The overheating is only an issue on the 7D. I think you're right it's not a "huge" issue, but it's something to take into consideration. Winter is just ending in Asia/U.S./Europe and I bet we see a lot more reports about overheating.

What is this obsession with shallow DOF? Now I'm certainly not saying that shallow DOF is or should not be desirable, but the case that so many 5D users seem to be making is that the shallower the better. In that case, the holy grail must be, like, one inch of focus at all times...

So deep DOF is worthless or just inherently inferior? If that's so, then much of the work of Gregg Toland, Orson Welles, and Jean Renoir must be unwatchable. Come to think of it, the popularity of shallow DOF in 35mm cinematography is a fairly recent phenomenon, so does that mean that none of the directors and DPs up to the Depression Era knew how to make good pictures? I wonder why VistaVision didn't last very long, or why filmmakers never demanded to make all of their movies in 70mm...

I thought that the point of HDSLRs, and the 35mm adapters that came before them, was to make images that more closely resembled movies that you see in a theater. The goal was shallower DOF, not shallowest DOF. How did people lose sight of that along the way? In the movies, pretty much nobody shoots at f/1.4. If Kubrick used f/0.7, then it was only because he wanted to shoot candlelight, not because he was striving for shallow DOF.

I can understand the argument that the 5D allows you more options with shallow DOF, just like it offers more options with wide-angle lenses. But unless someone really needs those options, or specifically going for a certain look, then I just can't understand such blanket statements about shallow DOF and HDSLRs or the need to spend so much more money on something that might not actually be in line with a shooter's original goals.

You know, I used my 5D for the vast majority of the footage on a short that I made last fall. And the vast majority of that footage was shot on one weekend. Now, Septembers here in Texas can be quite warm, but the temperature wasn't sweltering on those two sunny days either. On the Sunday, I only had two or three scenes to shoot, one of which was shot entirely with my Panasonic GH1. But I did carry my 5D, in its camera bag, everywhere that I went that day.

I believe that I actually used the 5D for less than an hour. The scene was outdoors, at a swimming pool. When I reviewed the footage on my computer later, I was shocked to discover that the last take of the last set-up from that day had really ghastly noise. Basically, it looked like I had been shooting at ISO 6400. But the take immediately preceding it, which had the same set-up and the same settings, looked OK. The only explanation that I have is that the camera overheated. Literally nothing else would make sense.

Some 7D users have reported shooting for hours at a time in hot environments (like 90-100 degrees) without any problems. I really think that the difference between the 7D and the 5D, in regards to the overheating issue, is not very significant.

My 5D2 overheated once. I had left it on a tripod with the sun shining into the LCD. I got a warning message, shut it down for five or ten minutes, and haven't had a problem since.

This is especially important to avoid when using a loupe. You can burn a hole in the LCD!

I should get some opaque, black cloth, like photographers used to wear with view cameras and flash powder. :)

We live in the South of France which while not as hot as Texas is frequently very sunny & warm. The only time that ether of our 5DIIs has overheated was a very similar situation to that mentioned by Jon with the camera on a tripod left in full sunshine in summer. So without the application of external heating I don't think that overheating is much of an issue for the 5DII. The 7D has two DigicIV processors versus the single one in the 5DII so perhaps they run hot & that is why the 7D is more prone to overheating.

Well...as I mentioned elswhere I've had my 7D now over two months and have yet to see the indicator for overheating. Also, there have been at least two folks so far that has complained about the new T2i'/550D's overheating. So it seems a cam with two sensors (like the 7D) is not necessarily the issue. If anything the 7D's very tight seal should contribute more to the problems we've seen IMO.