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08/10/2007 06:03:33 AM · #51 |
Originally posted by silverfoxx:
could you please tell me what backfocusing is?
and recalibration? |
Back focusing is where the lens focuses behind the intended target. Front focusing is the opposite. Recalibration sets the lens to focus on the intended target instead of in front of or behind.
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08/10/2007 06:16:53 AM · #52 |
oh, thank you!
i thought it's only the photographer's fault
i always focus on my backgrounds, not on me
is it a lens problem or my fault? |
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08/10/2007 06:20:39 AM · #53 |
Originally posted by silverfoxx:
oh, thank you!
i thought it's only the photographer's fault
i always focus on my backgrounds, not on me
is it a lens problem or my fault? |
Do you do that intentionally? Meaning, do you (for example) aim the focus point at the background and then recompose? If so, then it's your fault, haha. If you focus on your eyes (with shallow DOF), and your hair is in focus then it's a lens issue. You can google "focus test" and print out the page it gives. That will tell you if your lens is missing focus at all.
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11/16/2007 08:17:59 AM · #54 |
I ´ve checked six 70-200 F.4 , IS lenses with 3 different cameras:the same problem :backfocus ,more noticiable at short distances.The last one was sent to Canon twice for calibration with the same bad results.I ´ve no answer at all from Canon about this problem
Here at F.5.6 both v.s. 18-55 kit lens after calibration
//img453.imageshack.us/img453/7095/prueba70200xx2.jpg
Message edited by karmat - keep the longest side under 500 pixels in the forums, please. |
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11/16/2007 09:54:23 AM · #55 |
| Interesting backfocus test. Flat image parallel to the lens. |
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11/16/2007 10:14:06 AM · #56 |
| yes:tripod ,cable release , I:S off |
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11/16/2007 10:14:41 AM · #57 |
Originally posted by colacao:
I ´ve checked six 70-200 F.4 , IS lenses with 3 different cameras:the same problem :backfocus ,more noticiable at short distances.The last one was sent to Canon twice for calibration with the same bad results.I ´ve no answer at all from Canon about this problem
Here at F.5.6 both v.s. 18-55 kit lens after calibration
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I'm sure you are using a tripod for these, aren't you ?
A better backfocus test is to have something angled away from the lens, so you can see where it has actually focused- if at all.
Message edited by author 2007-11-16 15:14:59.
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11/16/2007 10:32:18 AM · #58 |
after 2º calibration center image , all lenses at f:5.6
//img339.imageshack.us/img339/7891/4centropr6.jpg
Message edited by karmat - keep the longest side under 500 pixels, please. |
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11/16/2007 10:35:09 AM · #59 |
near the left edge , all lenses f:5.6
//img220.imageshack.us/img220/4066/4esquinasoa4.jpg
Manual focus vs autofocus at f:5.6 both the same lens 70-200 IS F:4
//img266.imageshack.us/img266/3867/enfoquemnualafhz3.jpg
Message edited by karmat - see previous posts. |
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11/16/2007 10:45:56 AM · #60 |
Can you post thumbnails not full size images?
Did you do any tests with the test pattern tilted away from the lens? Looks like the lens focus is dead on in manual and that you've got AF issues.
Message edited by author 2007-11-16 15:46:37. |
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11/16/2007 10:51:50 AM · #61 |
| The same result with 3 different cameras,at far distances use to focus right , sometimes fail |
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11/16/2007 10:58:39 AM · #62 |
far distance backfocus after first "calibration".The only active focus point was the far right:
//img257.imageshack.us/img257/6589/backfocuslargadistanciasq7.jpg
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11/16/2007 09:35:17 PM · #63 |
With my 10D and 70-200 4L IS, I experience back-focus by 1/2 to 1 inch using One-Shot center-point focus (F4 200mm at 5 foot focus range).
However, when I put it in AI Servo, and move the camera around the focus point in a 1 to 2 inch circle, and then settle on the focus point, the focus is very good. It takes a bit of time, and you do not get the reassuring "beep" in AI Servo mode, but it seems to improve the focus accuracy. |
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