Gyro advantages and disadvantages?

[denen]

Hello all,

Like probably a lot of you I encountered distracting vibration issues in my action footage and started exploring image stabilization options.

After going through this forum and other resources here is a summary of what I found and some question for your review, I hope the ensuing discussion will benefit other users. Any competent correction or answer would be highly appreciated.

Hand jitter can introduce 2 problems in video, blurry individual frames and frame-to-frame jitter.

We cannot correct for blurry individual frames in post-production (incl gyro stabilization).
Since optical image stabilization is not available in Git2, we could minimize frame blur by filming with enough light (to have a fast shutter speed) or setting a fast shutter speed manually.
Q: Does the frame rate have an indirect influence on minimizing frame blur, I thought I read somewhere that having 60fps might be beneficial over 30fps due to higher needed shutter speed?

Frame-to-frame jitter can be corrected with EIS (Electronic Image Stabilization) ie our gyro stabilization or after the fact in software like virtual dub deshaker or adobe premiere warp stabilizer.

Advantages of gyro stabilization include enhanced stabilization due to movement information from the gyro sensor and getting the stabilized output written directly in the camera.

Drawbacks of gyro stabilization include reduced field of view (similar to sw stabilization), battery drain, possible resolution change and effects of image quality.
Q: What percentage of field of view is lost when using gyro?
Q: How much of the real resolution read from the sensor we get when using gyro and in which cases we start to loose resolution? Is this resolution dependent ie is the gyro in 1080p more effective than in 1440p 4:3?
Q: Does the frame rate affect gyro ie is it as effective in 1080p60 as in 1080p30?
Q: What are the effects on image quality?
Q: Is the gyro prone to similar warping effect as software stabilization?

Thank you for your contribution!

 

[Nigel]

Q: Does the frame rate have an indirect influence on minimizing frame blur, I thought I read somewhere that having 60fps might be beneficial over 30fps due to higher needed shutter speed?

Minimum shutter speed for 30fps video is 1/30 seconds, minimum shutter speed for 60fps is 1/60 seconds - half the time so half the motion blur.
However this does mean that the 60fps video will appear darker than the 30fps video when there is not enough light for proper exposure at 1/60 seconds.
Note that most cameras will drop the shutter speed to 1/30th even in 60fps mode and will then duplicate the blurry frames to get 60fps, the Git2 doesn't do this.

Q: What percentage of field of view is lost when using gyro?

For the Git2, the question is how much field of view is gained when you turn the gyro off, because the FOV with gyro on is a normal FOV, with it off you get an extra wide FOV with increased fisheye distortion. Sometimes I turn the gyro off to get the extra FOV but normally I leave it on even if it is not needed so that I get the normal FOV.

Q: How much of the real resolution read from the sensor we get when using gyro and in which cases we start to loose resolution? Is this resolution dependent ie is the gyro in 1080p more effective than in 1440p 4:3?

For the Git2, because it has a 16MP sensor it has plenty of resolution to not loose resolution by turning the gyro on even in 4K resolution. There will be a small loss of sharpness due to manipulating the pixels but no real loss in resolution.

Most 4K cameras, like the GoPro use 12MP sensors and then there are no spare pixels for the gyro to use, then if you enable gyro stabilisation in 4K you do loose resolution - which is why the gyro stabilisation on the Hero 5 etc isn't available in the 4K modes while the Git2 can gyro stabilise 4K.

Q: Does the frame rate affect gyro ie is it as effective in 1080p60 as in 1080p30?

No, the gyro works far faster than the frame rate, it works on individual lines as the image is scanned, hence it is able to remove most of the jello effect caused by vibrations from quadcopter propellers which without a gyro causes wave effects down individual frames.

Q: What are the effects on image quality?

On the Git2 I don't notice much effect from turning it on/off other than the extra fisheye from the wider field of view when it is off, and the much smoother video when it is on!

Q: Is the gyro prone to similar warping effect as software stabilization?

No, because it actually measures the movements of the sensor instead of guessing from the content of the image it always gets it right, generally when you watch Git2 video you don't notice that the gyro is being used, the video is just a lot less shaky than it would be without the gyro.

Other cameras with gyros don't do so well, and I have one camera that does too much smoothing and when I watch the video I get sea sick from the floaty/flying effect.