What type of focusing problem is this?


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blurboiboi

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Jan 8, 2003
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#1
i focused on the word instructions but only the left right and top are in focus....
its a third party(Tamron) lens, anyone got any idea where i can send it for recalibration and roughly how much it cost?

 

tSkye

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#2
You'll have to sent it for lens calibration with the problem, back focusing.
 

Dream Merchant

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#3
Are you sure it's out of focus, as in, did you select only the center focusing point?

The tube is of OXY is tubular and tapered . Not exactly the best subject to use for a focusing test. Could be that the focusing locked on the further points (sides of tube, and the taoered portion), or that the lens was just that bit too close and past the MFD.

Sides, where does one get a Tamron serviced in Singapore?
 

ST1100

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#4
Hmm... has anyone ever successfully convinced either Canon or Tamron to calibrate a Canon/Tamron combination?
 

lsisaxon

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#5
i focused on the word instructions but only the left right and top are in focus....
its a third party(Tamron) lens, anyone got any idea where i can send it for recalibration and roughly how much it cost?
It looks like quite a close up shot where the DoF can be quite shallow. Before you blame the misfocus on the lens or the body, did you shoot this handheld or using a tripod? The reason for asking is if you had not used a tripod, there is a chance that you might have moved a little forward after you locked focus before the shutter was released.
 

blurboiboi

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#6
Are you sure it's out of focus, as in, did you select only the center focusing point?

The tube is of OXY is tubular and tapered . Not exactly the best subject to use for a focusing test. Could be that the focusing locked on the further points (sides of tube, and the taoered portion), or that the lens was just that bit too close and past the MFD.

Sides, where does one get a Tamron serviced in Singapore?
It looks like quite a close up shot where the DoF can be quite shallow. Before you blame the misfocus on the lens or the body, did you shoot this handheld or using a tripod? The reason for asking is if you had not used a tripod, there is a chance that you might have moved a little forward after you locked focus before the shutter was released.
hihi... thanks for the pointers... i did it by placing the camera on a table and shooting the tube with timer mode... i shall go test it again with tripod and perhaps shooting a flat surface this time round.... does newspapers help??
 

blurboiboi

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#7


hi all...
with the above pic can i confirm that my lens has back focusing problem??...
focusing point is boxed up in white.... shot with tripod and timer...
thanks so much....
 

Dream Merchant

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#8
Yeah, that looks like back-focusing.
 

karnage

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#9
It just looks like trying to focus nearer than the minimum focusing distance to me. The camera might have just selected the minimum focus distance and taken the shot, regardless of where you're trying to focus. :dunno:
 

lsisaxon

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#10
hi all...
with the above pic can i confirm that my lens has back focusing problem??...
focusing point is boxed up in white.... shot with tripod and timer...
thanks so much....
Yup.. confirm back focused. If your other lenses are ok, then you should call Tamron up to get the lens calibrated. Sigma is able to calibrate their lenses, so I guess Tamron should do the same rather than pushing the blame to the body. If still under warranty, Tamron should calibrate it for free.
 

lsisaxon

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#11
It just looks like trying to focus nearer than the minimum focusing distance to me. The camera might have just selected the minimum focus distance and taken the shot, regardless of where you're trying to focus. :dunno:
I don't think TS is so careless to try to focus at something the lens couldn't. And even if that might be the case, the focus would not lock and sometimes depending on the settings, the shutter would not release.
 

calkel20

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Jul 5, 2008
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#12
Focusing with F4, my lens is clear. But at F2.8, it seems to be double image! So is it back focusing problem as well? Just got the lens from a lens swop plus top up. Or does it has a problem working with 40D?
 

Feb 11, 2008
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#14
Either way, expect to face a one month waiting time for it to be sent back to Japan for calibration
 

Pokka

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#15
After reading all this, comparing the Tamron 17-50 and the Tokina 16-50, would you all prefer Tokina?
 

GELworkz

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Aug 26, 2008
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#16
After reading all this, comparing the Tamron 17-50 and the Tokina 16-50, would you all prefer Tokina?
that could be a solution, but give that tokina is abt 30% (600+ vs 900+) more expensive than the Tamron, it might make budget photographers like me think twice.

found this interesting comparison http://www.flickr.com/photos/nschaden/1332341897/
from my point of view, in terms of picture quality, it seems that tamron is a tad better

anyway coming back to the topic, yeah it sure looks like back focusing. wat lens r u using and on which body ah-boi?
 

Feb 11, 2008
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#17
If you own a Canon, not worth buying a 3rd party lens for 900+ when for a hundred or so bucks more, can get a original Canon lens...and an L at that.
 

jjj849

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#18
sorry but can someone explain what back focusing is?
 

Pokka

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#19
sorry but can someone explain what back focusing is?
Imagine 3 people A B C standing in a line. You focus at B who is standing in the middle but the camera's actual focus is on A. This is back focusing. If the focus is on C, it is front focusing.
 

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