing speed due to its cheap motor. Why not test on other objects? Again what type of focusing are you using in 7D? Centre pt af? Try centre pt af on other objects to see if the same thing occurs.
I've tried using Single point AF and Spot AF at various points including the center, doesn't seem to help. The misfocusing usually happens when shooting half and full body portraits.


The 50 1.8 tend to hunt for focus especially when light levels are low.
It doesn't hunt most of the time because I shoot in bright daylight, only misses.


Wondering if the 50 1.4 performs better in focusing with the Micro USM? Or will it just focus faster?
 

madmartian

Senior Member
May 2, 2009
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#7
Alamak! I thought there's a XMM by the name of Miss Focus holding a canon lens....................................:bsmilie: :bsmilie:.............................:sticktong.......................:angel:
 

LifeInMacro

Senior Member
Aug 8, 2008
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#8
Doctor, what f number do you shoot the portraits at? Did you open all the way up to 1.8?
 

tecnica

Senior Member
Dec 26, 2004
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#9
I have the same issue with the 50, on my 7D.

Problem lies with the lens, not body because the micro motor is not well damp like the USM. Hence, the lens tend to under/over-commit itself when focusing.

I sent my 50 for calibration but it did not help. I can't be bothered anymore since it's cheap.

I never have any issue with my 17-55 and 10-22, my previous 85 also worked very well with my 7D.
 

Sgdevilzz

Senior Member
May 16, 2010
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#10
use manual focusing. :thumbsup:
 

Jun 15, 2010
328
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Singapore
miltontan.com
#11
Alamak! I thought there's a XMM by the name of Miss Focus holding a canon lens....................................:bsmilie: :bsmilie:.............................:sticktong.......................:angel:
lol! Sorry to disappoint you! Hahaha


Doctor, what f number do you shoot the portraits at? Did you open all the way up to 1.8?
Usually at about f/2.0 most of the time.


I have the same issue with the 50, on my 7D.

Problem lies with the lens, not body because the micro motor is not well damp like the USM. Hence, the lens tend to under/over-commit itself when focusing.

I sent my 50 for calibration but it did not help. I can't be bothered anymore since it's cheap.

I never have any issue with my 17-55 and 10-22, my previous 85 also worked very well with my 7D.
Ah... I see. Gets really irritating sometimes when it happens. Time to consider the 1.4 then.


use manual focusing. :thumbsup:
The DoF gets way too shallow for me to manual focus though.
 

LifeInMacro

Senior Member
Aug 8, 2008
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#12
Yes, problem gets magnified when you shoot at f/2. That's why I resorted to getting the 50mm f1.4 after trying out the f1.8.

50mm f1.f is a beauty and the USM supports pretty good AF. Certainly a keepsake for many years.


lol! Sorry to disappoint you! Hahaha




Usually at about f/2.0 most of the time.




Ah... I see. Gets really irritating sometimes when it happens. Time to consider the 1.4 then.




The DoF gets way too shallow for me to manual focus though.
 

daredevil123

Moderator
Staff member
Oct 25, 2005
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lil red dot
#13
LifeInMacro said:
Yes, problem gets magnified when you shoot at f/2. That's why I resorted to getting the 50mm f1.4 after trying out the f1.8.

50mm f1.f is a beauty and the USM supports pretty good AF. Certainly a keepsake for many years.
If the lens last many years that is. 50/1.4's usm is reported to be quite fragile.
 

LifeInMacro

Senior Member
Aug 8, 2008
605
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#16
Well, hope it doesn't happen to you.

One of the many complaints online about this lens.
Flickr: Discussing AF problem in Canon 50mm f/1.4 USM.
Thanks. I should count my blessings in that case. Anyway, I'm not so hung up about gears and equipment so I usually don't look out for discussion threads like that; if it's broken, I'd just get it fixed or keep it if it is not repairable...and life moves on...there are more important things to do.
 

farbird

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Jan 14, 2004
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#17
which focusing screen are u using?

there shd be 3 focusing screens from canon , in which one is optimized for f2.8 apertures or larger.... for better AF on centre af point , i think
 

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