Wikir1. Canon Cameras
1.1. Canon 20D
1.2. Canon 5D MkII
1.2.1. Problems
2010-05-19 5D body stopped recognizing all lenses attached - first noticed with 24-105L. Aperture 00 was reported throughout the problem. Originally attributed to a low battery. There was a discrepancy between the on-camera charge rating (3 out of 4 bars) and the charged (25%, by the flashing of the charge lamp) but a full battery charge did not fix it. After a trip to the local Canon Authorized Repair dealer, it began working. Ambient temperatures were mid 80's (F) with mild humidity. Problem persisted about 16 hours.
2010-09-06 5D body stopped recognizing all lenses attached - first noticed with a 24-105L. Aperture 00 was reported moments after taking a few successful shots at f16 after doing some manual dust removal. Lens reseated multiple times. Both lenses tried are "like new" and the contacts are spotless. Tried 28-105mm lens and problem persisted about 40 minutes. Ambient temperatures were mid 70's (F) and dry. Problem corrected after switch lens into "live-view" mode for a few seconds.