Blur image at the corners


bbbddd

New Member
Apr 9, 2010
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#1
Hi CSer

I realize that the corner of my pictures are blur whenever I use a Tokina 11-16. My subject is also out of focus after the auto focus lock on it. I am currently using a D7000. I tried shooting using nikon 18-105 kit lens and there no problem with the pictures. So im wondering if there is a problem with my Tokina 11-16. May I know whats the main cause of the problem ?

This image is taken with nikon 18-105 kit lens. Settings: ISO 200, f/4.5, Exposure time 1/125s, Focal length 35mm


This image is taken with Tokina 11-16. Settings: ISO-100, f/3.5, Exposuretime 1/125s, Focal Length 16mm
 

Octarine

Moderator
Staff member
Jan 3, 2008
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Pasir Ris
#2
Where is your focus point? Even on the first picture the guy with red shirt is soft whereas the bystanders in background appear sharper. Second pic the same: the background is sharper than main object. Please verify which focus point you use. In addition, you can download a focus test chart, follow the instructions and test your lenses. (Google helps.)
 

Rashkae

Senior Member
Nov 28, 2005
19,105
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#3
Also, consider that you are shooting at f/3.5 - consider your DOF, when you are referring to points close to you while your focal point is the wall 20m away. Also factor in wide angle distortion.
 

bbbddd

New Member
Apr 9, 2010
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#4
My focal point is at the guy playing the instrument. I have several shots which focuses on him but it seems OOF
 

zzyzx

New Member
Aug 25, 2007
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#5
User problem. I guess must be auto mode, multi point focus
 

Rashkae

Senior Member
Nov 28, 2005
19,105
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#6
My focal point is at the guy playing the instrument. I have several shots which focuses on him but it seems OOF
Did you use spot focus? In both pics, the focus is on the back sign.
 

bbbddd

New Member
Apr 9, 2010
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#7
Did you use spot focus? In both pics, the focus is on the back sign.
I was shocked to see the photos too. It can't bee i miss the focus point for all my shots.
 

Rashkae

Senior Member
Nov 28, 2005
19,105
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#8
I was shocked to see the photos too. It can't bee i miss the focus point for all my shots.
What focus mode did you use? This is the 3rd time we are asking...
 

bonrya

Senior Member
Dec 16, 2010
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In a mobile cage
#9
Try iso 800 with f8 on av mode and see if it's still like this....
 

zzyzx

New Member
Aug 25, 2007
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#10
The only solution to ts problem is read the user manual and understand how to operate a dslr.
In this case ts had lost control and the dslr had taken over the situation and the result isnt what ts expected (of course)
 

edmo0001

New Member
Apr 13, 2011
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#11
Could be back-focusing issue.. this is only if you can confirm that you have focused on the man playing the instrument.. My friend's Tokina 11-16 also had this issue, and he brought his camera (D90) with the lens to Nikon SC for adjustment.. As what Octarine said, you can also download and print Focus test chart (http://focustestchart.com/focus21.pdf) and test your lens on it.. see if it back-focuses.
 

zzyzx

New Member
Aug 25, 2007
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#12
Could be back-focusing issue.. this is only if you can confirm that you have focused on the man playing the instrument.. My friend's Tokina 11-16 also had this issue, and he brought his camera (D90) with the lens to Nikon SC for adjustment.. As what Octarine said, you can also download and print Focus test chart (http://focustestchart.com/focus21.pdf) and test your lens on it.. see if it back-focuses.
Does front or back focusing even applies to this situation? If ts really focus on the man and end up the signboard is in focus, i wonder how they going to adjust the lens
 

bbbddd

New Member
Apr 9, 2010
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#14
Could be back-focusing issue.. this is only if you can confirm that you have focused on the man playing the instrument.. My friend's Tokina 11-16 also had this issue, and he brought his camera (D90) with the lens to Nikon SC for adjustment.. As what Octarine said, you can also download and print Focus test chart (http://focustestchart.com/focus21.pdf) and test your lens on it.. see if it back-focuses.
The adjustment is made on the camera's body or the lens ?
 

edmo0001

New Member
Apr 13, 2011
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#15
Does front or back focusing even applies to this situation? If ts really focus on the man and end up the signboard is in focus, i wonder how they going to adjust the lens
I thot that exactly what back focusing means? If the camera AF actually misses the focusing point and focuses slightly behind the subject supposedly in focus? The adjustment would be both on body and lens, not only the lens. This pic could be one of the many examples of back focusing problem..
 

bbbddd

New Member
Apr 9, 2010
117
0
0
#16
I thot that exactly what back focusing means? If the camera AF actually misses the focusing point and focuses slightly behind the subject supposedly in focus? The adjustment would be both on body and lens, not only the lens. This pic could be one of the many examples of back focusing problem..
So if i bring the Tokina 11-16 down to NSC, will they adjust the tokina as well? or do i have to go to tokina's service ?
 

edmo0001

New Member
Apr 13, 2011
367
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0
#17
So if i bring the Tokina 11-16 down to NSC, will they adjust the tokina as well? or do i have to go to tokina's service ?
From my friend's experience, NSC will adjust the camera but they need the lens to try out their adjustment. Before going, try on the focus test chart first and see if it's really back focusing issue. Shoot at 45-degree angle wide open.
 

zzyzx

New Member
Aug 25, 2007
784
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0
#18
I thot that exactly what back focusing means? If the camera AF actually misses the focusing point and focuses slightly behind the subject supposedly in focus? The adjustment would be both on body and lens, not only the lens. This pic could be one of the many examples of back focusing problem..
If the lens or body had focusing issue, the difference in off focus distance would not be this big. Thats why your focusing chart is only this big. A goid example of focusing problem of lens or body would be at widest aperture, if you focus on a model's eye, the image turns out the ear in focus. This is the focus error distance we are refering to. Either the lens or / and the body needs micro adjustment.

Ts prob here is likely he accidentally focus on wrong subject.

If i'm wrong pls correct me. Open for discussion
 

zzyzx

New Member
Aug 25, 2007
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#19
Problem with ppl is they always blame the equipment for not producing what they want. But the fact is 95% of the time is user problem and ppl always fail to realise
 

catchlights

Moderator
Staff member
Sep 27, 2004
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www.foto-u.com
#20
front or back focus won't be that bad until 10-20feet away, unless is a lemon lens,

you could be accentually switch to AF-C, doing a auto focus and recompose. or even the switch to manual focusing with noticing it.

check how the way to shoot, and also shoot a focusing test chart.
 

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