Hi,
As I see posts with varying degrees of knowledge, guesswork and plain wrong facts about this matter (not to mention very different approaches to discuss and analyze this matter) I'd like you to read and understand some FACTS about 10D focus issue. I have many of these from Canon, and based on my own 10D experience.
(ADDENDUM 9.7.2003)
FACT: "The vertical component of the center focusing point for the 10D is equal in coverage to that of the D30 and D60, whereas the horizontal component is approximately 20% longer. In all cases, the actual area that can potentially be evaluated by the AF system is larger than indicated by the AF frame engraved on the focusing screen." From http://robgalbraith.com …&Number=148832#Post149286
**Previous Test chart no longer available. Here is a good one as of August 2009;
http://www.hkdotnet.com …st/AF_test_chart-a4-w.bmp
and
"The verbal way of describing the length of the 10D's 5 vertical AF sensor arrays is that they are approximately 2.25 times longer than the vertical dimension of the frames that are engraved on the focusing screen. The 3 horizontal arrays are the same length as the 5 vertical arrays. All sensor arrays are slightly narrower than the area indicated by the engraved frames."
from http://www.robgalbraith.com …&Board=UBB8&Number=149393
Both texts and AF array image by Mr. Chuck Westfall (Director/Technical Information Dept.)
(ADDENDUM 9.7.2003)
FACT:
10D camera body has no focus issue.
FACT:
Some 10D's camera bodys have problems in focusing or getting sharp photos.
FACT:
To make sure there is no user error in question this problem must be verified with testing, and the test should be done (according to Canon Japan):
- from 2.5m
- with a 50mm lens
- in at least 12EV light (ISO 100, 5.6 1/125 equiv.)
- on sturdy tripod (mirror lock and external/timed release)
- "One shot" focus mode
- manual focus point (center).
- Largest aperture of the lens. This means use smallest f-number you can get.
The testing target can be built from a paper with some scale, and a cardboard focus point with white rectangle of black background. Canon test setup is something like this:
 | HTTP response: NOT FOUND | MIME changed to 'text/html' |
(The drawing is not in scale, sorry). The focus rectangle should be tack sharp and on the scale you can see how depth-of-field distributes. If rectangle is out of focus the scale tells you how much it is out and into what direction.
Image of this test (from Canon's Finnish repair center), with 200mm lens:
| HTTP response: NOT FOUND | MIME changed to 'text/html' |
Other usable test is at http://www.hkdotcom.net …channel/AF_Test/index.htm
- you can use that chart in above Canon type testing, but you don't want to focus to the chart itself as told on that page. It is important that what you focus to is a flat plane facing to the camera - any 3D information there makes test results unreliable.Make sure that viewfinder focus rectangle sees only one possible focus point. Always use One Shot focus mode with center point only for testing. Alighn the test so that the plane of focus is not slanted - if you think you can't do the test ask someone more experienced to do it for you.
FACT:
Do not to fully trust you own tests - they just indicate something. If you get repeatedly off focus results, take the camera to repair and let them test it again there and make their own concusions. In the end Canon is the only authority that can confirm any focus errors in your camera body.
FACT:
Of those problematic 10D's some can be fixed by calibrating, some must be replaced.
FACT:
No one knows how many cameras has this problem. Perhaps only few. Perhaps more. Fact is that no one knows.
FACT:
This problem is not related to body serial numbers.
FACT:
There is no "body thickness issue" - it was a false alarm, it was tracked to be an error in Canon 10D repair manual.
FACT:
There is really no reason to know in technical terms what causes this problem. Canon repair fixes or replaces those bodies, that should be enough.
FACT:
Canon has been really polite and helpful on getting those bad seeds replaced or fixed. So please don't overreact and pour you anger onto them, even if Canon Japan has not made no official comments on this problem.
FACT:
Focus error can be "front" focus or "back" focus. Front means camera focuses closer to you, back means the camera focuses further away from intended focus point.
FACT:
Slight focus shifting (repeated tries give slightly different focus lock) is normal to autofocus systems. Focus shifting may be increased by dust and dirt inside camera body parts, dust or dirt on lens back, dust or dirt on filters/lens.
FACT:
Focusing can get out of calibration if you drop your camera or handle it rough.
FACT:
Resetting camera does not fix focusing.
FACT:
10D is the "most recommended" digital SLR I know, I really really like it.
FACT:
I may have forgotten some facts.
