Making and Using a Pinhole Camera

A pinhole camera is wonderfully simple: just a light-tight container with a pinhole in one end and a sheet of photo-sensitive paper in the other.

If the hole is tiny and perfectly round, light rays from the subject cross over as they pass through the hole and form an inverted image on the back wall of the box. This exposes the photo paper, and when you develop it you get an upside-down negative image.

Here are a couple of links to some pinhole sites, just to give you a taste of the possibilities. There are tons more out there on the net.

http://www.steveirvine.com/pinhole/index.html – my friend Steve Irvine's site

http://www.ebsqart.com/Galleries/cmd_Art_Gallery_Photography%3A+Pinhole_1_1_G.htm – a random site I found through Google

http://www.pinhole.com/gallery/ – yup, it's what it sounds like!

Here's a link to a site that demonstrates how a pinhole works, and what happens when you change various parameters such as the hole size.

Use it to answer these questions in your notebook (under the heading "Pinhole Questions")

What happens to the image of the F as it passes through the pinhole and is projected onto the back surface?
What happens to the image as you drag the F further from the camera? (drag it by its base)
What do you think would be the effect if the camera was longer? (more distance between the pinhole and the back where the image is projected. You can't do this with the model, but think about it…)
What happens as the pinhole gets bigger?

Steps

Acquire a large coffee can or similar can with a tight-fitting lid
Think like a vampire
Create a pinhole aperture
Create a shutter
Add a way to stabilize the camera while shooting
Load photo paper into the camera
Choose a subject
Set up and expose
Develop the paper
Assess and re-shoot

Suitable Cans

You can use any type of container that is the right size, is clean and has an easily removable tight-fitting lid. We used to use cardboard boxes, but they're bulky and hard to seal.

I suggest a standard large coffee tin – 1 kg size. You could also try a large clean dry paint tin ( about 4 litres), as long as the lid isn't bent and can easily be removed and re-sealed. If there's a lot of dried up paint where the lid fits, like the one below, it won't work well.

Think Like a Vampire: Avoid Light!

Inside the can, just like the undead, you hate daylight! Here are some of your worst nightmares:

	Cracked lid. This would be hard to seal consistently. Solution: Don't use a lid like this. You might be able to tape it, but it's not worth the risk of ruining your photos.
	Bent lids; Dried paint in the groove Solution: Don't use a can like this. A paint can that's been used all at once and then rinsed is best.
	Translucent Lid Plastic lids may look opaque at a glance, but if you hold them up to the light you'll see they all let some light through. What would Dracula say?! Solution: Paint it with flat black paint, inside and out. Watch for cracking, peeling and chipping if it bends. Try to remove it with a minimum of bending. In addition to the paint you could also carefully attach an opaque black cardboard disk to the inside.
	Shiny reflective interior You don't want the light from the pinhole bouncing around inside, fogging your photo. Solution: Paint all inside surfaces with flat black.

Making the Pinhole

The hole that lets light into any camera is called the aperture. In our case the aperture is a very small pinhole. Tiny apertures have the amazing property of creating an image that's completely in focus at any distance, without the need for a lens.

The quality of the pinhole determines the quality of your images. Basically you want a very tiny perfectly round hole with no tiny burrs or rough edges.

You can either make the hole directly in the bottom of the tin or in a piece of metal or foil that you attach under a larger hole in the bottom.

The direct method is simpler, but making the hole is a separate piece makes it easier to get at as you create it. You can also change pinholes this way, trying different apertures etc.

If you're making a hole in metal (like the can's bottom), make sure there's a hard surface underneath it that you can dent (not a desk!). Tap an awl or sharp small nail so that the head just barely begins to stick through. Then finish and round the hole by pushing a #10 sewing needle through it. Rotate it as you push. Clean off burrs with very fine sandpaper, poking the needle halfway through again.

If you make the hole in tin foil, sandwich it between two heavy cards. Then press through with a #10 needle, rotating the needle as you go.

Make a slightly larger hole in the centre of can's bottom, cleaning off any burred metal. Attach the pinhole piece on the inside of the can so the holes line up. Use black electrical tape to ensure a light-tight seal.

Pinhole (marked by the red arrow).

This is magnified about 4X the actual size.

It was made with a needle in pop can aluminum. The small piece of aluminum was then taped over a bigger hole drilled in the bottom of the coffee can.

The cleaner and more perfectly circular the pinhole aperture, the crisper your images will be.

Shutter

Now you need a shutter to keep light from entering the aperture when you're not shooting. A small piece of opaque tape works fine, as long as it doesn't leave behind sticky residue when you open it. A better solution is a small cardboard flap with a tape hinge.

Whatever you use, make sure it's light-proof and easy to open and close. You can't hold it open (the camera will jiggle), so provide a way to keep the flap open – maybe another piece of tape.

Shutter closed	Shutter open

Note: This shutter would be better if the tape was opaque and covered all edges of the flap completely.

Stabilizing Base

Your exposure times will be very long, so you have to somehow keep the camera perfectly still while you shoot. There's no way you'll get a sharp image if it's hand-held, so you need some kind of base.

One solution is to use two hunks of modeling clay or plasticine to make feet that will rest on any surface.

Another is to fashion a cradle out of a shoe box or cardboard. You might need a big elastic (bungie?) to keep your baby from rocking in the cradle due to wind.

Or, you can screw or hot-glue feet onto the can.

What other methods of stabilizing can you dream up?

Three approaches to glued-on feet

If you use two long horizontal feet, they need to be parallel.

The best way to guarantee that the camera won’t rock is to have 3 points of contact i.e. a tripod. The camera on the right would be good if the feet were a little longer – then it would sit on the tips of the 2 feet plus the bottom of the other end of the can, a sturdy tripod.

