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-   -   Cinemode shutter finding (https://www.dvinfo.net/forum/canon-vixia-series-avchd-hdv-camcorders/94313-cinemode-shutter-finding.html)

Brian Tori May 17th, 2007 07:09 PM

Cinemode shutter finding
 
Using the method described on this forum on obtaining a readout of both aperture and shutter by pressing the photo button, I have discovered an apparent shortcoming of using Cinemode. It appears as if when shooting in Cinemode the camera is automatically adjusting the shutter speed in relation to the iris. The iris is adjustable as usual, but, the shutter is changing on its own. When adjusting the iris, the shutter varies between 1/48-1/17 of a second according to the shutter readout in 24p mode. This is somewhat of a disappointment considering the extra latitude of the mode.

Anyone have a similar experience?

Barry Green May 17th, 2007 08:21 PM

Yes, that's exactly what will happen. The CINE mode adjusts both iris and shutter, whereas Tv adjusts the iris automatically but leaves the shutter locked, and Av adjusts the shutter automatically but leaves the iris locked.

You have to keep an eye on that before every shot and use the EXP lock function to make sure that you're getting an iris and shutter combination that won't ruin your shot on you. 1/48 exposure and f/2.0 to f/8 would be the right range to stick to.

Ajit Bikram May 17th, 2007 08:30 PM

Quote:

Originally Posted by Brian Tori (Post 681322)
Using the method described on this forum on obtaining a readout of both aperture and shutter by pressing the photo button, I have discovered an apparent shortcoming of using Cinemode. It appears as if when shooting in Cinemode the camera is automatically adjusting the shutter speed in relation to the iris. The iris is adjustable as usual, but, the shutter is changing on its own. When adjusting the iris, the shutter varies between 1/48-1/17 of a second according to the shutter readout in 24p mode. This is somewhat of a disappointment considering the extra latitude of the mode.

Anyone have a similar experience?

Does this mean that you can adjust iris manually in cinemode too?? How do you do that??

Chris Barcellos May 17th, 2007 10:51 PM

Quote:

Originally Posted by Ajit Bikram (Post 681354)
Does this mean that you can adjust iris manually in cinemode too?? How do you do that??

When you activate the exposure adjustment with the joystick, that will lock the exposure at what ever you set it at..

Ajit Bikram May 18th, 2007 09:50 AM

Quote:

Originally Posted by Chris Barcellos (Post 681409)
When you activate the exposure adjustment with the joystick, that will lock the exposure at what ever you set it at..

Thanks Chris.
So by locking exposure in cinemode and changing it using (+/-) would allow me to adjust overall exposure (combination of iris and shutterspeed) but not one of them individually as in Tv or Av mode. But I can use other tricks (like pointing to light or cover the lens with hand) to bring in some more control.
Am I correct??

Povl H. Pedersen May 18th, 2007 02:43 PM

My simple test on PAL CINE mode is, that the HV20 will aim for 1/50s.

If there is less light, then it will step down to 1/40s, 1/33s, 1/29s, 1/25s after this it will increase gain for 7 clicks, before it will start to slow down shutter even more to 1/20s, 1/17s, 1/14s. I have not seen it go slower even in pitch dark.

To the other side (more light), when it hits f/8.0, 1/50s, then it starts increasing shutter speed to 1/60s, 1/75s, 1/100s, 1/120s, 1/150s, 1/180s, 1/210s, 1/250s, 1/300s, 1/350s, 1/400s, 1/500s.

So basicly, you have nice 1/50s shutter for anything that goes with that speed, and f/1.8 - f/8.0. That is 4.5 f/stops. Anything beyond that, you will need to use a locked exposure, and reclaim the overexposure/underexposure in the lab (postprocessing).

You need a memory card to play with exposure values, and lock the camera at known values.

Chris Barcellos May 18th, 2007 10:20 PM

Quote:

Originally Posted by Ajit Bikram (Post 681619)
Thanks Chris.
So by locking exposure in cinemode and changing it using (+/-) would allow me to adjust overall exposure (combination of iris and shutterspeed) but not one of them individually as in Tv or Av mode. But I can use other tricks (like pointing to light or cover the lens with hand) to bring in some more control.
Am I correct??

Yes. That is correct.

Povl H. Pedersen May 19th, 2007 03:08 AM

And as I wrote, if you have the memory card, you can map what exposure settings the US version will give, and use this for reference. Then you will know what sets of exposure/shutter speeds you can chose.

Paul V Doherty May 20th, 2007 07:00 PM

LCD panels make perfect references for exposure!
 
I use the LCD panel on a Yamaha PM1D audio console as an easily repeatable source of known light for setting exposure.
Simply turn on the HV20 with it pointing squarely at the LCD panel and at sufficient distance to fill the HV20's FOV entirely.
Engage the manual exposure and set to minus 5.

Voila! HV20 is now set at f2.8 and Shutter 1/48 - perfect for shooting the shows in my workplace.

Try it with a uniform source of light, such as a grey screen on your laptop or desktop LCD panel. It is easily controllable and repeatable :)

Pauly


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