synchro scan problems at DVinfo.net

Scott Auerbach · June 17th, 2006, 08:42 AM

The other day, I tried to use the synchro scan mode to get a clear picture of computer monitors (set to around 85 Hz, as I recall...) Nothing I did to the shutter speed in synchro mode seemed to make any difference... same picture, no matter what. I finally ended up having to reset the monitors to 60 Hz on the computer itself. Needless to say, this is a worry, since I do a LOT of corporate work. Has anyone else run into this and, if so, is there some step in the process (that isn't immediately apparent) that you think I'm missing?

Leonard Levy · June 17th, 2006, 07:42 PM

Describe your settings and how you set the synchro scan in more detail.
That would be helpful.
Did you see the shutter speed come up in the screen display?

Barry Green · June 17th, 2006, 08:29 PM

You might not have had the shutter speed set to the actual synchro scan system.

Use the "shutter" and "speed sel" buttons to make sure that the camera's shutter speed is set into syncro scan mode. Then the changes you make will be immediately visible.

Scott Auerbach · June 18th, 2006, 10:58 PM

Quote:

Originally Posted by Barry Green

You might not have had the shutter speed set to the actual synchro scan system.

Use the "shutter" and "speed sel" buttons to make sure that the camera's shutter speed is set into syncro scan mode. Then the changes you make will be immediately visible.

I've just gone back and retraced my steps... I have been too busy to do that until now. One thing that I thought was odd was that the only way I could get into synchro scan mode was in Film Cam mode, so my only "shutter speed" was actually in shutter degrees, not speeds. Still, that should (I assume) behave just the same way as adjusting the shutter speed in Video Cam mode.

I was definitely seeing shutter angles changing on the OSD as I made adjustments, but no effect on the picture on the flip-out. Was in the factory default F1 scene file, shooting DVCPro50.

I see now that, even though the shutter speed next to Synchro Scan (1/48) was in blue (which usually indicates a parameter that can't be changed, I thought), that you can actually adjust it. I guess in this case, since the values change from blue to white once you hit 1/60th, that blue means "this is a value that isn't compatible with your frame rate." If that's in the manual somewhere, I missed it.

I don't have a CRT here to check it, but I'm assuming I'll be able to get it to work next time.

Thanks for the heads-up on needing to depress the shutter button AS WELL AS setting the synchro shutter speed in the menu. I'd tried that before, but you can't get to a synchro shutter speed with the buttons until you've already gotten the values out of the blue range.

Barry Green · June 19th, 2006, 08:49 AM

That's correct, if it's blue it's not possible to use it. You can't use a syncro-scan shutter slower than your frame rate, so when shooting 60i/60p, 1/60 is the slowest you can go; 1/59 would be blue and disabled.

You can definitely use syncro-scan in either film cam or video cam mode, and no they don't behave exactly the same. In film cam mode the shutter is expressed in terms of degrees, and tracks with the frame rate (so 180 degrees gives you 1/48th exposure at 24fps, but 1/120th exposure at 60fps); whereas in video cam mode the shutter is expressed in fractionals like 1/63.2, and that is a fixed exposure regardless of what frame rate you're running at.

June 17th, 2006, 08:42 AM	#1
Scott Auerbach Major Player Join Date: Feb 2006 Location: Atlanta Posts: 291	synchro scan problems The other day, I tried to use the synchro scan mode to get a clear picture of computer monitors (set to around 85 Hz, as I recall...) Nothing I did to the shutter speed in synchro mode seemed to make any difference... same picture, no matter what. I finally ended up having to reset the monitors to 60 Hz on the computer itself. Needless to say, this is a worry, since I do a LOT of corporate work. Has anyone else run into this and, if so, is there some step in the process (that isn't immediately apparent) that you think I'm missing? __________________ DP/Editor, Sputnik Pictures \| Atlanta HD video and RED digital cinema production

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June 17th, 2006, 07:42 PM	#2
Leonard Levy Trustee Join Date: Feb 2006 Location: USA Posts: 1,684	Describe your settings and how you set the synchro scan in more detail. That would be helpful. Did you see the shutter speed come up in the screen display?

June 17th, 2006, 08:29 PM	#3
Barry Green Barry Wan Kenobi Join Date: Jul 2003 Location: North Carolina Posts: 3,863	You might not have had the shutter speed set to the actual synchro scan system. Use the "shutter" and "speed sel" buttons to make sure that the camera's shutter speed is set into syncro scan mode. Then the changes you make will be immediately visible.

June 19th, 2006, 08:49 AM	#5
Barry Green Barry Wan Kenobi Join Date: Jul 2003 Location: North Carolina Posts: 3,863	That's correct, if it's blue it's not possible to use it. You can't use a syncro-scan shutter slower than your frame rate, so when shooting 60i/60p, 1/60 is the slowest you can go; 1/59 would be blue and disabled. You can definitely use syncro-scan in either film cam or video cam mode, and no they don't behave exactly the same. In film cam mode the shutter is expressed in terms of degrees, and tracks with the frame rate (so 180 degrees gives you 1/48th exposure at 24fps, but 1/120th exposure at 60fps); whereas in video cam mode the shutter is expressed in fractionals like 1/63.2, and that is a fixed exposure regardless of what frame rate you're running at.