Has anyone else noticed this behavior? at DVinfo.net

Jay Bratcher · April 21st, 2010, 07:25 AM

Hi -

I have recently noticed something unusual with my GH1, and I'm curious if anyone else is seeing this...

First, my camera settings - I am in FHD movie mode, ISO = any (tested at ISO 100 and ISO 1600), Manual or Shutter priority mode (both exhibit this behavior), Nikon AI lens attached via Fotodiox adapter. Shutter speed is set to 1/50 (other shutter speeds do the same thing though), and the iexposure thing can be at any setting (I have it off right now). Gain - when in shutter priority mode - can be at any setting. Film mode is set to My film, which is contrast -2, saturation 0, color 0, and NR +2 (film mode doesn't seem to have any bearing though).

The behavior: If I point the camera at something dark - say, a poorly lit part of the room, then point the camera at a brighter portion of the room - say, a light, or a monitor - the camera seems to increase the gain. At first I thought nothing of this - I thought the camera was adjusting the LCD as it does in still photo mode. But then I realized that if I lock the exposure, the camera is more sensitive when I point back to a dimmer scene.

So last night, I did a quick test in my living room. I had the lights off, but had ambient light from an adjacent room (it was fairly dark). I set the ISO to 1600, set shutter priority mode, cranked the gain all the way up, then checked to see if I was still getting this behavior. Sure enough, if I pointed at the light in the next room, the camera would gain up. I locked the exposure while pointed at the light, then panned around the dark living room. The clip I got was by far the brightest image I have seen out of this camera.

The downside of course, is that it seems I don't really have as much control over the camera as I thought - it is bumping up gain when I am not expecting it ( and the wrong way it seems - why would gain increase when I point the camera at a light?). Of course, locking exposure seems to prevent it from changing, but still...

Sami Sanpakkila · April 24th, 2010, 03:23 AM

Are you sure its the footage thats changing as well or just the preview? theres a mode that you can switch off that changes the LCD brightness.

Jay Bratcher · April 24th, 2010, 07:48 AM

Hi Sami -

Thanks for pointing out what should have been obvious to me :) I turned it off, and the behavior has gone away. I'm going to do another test though (tonight, since it's far too bright to test right now). I am still pretty sure I was getting more gain by doing this when I had the LCD setting on. I'll post back with some test results...

Thanks,
Jay

Jay Bratcher · April 28th, 2010, 05:11 PM

Testing was a bust. I could not affect gain by the method I described. I do still find it somewhat curious though - why would I be able to lock exposure on the LCD if it has no impact on the recorded image? Oh well, maybe I need more sleep or something. Nothing to see here folks - please keep moving :)

April 21st, 2010, 07:25 AM	#1
Jay Bratcher Regular Crew Join Date: Jan 2009 Location: Round Rock, TX Posts: 110	Has anyone else noticed this behavior? Hi - I have recently noticed something unusual with my GH1, and I'm curious if anyone else is seeing this... First, my camera settings - I am in FHD movie mode, ISO = any (tested at ISO 100 and ISO 1600), Manual or Shutter priority mode (both exhibit this behavior), Nikon AI lens attached via Fotodiox adapter. Shutter speed is set to 1/50 (other shutter speeds do the same thing though), and the iexposure thing can be at any setting (I have it off right now). Gain - when in shutter priority mode - can be at any setting. Film mode is set to My film, which is contrast -2, saturation 0, color 0, and NR +2 (film mode doesn't seem to have any bearing though). The behavior: If I point the camera at something dark - say, a poorly lit part of the room, then point the camera at a brighter portion of the room - say, a light, or a monitor - the camera seems to increase the gain. At first I thought nothing of this - I thought the camera was adjusting the LCD as it does in still photo mode. But then I realized that if I lock the exposure, the camera is more sensitive when I point back to a dimmer scene. So last night, I did a quick test in my living room. I had the lights off, but had ambient light from an adjacent room (it was fairly dark). I set the ISO to 1600, set shutter priority mode, cranked the gain all the way up, then checked to see if I was still getting this behavior. Sure enough, if I pointed at the light in the next room, the camera would gain up. I locked the exposure while pointed at the light, then panned around the dark living room. The clip I got was by far the brightest image I have seen out of this camera. The downside of course, is that it seems I don't really have as much control over the camera as I thought - it is bumping up gain when I am not expecting it ( and the wrong way it seems - why would gain increase when I point the camera at a light?). Of course, locking exposure seems to prevent it from changing, but still...

April 24th, 2010, 03:23 AM	#2
Sami Sanpakkila Major Player Join Date: Nov 2007 Location: Finland Posts: 317	Are you sure its the footage thats changing as well or just the preview? theres a mode that you can switch off that changes the LCD brightness. __________________ www.samisanpakkila.com www.vimeo.com/samisanpakkila

April 24th, 2010, 07:48 AM	#3
Jay Bratcher Regular Crew Join Date: Jan 2009 Location: Round Rock, TX Posts: 110	Hi Sami - Thanks for pointing out what should have been obvious to me :) I turned it off, and the behavior has gone away. I'm going to do another test though (tonight, since it's far too bright to test right now). I am still pretty sure I was getting more gain by doing this when I had the LCD setting on. I'll post back with some test results... Thanks, Jay

April 28th, 2010, 05:11 PM	#4
Jay Bratcher Regular Crew Join Date: Jan 2009 Location: Round Rock, TX Posts: 110	Testing was a bust. I could not affect gain by the method I described. I do still find it somewhat curious though - why would I be able to lock exposure on the LCD if it has no impact on the recorded image? Oh well, maybe I need more sleep or something. Nothing to see here folks - please keep moving :)