I did my homework and found out that many other people have discovered exactly the same problem I have with the shutter release button, and it looks like it’s not just the 40D but other models as well. Judging by what people have written, Canon denies that this is a construction issue and sure enough when I called the support ”this is the first I’ve heard of it”. So I’m on my own to get it fixed unless the Canon service centre agrees with me that this is a factory fault and the 3-year extended warranty applies.
I did some testing tonight and found out that the problem largely depends on how I press the button, it’s a little bit loose so not all clicks are created equal. Most of the time it happens when I pause halfway to focus and meter, then when the button is pressed fully it blanks out. If I don’t stop in the middle, it’s normally ok. It also seems to be possible to press down the button in different ways, so if I put pressure on one side only it’s a dud, but if I keep my finger right in the middle of the button so it’s pressed straight down, it works. (Did that make any sense?)
Anyway, since I have to pay to get this fixed, I’ve decided to keep using it as it is now, the problem is intermittent and I have a semi-decent way of avoiding it. I don’t want to send it to service and pay for the postage and examination only to have it returned with nothing done because it was working fine when they tried it. So I will wait until it is really broken, the cost to fix it will be the same anyway.
I’ve had 6 Canon cameras in a row and this is the first one with problems. I guess my luck was bound to run out.
Grrr.