UKC

Anyone had a lens overheat so it stopped working?
As in refuse to focus and camera sometimes telling you it cant communicate with the lens, the leave it for a while and it will be fine for a few shots.

it happened today to me at Waddington Air Show, my 70-300 started playing up, at first i thought it was the camera due to low battery, but then i would stick the stock lens on ad that would work fine.

One thing i also noticed was that the light coming through the lens would be dramatically limited, it was like looking through a lens with a whole stack of ND filters.

In reply to Mikkel:

I've seen it happen with long Sigma and Nikon lenses: Canon's big white lenses aren't white only for show!

In the last scorching 4 days at Silverstone, I've had camera bodies almost too hot to handle attached to big whites which still feel normal.

I'm sure that there are plenty of stories from the SW US in particular of overheating lenses. I hope that yours recovers.

In reply to Mikkel:
I've had a lens fail in very hot temperatures (canon ef-s 17-85) in while out climbing in a Hong Kong summer. After leaving it for a little while, it did work a few more times. However, it stopped working altogether after that. My best guess is that some lubricant oil (for diaphragm?) drained away from the elements in the heat, and then they stuck fast. Of course, I've no idea and it could have suffered a fatal impact I wan't aware of (not likely though).

In reply to Jon Read: I have experienced two different Nikon 28mm lenses on which the diaphragm blades stuck wide open. Not sure whether heat was to blame or not, but they required disassembling and relubricating.

In reply to John2:

It seems to work ok again now, thinking it might have been to different issues.
Electronics overheating and failing, why the camera told me to clean the contacts.

and the diaphragm blades sticking shut why it would not let much light through, will have to see how it perform in the future, for a 90 quid Tamron lens i doubt its worth having anything done to it.

In reply to Mikkel:

I've had a Sigma zoom fail on my Nikon in cold weather - it works fine on a friend's Nikon in the same conditions. I think what is happening is that each component is at one end of the variation in tolerances that any manufacturing process has. When the temperature drops (or in your case rises) then the interface between the two units moves beyond the designed limits. My lens would indicate focus but the camera body couldn't actuate the focusing motors.

ALC