Analog Slit-scan Camera

INTRODUCTION

For those who don't already know the concept, here there are two links explaining what slit-scan photography consists in: Wikipedia, PetaPixel

CONSIDERATION

If we understand a photography as a representation of the space (where we are capable to perceive 4 dimensions: 3 spatial ones, that can be represented in a Cartesian coordinate system with the X, Y and Z coordinates, and one forth temporal dimension). In traditional photography, the temporal dimension is blocked by choosing the moment when we press the camera shooter and one of the three spatial dimensions is also blocked as we choose a projection of the space by deciding the perspective. For this reason, the resulting photography can be represented in a 2 dimension plane: the camera film and later a photographic paper.

We can say that a common photography is representing the X and Y coordinates of the space and fixing the time and 3rd space coordinate (despite actually a photography is a 2D projection of the 3D spatial coordinates rather than a slice of the space volume).

Slit-scan photography allows us to substitute one of the space coordinates translated to the photography by the time dimension. Thus representing the time instead of the X spatial coordinate. In other words, you are recording the visual information of what you can see through a slot (with theoretically a differential thickness) with the pass of the time. This allows capturing the time in the image (by sacrificing one spatial dimension).

It can be interesting to apply this technique to represent the evolution of things through time. Especially when the motive is dynamic and its shape evolves with the time. My personal interest in photography is basically the sea and the waves (Flickr), for this reason, I have used this technique to represent the dynamism and shape transformation of sea waves from a different and interesting point of view.

PROJECT SCOPE

The purpose of this project is to adapt an affordable analog camera (Pentax K1000) to make this kind of photos.

The majority of the parts that have to be built to adapt the camera are designed to be 3D printed. Moreover, the same results could be achieved with parts fabricated with other techniques (maybe not as accurate) to fulfill the same functions.

This project is presented for a Pentax K1000 but with few CAD skills the parts can be redesigned for ANY FULLY* ANALOG CAMERA (*Camera without automatized parts such as rewind motors).

BUDGET

5 - 15 € (Obviously camera not included in this budget)

I hope you find this post interesting and you become encouraged to enroll in slit-scan photography

CUT

The slit can be cut with laser cut if you want to be accurate. If you don't have this technology available, it can be cut with a cutter and a ruler.

MATERIAL

Any material can be used. The only requirement is that it has to be completely opaque, as thin as possible and preferably black (or as dark as possible) and mate in order to avoid reflections. I recommend using either a piece of black posterboard, or a sheet of plastic, or a sheet of tin painted in black.

DIMENSIONS

The slitten cover outline dimensions need to be big enough so as to cover all the film frame only allowing light to pass through the slit.

The slit heigh should be long enough to span all the film's height (35 mm at least).

The slit width should be as small as possible as the smaller it is, the sharper the resulting image is (because the merge of images belonging to different moments of time is smaller); However, it has to be ensured that there is no contact between both sides of the slit. The smallest dimensions you can obtain depend a lot on the material and the cutting technique. I would say that the best result would be obtained if it is made out of laser cut tin. In my case, I used posterboard and a cutter which it is probably the less favorable case. That's why I did a 1 mm span.

PROCEDURE

The slitten cover should be placed in the same plane as the film (in contact with the film) in order to obtain a sharp image. Then it has to be glued to the center of the frame. I recommend using paper tape instead of glue so that this material will not scratch the film and is a provisional modification.

ATTACHED

A DXF file of the slit cover dimensions.

IDEAS

If instead of doing a vertical slit, you try with oblique slits or curvy slits in S or Z (zig-zag) shapes (never reaching the horizontal angle) you can get warped/weird images.

PARTS

Parts to print: (STL files attached)

• Rewind crank
• Rewind crank handle
• Film rewind button holder

Parts to buy:

• 1/4" Tripod screw (1,19 €) Aliexpress

PRINTING SETUP

Parts designed to be printed with an FDM printer although it other printing techniques can be used as well. If printing with FDM, I highly recommend printing with a 100% infill as the parts are functional and are designed to support mechanical charges (especially the crank). For the same reason, it is better to use ABS than PLA.

DESIGN

Please note that the parts have been designed to fit the Pentax K1000 but the design would be very similar for any other analog reflex camera. For this reason, I have also attached the SolidWorks (2016) CAD files just in case you want to modify them (sorry for not using free CAD software).

