During Imaging USA in New Orleans I asked a vendor some information about sport cameras and propeller interaction and he told me that the problem is caused by the CMOS sensors.
CMOS sensors have what is called “Rolling Shutter”, that means that the CMOS sensors acquire the picture one line at time, instead the CCD get the picture all at the same time.
CMOS sensors create problems with fast moving object for this reason, creating distortions or “Jello” effect.
An interesting video I found on youtube really show this problem in a creative way:
For your propeller basically you need a CCD camera!
The problem with CMOS and propeller can be made less worse using a neutral density filter in front of the lens to slower the shutter speed (I noticed that the only decent video I made was in a cloudy day and now I know why) but still the “Jello” effect remain.
The best thing to film a propeller is to get an old CCD camera, or spend a lot of money for a new professional one (Sony make some CCD sensor that can be found in some expensive sport cameras). I have an old Sony camera and I will try to use it also if is not small and easy to fit in the cockpit as the GoPro.
If you want go deep in this argument I suggest this article by Barry Green, really well explained and written.
On the flying side, I solved my little health problem and I will find a school and start to fly again I hope next week. I passed by KPIE yesterday to speak with 2 schools but without phone before and I found both of them closed. Tomorrow I will try again if I will be in the mood… but I’m also attracted by a lazy day in the pool :D