Okay, this happened to me again tonight and I'm wondering if anyone is familiar with this phenomenon.
I was shooting some portraits using my 7D with two 580 EXIIs mounted off camera and a 430 EX II as a third light to separate the subject from the background. Triggering the flash through the on-camera infrared pop up.
Shooting RAW. Initially, while shooting, everything was going fine and then I began to have a problem where the shutter button would not work and the viewfinder readout says "busy." I'd have to pause and wait for several seconds before it would clear and let me shoot. I'd get off one shot and it would do the same thing.
When this first happened, I thought the camera was waiting for the flashes to recycle, so I bought battery packs for the 580s. But, it still happens. I thought maybe it was the 430 not recycling, so tried shutting that down. Still hangs up.
This has happened on a number of occasions and I've tried several different things, but can't seem to figure out where the problem is. One time, I tried switching out the memory card, even though it wasn't full. That seemed to help, but not consistently.
Clearly, the camera is waiting for something to clear or recycle, but I can't figure out what it might be. Anyone else ever have this problem or have any ideas.