A l'aide! Eos 400, image trop sombre!!!

[silver_dot]

les EOS400D ont un réglage d'usine sous-exposant de 2/3 de diaph (à l'opposé du 350D qui surexpose d'origine d'autant)

une circulaire est passée dans les SAV pour modifier la procédure de réglage d'exposition en comparant l'expo de l'EF-S 18-55 vendu en kit et un EF50mm

[salicorne]

Si vous avez qques difficultés à trouver les posts chez DPreview et si vous n'êtes pas fâchés avec la langue de Shakespeare, voici 2 messages qui convergent vers une source potentielle de ce problème :

"This week I forwarded an email and link to Canon that a Xti owner explained that he spoke with a Canon tech in Europe that repaired his camera, he explained that some models of the Xti has problems. He had repaired a few of them before, they all had under exposure problems. The problem was an incompatible mainly with the kit lens and some canon lens slower than f5.6. It seems that the focusing screens is the main problem, because they are made in different factories.
By replacing the focusing screen and recalibrating the software the under exposure problems was solved. In my email I said please do not insult me and tell that my camera is in specs so it must be the way that I am taking the pictures. I mentioned what if the focusing screen the tech replaced was from the same factory that made my original one, would they please ensure it was from a different factory...
...Well she explained that they heard from Canon Japan, they admit there seems to be a problem with some models of the XTI. From my serial number mine was one of them. Canon Japan is in the process of working on new software that will fix the problem. Not sure if the focusing screen would still have to be changed or the new software would be specifying new specs for the service department to adjust to..."
"I talked with Canon technicians in the two labs where my camera was tested. They found it was defective and they fixed the underexposure issue. If I understand well (I am not a technician) the cause was an incompatibility between the camera software and the focusing screen mounted. Maybe I must say "my" camera because they said not all the 400D mount the same identical focusing screens. These parts were produced in different factories and the camera have to recognize them. If this not happens the light mesaurement, with some lenses having not a great aperture (ie 5.6), give wrong reading and produces underexposed pictures. The underexposure was more noticeable with 18-55, they said, most at long focal lenght (around 50mm) than at short (18mm). They found the same issue also with other 5.6 lenses.

The underexposure can be corrected changing the focusing screen or changing some part of the software related to its functions. In my case they corrected the software. The technician said also that I was not alone... the same issue was found in other 400D cameras."

A+