Kit 25: Twin-lens Reflex Camera

Kit #25 is the 3rd camera from Gakken in the Otona no Kagaku (Adult Science) series so far. Is there really that much to plumb from cameras to justify yet another one?

The answer is “yes”, of course. Kit #3 was just a simple pinhole camera and (apparently, since I haven’t bought this one and only looked at the online magazine) you were given instructions for making your own photographic paper. The concept is very straightforward. The paper is placed inside a sealed box. Light passes through a small hole in the box and hits the paper. The nature of light and the size of the hole work together to allow the image to be focused at the plane of the paper. The sharpness of the image on the paper depends on the exposure time. For room-lit conditions and 100 ASA paper, figure a 3-5 second exposure (bright sunlight, about half a second). So, you’ll also want a tripod or a stable surface to set the camera on.

Kit #14 brought us the stereo pinhole camera, which actually has 3 pinholes. A rotating lever raises and lowers a piece of plastic within the sealed box. This time, we’re using standard 35 mm roll film and a little crank for advancing the film. When the plastic piece is rotated up out of the way, and using the central pinhole, you can take panorama pictures across two frames of film simultaneously. When the plastic piece is rotated down, it separates the two frames and the two outer pinholes essentially allow you to take two photos at a time with the parallax slightly offset in each. Looking at the stereo photos with a special holder, you can get a kind of 3D effect. Again, the focus depends on the exposure time, the speed of the film and the amount of ambient light.

There are several drawbacks to pinhole, and stereo pinhole cameras. First and foremost is that you can’t focus them. The best you can do is time how long the film has been exposed and make an educated guess. The second is that you MUST have a steady mount for the camera. With such long exposure times, any jiggling of the camera will smear the photo. Third, you can’t be exactly sure of how the shot is being framed. You can look over the camera at the subject, but you can’t see what the film sees.

(Former prime minister Aso.)

This is where we start getting into mechanics and real optics. The twin-lens reflex camera adds two focusable lenses, one in front of the aperture and the second in front of a mirror that bounces the light up to a smoked plastic screen, allowing you to see the subject as it will be framed on the film. Pressing the shutter lever down exposes the film to the incoming light. Exposure times are reduced because the lens is focusing the image for you, so you don’t need to worry about jitter as much (letting you hold the camera in your hand during the shot). Better yet, because the film is advanced by hand, you can choose to play with optical effects by double- and triple-exposing the film. (If you can get the film shop to develop the paper without cutting it, you can have lots of fun with multiple exposures across the entire roll.)

(Triple exposure; two friends in front of a white building, moving, on top of a shot of the street).

The instructions suggest a 1-hour construction time, but it took me 90 minutes largely because I wasn’t exactly sure what I was doing. There is an error in the book, where springs A and B are mislabeled, but it’s easy to tell that this is a mistake because they’re different-sized springs. Be careful about over-tightening the main shutter lever – there’s supposed to be a 1mm gap between the lever and the screw to allow the shutter to snap properly, but you don’t want it too loose either. When you put the camera case panels together, don’t tighten the 6 screws down right away; the case needs to be able to flex to snap all of the panel pieces into place first. You’ll probably need to use the included screwdriver to reach the hard-to-reach screws at the end when you do tighten them all down. The one thing that threw me was the view screen. It’s a clouded plastic sheet, which I initially thought had gone bad. Actually, it’s supposed to be clouded in order to give the image of the subject from the mirror something to project on to. My main suggestion is to keep testing the shutter lever and other moving pieces as you assemble the kit to ensure that they’re working correctly at each step. And, make sure that when you put the double-sided tape on the mirror, that the tape goes on the side with the clear plastic protector sheet (the blue side doesn’t get the tape).

(Shooting towards the sun. Very washed out.)

For actually using the camera, the book suggests 400 ASA film outdoors and 100 ASA indoors. (You can’t adjust the shutter speed to match the ASA rating of the film). Put the film in the camera, close the camera up, and advance the film to the end of the roll. Then, looking at the “counter” dial, rewind the film 24 or 27 frames before taking your first shot (so that you have enough leader at the beginning of the roll to avoid ruined frames from when you put the roll in the camera; actual number will depend on the roll you bought). It’s a very sturdy package and generally you don’t have to worry about stripped screw holes unless you take the screws out and put them back in too often. The protector panels over the view screen fold down when the camera’s not in use. Pull the little tabs of the top panel outward in order to open the panels up for using the camera. There are no lens covers so you may want a protective case for the camera during storage.

(My favorite shot. A double exposure with a close-up of a pot of flowers followed by a long distance shot of a truck on the street.)

The mook starts out with a number of photos taken by various amateurs using the kit camera, and then switches over to professional shots with antique boxes. There’s another round-up of various styles of cameras, and a feature story on how to make your own daguerreotype images on glass plates. One article discusses JAXA astronaut Koichi Wakata’s shots of Earth from space. A second suggests modifications to the kit, which largely consist of gluing pictures or glass beads to the case. A third article shows a disassembled scanner being used as a camera, and there’s also a piece on a laptop-driven pencil (used for automating “hand-written” letters). There’s also a “how-to” for making models of giant robots using rubber erasers, the history of roll film (starts out in 1889), an overview of how 3D TV screens work, a manga describing the H1N1 influenza (swine flu) and a second manga exposing the secrets of some “diet supplement” in Japan (it’s actually the stimulant ephedrine).

Links in the mook include:
Nature photos, Arizona
Space photos
Scanner camera

Overall, this is a good kit and a good mook. The photos of old cameras aren’t as interesting as, say, the photos of old gramophones or synthesizers, from some of the other kits. But, it’s still a good introduction to film-based optics. It is getting harder to justify the costs of developing roll film when digital cameras are so cheap and easy to use, but film cameras will probably never really go away because they’re so cool. The shutter mechanism on this kit is a fun combination of a couple of gears and springs, and the way the image shows up on the smoked plastic screen is almost magical (even though it’s just the 1 lens and a mirror).


A comment on the photos I took. Granted, this is the first time I’ve used this kind of camera, and that the film had passed its freshness date. But, I can say a few things here. First, I used 400 ASA film, which really does not like being used indoors. Even under bright lights, indoor shots turned out underexposed and very grainy. Second, when something’s focused at the center of the shot, everything else goes out of focus as you go towards the edges of the frame (a problem with using an inexpensive lens). But, this is a good thing if you want a soft focus around the subject. Third, shooting facing the sun will give you washed out photos. Shooting away from the sun gives you better colors. Fourth, if you’re going to go for trick shots and multiple exposures, there’s an all new set of rules.

First, for multiple exposures, if you want the subject to move and the background to be solid, make sure that the camera is bolted to the ground. Any movement when you’re pressing the lever will mess up the shot. Being on a tripod is NOT the same as being bolted to the ground. Second, don’t do more than 2 or three exposures – any more than that will just create a mess. Probably, you should shoot the darker image first, then the lighter ones on top of it. Third, play around and have fun. The best shot of my first roll was completely accidental.

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