March 19

Tutorial: Geeky Photography with Flash Stencils

Help! My house is being Space Invaded!

Lounge Space Invaders

Alright it isn’t – it’s just clever camera trickery in the form of flash stencilling. But it’s a pretty neat effect and a lot of fun, so I thought I’d share with you how it can be done.

You will need:

  • A camera capable of taking long exposures (30 seconds is about right)
  • A tripod or stable surface
  • An external flash (or a very bright torch)
  • A box
  • Card
  • Craft knife and cutting tools
  • Black tape
  • White paper

Basically what we are doing here is enclosing the flash and creating a window of a specific shape to let the light through, and then ‘light painting’ for the camera.

Step one
Print your design onto the card. I’ve thrown together a few different stencil designs that you can download by clicking here, but I stuck with the classic invader design.

Step two
Cut out your stencil. Remember to check that your design fits on the face of your box before you go to all the trouble of cutting out all those pixels. If you have some kind of magic square stamp or something, use it. Because this hurt my finger after about the 8th pixel.

Space Invader Stencil
Step three
Cut a large window in your box big enough that the the stencil fits in the gap (once trimmed).

Step four
Cut a hole in the bottom of your box about the right size for the end of your flash (or torch) to poke through. Mine was just the right size that the box mostly stayed in the right place by itself, without the need for tape.

Flash Stencil in Progress
Step five
Trim your stencil and tape it over the window in your box. Think about which way up to stick it, with the position of your flash in mind. You may decide to hold yours the other way up to me, so it’s easier to get low to the ground.

Step six
Cover any gaps in your box with black tape. You want all the light directed forward through the stencil, and no weird light leaking through seams etc.

Light Stencil in Progress

Step seven
Test! Check for any further holes to cover up and make sure that the flash/torch has no obstructions inside the box causing shadows.

Space Invader Light Stencil

Step eight
Compose your shot. You need the room to be fairly dark, but keeping a light on in the next room with the door ajar means you will be able to see the surroundings as well as the light painting.

For your camera settings, start with something like f/10, for 30 seconds using ISO 100. If you aren’t sure how to use manual mode (or don’t have one) put it into shutter priority mode (e.g. S or Tv) so that you can set the exposure time as long as possible, and use ISO 100 to avoid graininess. If you are using a flash for your light stencilling, set it to its lowest power setting – the recovery time is fast enough then to fire multiple flashes in one shot.

Step nine
Set your camera timer, hit go and run into position to trigger the flash wherever you want your Space Invaders to appear. Since you’re ‘painting’ blind, this does take a few attempts before you get the positioning close to how you want it, but stick at it. 30 seconds should give you enough time to fire a good number of flashes.

Step ten
Check out your photo!

Keyboard Invaders

Don’t stand too still when the camera is shooting otherwise you may end up appearing as a ghost in your image. The long exposure means you can get away with being in the field of view as long as you aren’t in the same spot for too long. Once you are done ‘painting’ get out of the shot.

Remain behind your flash. If any light is directed at your arm/face the camera will see you.

Your flash probably has lights on it. Be aware of this and cover them if necessary. Unless you can make the lines of light work in the shot, of course!

You may find that you can see the back of your box or even the flash itself in some of your shots (see middle front Space Invader in my lounge room shot). For subsequent shots I actually covered the stencil with thin white material to diffuse the light from inside the box and give a more even flash. Hence “white paper” in the list of required goodies.

If the card you used for your stencil is a little thin you may see a faint rectangle around your Space Invader where light is getting through – pretty obvious in the garden shot below. This can be helped by the tip above, but if it is really bad consider using thicker card.

If you are using a torch you may find that you need to hold the light on for longer to get enough brightness, but this can cause blurring as you wobble! You can also try a wider aperture (smaller f/numbers) to let more of the light into your camera, but you may have to make the room darker as a result.

If there isn’t enough ambient light in your shots try flicking the light on for a couple of seconds whilst shooting, or getting back behind the camera at the end and just direct your flash at the room. You can also experiment with a wider aperture for this as well.

If you want to get people involved, set your shot up in exactly the same way, ask your subject to stand fairly still while you do the stencilling and then before the shutter closes fire your flash toward the person to light them up and capture their image as well. This might take a bit of practice but would made for some hilarious Facebook profile pictures.

If you give this a go we’d love to see what you come up with so don’t forget to post in the comments!

Dinner Invaders

Laundry Invaders

Windscreen Invaders

Garden Invaders

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Posted March 19, 2013 by Skels in category "Craft", "Geek", "Sci-Fi", "Tutorial", "Video Games