40D focus failure issue in the cold :(

Hi All

Out yesterday in very cold conditions (RAF Cottesmore for the last flight of the Harrier) the kit acclimatised in the bag and came when the activity started ~ got I hope some worthy of keeping???

However, at IMO a critical tog moment/period (taxi'ing close with cockpits open & waving back at the crowd) the 40D focusing failed to work (70-300mm Zoom mounted) cold and fuddled brain could not suss it out , unlocked lens twice to clear the contacts but no go. A few moments later tried the same trick a few more times but rotated it fully to the dismount position rather than just a few degrees rotation, this apparently sorted it but as I say too late to get some good shots at that critical moment

I sumise this was due, maybe, to some condensate on the lens/body contacts even though after three hours at the same temp this should have been unlikely or maybe the chill factor caused some glitch!

Has this happened to anyone else and if this is entirely down to the 'conditions' is there anything a Canon service of the body can do to mitigate against it happening again??? Would hate it to let me down again at another key event?

TIA for any insight

From your description, my guess is that you didn't have the lens mounted and locked properly to begin with or you had inadvertently somehow pressed the lens release button causing it not to make a proper connection with the contacts.

philwillmedia wrote in post #11461745
From your description, my guess is that you didn't have the lens mounted and locked properly to begin with or you had inadvertently somehow pressed the lens release button causing it not to make a proper connection with the contacts.

Hi Phil

Thanks for the feedback

I take your point but rest assured the first thing I confirmed was that the lens was still locked in place i.e. I had to depress the lock button to get it to rotate to start my endeavour to 'sort it'. As mentioned I only managed to "clear" the problem by doing the "unlock, rotate to full dismount position, rotate again & lock" approx 3 to 5 times (cannot recall the exact numder of times) in succession checking each time whether it would focus as all!

By doing so I am surmising that the cold (and damp???) had affected the contacts integrity.......hmmm I am sure the meter was working OK so those contacts were alright? Anyone know which contacts do what function???

Box Brownie wrote in post #11461731
Out yesterday in very cold conditions

What was the temp? I believe the 40D is rated for an operating range of 0 C to 40 C. Outside that range, you should expect sluggish behavior. Batteries die quickly in those temps.

Gatorboy wrote in post #11461830
What was the temp? I believe the 40D is rated for an operating range of 0 C to 40 C. Outside that range, you should expect sluggish behavior. Batteries die quickly in those temps.

My feet told me they were in the freezer but seriously airtemp was above 0 but the wind was biting so with windchill possibly around minus 1 or 2 maybe??? Batteries wise the grip and two batts behaved well and I could not 'detect' any operational differences due to the possibly 'out of operational temp range' temperature?

As for the failure of the focusing it was not a matter of sluggish as up until that point it was snapping into focus without issue

Anyone else experienced such 'cold problem' events???

I took my rebel XSI up to Nunavut with me (-15*C temps at the time we went) and had no issues at all. Other than keeping myself warm while trying to take pictures, and of course the batteries didn't last as long.

Never had a problem with my 30D, 50D, 1Dmk2, or 5D in temps down to -45C other than the screen being almost entirely useless.

I suspect the batteries took a dump. As has been said, batteries don't last as long in the cold and most photographers who shoot in the cold will carry a replacement set in an inside pocket and swap them back and forth periodically.