I recently filmed the new Nissan 370Z roadster. It was shot over two days and three separate locations with the Canon 7D.
On the first day the car was shot in Spanhoe airfield in Laxton. We filmed in an old aircraft hanger which was a great location to start with, but naturally a little dark.
HD DSLRs are supposed to be fantastic in low level light and while that is true to an extent, don't go expecting miracles from them. If you get the iso settings wrong then you will end up with quite a lot of video noise that is hard to remove, if not impossible. I have noted that the 7D in particular starts to introduce noise after the 800iso mark. Of course it all depends on the speed of the lens and exposure setting which will be different in each instance...but it is worth making a mental note to check for noise in playback after you have filmed a low light situation with an iso higher than 800.
Of course you will need a monitor for playback to see the noise. The small viewfinder on the back of the camera is not capable of showing detailed noise and so if it looks good on the back of the camera, it des not necessarily mean you won't find noise on the image when you get it back to the studio. There is nothing worse than getting it back and seeing that the image is not usable.
However, if you get the balanced settings correct in low level light then the image will look great with minimal lighting budget and costs.
The Second location was still in Laxton near to a fantastic viaduct, which gave us some great images.
On the second day we filmed in Chobham near to a National trust reserve and just off the motorway. It was a great location, but again I noticed a fair bit of the 'jelly' effect that the HDLSRs are known for.
The roads where not perfectly smooth and so whenever the car bounced over a bump, it then had an exaggerated effect on the camera.
I have to say that this jelly effect is highly frustrating at times, especially as you know it is a problem that would not happen to say the more expensive digital cameras like the Red One or the Arri D21. I know there is a massive price difference between the cinema cams and the Canon 7D, but I am beginning to wonder if the trade off is too costly in terms of time spent having to re-secure or steady images.
I don't feel like I would be confident to direct a film on the Canon that entailed a lot of motion or traversing of the camera. I could happily live with the noise issue and just add some extra lighting to counter it...but the jelly effect is something I don't think I could ever get use to.
Having said that, the 7D is a fantastic camera that is accessible to most budgets and as long as you are not planning to shoot the first 15 mins of Saving Private Ryan, you shouldn't encounter too many problems with the image shaking and causing the dreaded JELLY EFFECT!