Michael J Shupe wrote: As usual with cameras, try replacing the batteries first. Another thought is that it could be a contacts problem with the grip.
Ralf Schmode wrote: > this seems to be a problem familiar to 300/4 L IS USM users. I have one > and have seen the same thing occur on my EOS 50 *and* my D60. It never > happens with my 80-200/2.8 L. Here is what I wrote in October 2001, > containing somewhat more details which may be (or become) interesting in > your pursuing the issue: > > <quoting me> > > since I have the 300/4 L IS USM lens for my EOS 50, a problem occurred > every now and then: As soon as the trigger was pressed lightly to > activate AF and IS, the camera would all of a sudden fall into a state > as if no (or an unrecognized) lens was mounted. The stop would read as > "00" and the "MF" symbol would flash. There would be a short "clack" > sound of the IS and/or AF which would both be "dead" afterwards. A few > seconds later, the stop would read correctly again and the camera would > work perfectly for a large number of shots again (until today) or very > likely show the same behavior (since today). > > If the trigger was pressed after this has happened, the mirror would > swing but the film would not be transported nor exposed, i. e. the > shutter would not open. It would then be needed to switch the camera off > in order to release the mirror, after which it would be operational > again. > > This usually happened about every 30 shots and could be dealt with - > until today, when all of a sudden things got worse and the problem > occured almost every single shot. I found out this could be worked > around by unlocking the lens, turning it some degrees, turning it back > into locked position and activating AF and IS immediately (i. e. within > a second) by lightly pressing the trigger. But this cannot possibly be a > forever solution! The unit will continue working as long as the trigger > remains pressed lightly (i. e. AF/IS remain activated) but as soon as > the button is released and AF/IS deactivated, things start all over > again. > > The problem occurs inrespective of IS or AF being switched on or off. It > even seems to get worse with both off. > > There are two guesses of mine as to the reason of this problem: > > 1. Contact problems - this would explain why things will work > immediately after turning the lens forth and back into locked position. > It would, however, not explain why the camera will work if the trigger > is pressed *immediately* but won't work if done so a second later. > > 2. Voltage/load problems - my presumption is that this lens, especially > starting IS and AF is some nice energy sink which may pose too much of a > load on the 2CR5 battery. This would explain the "immediate/1 second > later" behaviour of the workaround described. It would, however, not > explain why things get worse with AF/IS off. > > I am thinking of testing the combo with the battery pack instead of the > 2CR5 battery (should be more stable under load). I am not even sure if > the problem is with the lens or the body, though the lens is more of a > suspect because the camera works perfectly with the 80-200/2.8L. > > All the contacts have been cleaned repeatedly, to no avail. Anyone in > here able to provide some help? Is this a known issue, maybe even known > to Canon itself? > > <unquote> > > From my knowledge of today I should add the following: > > Unlocking and turning back and forth of the lens seems the safest method > of getting the combo back to operation. Switching the camera off and on > doesn't always work, neither does waiting until the AF/IS deactivates > again. I have, however, never again experienced the problem to be as bad > as when I wrote the quoted part; my "normal" workflow, if it occurs > every 50 shots or so with my EOS 50 or D60, is to unlock/relock the lens > as described which will render the camera operational again. > > In my following attempts to find the culprit and a remedy, voltage > problems became more and more unlikely because even using a laboratory > DC power supply didn't help out. My "cure", accidentally found, was > rotating all control knobs available on the EOS 50 several times, after > which the combo would suddenly work fine again (the problem still > occurred but only, say, every 50 shots or so). It doesn't occur more > often on the D60 I currently use, so I haven't experienced it to be a > major PITA with this camera body. Nonetheless I still haven't found a > convincing explanation for the issue and I haven't heard of Canon > offering one or even recognizing that there *is* in fact an issue. Michael and Ralf, Thanks for the input. My first thought was that it was battery power. My second was that perhaps the lens movement while being carried was turning on the IS, which then turned on the camera!!! No, I don't know how that could happen either. Keith Green wrote: > I half-pressed the shutter release, then released it and everything > shut down. I was not very clear here. What I meant to say was that half pressing the shutter release, and releasing, caused the metering and IS to de-activate, leaving the camera ready to shoot. Oh well, looks like I shall have to do some more testing. I left the combo sitting on a shelf yesterday afternoon, and did not notice any funnies. Perhaps I just need to turn the IS off more often, but I think that I need to investigate the batteries first. Cheers Keith * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
