The terraPin 6X6 is a pinhole camera for 120 film with a 6X6 frame, in a square format. This design consists of a slide-in replacement extension that changes the focal length of the pinhole camera. This affects "shutter speed", angle of view, and, possibly, depth of field.
Designed for 0.18mm diameter pinhole
f/100 center, f/127 nominal
Horizontal and vertical angle of view:114.6°
CLICK HERE for first shots made with this extension, By Donna (the "D" in DX18)
This is a "fast", wide-angle extension for the terraPin 6X6. The DX18 slides into the camera body with the terraPin Slider system. The shutter is a captive sliding vane that allows for easy control over exposure. The recessed design prevents interference if you prefer to uncover/cover the aperture with your fingertip.
Because of the short "focal length" of this extension, there is significant light "falloff" at the edges of the frame and the corners in particular. The geometric center of the frame is f/100 and a 14mm ring radiused around this point is f/127, which gives a good compromise between the frame's extremes of f/100 - f/185 (see diagram)
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There are only five pieces to this extension, and assembly should be obvious from the exploded diagram.
You will need:
0.18mm diameter pinhole in thin metal stock
misc finishing and shaping tools (files, sandpaper, X-acto, etc)
I recommend that the inside surface of wide angle extensions be painted with a flat black to avoid internal reflections and ghosting on your exposed film.