Shooting a computer screen with FS7

[Jeroen Wolf]

With my EX3, when shooting 25P at 1/50, I would go to shutterspeed (1/33) to eliminate computer screen flickering. With the FS7, I can go to 1/25 but it doesn't eliminate it. 1/60 looks worse.

How do you get rid of the nasty flickering?

[Dave Sperling]

Switch the shutter mode to ECS (extended clear scan) and adjust shutter speed to minimize screen problems. I've run across monitors operating at many refresh rate frequencies, so I don't think there's a specific magic number...

[Jeroen Wolf]

Thanks, Dave. Do you also use this mode when shooting an interview with a computer screen in the background?

[Dave Sperling]

Certainly use ECS for interviews if needed.
A flickering computer screen can be rather annoying, so best to eliminate the flicker.
I do try to keep the shutter speed close to 2x the frame rate if I can. (Sometimes more than one ecs speed will work, so I use the one closer to 2x frame rate.)
Where you can start running into trouble is if you have a lot of screens and/or light sources that are flickering -- then you need to pick the best one, try to turn off other sources, and possibly even change refresh rates/programs on some of the computers.
Recently I've occasionally also run across issues with dimmed LED overhead lights running at a different 'flicker' rate than when they are at full power!

[Jeroen Wolf]

Originally Posted by Dave Sperling

Certainly use ECS for interviews if needed.
A flickering computer screen can be rather annoying, so best to eliminate the flicker.
try to turn off other sources, and possibly even change refresh rates/programs on some of the computers.
Recently I've occasionally also run across issues with dimmed LED overhead lights running at a different 'flicker' rate than when they are at full power!

At the newsroom of a major newspaper today I spent an hour and a half changing the refresh rate of 24 computer screens, I turned the overhead lighting off and on at least six times and asked all the reporters to turn off their cellphones and be quiet for the half hour interview we were about to do and I got this really hostile vibe... can a guy do his work with a little bit of consideration these days..?!

[Bruce S. Yarock]

Dave
Does switching to ECS working with a flickering overhead fluorescent?.
I had that problem in a recent exercise facility web commercial. My editor was able to fix it somehow in post, but it was a pain.
Thanks
Bruce Yarock
VIDEO PRODUCTION FORT LAUDERDALE, SOUTH FLORIDA|MIAMI|PALM BEACH AREA

[Donald McPherson]

Would changing the hertz make any difference? On the computer.

[Dave Sperling]

Originally Posted by Bruce S. Yarock

Dave
Does switching to ECS working with a flickering overhead fluorescent?.
I had that problem in a recent exercise facility web commercial. My editor was able to fix it somehow in post, but it was a pain.
Thanks
Bruce Yarock
VIDEO PRODUCTION FORT LAUDERDALE, SOUTH FLORIDA|MIAMI|PALM BEACH AREA

The answer here is tricky -- and it's often a 'maybe'
There can be a number of issues involved, If one bank of overheads on a single dimmer are the only issue, I can say that there have been times that I've managed to be successful in minimizing flicker. However I've had other times when the only solution was to get rid of the lights completely. And of course the issue is complicated further if you are dealing with computer screens that require using a different scan rate, since you can only set to a single shutter speed with ECS.

I recently did a corporate interview shoot where they wanted the company logo on a conference room screen behind the subject. This was fed by a laptop computer -- and the output was at a non-video speed refresh rate, so I used ECS to stabilize the logo.. There were also overheads in the room -- which didn't produce a flicker when on maximum brightness, but did when dimmed. Unfortunately the overheads were ugly (and a very different color temperature than the screen) so I went to turn them off. The switch would only bring them down to about 20% brightness - at which point the flicker was horrendous. We were in a large office building, so turning off the circuit breaker was not an option -- and there were a lot of overheads and no time to remove all the bulbs. The eventual solution was simple but non-intuitive -- they were controlled through a motion sensor in the ceiling which would turn them on (even if the switch was 'off') if anyone moved in the room. We took a large piece of Black Wrap and completely covered the motion sensor. Five minutes later - these things work on timers - the offensive flickering overheads finally went off.

In terms of adjusting scan refresh rate on computer -- that can sometimes work -- but if you're trying this it's absolutely imperative that you are displaying the screen that will be on the computer during the shoot. I've found that sometimes computer outputs will operate at different rates when displaying different programs. One trick that we sometimes try is to take the image(s) that we want displayed on the computer and make a long video file of them -- then play the video full frame on the computer. In many cases this syncs up well with the camera. (and for some client logos we'll even add a little animation 'glow' or 'highlight' to make them feel we're taking it to the next level -- of course this also requires some prep/rendering time, so not a good last minute option)

[Mike Watson]

Originally Posted by Jeroen Wolf

At the newsroom of a major newspaper today I spent an hour and a half changing the refresh rate of 24 computer screens, I turned the overhead lighting off and on at least six times and asked all the reporters to turn off their cellphones and be quiet for the half hour interview we were about to do and I got this really hostile vibe... can a guy do his work with a little bit of consideration these days..?!

I laughed and then snorted, my wife asked what was so funny. I don't have anything to add on an ECS front, but I did want to relate that sometimes I show up at someone's house to shoot an interview, I see the livingroom and say out loud "this will work just fine", then spend the next 45 minutes moving every stick of furniture and borrowing lamps and nick-knacks from neighboring rooms until the house is shambles of it's former self and the interview shot looks perfect. I'm just glad to know there's someone out there like me!

[Jeroen Wolf]

Originally Posted by Mike Watson

I laughed and then snorted, my wife asked what was so funny. I don't have anything to add on an ECS front, but I did want to relate that sometimes I show up at someone's house to shoot an interview, I see the livingroom and say out loud "this will work just fine", then spend the next 45 minutes moving every stick of furniture and borrowing lamps and nick-knacks from neighboring rooms until the house is shambles of it's former self and the interview shot looks perfect. I'm just glad to know there's someone out there like me!

Salute...!