[klkitchens]

Edit: Used the term OIS incorrectly, figuring it applied to ALL forms of image stabilization and not just lens-based. I meant digital shake reduction in camera. Apologies for the confusion.

Just shot some quick video today of kids at church answering some questions about VBS. I'm putting this together for a small segment to run during a future service.

Was using the K1 and the Sigma 70mm Macro. I didn't think to check if OIS was on (tripod mounted), but assumed it would not be since it's video and the subjects would be expected to move anyway, right?

Anyway, when watching the playback I noticed the oddest thing. The backdrop behind the kids would move. There was no AC or blower going and when I checked it during the shoot, I saw no motion. But it appeared on screen, the lines in the backdrop swayed some from left to right or right to left as the kids were just talking (and naturally shifting subtly on their feet).

It's not a problem and won't impede using the video shot, but I found it interesting. Only thing I could think of was that the OIS was compensating for the child's sway and doing some sensor shift or something, resulting in this apparent motion?

Had I been able to blur the background a little more with distance (room was a bit small) I probably wouldn't have noticed it.

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Last edited by klkitchens; 03-13-2017 at 06:23 AM.

[Adam]

Just shot some quick video today of kids at church answering some questions about VBS. I'm putting this together for a small segment to run during a future service.

Was using the K1 and the Sigma 70mm Macro. I didn't think to check if OIS was on (tripod mounted), but assumed it would not be since it's video and the subjects would be expected to move anyway, right?

Anyway, when watching the playback I noticed the oddest thing. The backdrop behind the kids would move. There was no AC or blower going and when I checked it during the shoot, I saw no motion. But it appeared on screen, the lines in the backdrop swayed some from left to right or right to left as the kids were just talking (and naturally shifting subtly on their feet).

It's not a problem and won't impede using the video shot, but I found it interesting. Only thing I could think of was that the OIS was compensating for the child's sway and doing some sensor shift or something, resulting in this apparent motion?

Had I been able to blur the background a little more with distance (room was a bit small) I probably wouldn't have noticed it.

You'd have to turn off electronic movie SR- was it off?

[klkitchens]

You'd have to turn off electronic movie SR- was it off?

Nope... Pretty eerie result given the parameters of my shoot. Probably great in most cases, but definitely something I'll check for next time... I just wouldn't have figured any sort of SR/OIS for video as the default. But as I'm only 1 week into my new beast, just a feature I didn't know about.

Thanks!

[lithedreamer]

Nope... Pretty eerie result given the parameters of my shoot. Probably great in most cases, but definitely something I'll check for next time... I just wouldn't have figured any sort of SR/OIS for video as the default. But as I'm only 1 week into my new beast, just a feature I didn't know about.

Thanks!

Electronic Movie SR is always horrible, that's why the PF reviews often suggest turning it off under their 'recommended settings' page.

[Steve.Ledger]

I didn't think to check if OIS was on (tripod mounted), but assumed it would not be since it's video and the subjects would be expected to move anyway, right? .

OIS = "Optical Image Stabilization" which is lens based.. Perhaps you were meaning the in-body Sensorshift Image Stabilization which works great for stills?
And just in case you weren't joking, SR helps cancel out camera movement, not subject movement

And yeh, as has been said keep Pentax's MovieSR disabled, it's destructive.

[Na Horuk]

I don't think that lens has optical stabilization?
OIS= in-lens stabilization. Most brands have this. It can make things look.. like you are on a boat. It can cause motion sickness with some people. Basically, some parts are moving, but they stay sharp. Good for telephoto and macro, silent, but takes energy and requires more parts in the lens barrel
SR= Shake reduction, Sensor shift stabilization. Pentax has this, as does Sony and a few others. Not so quiet, but it works with any lens you mount, even wide angles, primes, old lenses,.. BUT Pentax does not use this in Video mode.
Digital stabilization= Nothing actually moves, not the lens, not the sensor, but the chip tries to digitally reduce the effect of shaking. This is what Pentax uses in video. It is the worst method and a lot of Pentaxians are not happy with it.

My theory is that what you are seeing is the digital stabilization trying to do something even when it doesn't have much to do (so it might be overcompensating). Secondly, the codec in which the movie is recorded can make this look even worse, more pronounced. I think it is best to turn off the SR when taking Video, unless you are handholding in really low light. But even then, it is rather bad.