Ben Edwards has put together a 'Rough' guide to DSLRs. If you're just starting out or are curious about shooting video with DSLRs, there's plenty of 'disadvantages'. Of course the many 'advantages' of shooting DSLR video outweigh, so it's been a growing trend. Tidbits of information over at the jump. [Thanks Ben]
Rough Guide to DSLR Video
JS OBrien
Not bad, at all, and a very good primer. One disadvantage of DSLRs you missed, though, is the same as their advantage: Low-light sensitivity. Just try getting lots of bokeh outdoors in bright light. You turn the ISO setting all the way down, and you still have to stop the lens down a lot to get a proper exposure, which means you've now got a much wider depth of field than you may have wanted. Good video cameras have neutral density filters that reduce the amount of light coming in through the lens to deal with this. DSLRs do not, though you can buy lenses that screw on to deal with this -- which is a pain. I have friends who have bought matte boxes as solutions, but those, and the filters you use in them, are expensive, and tend to balance the camera even more toward the lens side.
I've also heard reports that DSLRs tend to be too sensitive to light bleed on sets, meaning you have to mask everything, and that practicals can color the whole set yellow-orange if you're shooting while white-balanced for daylight.
Some other issues you missed:
1. Aliasing: DSLRs tend to go from their high pixel counts to much lower pixel counts (to produce only 1920 x 1080 lines) by not using all the lines in the sensor. This leads to bad aliasing, especially when shooting things with strong patterns, like brick walls and blinds.
2. Rolling shutter: Many professional video cameras have CMOS-induced rolling shutters these days (the RED, for instance), but the rolling shutter effect can vary greatly in its severity. Many DSLRs will create a jello effect to the footage if not handled properly, and if you use one for weddings, or any other event where there are many flashes going off, you'll get an odd and unpleasing strobing effect that pro video cameras with CCDs don't produce.
In the end, DSLRs are a wonderful new video tool, but like any tool, are good for what they're good for, and are not universally good at everything. I don't believe you're technically correct that the BBC accepts footage shot on DSLRS (last time I checked, they required at least a 50mbs throughput on an interframed codec, and 100mbs on long GOP), but like any outlet, they will reduce those requirements for suitable material, such as ENG work. DSLRs are particularly useful for music videos, since sound isn't an issue, but DOF may be. I also like the fact that the image has been tweaked and tweaked over the years to mimic still film, and that is what produces those great images. One can get much the same thing from a pro video camera, but only after much tweaking. For the enthusiast, DSLRs produce this effect right out of the box.
Once again, very good job, indeed.
Ben Edwards
Mickey, I have just updated the guide saying
'The Canon 7D, 550D/T2i and 60D all have the same sensor but the 60D has improved features so out of these is probably the one to go for. If you are on a very tight budget picking up a used 550D is a good option (see this article for more info).'
Ben
Ben Edwards
Thanks Mickey, if you could provide a couple of sentences on the differences between the cameras I can add this. Always open to corrections.
Mickey Jones
Good guide for beginners.
I take some exception to this line:
(Canon 7D, 550D and 60D all have the same sensor and electronics so there is very little to chose between them apart from build quality)
Intermediate ISO settings, HD out, weather sealed, 8 FPS continuous, easier controls etc
but otherwise good information for explaining DSLR video to someone.