I am an owner of the HDR-CX12 and have taken it in the air on almost 10 jumps over the past two weeks. I can 100% confirm that the CX12 has the same image stabilization / image shakiness issue as other recent sony models (CX7). Here are a couple example sitfly videos:
Low Quality YouTube:
http://www.youtube.com/watch?v=KyUIYeOEvYU
http://www.youtube.com/watch?v=_qNcr6l7Frw
High Quality 720p HD:
http://69.59.17.157/skydive/jump196-720p.avi
Moving forward - As someone else suggested in this thread, it may be possible to operate and modify the camera to reduce/resolve the issue. I was actually crazy enough to take my entire camera apart, and locate the component responsible for the shaky video. I took pictures of the entire operation, but unfortunately do not have them available to post online at this time. I will be happy to post them as soon as I can!
The optical image stabilization consists of a single lens that slides on two axises. The movement of this lens is dictated by two electromagnets that "float" the lens in to position. During extreme freefall, it appears that the magnets are not powerful enough to hold this lens in a solid position.
Someone had mentioned that we should try to "glue" the lens in to place. Well folks, I took the plunge.
After completely disassembling the unit and locating the image stabilizer, I proceed by filling in the area where the lens has room to slide in either direction with a RTV silicone compound. This substance dries to a rubbery consistency, and would be removable in case the entire operation turns out to be a failure.
Once the silicone had dried and I managed to reassemble the device, it was time to do some testing on the ground. The first thing I noticed was that when powering the camera on, it took a solid 15 seconds to "turn on". Once the unit was on, an error code (E:62:10) flashed on the screen consistently. Apparently the device has detected that the image stabilizer lens is not operating "normally". Disregarding both of these new "issues", the camera appeared to be working perfectly normally!
After taking a few random videos and viewed them at full resolution, it was immediately apparent that my modification was NOT SUCCESSFUL! =( The image randomly flutters very similar to how the sitfly skydive videos turned out.
I believe the camera is trying to "fight" the silicone and causing the stabilization lens to vibrate back and forth. The choice of using a rubbery substance to lock the lens in place turned out to be a poor choice, as it provides enough wiggle room for the lens to vibrate.
I foresee 3 position solutions:
1) Use a real adhesive such as super glue!
2) Find a way to disable the electromagnets which control the lens
3) Give Sony a nice kick in the rear for not catering to the extreme sports market :]
I hope this information helps inform the community! Let me know if any of you have any questions!
-Tommy