Z-1 color issues at DVinfo.net

Jeff Mack · December 16th, 2010, 01:51 PM

The other night I shot an interview with my Z-1. HDV 1080i60. Manual Iris, Auto Focus, Accidentally set to 12 db gain, iris wide open. I set up the shot and I thought it looked pretty good. I forgot to turn the gain off from the night before. Halfway through the interview I saw this but did not adjust so all of the footage woud look similar.

I was applying a simple 3 way color corrector in Final Cut and it looked pretty good. Then like 10 minutes into the clip, the color totally shifted. No idea why. In the color correction, I brought out the saturation a little but 10 minutes in, everything changed. I removed the filter and checked the raw clip and lo and behold, it is different in the clip.

The talent was sitting on a couch with a lamp in the corner. He moved very little and if he did, he moved right back. I see no evidence where when he moved, the color changed and when he moved back, the color changed back. It was like right after the 10 minute mark, everything kind of went flat. I am thinking my led light on my camera must have been losing power and caused the adjusted color.

This happened once before shooting under fluorescents. My lcd was actually changing coors like one of those christmas wheels that lights an aluminum tree. The reason I mention this is that someone told me I must have had auto exposure set to on. I had Iris on manual. Anyone know what I may be doing wrong?

Jeff

Daniel J. Mears · December 16th, 2010, 05:25 PM

Hi Jeff,

Quote:

Originally Posted by Jeff Mack

This happened once before shooting under fluorescents. My lcd was actually changing coors like one of those christmas wheels that lights an aluminum tree. The reason I mention this is that someone told me I must have had auto exposure set to on. I had Iris on manual. Anyone know what I may be doing wrong?

Jeff

I have seen this before on some footage, I believe what could have caused it is the shutter speed being on auto, as if the shutter speed is not a multiple of the refresh rate of the fluorescents, or is too high (?) then this phasing colour shift occurs. The Z1 does it's best to try and 'auto expose' your picture unless you have everything on manual, including iris, gain and shutter. So if the shutter was on auto the wrong shutter speed could have been selected, causing the colour shifts.

Were there any fluorescents in your most recent shoot as maybe your shutter speed could have changed at the 10 minute mark causing the shift in colour? I assume the white balance was on manual?

Hope that may help!

Dan

Jeff Mack · December 16th, 2010, 05:47 PM

Dan, My shutter speed was set to 60. I am assuming the only way to take it out of manual is to switch the slider from manual to auto. It was always on manual, this is how I adjust the Iris as well. I am thinking that my LED light was losing power, therefore reducing my color.

I also noticed two settings that I haven't ever used. One is the AF Assist. It was off and I switched it to on just now. I guess I am spoiled. 95% of my shooting is fast run and gun so I always use auto focus. There are times though in changing lights (music venues) that I go out of focus. By turning this on, will this do a better job of focusing for me?

Second, right below the AF Assist menu is the AE Response. I can put it to fast, middle or slow. I don't know what this does. Again, I am set up in the manual mode.

Thanks,

Jeff

Alec Moreno · December 19th, 2010, 02:10 AM

AF Assist (auto-focus assist) does not do a "better" job of focusing. It simply allows you to adjust the focus ring to aid the camera in selecting the correct subject when in auto-focus mode. For instance...if you're shooting a subject that is 10 feet away against a bright high-contrast background that is 30 feet away, then the camera may choose to focus on the background instead of your subject. With the AF Assist turned off, you're out of luck, but if you have it turned on, then you can get the subject in focus using the focus ring. Of course, the camera may decide to refocus on the background at any time.

I always leave the AF Assist turned on.

Side note...the FX1 does not have this feature.

Alec Moreno
Wedding Art Films - Southern California - Los Angeles - Orange County - Video

Alec Moreno · December 19th, 2010, 02:20 AM

AE Response (auto-exposure response) is simply a matter of how quickly you want the camera to adjust exposure to changing lighting conditions when shooting in any type of auto-exposure mode. You'll need to play with this setting to find what suits you best. I prefer to leave it in "slow" at all times for my style of shooting.

