Ask David Mullen ANYTHING

[Thomas Wright]

Hi David,
Thanks so much for your invaluable input on this forum.........like so many others, I'd just like to express my gratitude!!!

I've got a shoot coming up that will require filming a number of computer screens, and am aware of some of the issues involved. I was under the impression that adjusting my settings in syncro-scan would alleviate these issues but on testing, I still find that I can't get rid of the related noise/flicker.

Would you have any suggestions?

best
joe

I've not managed to get that feature to work either, I've asked about it many times but no one's ever answered me. I think it's like the record button on the Alexa. :001_unsure:

 

[Subhadip Sen]

Hi David,
Thanks so much for your invaluable input on this forum.........like so many others, I'd just like to express my gratitude!!!

I've got a shoot coming up that will require filming a number of computer screens, and am aware of some of the issues involved. I was under the impression that adjusting my settings in syncro-scan would alleviate these issues but on testing, I still find that I can't get rid of the related noise/flicker.

Would you have any suggestions?

best
joe

Most computer screens are 60 Hz. Using a 1/60th shutter speed seems eliminates flicker. In case you have one or two monitors still flickering (75 Hz is common as well, especially in North America), you can simply change the Refresh Rate to 60 Hz temporarily. In Windows 7, this is Screen Resolution (right click on Desktop) > Advanced settings > Monitor > Screen refresh rate. This has worked well enough for me.

 

[Phil Jackson]

Of course you as a DP could light your subjects with some degree of separation so the DI is more effective in this aspect.

I'm no David Mullen, just trying to help.

Thanks. I'd actually read and was familiar with Stu's blogs on the subject, I was just wondering if it could be done photochemically or practically because that look is prevalent to a lesser degree in movies like The Dark Knight (the bank vault) and Inception which did not undergo a D.I. but I suspect that might just be uncorrected light.

http://www.blu-ray.com/movies/screenshot.php?movieid=743&position=16

 

[David Mullen ASC]

Hi David,

I've got a shoot coming up that will require filming a number of computer screens, and am aware of some of the issues involved. I was under the impression that adjusting my settings in syncro-scan would alleviate these issues but on testing, I still find that I can't get rid of the related noise/flicker.

Would you have any suggestions?

Well, I've avoided that scenario over the years, lately by insisting that all the computer screens be LCD's, which have a long enough decay time that there is no flicker problems.

With multiple CRT computer screens, the problem is that they all run at different refresh rates and you'd first have to get them at the same rate and then get them in sync with each other... normally you'd hire an expert at that. Or you'd use CRT TV sets as fake computer screens and feed them with video. Or put an LCD screen inside a CRT housing, which is what I usually try to get the art department to do for me.

I haven't had problems getting the flicker out of a single CRT computer screen with syncro-scan on most HD cameras, as long as the camera doesn't pan around.

 

[David Mullen ASC]

What about an eye-light? Do you think it's neccessary?

If your key light creates a reflection in the eye, then I don't think an eyelight is necessary, though it may be a good way to reduce bags under the eye.

I'm not a fanatic about getting eyelights in every shot, it can be artificial, but I do find that in dark scenes, like in moonlight, they really help draw your attention to the actor's expressions in the dark.

 

[ericyoung]

...I've got a shoot coming up that will require filming a number of computer screens, and am aware of some of the issues involved. I was under the impression that adjusting my settings in syncro-scan would alleviate these issues but on testing, I still find that I can't get rid of the related noise/flicker.
...

I've not managed to get that feature to work either, I've asked about it many times but no one's ever answered me. I think it's like the record button on the Alexa. :001_unsure:

Are you both aware that apart from adjusting the "degrees", you also have to enable it in the Shutter "Mode" menu? I got caught out by this initially because you can click, highlight & adjust the shutter "Speed Adjust" on the Shutter Synchro button, but it has no effect until you also select the Shutter Mode!

 

[ericyoung]

Well, I've avoided that scenario over the years, lately by insisting that all the computer screens be LCD's, which have a long enough decay time that there is no flicker problems...

Interestingly, I've come across some LCD/plasma screens that do flicker/roll, and require camera scan adjustment to minimise it on a couple of different occasions. They were both types of large flat screens at different venues, but don't know the makes or models.

