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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Shooting (Old) CRT Monitors ??

Dominik Muench said:
Hi all,

I was wondering if anyone could recommend shutter/phase settings for the RED when shooting old CRT monitors or tv screens ? is there a trick that works best ?

thanks for any help.

dom
Click to expand...

If you are shooting 24fps, then your best bet is to get a 24-frame capable TV from a rental house that has altered it to accept 24-frame (48hz). The process then is to process the source footage through a 24-frame converter box when playing back on the CRT. You also will need to provide sync to both the converter and the Camera via a black burst generator (Tri-Level Sync). This is done by outputting from the sync generator to the Genlock inputs on both the converter and the Camera.

After this step, you should be able to adjust phase on the Camera from within the Shutter Menu. You will see an option for Phase.

From the RED Operations Guide:

"Phase: provides a delay relative to the start of the frame for the exposure time. Phase may be adjusted over the range - 45 to + 45 degrees. Default value is 0."

Or if this does not work - or it is not possible to connect cables to the Camera (Steadi-Cam shot, etc.), you can always manually adjust phase on the converter. This will synchronize the open shutter with the "painting" of the last scan-line on your CRT monitor. If you do not do this, even though you have both sources at the same frame rate, you can get double exposed scan lines which can appear as a line or bar through your image on the CRT.

If you are shooting 30fps, then you wouldn't necessarily need the converter, but you should still Genlock.

Also, many converters have color correction controls in them, so you can compensate for Tungsten lit sets. For example, you could correct your video to 3200 degrees kelvin so that it matches the lighting of the set (if using Tungsten) - otherwise the TV will appear blue (which some DPs and Directors allow to happen for nostalgic effect, but mostly it is a mistake or something no one paid attention to during shooting).

I've shot 24-frame CRTs with RED a few times now with converters, and it's always turned out fine.

If you are looking for playback engineers for this type of work on Union productions, you can visit www.695.com, as it is a Local 695 position.
 
Go read any basic film production book. This is film 101. Tons of information and charts out there. ASC manual, John Fauers books, CEs website. If you don't know this stuff you are missing the basic fundamentals on how the whole system works. I really don't understand how so many people thought that they need a $20k camera, yet have no clue about the basics of how to use it.

Sorry for the rant, but doesn't anyone read anymore?

Nick
 
If you're talking about a 60 Hz country like the U.S. and about shooting at 24 fps, then first remember that NTSC runs at 59.94 Hz / 29.97 fps.

If you are using a film camera, the methods are:

Run the camera at 23.976 fps and set the shutter to 144 degrees. This will make the exposure time 1/59.94 of a second per frame. It will reduce the size of the CRT roll bar from a wide line to a thin line and using a phase adjustment in the camera, you adjust where the line stop appears on the screen. You can't move it out of the monitor image though because it's really three lines and your choices are either to see one line in the center with the other two off the edges, or see two lines at the top and bottom third of the screen.

Run the camera at 29.97 fps with a normal shutter. But the shot will be slightly slow-motion when played at 24 fps, so you can't shoot dialogue scenes that way if the rest of the project is 24 fps.

Get a 23.976 fps monitor and playback system, convert your footage to be played at 23.976.

Get the art department to stick an LCD TV screen into the CRT housing and don't worry about sync...

For video cameras, generally you end up setting the shutter to around 1/60th or 59.94 Hz; you can usually get rid of the roll bar this way by fiddling with the "clear scan" function. But you may run into the issues I just listed regarding film cameras.
 
thanks so much for the help guys.

the shoot is in australia and here we have 50 Hz, the DOP is shooting on RED and using my camera, he asked me if I've done it before and that's why I posted here because i have no experience with shooting screens.

I suggested to play around with the phase function too. The shoot is today, so I guess they will let me know tonight how it went.

arrinick: This question came from a very experienced local DOP here who has won several ACS awards... so obviously not everyone seems to have the same opinion on whats "basic knowledge" and what isn't ;)
he has hardly done any work with the RED though before.
 
While the original question was regarding shooting CRTs with RED Cameras, David brings to light some other good info here.

David Mullen ASC said:
If you are using a film camera, the methods are:

Run the camera at 23.976 fps and set the shutter to 144 degrees. This will make the exposure time 1/59.94 of a second per frame. It will reduce the size of the CRT roll bar from a wide line to a thin line and using a phase adjustment in the camera, you adjust where the line stop appears on the screen. You can't move it out of the monitor image though because it's really three lines and your choices are either to see one line in the center with the other two off the edges, or see two lines at the top and bottom third of the screen.
Click to expand...

Actually, there are a couple of other interesting points to be made here. First off, many film Cameras don't have a phase adjustment built in (at least one that you can adjust while running the Camera to see the "bar" move out of frame), so an external third party sync box accessory is often times used.

The way this works is that both the Black Burst (Sync Generator that is Genlocked to the 24 frame (23.976) Converter) and the sync box that plugs into the accessory port on the Camera are timed to the same crystal. The sync box then allows the Engineer/Operator to control the timing or phase of the shutter while running the Camera for a short time to "bury the bar" as it is pushed off the bottom of the monitor while watching through the viewfinder. This works great since it is a wireless solution for the Camera. The idea was actually pioneered by Hal and Alan Landaker of Warner Brothers Production Sound and Video and won a Technical Achievement Award from the Academy in 1981.

