I’ve been watching NASA TV and the recent un-docking of the orbiter from the ISS.
I noticed the crew in the shuttle taking pictures of the station with what seems to be digital SLR’s.
I have one too and it has Image Stabilization incorporated into it.
My question is:
Does image stabilization as it is implemented in earth-bound digital cameras work in zero gravity?
Earth orbit isn’t zero gravity. They’re in constant free fall, but it’s a gravitational field.
I am not an expert in mechanics but I would say that yes, it would still work in zero-g.
There are actually a number of techniques that can be used to achieve image stabilization. In a still camera, this is likely based on gyroscopes. There are systems that use the gyroscopes to adjust the position of the lens and others that stabilize the image sensor.
I was curious if the stabilization was from mechanical sensors (hence the gravity question), or if it was programmed into some sort of digital motion pixel sensors.
And yes I am aware of micro-gravity.
Here is a description of Nikon’s VR system.
But I’m still not clear if these “Angular velocity sensors” are dependant on a gravitational force in order to work properly.
I hope I’m making myself understood. It’s in the wee hours, and my brain becomes inefficient after midnight. 
The cameras we have on earth can be used upside down and still the image stabilisation works, with gravity (although still there) working in the opposite direction. I guess it would also work if you were a parachutist in freefall, although i’d have to give it a try to find out.
Maybe searching online for pictures taken by sky divers would answer your question?
They rely on inertia, not on gravity!
Basically I don’t know the precise answer to your question directly, and unfortunately what I do know I am not really allowed to tell you. I’ll tell you what I can though.
In general angular accelerometers should be relatively immune to linear acceleration, and the specification sheet should include information on what kind of error linear acceleration can introduce. This means that in most cases a quality built stabilization system should be able to sense the roll and yaw correctly.
In practice (and there is a practice, since a lot of people skydive and like to take pictures and videos while doing so) some stabilization systems go a little haywire when in free fall and enter a feedback loop of overcompensating. This might be due to the fact that the mechanical system that actually moves the lens has issues with linear acceleration. I only know of some anecdotal reports of Canon GL-1 camcorder doing this, so it might be a defect confined to that model. In general lots of pictures are taken when skydiving and based on a cursory scan of skydiving newsgroups people look for camcorders and SLRs with best optical image stabilization possible to eliminate blur due to vibration introduced by wind. This tells me that most will work in free fall, hence orbit.
If you have a device capable of discerning presence of a gravitational field from linear acceleration in your digital SLR I think there are some people at some universities that want to have a word with you.
I seem to be posting in lots of camera threads today. I think what **Anaglyph **was referring to was the fact that the lenses use inertial sensors to detect movement and move lens elements to compensate, not that they can distinguish between gravity and acceleration. I certainly know that Canon’s IS lenses work upside down, so I would suspect that gravity doesn’t play a part in their operation, but that’s really a WAG.
Quotes from here about Canon’s technology:
So gyro sensors are used to detect rotation, which is what most camera shake is - forward and backward movement is less of a problem. This would seem to work whether or not the camera is in free fall.