Jump to content




Photo

Exposure question: shooting dust against a black background


  • Please log in to reply
4 replies to this topic

#1 Mara Fortes

Mara Fortes

    New

  • Basic Members
  • Pip
  • 2 posts
  • Student
  • Mexico

Posted 17 November 2015 - 09:11 PM

Hi! I am looking for some advice on exposure. I am shooting 16mm Tri-X reversal, and want to capture dust in the air against a black background.  I did a first experiment, and used and exposure meter, and exposed to a grey card, hoping this would most resemble the dust. But the developed film did not come out (basically the black background appears grey, and the dust is invisible).  Any advice as to how to expose the film would be greatly appreciated (I am going to try again using different exposures, but any suggested settings would be immensely helpful).  I am using two light sources (placement might also make a difference), and also have contrast filters available, if these would help intensify the effect.

 


  • 0




#2 Satsuki Murashige

Satsuki Murashige
  • Sustaining Members
  • 3081 posts
  • Cinematographer
  • San Francisco, CA

Posted 17 November 2015 - 11:16 PM

Well, first you have to backlight the dust for it to be visible against black. And your background should be at least three stops darker than middle grey for reversal film if you want it to appear black. Watch out for lens flare, as this can wash out your black background and make it appear grey.

If you are using an incident meter, then pointing the dome at the light source and opening up one stop would be a good place to start. If you are using a spot meter and want to get the same result, face the grey card towards the light, meter, then open one stop. If you want the dust motes to appear less bright, then don't open up.
  • 0

#3 John E Clark

John E Clark
  • Basic Members
  • PipPipPipPip
  • 780 posts
  • Other
  • San Diego

Posted 18 November 2015 - 12:54 PM

Well, first you have to backlight the dust for it to be visible against black. And your background should be at least three stops darker than middle grey for reversal film if you want it to appear black. Watch out for lens flare, as this can wash out your black background and make it appear grey.

If you are using an incident meter, then pointing the dome at the light source and opening up one stop would be a good place to start. If you are using a spot meter and want to get the same result, face the grey card towards the light, meter, then open one stop. If you want the dust motes to appear less bright, then don't open up.

 

There is the 'shafts of light' but it does require a fairly powerful light to achieve the effect. The same is true for 'rain', needing some sort of side/back light against a 'darkish' background.


Edited by John E Clark, 18 November 2015 - 12:55 PM.

  • 0

#4 Mara Fortes

Mara Fortes

    New

  • Basic Members
  • Pip
  • 2 posts
  • Student
  • Mexico

Posted 18 November 2015 - 01:29 PM

Thank you for your advice!  I am using a black background, and two studio lamps.  I am guessing I should place the lights at a right angle to the camera, behind the dust, and block so that no light hits the background.  Will separating the dust and the lamps from the background intensify the effect?  I know "shutter speed" is not as flexible with a film camera as opposed to a still photo camera, but do you think running the film at a lower speed (8, 12, or 16 fps) would also help intensify the effect?  


  • 0

#5 Satsuki Murashige

Satsuki Murashige
  • Sustaining Members
  • 3081 posts
  • Cinematographer
  • San Francisco, CA

Posted 18 November 2015 - 09:53 PM

Thank you for your advice!  I am using a black background, and two studio lamps.  I am guessing I should place the lights at a right angle to the camera, behind the dust, and block so that no light hits the background.  Will separating the dust and the lamps from the background intensify the effect?  I know "shutter speed" is not as flexible with a film camera as opposed to a still photo camera, but do you think running the film at a lower speed (8, 12, or 16 fps) would also help intensify the effect?  


This would be my suggested lighting setup:
image.jpeg

Running the film at a slower speed will make the dust seem to move faster, which could be good if you want a flurry of movement. The downside is that there will be more motion blur. Why not experiment and shoot several different speeds and see what you like? It might even be cool to shoot single frame timelapse with a cable release so the dust motes jump around across the frame.
  • 0


Zylight

Abel Cine

Pro 8mm

Visual Products

Media Blackout - Custom Cables and AKS

Tai Audio

Paralinx LLC

Willys Widgets

CineLab

CineTape

The Slider

rebotnix Technologies

Aerial Filmworks

Glidecam

Broadcast Solutions Inc

Technodolly

Rig Wheels Passport

Ritter Battery

Broadcast Solutions Inc

Rig Wheels Passport

Paralinx LLC

Media Blackout - Custom Cables and AKS

Willys Widgets

Technodolly

Visual Products

Ritter Battery

The Slider

Tai Audio

Aerial Filmworks

CineLab

Abel Cine

Zylight

CineTape

Glidecam

Pro 8mm

rebotnix Technologies