Another part of the problem, as David mentioned, is that the "bar" will roll off the bottom of the screen while phasing and immediately reappear at the top of the frame, unless dealt with properly.

With a professional frame rate converter system, you can actually completely get rid of the "bar" or double exposed lines. Since each frame consists of a total of 525 scanlines, of which 486 make up the visible raster (NTSC), a properly configured converter not only is changing the framerate, but rescaling the video, so that the extra scanlines are used "off screen". The image is vertically scaled (squished), and the monitor's vertical settings are stretched to compensate. This reduces overall resolution slightly, but allows for complete removal of the artifact.

David Mullen ASC said:
For video cameras, generally you end up setting the shutter to around 1/60th or 59.94 Hz; you can usually get rid of the roll bar this way by fiddling with the "clear scan" function. But you may run into the issues I just listed regarding film cameras.
Click to expand...

Also, on computer monitors, you have the option to manually reset the scan-rate to an NTSC friendly refresh rate (60Hz). (Or PAL, HD friendly rate.)
Many computers these days default to a higher refresh rate, such as 75hz or 85hz, which looks nicer to the eye, but obviously is not in sync with a 24 or 30 frame Camera.

ClearScan is a good solution, but a couple of factors must also be kept in mind. First of all, not every Digital Camera has this feature. ClearScan is actually the Sony term for the ability to fine tune specific shutter adjustments. It normally works well, but since you are changing the shutter, just factor in other things that might be effected, such as practical light sources and other computer generated displays, which may have different refresh rates, such as digital signage.

David Mullen ASC said:
Get the art department to stick an LCD TV screen into the CRT housing and don't worry about sync...
Click to expand...

While this is sometimes a cost effective solution, there are quite a few reasons why it is not the preferred method. Matching housings can be a bit of a pain, but it is more the technical aspects of image quality that come into play. Unfortunately, on may productions, consumer quality TVs are used since they are often obtained for free through product placement. This can result in poor quality images due to the drawbacks of lower priced LCD screens. For instance, all too often, I have witnessed an upset DP on set when they realize that their money saving Art Dept has brought in a TV that can be shot off angle. Sure it looks great straight on, but the brightness, contrast, and color properties drop off severely the further off-axis you get.

If a TV screen or computer monitor is important to your story or production, I would recommend not skimping on a low quality brand.Also, many screens are not capable of dialing in the proper color temperature adjustments to compensate for the production's lighting choices, so it is best to consult your Video Department in advance of picking any on-set monitors. They will also be able to provide you with the proper color-correction gear for playback on-set.
 
unfortunately I didn't really get much information from the production. I was just told the DOP wants to shoot some old 70's style screens and If i had any suggestions shooting them on the RED. Never really had to do it myself so far.

I will definitely print out this thread and keep it as future reference :) Thanks again Casey.
 
arrinick said:
Go read any basic film production book. This is film 101. Tons of information and charts out there. ASC manual, John Fauers books, CEs website. If you don't know this stuff you are missing the basic fundamentals on how the whole system works. I really don't understand how so many people thought that they need a $20k camera, yet have no clue about the basics of how to use it.

Sorry for the rant, but doesn't anyone read anymore?

Nick
Click to expand...

Wow... tough crowd...
 
Arrinick:

What's it like having all that knowledge and no interest in sharing?
 
Arrinick:

What's it like having all that knowledge and no interest in sharing?
Click to expand...

Ok,OK, was grumpy, I apologize. I have offered advice on many topics to many people in the past and will in the future.

Nick
 
arrinick said:
Ok,OK, was grumpy, I apologize. I have offered advice on many topics to many people in the past and will in the future.

Nick
Click to expand...



no need to apologize, I had a rough weekend too:umm:
 
yes, shooting 25fps is a good solution.

You will still have to deal with the phase issue, however.

Another note... one other reason to use a sync generator and accessory sync box with Film Cameras as opposed to phasing on the Camera (if the option is available) is that a sync box will hold the sync once it is set. Manually phasing the shutter on the Camera must be done each time the Camera rolls on a new take.
 
when speaking of film Cameras, the sync box allows for manual control of the shutter for phasing. Film Cameras that have this ability, such as some of the newer Arri's allow for this, but the difference is that you only need phase the shutter once (run the camera, and watch the "bar" as you move it out of the frame) since it is locked by a crystal frequency in the sync box and sync generator.

You can also achieve phasing manually on Film Cameras by starting and stopping the Camera until you get lucky and the phase lines up by sheer random coincidence. But this method is difficult and can take many attempts and wastes film. :-)
 
David Mullen ASC said:
Do you have to shoot 24P if this is a 50 Hz country? Can you shoot the project at 25P? It's simpler to sync a 25P camera to a 50i PAL monitor.
Click to expand...

The whole film or just this section... 25fps production is very useful in 50hz countries (for CRT's practicals etc) even if the project is 24fps.

regards

Michael L
 
Only TV screens in PAL regions are 50 Hz, many CRT computer monitors were 60 Hz (or more). I'd check this first before deciding on 24 vs. 25 fps.
 
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