For shots from the ground, it helps if the feet raise the can a bit, or angle it upward.

Loading the Camera with Photo Paper

By now you should know that photo paper is sensitive to even small amounts of light – that's why it works when we expose it in our camera! But to load the camera, you have to work under the safelight in the darkroom.

In the darkroom, gently open up your can. Cut a piece of photo paper to fit the bottom of the can. Return the unused part to your light-proof envelope, and don't forget to seal it. The paper can be cut to a square, rectangle, circle or any other shape that looks good and covers most of the top of your can.

Attach it, shiny side out, to the inside of the top of your can, using bits of masking tape folded over. Keep it flat, and don't obscure any part of the paper.

Put the lid back on, making very sure that it's a tight seal.

Close the shutter, put your paper away, and you're ready to go out and shoot!

Shooting Tips

Subject

A short can will have a wide field of view, so your camera is good for wide-angle shots like landscapes, buildings and crowds.

It also should have a deep depth-of-field, meaning both close and faraway things should be in focus, so try to construct your shot with objects in both the foreground and background.

You need lots of light, so outdoor daylight shots are far more effective than indoor shots. Did you know that sunlight is often ten times brighter than even bright artificial lighting? If you do try indoor shots, you'll need to have your subject lit by a bright window, or use a really long exposure time.

Other than that, as always, look for an interesting, compelling subject. Your shots should reflect an artistic eye as well as technical skill.

Avoid the temptation to put your camera on the ground, even though it’s convenient to steady it there. Prop it solidly on something high. Try for some unusual angles.

NEVER attempt to hand-hold it, unless you like blurriness.

This is a pinhole shot by Margaret D Helthaler

http://www.ebsqart.com/Galleries/cmd_Art_Gallery_Photography%3A+Pinhole_1_1_G.htm

It's different than what you'll produce in some ways (it's a colour positive, for one thing), but shows good pinhole composition: interesting fore-, mid- and background; natural unmoving subjects as well as a human subject who inevitably moves a bit.

Exposure

How long should the shutter be opened? There's no simple answer to this. It depends on the size of your aperture and how much light is on your subject. For this reason, shoot a few test strips before using full sized paper. As a guide, I'd start with a sixty second exposure on a bright day. If it's over-exposed (the paper goes dark quickly), try 30 seconds; if it's under-exposed, try a two minutes or five – you get the idea.

Some students have tried indoor shots that took half an hour! No live human will stay still for that long, so expect motion blur.

You can use the long exposure time to create motion blur and ghostly effects. Try having your subject steadily rotate his or her arm through 90 degrees for the whole exposure, or have subjects arrive or leave halfway through the exposure. Traffic that stops for a while and then drives off could also be interesting.

What happens if you shoot towards the sun?

Again, remember that the camera and your subject have to be absolutely rock-still for the whole exposure to get a crisp image. Rest the camera on a solid base, and don't let it jiggle, rock or vibrate. Don't try to hold it by hand, or even touch it while exposing.

Once everything is set up and the camera is on a solid base aimed at the subject, gently open the shutter and tape it open. Measure your exposure time, and don't touch the camera. Close the shutter tightly at the end. Record your exposure time, and when the strip or final shot is developed and dried, write the time on the back. This helps you remember what works.

Did It Work?

Develop your paper exactly like you did for the photograms (isn't it nice to suddenly be an expert?!). Once it's fixed and rinsed, have a close look in the light.

How's the exposure – do you need more or less time?

Is everything pretty clear? Look for signs of the camera shaking – streaking ghosting, lack of clear edges.

If all your photos are blurry, your pinhole could have rough edges, or be too big or not perfectly round. Make a new aperture.

If the photos are grey, streaky and lack contrast, your camera could be leaky. Check carefully to see where light could be sneaking in – it doesn't take much!

If all your photos are consistently fogged, especially at one end, you may have let a bit of light into your photo paper envelope. Bad news! Try to use the unexposed ends, and hopefully the inner sheets didn't get as fogged as the top one.

My Experiments

Coffee can pinholes are new to me, but I’m having fun seeing what I can do. There are some later experiments here.

I titled my first effort “Bike Failure”! Sun & shade, exposure time 45 seconds (too short)

At first glance it was almost indecipherable – what is all that stuff?! Which way is up?

I scanned it and rotated and darkened in Photoshop. That makes more sense!

Photoshop also lets you invert the image, so you can get a positive. (image menu, Adjustments, Invert)

No longer a complete failure, but not very interesting…

Ghostly Self-Portrait with cars and grass. I actually prefer the negative image this time. Bright, hazy; 75 second exposure. I ran into the photo after opening the shutter, so the van can be seen a bit through my leg before I was blocking it. It’s hard to stay frozen for a whole minute squatting like this, so there’s motion blur on me, although everything else is crisp. This one shows the amazingly deep depth-of-field characteristic of pinholes. The blades of grass a few centimeters from the camera are as focused as the cars 10 metres away!


Sculpture Garden. Cloudy; exposure time 2 minutes. The regular camera pic on the right is not good – underexposed for the foreground, but more exposure would wash out the clouds. The pinhole isn’t great either, but it’s interesting to compare what you get from a $600 lens at its widest angle and a free pinhole lens! Notice the blurry bits of leaves at the side of the pinhole iamge, and the blurred tall grasses. They’re not as clear as the regular camera because the wind was whipping them around, which doesn’t show in a 1/125^th second exposure, but definitely does in 120 seconds – that’s about 15,000 times as long!

	Positioning, and the Camera at Work The day was very windy, so I had to shelter the camera in the lee of a boulder. The angle would have been better from on top of the rock.