Panasonic HC-X900M Iris Control

HDC-TM900, HDC-HS900, HDC-SD900, HDC-SD800 (2011). HMC150, HS250, HS300, HS60K, HS700K, SD60, TM700.
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Panasonic HC-X900M Iris Control

Post by bhoy022673 » 10 Apr 2013 20:31

Hi -

Not sure if this forum is too active, but I thought I would try my question here.

I just got a Panasonic HC-X900M camera and I will be using it to shoot live video. Sometimes the shows will be very dark, sometime very bright. I will need to control the iris. With all the other cameras I've owned, it has been simple. One control. However with this camera, it seems like first I set the Shutter speed, and then from there I control the iris.

My question is, how do I know how to set the shutter? If I leave it at its brightest setting 1/60, I can then turn down the iris if there is too much light. However, what is the price I pay for the 1/60 shutter? What if I could get the same exposure level with the shutter at 1/180, say, for example?

Could someone explain to me how this works, and give me a ballpark of how I might first decide which shutter to use? I worry that I might set the shutter too dark and then not be able to set the iris open enough to get a decent picture.


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Re: Panasonic HC-X900M Iris Control

Post by Doughie » 11 Apr 2013 21:33

If the camera was bought in an NTSC country, then the standard is usually 30fps (frames-per-second) (well, actually its 29.97fps..) and so the camera if left on auto-exposure will try really quite hard to maintain 1/60th sec. That is essentially a 180degree shutter (a term derived from the old days of film).

Its only when it gets really quite bright (almost only ever outdoors) that a videocamera will start to shorten shutter speed past 1/60th sec.
Inside it will be using 1/60th sec 99% of the time, and that is a good thing. In most indoor situations the iris is also likely to be around f4 or larger indoors, and at that point if it needs more exposure for the scene it will start to ramp up gain (expressed in +dB).

Generally it sounds like you will be using the machine for indoors fairly-poor lighting so use MAXIMUM iris for all this stuff, and shutter 1/60th sec or slower (if that model of camera allows you to set the shutter slower than that. Some consumer camcorders permit manual selection of shutter speed, and some do not).

I just checked and that model maximum iris is f1.5 at wide end of the lens and f2.8 at the tele end. And it shoots 60fps, but i would probably be using a 30fps mode for most shooting if it will allow that.

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