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Controlling Exposure on the Canon HV20 Controlling Exposure on the Canon HV20
Jason Ramsey
05-07-2007
  #1  
Dennis Wood on 05-07-2007, 12:21 PM
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Nice Barry :-)

Two comments:

1. I'll confirm that the XH-A1 does give you gain information if you play HV20 tapes in it, providing you've got the XH-A1's data display configured during playback.

2. Pressing the photo button halfway down (from Jenningsp's video tuturial) on the HV20 will show the aperture in use, and by varying, you can determine gain "real time".

So really, the exposure locking issue is pretty much a question of information and using the camera a bit differently...great news for HV20 owners.
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  #2  
Noel Evans on 05-07-2007, 03:01 PM
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Excellent Barry. Once again saved me all the hard work.
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  #3  
Phil H. on 05-07-2007, 05:56 PM
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Great article, Barry! With my cell phone (Sony Ericsson T637) I set the wallpaper as a plain white image and am able to go from -11 all the way +8 before the shutter changes to 1/30 at +9.

This will be really helpful while I'm using my 35mm adapter, lenses and accessories... which cost several times what the HV20 cost... haha.

Great fun!
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  #4  
henry cho on 05-07-2007, 08:52 PM
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that was an AWESOME article. many thanks for taking the time to put that together.
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  #5  
Jack_Felis on 05-07-2007, 10:12 PM
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Alright, so if I understand correctly, the basic workflow goes like this:

1. Set camera in Cine Mode with HDV 24p

2. Shine light or bright screen into the lens

3. Set Exposure bar according to chart

What about taking a white picture (maybe a Windows Paint blank white picture) and using a Sony PSP screen? Or what if you just shine a bright video light into it? I have a 20w Sima video light I bought a while back when I first got my GL1, would this be better for this process?

Last edited by Jack_Felis; 05-07-2007 at 10:18 PM..
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  #6  
nycshooter on 06-07-2007, 02:46 PM
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Barry,

I have a miniSD card. The only way I can check the shutter speed is if I have the camcorder switched to camera mode via the switch on the right side of the camcorder located below the auto/program switch. Only then can I press the photo button halfway to get the shutter speed and aperture. Pressing the photo button halfway while in camcorder mode, specifically 24p cinemode and with the exposure menu on after pressing the joystick and navigating to exposure than pressing the joystick upward, yields me no shutter information. Instead I get a red camera icon to the left of the screen denoting the camcorder is not in photo mode. What am I doing wrong here? Also, would it be more effective to try your cellphone trick rather than guessing the camcorder will stay at the same shutter speed after you've checked it with the photo button. How about if there's a subtle light change when you pan? Wouldn't this affect your shutter speed in cinemode. How would you check for that? Argh. So frustrating. I'm so close to getting ready to shoot a short but I don't know how to immediately get the settings I need from this camcorder. Your suggestions are very much appreciated.

Thanks!

Last edited by nycshooter; 06-07-2007 at 02:55 PM..
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  #7  
Barry_Green on 06-07-2007, 03:07 PM
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Once you lock the exposure, it's locked. If you don't lock the exposure then yes, during that pan it may very well change the iris or shutter on you. But if you lock it, nothing will change.

The switches on the side of my HV20 are set to the "P" and to the tape. Make sure yours are as well. Then, when you're in camera mode, if you have the miniSD card installed, a light press of the PHOTO button on top of the camera should show the aperture and shutter.
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  #8  
nycshooter on 06-07-2007, 06:57 PM
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Barry,

Ok. I think I have it. So one does have to switch from tape to camera mode in order to access the aperture and shutter information.

The charts you mentioned work if you have the constant of the light(nokia phone in your case) present when you go to lock the exposure. The exposure range would show up as you described. But if I don't want to use that method but instead use the info from the camera mode coupled with the miniSD card, how do I reference the chart? For example, If the readings from pressing the photo button give me a 2.4f and 1/48 shutter, I should assume I'll have 0 gain if I then lock the exposure in the range of -9 to +6. Is this correct?

Thanks again. I am new to this and the technical side can be somewhat overwhelming yet I am absorbing as much as I can as quickly as I can and hope to continue to learn as I proceed with my upcoming project.
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  #9  
Barry_Green on 06-07-2007, 07:21 PM
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No, if you are in tape mode the button works, but only if there's a miniSD card in the slot.

If you have the miniSD and are using the photo button, then you don't really need any chart. You just want to make sure that the iris is between 2.0 and 8.0 and you're assuring yourself there won't be any gain. If you lock the exposure and then go to the '+' side of the scale, you may be introducing gain if the iris goes more open than 2.0.
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