Why do the center AF points on my Canon 6D stop focusing after reassembly?
Asked 1/13/2018
5 views
2 answers
0
After repairing and reassembling my Canon 6D, only the center column of autofocus points stopped working. The AF points light up normally, the lens makes one focus attempt, then stops. If I use automatic AF point selection, the camera focuses using the other points but never the center column. The issue happens with multiple lenses, so it does not seem lens-specific. I checked the mount contacts, inspected the mirror and focusing screen, and blew air toward the AF sensor area, but nothing changed. What could cause a selective failure of just the center AF points after a repair?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
8y ago
2 Answers
0
The problem probably has nothing to do with your PDAF sensor array. It most likely has to do with the data connection between the PDAF sensor array and the camera's processor that does all of the computations based on the data collected by the PDAF array.
You say you "needed to repair the controls of my Canon 6D, after it received kitten damage." Did those repairs require disassembly to the point that any ribbon cables or other connections between various parts of the camera and the main PCB had to be unplugged? That's where I would start looking. Hopefully it is just a loose connection, and not a damaged cable.
Originally by user15871. Source · Licensed CC BY-SA 4.0
user15871
8y ago
0
Generated from our catalog & community — verify before relying on it.
The most likely cause is not the AF sensor itself, but a connection problem between the phase-detect AF module and the camera’s main board. Since the failure appeared after disassembly/reassembly, a loose ribbon cable, partially seated connector, or damaged flex cable is the strongest suspect.
A selective failure of only one group of AF points fits an incomplete data path better than dirt on the mirror or mount contacts, especially since:
- the issue occurs with multiple lenses
- other AF points still work normally
- the affected points illuminate and attempt focus, but do not complete it
The best place to start is reopening the camera and checking any ribbon cables or connectors that were unplugged or disturbed during the repair, particularly those related to the AF assembly or main PCB. If a connector is slightly loose or a flex cable was damaged during reassembly, that could explain why only the center column fails.
Recommended products
UniqueBot
AI8y ago
Your Answer
Related Questions
Is it wrong to use only the center autofocus point?
Why does my Canon 5DS only autofocus with the center AF point?
How evaluative metering uses AF points on the Canon EOS-1V
Should off-center AF points still focus correctly with a lens that has field curvature?
Can a lens cause different autofocus accuracy on different AF points?