This may be a totally irrational question. When I was researching the idea of using DSLRs for timelapse work, I found that cameras were rated for a set number of "exposures." The fact that this was a relatively low finite number bothered me. (While 50,000 exposures may seem adequate for years of still photography, it's a different story when you're shooting at 30 fps.)
I assume this is in part due to the mechanical action of a DSLR: mirror down for viewing, up for exposure, shutter, mirror down, etc.
Is there a way to lock up the mirror and minimize the wear and tear on the camera when shooting video?
[Bob Cole]"Is there a way to lock up the mirror and minimize the wear and tear on the camera when shooting video?"
If I'm incorrect, hopefully a 7D actual user will chime in... but I believe on the 7D (or 5D or most any DSLR) the mirror does automatically lock up when shooting video. In fact, I don't think there's a way to make it not lock up in video mode.
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Todd is most correct, the shutter only fires once for video... it just opens up to let the sensor be exposed to the light and locks in place. Timelapse and rapid-fire sports style photography (or 8fps movies done in all stills) are where your shutter wear and tear are going to come from, the shutter just moves out of the way in video mode.
Supposedly the 7d is rated for 150,000 shutters before it goes out. But reports haven't started coming in yet from the field as to whether or not this is true. But it is my understanding that a shutter element on a camera like that isn't going to break the bank, and if you only shoot video with it (or mostly) I wouldn't worry about it.