Tuesday, January 12, 2010

First Impressions on the Gakken-Flex

The Mighty Gakken-flex

In early December I purchased a Gakken-flex kit from a Flickr contact (mijonju) in Japan. The Gakken-flex, for those that must never have looked online, is a 35mm twin-lens reflex plastic camera kit. It's a shame that there are no equivalent US magazines like that of Gakken's Otona no kagaku (大人の科學) magazine. However, the US-based MAKE Magazine is now selling many Gakken kits online, including the stereo pinhole camera (next on the list?). The Otona no kagaku magazine (#25) has a wonderful-looking section on the history of photography and twin-lens reflex cameras. I wish I could read Japanese! For the relatively modest sum of $58, which included 2-day shipping, I had the kit in my hands in time for my birthday, as a present to myself. However, it wasn't until last weekend that I finally assembled the camera.

First of all, if you have assembled any plastic models in your spare time, you don't need to be able to read the instructions. While there were some places in the assembly that I had to think about before proceeding, the camera went together with relative ease, and I am impressed with fit and finish of the plastic parts. All you need in the way of tools is the small Phillips-screwdriver that is provided in the kit. Forceps are useful for holding small springs or screws in place, so you may want to get those out if you have them. There is a misprint in the instructions where the springs A and B are mislabeled, but if you look at the assembly diagram, you would realize that the functions of those springs are such that it's easy to figure out. (Here is the correction). Anyhow, I probably had the camera together and working in about 45 minutes. It's important to test the sub-assemblies before you screw everything together so that you know how things work. That's the beauty of building your own camera.

The lenses are geared to focus together, so what you see on the frosted plastic waist-level viewfinder should pretty much be what you get on film. The lenses extend far enough from the film plane that you can close-focus to about 18" from the camera. If you have some series 5 or 6 filter holders that are about 25 mm (viewing lens) - 27 mm (taking lens) in diameter, you can put diopters, neutral-density, and color filters in front of the lens.

I loaded a roll of Kodak Plus-X pan (ISO of 125) into the camera the next day, and shot a roll. Note -- the camera has a nominal aperture of f11 and a shutter speed of about 1/150 sec. On a sunny day, ISO 100 film should be just fine. Also note that it might be ambiguous in the instructions that you only need to advance the film 1/2 turn, not 1 full turn. That is why there are two index marks around the film advance knob. I did a full turn, just for safety's sake and after developing I realized that a 1/2 turn was all that was necessary.


Photos? Oooh, what dreamy goodness! After shooting only about a dozen shots on my first roll, I think I have a good idea of what to expect in the future. The lens is a single-element, so there is aberration and dreamy out-of-focus areas when you shoot close-up. Even for shots at infinity, the focus seems to have places where its sharp in the center and OOF around the edges. There is some vignetting close-up. The magazine has easily deciphered hints on modifying the camera, including making a square mask.


Expect more images from me later on , but I give this fun little camera a definite thumbs-up. There is a Flickr group, of course!


Tom Overton said...

Hey Mark,
A couple of questions. Is the viewing lens linked to the taking lens so that you can focus on the viewfinder? This is an annoying drawback on the Blackbird, Fly camera my daughter owns.

Secondly, is the lens glass or plastic? (...not that it matters, the shots you posted are perfect for this kind of camera.)

Thirdly, (ok... three questions) how sturdy doess the camera feel... especially in the winding and shutter mechanisms? This, again, is one of the areas where the BBF suffers most. The film rewind crank feels like it will fall off every time you unload a film.

Great shots, by the way!


Anonymous said...

you can also make an experiment with the aperture ring as explained in the book. put the ring in front of the lens and you will get more vignette effect. take the ring out and you will larger aperture (prob around f8).

Lena said...

Your blog is totally awesome!!!
so much good info! Thanks for sharing :)

Catherine Tang said...


i've run through 3 rolls of film already and love the shots and look that the gakkenflex produces. however, i totally estimate the focus!!!! i can't tell the difference in the image that the viewfinder (mirror) produces even when i'm moving the focusing knob about. thus lots of my far off images turn out blurry (but still nice), but my close up ones are fine, as i just turn the focus knob full out.

how do you work your focus?

there's no difference in mine!
thanks :)

aslah said...


I too have a Gakken Flex but for some reason my view is upside down. Do you know what I'm doing wrong? I've assembled it twice, to no avail.

If you have any tips, please email aslah_lenoir@yahoo.com