 

[David Mullen ASC]

Interestingly, I've come across some LCD/plasma screens that do flicker/roll, and require camera scan adjustment to minimise it on a couple of different occasions. They were both types of large flat screens at different venues, but don't know the makes or models.

Well, there's a difference between LCD's and plasmas, which is why it's important that you get the art department to understand that difference as well... plasmas often have a mild pulse running through the image, something like a 60 Hz cycle I believe that can be removed by adjusting the shutter.

 

[David Mullen ASC]

Thanks. I'd actually read and was familiar with Stu's blogs on the subject, I was just wondering if it could be done photochemically or practically because that look is prevalent to a lesser degree in movies like The Dark Knight (the bank vault) and Inception which did not undergo a D.I. but I suspect that might just be uncorrected light.

There is no single thing or technique that contributes to coloration of shadows/blacks -- it may be lighting (natural or artificial), it may be filtering, it may be the color balance, it may be how the film stock was exposed or processed, it may be an optical artifact (lens flare, etc.), and it may be created in post.

 

[Thomas Wright]

Are you both aware that apart from adjusting the "degrees", you also have to enable it in the Shutter "Mode" menu? I got caught out by this initially because you can click, highlight & adjust the shutter "Speed Adjust" on the Shutter Synchro button, but it has no effect until you also select the Shutter Mode!

I assume you speak of selecting Syncro in the sensor menu? Where is this "Speed Adjust" you speak of? Phase is phase: the launch angle of the sin (cos) wave, I don't want to change my speed nor shutter angle, just when the frame is exposing, on an Aaton all you need do is press the VAR button which makes the shutter spin fractionally faster till you get the bar off the screen and you release the button and, voila! 180 degree shutter, 25fps and no black bar. QED

PS anyone used a cinematography sync unit with their red?

PPS how would one write the degrees little circle superscripty thing on a UK keyboard so I don't have to actually write 180 degrees?

 

[Joe Shemesh]

Really appreciate the responses guys, but still not got it right

best
joe

 

[David Mullen ASC]

The short answer is that if you have a room full of CRT computer monitors, you can't sync to all of them at the same time since they are all running at different refresh rates. The simplest solution is to replace them all with flatscreen LCD computer monitors where the refresh rate shouldn't matter due to the decay time of the pixels.

 

[Martin Stevens]

Hello David,

When you create a "blue" moon light effect do you use Full Blue CTB color conversion gels,
or do you use a combination of gels?

 

[David Mullen ASC]

Hello David,

When you create a "blue" moon light effect do you use Full Blue CTB color conversion gels,
or do you use a combination of gels?

It depends on the movie, and it also depends on if there are any other colored sources in the frame, or if it is only lit by moonlight.

In general, I tend to opt for a half-blue color for moonlight, i.e. tungsten with 1/2 CTB or HMI's with half CTO, if I'm shooting on high-speed tungsten stock. This gives me some blue while still capturing other colors on the negative. Same goes for digital, I like the other channels to still get some information.

However, a lot depends on what the blue is mixed with. For example, if you have a campfire scene where people are lit with orange light, then even half-blue is going to look very blue, so if you want a more subtle difference, you might use quarter-blue (some people just use white light for moonlight if the scene is lit with orange firelight.) On the other hand, if the entire scene is just lit with blue moonlight, you have more flexibility to adjust the level of blueness in post. For ease, in that case, I may just use uncorrected HMI's for the whole scene and reduce the blueness in post to the level I like. That makes even more sense if shooting on the Red One which prefers daylight lighting. In that case, I'd use uncorrected HMI's (full blue) but set the color temp of the camera to something like 4200K for a pale blue effect.

Blue lighting for me is generally done for the psychological and symbolic effect, so it depends on the story whether a night scene should look blue-ish or not.

A few times I've added a bit of green to the blue, either with gel or in post, for more of a cyan moonlight.

 

[Michael Totten]

Mr. Mullen.

Thanks for this thread : ) amazing.
I had a question I was hoping you could help me with.

I'm going to be shooting through the windshield of a parked car and want to know the best way to prevent glare so I can get a nice clear shot of the actors who will be in the driver and passenger seat.

