Modern digital cameras use image processing technology to produce high-quality results. But this makes everyone’s pictures look perfectly identical, and it takes a lot of the satisfaction out of getting a good picture (at least for the author). In this article, you’ll discover how to use retro technology and 3D printing to create a super high-quality film camera that gives your photographs a real sense of occasion.
Have camera, will travel
Figure 1 shows the completed camera. The body is 3D-printed from designs at hsmag.cc/WillTravel. The body was printed in white PLA, which turned out not to be the most lightproof of colours. You should use a darker colour. The camera has since been sprayed with multiple coats of matt black paint – both inside and out, to make it more light-tight. The light proofing is not quite perfect on the author’s camera, but this is only a problem if the camera is used in direct sunlight. He plans to add some felt inside to improve this. The camera lens at the front is mounted onto a helicoid (the black cylinder with the three knurled rings behind the lens in Figure 1) which is turned to move the lens in and out and adjust the camera focus. There are also designs available which use 3D-printed threads on the lens holder to screw the lens in and out.
To infinity and beyond
One of the first things you need to do when you have built your camera is discover the focus position for infinity. Ideally, this would be when the lens is closest to the camera. Then, as you move the lens further away from the camera, it will focus on closer objects. You identify the infinity position by pointing the camera at a distant object and then adjusting the lens until the image is sharp. You can use this for ‘zone focusing’, where you just set the lens for the distance the camera is from the subject, and everything in that zone will be sharp. If you look at the camera in Figure 1, you will notice some white dots painted on the lens mount. The two you can see identify the infinity focus position. When the two dots are aligned, the camera is focused on the far distance. There is also a dot for 2m focus distance.
In the frame
To set up your photograph with the camera, you attach a viewing screen to the back, as shown in Figure 2. The screen is held in place with elastic cords. It contains a sheet of ground glass which is placed in the position that the film will be in when the picture is taken. The lens projects an image onto the ground glass. Because of the way lenses work, the image is inverted and flipped left to right, which makes the viewfinder interesting to use, but you do get used to it. The image can be hard to see, especially if you are outside. You can improve your view by putting a ‘dark cloth’ around the camera and over your head to keep out external light. This also gives your pictures a proper Victorian sense of occasion.
If you are using zone focusing, you can set your focus using marks on the lens and use the round optical viewfinder on the top of the camera to frame your picture. The viewfinder is based on a close-up lens which is sold for use on mobile phones. When you are ready to take your shot, you slide a film holder in front of the viewing screen.
Welcome to the dark slide
The film holder contains a ‘dark slide’ that protects the film from light. When the holder is on the camera, you remove the dark slide, take the picture (having remembered to set the shutter speed and aperture), and then put the dark slide back into the holder and remove the holder from the camera. A film holder contains two sheets of film, one on each side. The author owns two film holders, which means he can go out and take four pictures before he must come home again. Before any pictures are taken, the film and empty holders are placed into a special light-tight changing bag, which has light-tight cuffs sewn into it. You put your hands through the cuffs and then load the film into the holders. After the pictures have been taken, you use the changing bag to get the film out of the holders into either a light-tight box to be sent away for processing or a development tank.
Accentuate the negative
The development process produces a negative image; the darker parts of the negative are made from tiny grains in the film which have been illuminated and then turned to silver. You make a print from a negative by projecting it onto photographic paper which, like film, turns darker when exposed to light. This reverses the light and dark of the negative, resulting in a positive image. If you don’t want to do that, you can use a scanner to create an image file that can be processed by software to create the correct appearance.
The big picture
The camera takes pictures onto sheets of film that are 4×5 inches in size. These images contain lots of detail and, because the lens is a long way away from the film, you can get beautiful out-of-focus effects. Lenses have a property called ‘depth of field’, which determines how much of an image is in focus. A lens with a large depth of field would take a sharp picture of both you and a tree in the distance behind you. A lens with a shallow depth of field will be able to take a sharp picture of either you or the tree, but not both. You might think that having more sharpness in a picture is a good thing, but you can get some very pleasing effects by blurring parts of an image. The picture of the duck in Figure 3 looks better because the trees and fence in the background are blurred. Smartphone cameras are very small and put their lenses very close to the image sensor. Because of the physics behind the way lenses work, this means a phone camera has a large depth of field. Phones use sophisticated software that can analyse an image, decide which bits are in the distance and blur them. The results can be impressive, but our 3D-printed camera just puts the lens a very long way from the film and lets physics do the hard work.
Controlling exposure
When you take a picture with your phone, the camera works out how much light the sensor needs to get a properly exposed image. When you take pictures with the printed camera, you need to set the shutter speed (how long the film is exposed to the light) and the aperture (the size of the hole the light comes through). The easiest way to do this is to use a light meter application on your phone. You set the speed of the film in the app (how sensitive the film is to light), point your phone at the scene, and then copy the reading values onto the camera. If your shutter speed is less than a thirtieth of a second, you will need to put the camera onto something solid. Otherwise, camera shake will blur the image.
A camera can only capture a fraction of the range of light and dark areas in a scene; if you get your exposure wrong, you might find that the faces of your subjects are too dark or too light. You deal with this by measuring the light from the parts of the scene you care about. As you take more pictures, you can use this limited range to your advantage, making a subject stand out by blowing the background out to white or turning the background dark. Next, you will start using lights to control how the picture looks, and hey presto! – you are turning into a proper photographer.
Printing a camera
The most expensive camera in the world is still just a box with a lens at one end and something light-sensitive (film or an electronic sensor) at the other. So, if you want to make your own camera, you only really need a light-tight box. However, it’s not quite that simple. The size of the box must exactly match the lens you are using. A lens has a particular ‘flange focal distance’ (FFD), which is the ‘in focus’ distance from that lens to the surface of the film. You need to make sure that the box you make is the right size for your lens. The website at hsmag.cc/WillTravel has a lookup table you can use to find the FFD for your lens. You can then select an appropriate design from the ones available.
The Will Travel body contains threaded holes you can use with 3/8” to 1/4” adaptors to allow you to put the camera on a tripod. There are three accessory shoes you can use for flash-guns, lights, or the viewfinder. There are also holes into which you can fit spirit levels. The handle can be used on either side of the camera body.
Occasional photography
The 3D-printed camera brings a real sense of occasion to taking a picture. On a good day, the results will stand comparison with very expensive cameras. The lenses and shutters might be old, but the results they generate are very impressive and can be made into enormous images. Also, taking photographs ‘the hard way’ teaches you a huge amount about photography, and how to use the limitations of the medium to get the best results. If you are of a certain age, you might even find it fun to revisit the days of home development and seeing pictures appear before your eyes in the darkroom. The author has had a lot of fun with this and hopes you do too.