Also note that the AE Response feature can slightly affect your exposure when in full manual mode. I know...this sounds crazy, but it's true. When in full manual exposure (gain, iris, and shutter speed) and the lighting conditions change, the camera may slightly compensate by adjusting the exposure accordingly. This effect is somewhere between imperceptible and nonexistent if you set the AE Response to "slow." However, if you set it to "fast" you may notice this change in exposure...very annoying.

Alec Moreno
Wedding Art Films - Southern California - Los Angeles - Orange County - Video

December 16th, 2010, 01:51 PM	#1
Jeff Mack Regular Crew Join Date: Mar 2005 Location: McKinney, TX Posts: 195	Z-1 color issues The other night I shot an interview with my Z-1. HDV 1080i60. Manual Iris, Auto Focus, Accidentally set to 12 db gain, iris wide open. I set up the shot and I thought it looked pretty good. I forgot to turn the gain off from the night before. Halfway through the interview I saw this but did not adjust so all of the footage woud look similar. I was applying a simple 3 way color corrector in Final Cut and it looked pretty good. Then like 10 minutes into the clip, the color totally shifted. No idea why. In the color correction, I brought out the saturation a little but 10 minutes in, everything changed. I removed the filter and checked the raw clip and lo and behold, it is different in the clip. The talent was sitting on a couch with a lamp in the corner. He moved very little and if he did, he moved right back. I see no evidence where when he moved, the color changed and when he moved back, the color changed back. It was like right after the 10 minute mark, everything kind of went flat. I am thinking my led light on my camera must have been losing power and caused the adjusted color. This happened once before shooting under fluorescents. My lcd was actually changing coors like one of those christmas wheels that lights an aluminum tree. The reason I mention this is that someone told me I must have had auto exposure set to on. I had Iris on manual. Anyone know what I may be doing wrong? Jeff

December 16th, 2010, 05:47 PM	#3
Jeff Mack Regular Crew Join Date: Mar 2005 Location: McKinney, TX Posts: 195	Dan, My shutter speed was set to 60. I am assuming the only way to take it out of manual is to switch the slider from manual to auto. It was always on manual, this is how I adjust the Iris as well. I am thinking that my LED light was losing power, therefore reducing my color. I also noticed two settings that I haven't ever used. One is the AF Assist. It was off and I switched it to on just now. I guess I am spoiled. 95% of my shooting is fast run and gun so I always use auto focus. There are times though in changing lights (music venues) that I go out of focus. By turning this on, will this do a better job of focusing for me? Second, right below the AF Assist menu is the AE Response. I can put it to fast, middle or slow. I don't know what this does. Again, I am set up in the manual mode. Thanks, Jeff

December 19th, 2010, 02:10 AM	#4
Alec Moreno Regular Crew Join Date: Jun 2008 Location: Glendora, CA Posts: 184	AF Assist (auto-focus assist) does not do a "better" job of focusing. It simply allows you to adjust the focus ring to aid the camera in selecting the correct subject when in auto-focus mode. For instance...if you're shooting a subject that is 10 feet away against a bright high-contrast background that is 30 feet away, then the camera may choose to focus on the background instead of your subject. With the AF Assist turned off, you're out of luck, but if you have it turned on, then you can get the subject in focus using the focus ring. Of course, the camera may decide to refocus on the background at any time. I always leave the AF Assist turned on. Side note...the FX1 does not have this feature. Alec Moreno Wedding Art Films - Southern California - Los Angeles - Orange County - Video

December 19th, 2010, 02:20 AM	#5
Alec Moreno Regular Crew Join Date: Jun 2008 Location: Glendora, CA Posts: 184	AE Response (auto-exposure response) is simply a matter of how quickly you want the camera to adjust exposure to changing lighting conditions when shooting in any type of auto-exposure mode. You'll need to play with this setting to find what suits you best. I prefer to leave it in "slow" at all times for my style of shooting. Also note that the AE Response feature can slightly affect your exposure when in full manual mode. I know...this sounds crazy, but it's true. When in full manual exposure (gain, iris, and shutter speed) and the lighting conditions change, the camera may slightly compensate by adjusting the exposure accordingly. This effect is somewhere between imperceptible and nonexistent if you set the AE Response to "slow." However, if you set it to "fast" you may notice this change in exposure...very annoying. Alec Moreno Wedding Art Films - Southern California - Los Angeles - Orange County - Video