My 10D saga update

[Pekka]

Today the repairman took my 10D on the table and tried to calibrate its autofocus system with their EF 200mm f/2.8 L USM II (which he said was good reference they used for calibrating).

He was not able to tweak my 10D to even near the correct point. The chart they used showed still back focus of +2.5 even when all calibration room was totally used.

He contacted Canon Europe and asked them to send a new unit for comparison, because the reason for inability to calibrate seemed to be "wrong body thickness": lenght from lens back to sensor was not correct, according to specs. Testing the new unit's calibration range should tell if my unit is simply a flawed one. If the new unit is off as well the next step would be try to get info from Canon how to proceed.

If the new unit's calibration room is ok, then it is most likely that I will get that new body and the old one will remain at Canon for investigation.

He tested all my Canon lenses and they seemed all back focus some. So when body is ok my lenses should be quite ok, too. He added that I can of course bring those lenses in for final calibration when we have got the body in order so that all will be secured.

On monday he will contact his contact persons at Canon Europe for more details on my 10D's body thickness issue and if there is any knowledge about that.

It is great to see that this person is dedicated in finding a reason from problems and also in getting me a well calibrated camera.

I got a D60 from them so I'll have a camera while 10D is in repair. Excellent service.

[CyberDyneSystems]

Wow that is disappointing that it is giving you so much trouble :(

I hope it all works out eventually. It will be interesting to see if it is indeed a "bad" camera and not a design issue?

It is at least good news that you are getting the help you need with it.

Keep us posted.

[Jeppe]

Yepp.. Im have been testing mine today and it seems like i also have back-focus on mine..

The longer to subject, the more faulty AF..

http://www.naturfotografen.net/10D/backfokus.jpg

The red square represent locked fokus.

Distance 10 m.
EF 70-200/4L @ 70/4

[Pekka]

Jeppe,

Your example data looks to me as wrong focus lock, not backfocus. Backfocusing is never as strong. What focus mode were you in (AI Servo, One shot?).

The focus "square" is in real life a bit bigger than the graphic you see in viewfinder so in above photo the camera may have found more contrast on background and focused to that instead.

Only way to be sure if you have real focus issues in your body/lens combination is to do a controlled test like in http://www.hkdotcom.net/Francis%20Photography%20channel/AF_Test/index.htm

My results and photos:
http://photography-on-the.net/forum/showthread.php?t=10052#46735

[Jeppe]

Exif:

File Name
111_1167.CRW
Camera Model Name
Canon EOS 10D
Shooting Date/Time
2003-04-25 17:14:58
Shooting Mode
Manual
Tv( Shutter Speed )
1/2500
Av( Aperture Value )
4.0
Metering Mode
Evaluative
ISO Speed
400
Lens
70.0 - 200.0mm
Focal Length
70.0mm
Image Size
3072x2048
Image Quality
RAW
Flash
Off
White Balance
Auto
AF Mode
One-Shot AF
Parameters
Contrast Normal
Sharpness Normal
Color saturation Normal
Color tone Normal
Color Space
Adobe RGB
File Size
7233KB
Custom Function
C.Fn:01-1
C.Fn:02-1
C.Fn:03-0
C.Fn:04-1
C.Fn:05-1
C.Fn:06-1
C.Fn:07-0
C.Fn:08-1
C.Fn:09-2
C.Fn:10-0
C.Fn:11-0
C.Fn:12-0
C.Fn:13-1
C.Fn:14-0
C.Fn:15-0
C.Fn:16-0
C.Fn:17-0
Drive Mode
Single-frame shooting
Owner's Name
© Jesper Ekvall
Camera Body No.
0130101168

I will redo the test tomorrow, this time on an tripod, but i shot another frame with refocussing (and confirmation from illuminated AF-point). Same result

[Arnie]

Pardon my ignorance, but can some please define what is back focussing and front focussing and why it is bad. I have encountered these terms in several forums and not sure if my understanding is accurate or complete. I think with a good definition of these terms we have a common understanding of the problem.

One more thing, i've seen photos posted to illustrate their point and i noticed some photos that shows the active focusing point together with the other focus points. Is this a feature of the 10D (as part of the EXIF info) or, they were manually added by the photographer?

[CyberDyneSystems]

Arnie,

Check out the links in Pekka's post here;


Pekka wrote:
Only way to be sure if you have real focus issues in your body/lens combination is to do a controlled test like in http://www.hkdotcom.net/Francis%20Photography%20channel/AF_Test/index.htm

My results and photos:
http://photography-on-the.net/forum/showthread.php?t=10052#46735


I think all the info can be found in these threads.

[henrik]

And if one _really_ wants to dig into the problems with autofocus in general there's

http://medfmt.8k.com/third/af.html

[photography By Evangelos]

Hello I am having alot of problems with my 70-200 F2.8 L canon lens. I only use the center focusing point and keep getting every thing in focus but what I focus on in the center? Strange bowth cameras do it. I never had problems like this with the D60?