Pinhole Camera (part 3)
I am finally getting around to explaining how I built my digital pinhole camera. If you have ever made a pinhole camera, you recognize that there are major drawbacks to traditional pinhole photography. Fortunately, our hybrid digital pinhole camera isn’t limited by the traditional obstacles that make pinhole photography impractical. For example, with our digital pinhole camera, it is easy to get full color images. There isn’t any processing or light sensitive materials. There isn’t any fumbling around in the dark trying to load your camera. You can take as many photos as your memory card will allow, and best of all, you get instant results. Let’s get started…
First, let me explain how our digital pinhole camera is going to work. Just like a traditional pinhole camera, we have a lightproof box with a pinhole on one side. On the opposite side from the pinhole is a white wall where the light will be projected. Normally this wall would be where the photo paper or film would go. Since our camera is digital, we don’t have to worry about any photo sensitive material. By placing the camera inside our lightproof box we can take a picture of the image being projected onto the back wall of our pinhole camera. Now that we know how the camera is going to work, here are some tips to help you build your own digital pinhole camera.
If the walls of your camera aren’t very thick, light will leak through. My first camera was made of matte board which let light through during long exposures. To prevent this, I recommend covering your walls with aluminum tape. Because this tape is made of aluminum, light won’t pass through it. Make sure you cover the outside of your walls and not the inside. Your inside walls should always be black to prevent the light from reflecting in your box.
The distance from your pinhole to the back wall of your camera is the focal length. You can experiment with this distance, but I have found that 10-12 inches is ideal. Most digital cameras should be able to focus at this close range and it allows enough room for your camera to fit in the pinhole camera. Remember that the longer your focal length, the longer your exposures will have to be.
Making a Pinhole
You can make your pinhole in tin foil, but I recommend using aluminum from a soda can because it won’t get damaged as easily. Make a hole with a needle and then use a sander to open the hole to the desired width. If you want a very small hole, make a dimple in the aluminum with a pin but don’t puncture it. Sand on the bump until a hole is made. The size of the pinhole is very important. If it is too big, the image that is projected will be blurry. The smaller the size of the pinhole, the longer you will have to keep your shutter open. There are several online calculators that will tell you how big to make your pinhole. The distance from my pinhole to the back wall of the camera is 11 inches, and I find that a pinhole of 0.7mm is the ideal size.
Making a Preview Hole
Since the light entering the box through the pinhole isn’t bright enough to be seen on the screen of your digital camera, you are shooting blind. To help compose your shots, you can use a large hole to let enough light in that you will be able to see the image on your screen. A 0.25 inch hole will give you a very fuzzy image, but it is enough to allow you to roughly compose your shot.
Positioning the Digital Camera
It is important that the only light entering our box comes from the pinhole. Obviously if the camera is in the box, it is going to be hard to take a picture. The solution is to have the entire camera outside the box except for the lens. This allows us to have access to all the controls of the camera. The challenge is to create a hole that your lens will fit through that is tight enough that it won’t let light into our box. The best solution I found is to cut a circle in a piece of rubber (an innertube from an old bike tire works great) and use it to seal out the light. The connection should be tight enough that the digital camera is attached to the pinhole camera without any other attachments. If you are concerned that your digital camera will fall off, you could build a platform for it to rest on.
Since the lens of our digital camera can’t be in exactly the same place as the pinhole, we have to angle the camera slightly so that it is pointed at the projected image. This will cause some distortion, but it is minimal. The closer the lens is to the pinhole, the less the distortion will be. We want the lens of our digital camera to be as close to the pinhole as possible without blocking any of the light from coming through the camera. The red in the diagram below shows the place where you want to make sure your camera doesn’t enter.
Manual Settings On Your Digital Camera
The settings on your digital camera are very important. Your camera wasn’t designed to take pictures in a lightproof box, so we have to override the camera’s brain if we want to get a good picture. Depending on the type of digital camera you have, you may or may not be able to control these settings. I use a Nikon Coolpix 5000. This is a 5 megapixel camera with the ability to control many of the settings manually. Here are the settings you want to adjust, and why:
Focusing the camera can be difficult since your lens is enclosed in a dark box. Without any light, your camera will most likely not be able to focus at the correct distance. The Nikon Coolpix 5000 has manual focus controls that allow you to set the exact distance that it will focus on. If your camera has this feature, simply measure the distance from your lens to the back wall of your pinhole camera and set the camera to that distance. If your camera doesn’t let you set the focus distance manually, it will be almost impossible to get your pictures in focus. Since pinhole photos have a naturally blurred appearance, you might be able to live with your pictures being fuzzy.
We know that our exposure time is going to be long since we are taking a picture in a dark box. Obviously the light meter on your digital camera is not going to be able to give you a good reading, so just ignore it. On a bright day, you will typically have an exposure time of 30 seconds to over a minute. You will get better at guessing exposure times as you use your camera. If your camera doesn’t have the ability of taking long exposures, you can forget about making a digital pinhole camera.
The best way to take long exposures is with a remote shutter release cable. A shutter release cable lets you use the bulb mode of your camera without physically holding the button down on your camera. For the Nikon Coolpix cameras, the MC-EU1 cable is overpriced, and I recommend using a Palm Pilot to control the camera. You can learn more about that technique here.
Manually set the aperture on your digital camera to the largest opening (the smallest f-stop) to let as much light in as possible.
If your camera has a noise reduction feature, you should definitely use it. Any time you are taking long exposures with a digital camera you are going to have to deal with hot pixels. Even with noise reduction on, you will still have hot pixels. There is software that can help with these annoying pixels, but I am still researching the best way to handle this problem. I will let you know when I have decided on the best solution.
If your camera has the option, I recommend taking your cameras in RAW format. Unlike jpg and tiff formats, shooting in RAW format allows you to process the image later rather than applying the generic profile your camera assigns to the file. This prevents your camera from disregarding important photo data.
The Finished Digital Pinhole Camera
Here is a picture of the third design of my camera. I hope this was helpful to you. If you want to see some of my pinhole photography, I post them on www.foundphotography.com.