It'll be daytime exterior, most likely full shade (if a very tiny amount of dappled harder light).

I was planning on using a polarizer and lighting from within with mini-flos or rosco pads as well as laying some white cards in the actors laps.

How would you handle a situation like this?

Should I consider a large 12X12 or 20X20 to knock down reflections ?

kind regards,

michael

 

[Martin Stevens]

Thank you David for the Blue Moon Light info.

 

[ericyoung]

I assume you speak of selecting Syncro in the sensor menu? Where is this "Speed Adjust" you speak of? Phase is phase: the launch angle of the sin (cos) wave, I don't want to change my speed nor shutter angle, just when the frame is exposing, on an Aaton all you need do is press the VAR button which makes the shutter spin fractionally faster till you get the bar off the screen and you release the button and, voila! 180 degree shutter, 25fps and no black bar. QED
...
PPS how would one write the degrees little circle superscripty thing on a UK keyboard so I don't have to actually write 180 degrees?

When selecting Syncro in the Sensor>Shutter menu, the little window with the changing numbers is labelled "Speed Adjust". The original poster Joe Shemesh was talking about using the Syncro-scan feature and that seems to need to be enabled by select SYNCRO in the Sensor>Shutter>Mode menu before it has any effect. If you match a 25fps camera speed to a 50Hz CRT screen, I think Phase control alone actually does seem to have some effect on the start time of the camera frame.

If say a screen was refreshing at exactly 25fps, and your camera was shooting at exactly 25fps, then there would be no rolling line/bar, but a stationary frame line/bar might be visible because the starts of screen and camera frame would not start at the same moment in time. In that case, phase adjust alone could move the line/bar out of the way.

However, if the screen refresh frequency is anything but a whole multiple of camera frame rate, there will be a rolling frame line/bar and/or flicker and you have no choice but to either adjust shutter speed/angle in the case of the Red to make it stationary and/or adjust fractional camera frames per second in the case of the Aaton, and then use phase to move the frame line/bars to minimise their appearance. The Aaton XTR manual says:

"The phasing of the variable speed can be set to eliminate a roll bar while filming a monitor. Operate first with no magazine on the camera, because you first need to synchronise the camera speed to the monitor frequency. Run the camera. Press SET, then EX/VAR once, turn the jog, until the roll bar seems stable on the screen. Press SET to enter. Stop the camera, and then install a magazine. Run the camera. Press SET, then EX/VAR twice. Look through the camera at the monitor and press EX/VAR until the roll bar is out of view. Press SET to enter."

So the Aaton is maintaining shutter angle at say 180° by adjusting fractional frame speed. Can't say what that does to timecode/sound issues!

Any syncro shutter experts out there want to weigh in?


On the other topic, to get degree as "°" you need to use the "Character Palette" in Windows or "Character Viewer" in Macs to insert special characters in documents. See here:
http://www.ascendercorp.com/support/input/

 

[Gregory Lopez]

David,
You always say you have no experience with DSLRs, has that changed? I shot some blue screen stuff with a Canon 7D and got some very good results. Here is a link to a very interesting test, what do you think? http://www.zacuto.com/shootout. I hope the link works.

 

[David Mullen ASC]

Mr. Mullen.
I'm going to be shooting through the windshield of a parked car and want to know the best way to prevent glare so I can get a nice clear shot of the actors who will be in the driver and passenger seat.

It'll be daytime exterior, most likely full shade (if a very tiny amount of dappled harder light).

I was planning on using a polarizer and lighting from within with mini-flos or rosco pads as well as laying some white cards in the actors laps.

How would you handle a situation like this?

Should I consider a large 12X12 or 20X20 to knock down reflections ?

A Pola will reduce reflections but on a curved windshield you can only get one side or the other clear with the Pola, not the entire length, but that may be enough if the other side has dark trees above. The only way to kill it completely is to reflect black in the glass, hiding the sky. But too much and you lose all the ambience on the car so it tends to work better when you don't see much of the car body in the frame like the hood.

 

[Thomas Wright]

Cheers Eric, you champion, have you tried to make it work? I did but it didn't.

I suppose this topic is more apt for a different thread but I'd really like someone to say they'd done it and how they achieved that.