HOW TO USE IT

1. Open the camera back cover and tape the slit cover to the center of the frame (with the slit vertical). Tape it as close as possible to the film.

2. Load the film as usually (Youtube Tutorial) and close the camera back (obviously...)

3. Close the aperture to the maximum possible (f/22 for my lens) and set the speed to the maximum possible (1/1000) and put the lens cap (or go to a dark place). Then shot all the film advancing the film, frame by frame, with the film advance lever until you have all the film loaded to the right spool of the camera. Then, when you reach the end of the film, you will notice that the lever does not allow you to advance to the end of its path. Above all DON'T FORCE THE ADVANCE LEVER because you will either detach the film from the cartridge spool or you will break the internal gears. Once reached this point you only have to press the rewind button (placed in the camera bottom) and finish the advance lever path.

In this step, we are winding all the film to the camera right spool of the camera without exposing it to the ligth.

4. Place the "Film rewind button holder" in the bottom of the camera making sure that the rewind button is constantly pressed by this added part. Then screw the 1/4" camera screw and make sure that the "Film rewind button holder" is fixed and there is no wobble. In case it is, you can place washers to ensure a full contact of the parts.

5. Assemble the "rewind crank" and the "rewind crank handle". The assembly is made just by pushing one into the other.

6. Unfold the film rewind lever (left side of the camera) and fit the rewind crank assembly (The assembly is based on a press fit) so depending on your printer resolution you will maybe have to sand a bit the rewind crank fitting. If it's a bit loose don't panic! the part will do its work anyway.

Once reached this point. Be careful not to scroll the crank accidentally because this will make film advance or move back. Never scroll against the rewind direction.

7. Place the camera on a tripod. You will need both hands to shoot.

8. Release the lens cap and focus as usual. Set the aperture to obtain the right** exposure. Set the shutter to "Bulb" (B) position.

**This is a trial and error step. To achieve a correct exposure depends on many factors now: The amount of light on the environment (as always), the film sensitivity (ISO) (as always), the slit width and the film rewinding speed. I recommend you to shoot the first roll repeating every shot 3 times (one with maximum aperture, the other with medium aperture and the last with minimum aperture) then note for every shot the light meter readings. Once you have developed the first roll you will be able to know which should be the light meter reading that gives a right exposure. In a second iteration of the process, you can fine tune the exposure. If you don't want to deal with thinking wich amount of over or under exposure the lightmeter have to display to give you a right exposure, you can set the ISO to a wrong value that will give you a right display in the light meter. OF COURSE, all this process changes every time you change the rewinding speed. But with time and practice, you can manage not to burn or overexpose many shots just with intuition. Actually, the dynamic range of analog film is quite high (up to 8 stops) so it is not that difficult to stay in the right exposure.

9. Shot: Press the shooter (AND DO NOT RELEASE IT) and you will hear how the shutter curtains and the obturator move. Then start rewinding the film (ALWAYS ON THE REWINDING DIRECTION. FOLLOW THE ARROW SENSE. CLOCKWISE FOR THE K1000). The rewinding speed will determine how the time is represented in the "X" axis of the film. The faster you go, the more dilated the time will be. In other words, one same distance of film will represent a smaller amount of time. Depending on the change of shape of things passing through the slit, this speed has to be adjusted (And the aperture as well). On the paper, it looks like a difficult step but actually, it is quite intuitive. Once you have ended the shot, stop rewinding the film and release the shutter button.

10. I like to have a gap between frames so after every shot I rewind a little bit of film without the shutter pressed.

11. Once you are done, disassemble the "rewind crank" and the camera from the tripod. You can leave the "Film rewind button holder" installed if you want.

12. You will notice that the film is over when you don't have to do any force to rewind the film (It is the same filling that you have when you are rewinding the film in a normal analog camera). Then, you just have to remove the film cartridge and place a new one :)

RESULTS

Here I just attached some of the best shots I did with this technique to show you the results of my project.

I encourage you to try this technique with any other motive you may find interesting. When you start thinking about how this method can represent things from such a particular point of view, you realize that the possibilities are endless. I think this is a technique with a lot of potential.