I recently bought Canon s100. Unfortunately I found that when I record a video with indoor lighting, I get nasty flickering. I think I know why it happens. What is really annoying is that Canon can easily fix it in camera software, yet they don't. There was a firmware update released that fixed one kind of flickering, but the other one remains.
I am pretty sure that the flickering is caused by the lights and the scanning nature of the CMOS sensor. Different parts of the image get different parts of the light cycle, and thus different amounts of light. The way to fix it is to use exposure times, which are integer products of half the electricity time period.
The optimal solution:
1)Add a binary variable f that lets the user select between 50Hz and 60Hz. (or use the PAL/NTSC variable instead)
2) In video mode let the user choose between normal and indoor lighting.
3) In video with indoor lighting let the camera use only the following shutter speeds:
a) if f=50 then shutter speed in[1/100, 1/50, 1/33.3333, 1/25]
b) if f=60 then shutter speed in[1/120, 1/60, 1/40, 1/30, 1/24]
4) A bonus (not must have) would be to add 25fps video mode.
If this is too difficult, then just let the user select the shutter speed in video.
This is really a fatal flaw in Canon s100, and potentially other Canon CMOS cameras. For people in US with 60Hz grid, this is less severe, but for everyone else this is a disaster. If Canon don't fix this, will someone please solve it? This will be a huge thing for owners of Canon CMOS cameras all around the world.
I think that a standalone fix with no other features will be best for most people.
