Camera options for filming CRT televisions in 4k at 60fps

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vintage.digital

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Camera options for filming CRT televisions in 4k at 60fps

PostFri Dec 20, 2019 2:49 am

Hello!

I have been looking at Blackmagic cameras for the intention of filming 60hz footage of CRT televisions. Since this is the primary intention, the camera will need Genlock or other external controls in order to sync with the video footage, and it also needs to shoot 60 (or 59.94) FPS at 4k.

It appears that the Pocket can shoot in 60FPS at 4K but lacks external controls. The Micro Studio has external controls but lacks a 4k 60FPS mode.

Is there a camera option in this price range that has both of these features?

Thank you for any assistance!
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Howard Roll

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Re: Camera options for filming CRT televisions in 4k at 60fp

PostFri Dec 20, 2019 9:05 pm

Ursa Mini 4k checks both of those boxes, the cherry on top is the global shutter, used costs about the price of the P4k.

Frankly I’m struggling to understand how shooting a CRT is even possible with a rolling shutter cam. Though the frame rate is locked, at some point the trace and shutter scan are going to overlap unless you have a super fast rolling shutter integration that you could bury in the blanking interval.

Good Luck
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vintage.digital

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Re: Camera options for filming CRT televisions in 4k at 60fp

PostSun Dec 22, 2019 7:18 pm

Good point about the rolling shutter.

If the Ursa Mini 4k is capable of doing what I need, then I suppose my questions move to wondering how it would be done. I'm an amateur so I hope my questions aren't too basic.

I'd imagine that we need to expose the sensor for the entire frame in order to get the full picture. Is that possible? Even vBlank should probably be captured so that the amount of light captured during the time that the phosphors fade is relatively uniform. Is there a specification analogous to shutter speed?

I guess the next issue is in figuring out how to genlock to the very end of vBlank. I'm imagining that there's something that will take an RGB+Sync input (or RGBHV) and allow me to fine-tune the timing. It seems like it should be relatively easy to take the sync signal as a reference and then add enough time so that the shutter triggers right at the end of the vertical blanking interval. Is there a tool out there for this? I've heard that old cameras used sync boxes for syncing to computer displays, but the ones I've seen were specific to certain film cameras.

Thank you!
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carlomacchiavello

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Re: Camera options for filming CRT televisions in 4k at 60fp

PostSat Dec 28, 2019 12:22 am

Ehm, what is your target?
CRT, also if special recent recent is no more then a hd rappresentation, why capture it in4k 60fps?
Please give us a reason to do this complicated thing.


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ShareSquid

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Re: Camera options for filming CRT televisions in 4k at 60fp

PostMon Mar 13, 2023 8:13 pm

To answer the question 'why would you want to record CRT screens in 4K', to capture the magical 'lite-brite' look of retro games on retro equipment. Instead of chunky, hard-edged blocks of solid color that you get playing old videogames on modern LED / OLED screens, you got smooth, blended colors as the original game developers intended. So a 16 color game, looked like 1,000 colors thanks to blending.

To answer the question of what camera to use... I personally use two Panasonic Lumix FZ-80 cameras... https://amzn.to/3ynwMlp and the results (once I tweak the settings) bring a tear to my nostalgic eye! With the right settings, you'll seldom get a miscolored frame... here are two example videos that I shot with this camera off of two crt type screen.


Recorded in 4K from Tandy TGA monitor - pay attention to the slow motion/zoomed in replays after each death animation. I was amazed that YouTube preserved the CRT pixels so clearly at that zoom level.


Recorded in 4K from Sony Wega CRT TV
Recorded all the zoomed in footage in 4K in order to highlight the CRT pixels.

One caveat with this camera is that it can only record 4K for 15 minutes at a time. After 15 minutes, it autostops and you have to simply hit record again for the next 15. Hope this helps, and I can provide more info regarding the best settings for this camera https://amzn.to/3ynwMlp if you go that route. Good luck!
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John Brawley

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Re: Camera options for filming CRT televisions in 4k at 60fp

PostSat Mar 18, 2023 12:44 am

I'm not sure any camera can shoot 60 FPS on a 60Hz display without a roll bar of some kind, before you even get to the issues of genlock along with rolling shutter complications.

Some CRTs did have higher refresh rates and for film making higher refresh rates were often used for CRT monitors, but they were custom CRTs. Typically they were COMPUTER monitors with higher refresh rates made to display 60 hz input video like a television but at a higher refresh rate. Something that sounds easy today, but was "hi tech" circa 1997. If you're just using bog standard CRT monitors you might not be able to even do this.

In the film days, there were sync generators that had a magnetic sensor that you placed near the target monitor that picked up the CRT monitors sync and then phase locked the film cameras shutter to act like genlock. There's no need for that these days as genlock does this much more elegantly. Basically one of these
https://cinematography.com/index.php?/f ... c-control/

I remember that you also had to have all the monitors on the same power phase (circuit) or they would lock sync, but would be totally out of phase. This became hard if you had lots of monitors, trying to have them all be on the same power phase!

JB

*edit...

I'm also remembering vaguely that you could get "line doublers" that attempted to improve the apparent resolution and refresh rate. Perhaps you can find one. They were after market "black boxes" that some home cinema users had with early video projectors. Like this...

http://www.laaudiofile.com/iscan.html
John Brawley ACS
Cinematographer
Currently - Los Angeles
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justajeffy

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Re: Camera options for filming CRT televisions in 4k at 60fp

PostSat Mar 18, 2023 2:21 am

ShareSquid wrote:Hope this helps, and I can provide more info regarding the best settings for this camera https://amzn.to/3ynwMlp if you go that route. Good luck!


Great videos! Footage you shared looks fantastic. (You got likes from me on Youtube.) I too would like to capture video from my CRT monitors and I'd love to know the settings you used on your Lumix FZ-80.

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