Jump to content


Photo

Falloff issues


  • Please log in to reply
9 replies to this topic

#1 Rolfe Klement

Rolfe Klement
  • Basic Members
  • PipPipPipPip
  • 668 posts
  • Director
  • London | LA

Posted 14 April 2008 - 06:54 PM

I read the other post about large sources vs soft light but thought I would start a new topic anyway...

http://www.cinematog...?showtopic=4794

What would be the advice of the experts to reduce falloff across a room considering a small room and limited power?

Turning some 2.5Kw HMIs on the wall or the ceiling on max flood works OK but I still get about 1.5 stops difference across the room.

Lots of little lights cause hot spots and | or wiring or practical bulbs in shot issues

The best I have done so far is bounce an HMI into the ceiling and hang some black wrap skirting up high. The only issue is the "Birth" top light look.

Am I asking for the impossible... Has anyone done something clever with mirrors? Or something funky with a SatelliteX light?

Thanks

Rolfe
  • 0

#2 timHealy

timHealy
  • Basic Members
  • PipPipPipPip
  • 1252 posts
  • Other
  • New York

Posted 14 April 2008 - 08:18 PM

Unless there is a doorway or some sort of opening in a wall where one can bring a light or a bounce further back, I don't think you'll be able to beat the laws of physics.

One could try a full "Wendy Light" for the purposes of bringing a light way way back as David Watkin preferred, but your room is probably not big enough.

Best

Tim
  • 0

#3 Michael Nash

Michael Nash
  • Sustaining Members
  • 3330 posts
  • Cinematographer
  • Pasadena, CA

Posted 14 April 2008 - 09:55 PM

Yeah, I'm with Tim on this one; "Ya cannot change the laws of physics..." A soft source falls off more slowly than than a point source, but it still falls off. You can only make a bigger source or move it farther away.

Otherwise, the basic trick is to flag or scrim the subject(s) closer to the light, if you can do so without shadowing the far wall at the same time.

What exactly are you trying to do? Maybe with more info we could come up with more applicable solutions.
  • 0

#4 Xavier Plaza

Xavier Plaza
  • Basic Members
  • PipPipPipPip
  • 288 posts
  • Cinematographer
  • Guayaquil - Ecuador

Posted 14 April 2008 - 10:17 PM

Unless there is a doorway or some sort of opening in a wall where one can bring a light or a bounce further back, I don't think you'll be able to beat the laws of physics.

One could try a full "Wendy Light" for the purposes of bringing a light way way back as David Watkin preferred, but your room is probably not big enough.

Best

Tim


Sorry Tim but what do you mean when you say "wendy light", i know is an expression but i wanna know what it's ...


Xavier
  • 0

#5 timHealy

timHealy
  • Basic Members
  • PipPipPipPip
  • 1252 posts
  • Other
  • New York

Posted 15 April 2008 - 05:03 AM

I don't know the specifics but David Watkin inspired building a light of four panels of 7 rows of 7 coloums of DWE 650 watt bulbs. The light in total was 196 bulbs and rigged to a lift and brought back as far away a a long city block. That way he could have the same exposure without any falloff of light in the scene he was trying to do. The rig was usually complex involving several grips and electricians to do it.

And Wendy was David's alias so someone who knew him, well, got creative and blessed the light as such.

Best

Tim
  • 0

#6 Valerio Sacchetto

Valerio Sacchetto
  • Basic Members
  • PipPip
  • 94 posts
  • Student
  • Italy

Posted 15 April 2008 - 06:19 AM

http://www.panavisio...p...=278&cat=60

A bit too much but the concept is the same :P
  • 0

#7 Xavier Plaza

Xavier Plaza
  • Basic Members
  • PipPipPipPip
  • 288 posts
  • Cinematographer
  • Guayaquil - Ecuador

Posted 15 April 2008 - 09:33 AM

Thanks Tim and Valerio, now I remember years ago I saw on the same panavision web this light but i forgot the name anyway thanks for clarify your point...


Xavier
  • 0

#8 Serge Teulon

Serge Teulon
  • Basic Members
  • PipPipPipPip
  • 757 posts
  • Cinematographer
  • London UK

Posted 15 April 2008 - 09:53 AM

Lots of little lights cause hot spots and......


Hey Rolfe,
With smaller sources you can achieve a soft look by placing several units next to each other....so essentially it could work for you.

Cheers
S
  • 0

#9 Rolfe Klement

Rolfe Klement
  • Basic Members
  • PipPipPipPip
  • 668 posts
  • Director
  • London | LA

Posted 15 April 2008 - 04:19 PM

Thank you for the replies.

Flagging is a great idea but impractical. We are filming dance in small spaces. Soft sources falloff too quickly. The big lights are great but cannot rig them far away.

I don't expect to fix this issue now and I will have to come up with a plan - shutters on a bright source - to dim the closer talent is to lens.

BUT - I am wondering if there is a way to break or "bend" the laws of falloff.

Assuming a 5KW unit is powerful enough then the basic issue to resolve is to increase the distance between the light source and talent.

Maybe there is way to do this without putting units on Genie lifts or cherry pickers outside.

Something like this

2.jpg

So using mirrors if X = a+b+c+d+e

1.jpg

thanks

Rolfe
  • 0

#10 Michael Nash

Michael Nash
  • Sustaining Members
  • 3330 posts
  • Cinematographer
  • Pasadena, CA

Posted 15 April 2008 - 04:44 PM

I can't say that won't work, but it seems pretty complicated. Try to keep it simple. The problem with mirror gags is that each mirror acts as a "window" or iris in the light path, which reduces the size and softness of the source. If you've got a 4x4' mirror reflecting a 20x20' diffusion frame, you've effectively only got a 4x4' diffusion frame by the time the light hits the subject. The distance is preserved, but the spread and softness is diminished.

Try a soft keylight above the camera, and use grip scrims to fade the bottom edge of the beam as the subject gets closer to camera. Use soft fill lower down to fill in as the subject gets closer to camera, so the light doesn't get too toppy there. Then, if a single source is not not enough to carry the full distance of the room, repeat the keylight/scrim setup farther from the camera, taking care to diffuse the beam edge as much as possible to avoid any sharp toppy shadows as the dancer moves forward of that beam.

Imagine several rows of 4' 4-bank kinos mounted to the ceiling, perpendicular to the lens axis, the rows spaced several feet apart. Aim the kinos at 45 degree angle downward and away from camera. Then soften the bottom edge of each kino with diffusion to blend the pools together. As the dancer moves away from each keylight he/she will start to enter the next one. If the lights are close enough to each other and "bottomed" properly, it will act as a continuous keylight.
  • 0


Technodolly

Metropolis Post

Gamma Ray Digital Inc

Visual Products

CineTape

Paralinx LLC

Abel Cine

Willys Widgets

The Slider

Aerial Filmworks

FJS International, LLC

Broadcast Solutions Inc

Ritter Battery

Tai Audio

CineLab

Glidecam

Opal

Media Blackout - Custom Cables and AKS

Wooden Camera

rebotnix Technologies

Rig Wheels Passport

Visual Products

Rig Wheels Passport

Abel Cine

The Slider

Paralinx LLC

Tai Audio

FJS International, LLC

Opal

Aerial Filmworks

CineLab

Ritter Battery

CineTape

Gamma Ray Digital Inc

rebotnix Technologies

Media Blackout - Custom Cables and AKS

Broadcast Solutions Inc

Technodolly

Willys Widgets

Glidecam

Wooden Camera

Metropolis Post