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Fisheye66 Camera Project: 180 Degree Circular Fisheye on 120 Film

Fisheye photo of bridge and downtown Saskatoon: Parallel view , Cross view, Closeup (2d). Taken with this camera using my 17mm f4 Fish-Eye-Takumar lens. Not great 3d when seen on the web but gives you the idea of what the FE66 can do (~45mm diameter image. Sharp to the edges).

Moss and fall leaves : Parallel view , Cross view , Closeup (2d). Taken with Fisheye66 camera using 35mm f3.5 SMC Takumar lens (non-fisheye). Shows the bigger (~54mm) image circle of this lens vs the fish-eye.

Above is a photo of the camera with a real M-42 (Pentax) screwmount, replacing the original plywood friction fit mount. (Thanks to Tony Z). I have tested it using my 17mm f4 Fish-Eye-Takumar and my SMC Takumar 35mm f3.5 lenses with excellent results. The fisheye produces a sharp 45mm circular image. The 35mm lens produces a 54mm circular image with some colour fringing in the outer 2mm. The camera is basically completed except for gluing down the flocked paper that light seals the front and permanently attaching the fisheye viewfinder.

This photo shows the plywood plate I added to the bottom of the camera to prevent it tipping forward (which would scratch the fisheye's bulging front element) and to make a level surface for a tripod head to grip.

Project History: My latest project it to take a Pentax Fish-Eye-Takumar (17mm f4) lens and use it with medium format film. This lens is a full frame fisheye which means that it is 180 degrees angle of view only on the diagonals. But this means that the lens projects a circular image of at least 43mm diameter. So if you can use the lens with larger film you can get a circular fisheye image that is 180 degrees in all directions.

Pentax screwmount has a 45.46mm registration distance. This means that at infinity focus the lens flange is 45.46mm from the film plane. The rear element of the FE-Takumar is quite small (16mm dia) so a rear mounted shutter should work. The Copal #1 press shutter I have is 20mm thick and has a 30mm iris opening. The threads extend about 5mm behind the flange on the Takumar lens so there is about 20mm between the back of the shutter and the film plane. Some quick geometry shows that the shutter won't vignette the light cone coming from the lens.

For the camera body I got an old Franka 6x6 folder and removed the lens, bellows and front door. There is enough room in the cavity for the shutter to fit (in order to be close enough to the film plane). I constructed a bracket from 0.032" aluminum that holds the shutter and has flanges to attach it to the top and bottom of the camera body.

To hold the lens I made a temporary lens mount with 5mm 5 ply plywood. I drilled and sanded the hole to size so that the lens could self-tap mounting threads. I plan to replace this with an aluminum plate and a real M42 mount from a (scrapped) screwmount camera.

The photo shows a top view of the camera. The top silver portion of the camera body has been removed. The silver cylinder is where the advance knob goes.

The shutter speeds (1-1/125 & B) are visible at the top of the shutter. The knurled rim of the shutter is turned to set the speed. The shutter aperture is left wide open. Aperture is controlled on the lens. The shutter is tripped with a short cable release that exits from the bottom of the shutter. Focusing is done by the scale on the lens or it can be set for hyperfocal distance and left there. The shutter is flash sync'd for all speeds though I doubt you can evenly light a fisheye scene with a single flash. Still, it might be usefull for some -1.5 fill flash of the foreground.

This photo shows the front view of the camera with the top and advance knob in place.

Oct 5/99 Update: I installed the peephole viewfinder on the camera (red cable tie and blue poster putty :) It works great! No only can you get a good idea of what the photo will look like but you can see the lens through the viewfinder. So you can adjust aperture and scale focus while looking through the viewfinder.

The photo shows the front and back of the camera with viewfinder attached. I have also attached a circular bubble level (left hand side viewed from rear).

Another change to the camera was turning the shutter about 20 degrees so that the cable release comes out the side rather than the bottom. This will make using the camera on a tripod or flat surface easier. This means that the shutter speed scale is no longer exactly at the top. But I don't think this will be a problem.

After blackening the interior and sealing lightleaks I couldn't resist trying out my camera. Even though the infinity focus hasn't been calibrated yet. So what I did was to find the distance that infinity was in focus (was at 2.2m) and then used the DOF marking that lined up with infinity (f11 one) as my focusing mark. By checking infinity focus at the top, bottom, left and right of the image I could tell that the lens is slightly tilted relative to the film plane but only by the with of the 2.2 markings on the lens. So even at f4 the DOF should cover this tilt. At f8 and f11 that I shot at there should be no problems. My film (E100VS slide film) will be ready tomorrow after work.

Update: the test roll turned out very well. It produces a nice sharp 45mm diameter circular image. The image sharpness was excellent as expected. Only one photo has any artistic merit and I hope to get it scanned and get it on my web page ASAP.

To do: Permanently attach the door peephole viewfinder. Glue down black flocked paper in front.

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