I had this weird experience when I was out shooting at a park. Everything was fine for the first 30 exposures or so and I was not doing anything unusual when all of a sudden on one of my exposures my shutter clicks and HOLDS for a couple of seconds and then displays the Err01 text on the screen about not being able to communicate with the lens and suggesting that I clean the gold contacts. I half-pressed the shutter button to clear the screen and everything returned to normal and I was able to continue taking photos for the rest of the day. When I got back home I took the lens off and looked everything over - did not see any problems, but used a rocket blower anyway and the lens is continuing to work fine and I haven't had any problems since.

My question is: should I be concerned and bring the camera (or lens) in for a look by Canon Professional Services? My worry is that this is signaling there could be something wrong with either piece of equipment. Or am I just being too anal?

Thank you.


2 Answers 2


Auric Goldfinger says

Once is happenstance.
Twice is coincidence.
Three times is enemy action.

Similar applies to things electronic, but mayhaps not quite just 1 2 3 ...
ie almost anything can have a very very occasional fault "just because" unless exceptional steps have been taken to prevent it by the designer.

Alpha particles emitted from the plastic in ICs when they are struck by cosmic rays can cause random memory bit flips in dynamic RAMs which may cause crashes. That's close to happenstance.

If it was mine and was getting near the end of a warranty period I'd think harder about whether any other indication had been given recently of problems. But any other time I'd note it and wait to see if it happens again. Two in a dozen usage sessions is too many. Two in a year of frequent use is probably poor design but Canon are unlikely to fix it. Two in a month or few is too many.

I had a heavily used DSLR that very occasionally would produce bright purple images. The first time it happened was in the middle of a wedding and I did not know how to fix it. Backup cameras have their place. I found soon thereafter (next quiet spot during same wedding) that unseating and seating the lens fixed it. Happened infequently enough that it was not certain that contact cleaning helped. Definitely "enemy action" though.

My home LAN router crashes every few weeks - it's probably lack of robust design greatly helped by enemy action. The switch that distributes LAN signals around the house crashes about once every 6 months. Not quite coincidence but power glitches and a less than bulletproof design would explain it.

If your lens never does that again it's happenstance.
It may well be a dirty contact fault as John says.
But that may have been caused by an exceptionally rare whiff of something gaseous or some particulate (blown pollen?) when you last changed your lens. Or a timing waveform that is in spec 99.9999% of the time finding that 1 in a million is not that unlikely after all (all those 9's look good, but you need a few more than that for real reliability at processor speeds).


It's a lens to body communication error and may be as simple as some dirty contacts. If you clean these and the error comes back and persists then your lens and/or body may need servicing. Otherwise, I think you probably don't need to worry, especially since it has been fine ever since.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.