The Tinhole Camera - Pinhole Photography with a 3D Printer and a Tin Can
In the good old days of photography, that maybe some of you remember you had to choose carefully what you wanted to capture, as depending on your camera and film you had something between 8 (for medium format cameras) and 36 frames on your film roll. And there are reasons for hashtags like #staybrokeshootfilm; film is expensive. Probably today even more than in the past. If we jump back even further in photography history, there has been a thing called "Camera Obscura", which roughly translates into "dark room". Today it is more commonly known as a pinhole camera. In the "Camera Obscura" there has only been a small hole which would project an inverted image. In the early times people would trace the projected image and make a painting, before a permanent medium to capture the image was invented. Well long story short a pinhole camera is probably the easiest way to take pictures (and most likely also the cheapest). There are thousands of different designs, from a match box cameras to one made out of Lego, 3D printed or made from wood you name it. And in this wide variety of awesome designs I want to show you my contribution to the pinhole community: The Tinhole Camera
As the name already suggests, The Tinhole Camera is a pinhole camera made out of a tin can with a little help from m 3D printer. And the final version shoots a full roll of 35mm film. There are already many designs of pinhole cameras made from tin cans, but most of them include drilling into the tin can. And I wanted to make it as easy as possible to build it, so that you just need your 3D printer, a tin can and some film. That is why drilling was not an option. Hence I had to go with the opening that tin cans naturally have after using them. Furthermore I wanted to make the parts easy to print, so no supports allowed (if you are new to 3D printing and you are not familiar with support structures check this link here). To make it a little bit easier for me as a first task the only goal was to shoot a single frame. But do not worry, we will come to the full roll of 35mm in a bit. Pinholes themselves are rather easy to make. I tried some tin foil and pinched it with a needle. For a more sophisticated approach there are several online shops where you can buy laser drilled pinholes in a specific size, which leads to slightly better results in my opinion. Anyhow here are the rules summarized:
No supports while printing
Shoot one frame
Pinhole made out of tin foil with a needle
What do we need for our Tinhole Camera? Well not all too much. We need a:
cover to make the inside of the tin can dark
holder for the film
hole for the pinhole
a shutter for the pinhole
way to load and unload the film frame
The first step for the design of The Tinhole Camera was to figure out how much space I need between the pinhole and the film. And this pretty much depends on the size of the pinhole, which is quite hard to determine when you use tin foil and a needle. If you have calipers it makes sense to measure the tip of the needle and use this as an estimation. If not consider it to be around 0.4mm if you use the needle tip to make the hole. Fortunately it is not too bad, if your pinhole is a bit bigger or smaller after all. If you want to be absolutely sure, get a laser drilled pinhole which in most cases makes the picture slightly sharper. Anyways, I used this formula I found online to determine the pinhole to film distance:
d: pinhole diameter
f: focal length
Luckily the distance was short enough to fit into the tin can. So as a next step I made some experiments with black filament and how thick it needs to be for 100% lightsafety. After some try and error about 8-10 layers seemed to be enough (you can see my experiments in this video). Still as it would be devastating to loose a photo just because there was light leaking into the camera I added some more layers and made the cover about 10mm thick. In the center then I would add a hole for the pinhole. To allow enough light from all directions to enter into the pinhole I beveled the outside. I also added a holder to keep the camera in place, as otherwise it would simply roll away.
So far so good. We have a cover, a pinhole in that cover and know the distance we need to the film. Next step is the holder and this is where it gets tricky. Remember how I said I wanted to shoot a single frame at the beginning to make it easier? Well as the single frame needs to be loaded in complete darkness it is rather complicated to design a holder, that can be loaded safely while not scratching the frame when loading or unloading it. Eventually I came up with a two piece idea, where you would place the frame on the bottom part and clip the top part on. The then loaded frame holder would slide onto the feet of the cover to be in position for shooting. And as all of this is quite difficult to explain with words, maybe take a look here. I recommend getting a changing bag for analog photography as this allows to also insert new frames on the go. Alternatively you can use a darkroom to load your frames prior to your photo tour.
Last but not least we only want the pinhole to be open when we want to take a picture. Hence a shutter for the pinhole is necessary. The least fancy but somehow most effective way to do so is a simple slide cover. To open and close it you hold the camera in place firmly and carefully move the slider to the side.
Developing the frame
Here is it where it gets tricky and which is also why I ultimately switched to a larger tin can and the full 35mm roll: developing the single frame.
If you have a darkroom at home like I do it is easy peasy. You just load the frames you have into the spool like you do with a full roll, develop it and voilà. If you do not have a darkroom for this (or at least a changing bag in which you can load them into the developing tank and go on from there) I have bad news: At least the labs where I live only take full film rolls. So here we stand now at the crossroads: have a camera that is super easy to print and use, but have a hard time developing the frames vs. having a camera that is slightly harder to build (requires some tools) and be able to give the full roll to a laboratory that will take care of the development?
As the first option was already fully functioning and usable I thought (also due to some requests on youtube and reddit): Let's make it possible to shoot a full roll of film with The Tinhole Camera XL
Shooting a full roll of 35mm film
I quickly realized, that the 0th mechanical law would also apply for pinhole cameras in tin cans: if there is already one part in the way, there cannot fit a second one. Or in other words: the tin can I was currently using is too small to hold a 35mm film roll. So I went to the supermarket and bought the largest tin can I could find. Much to my surprise I have to say I will not become a fan of chili con carne out of a tin can. But for science sometimes you have to go through fire and flames if you know what I mean. With the larger sized tin can I figured out it would be possible to fit the film and some mechanics on the sides to move it forward. Luckily some parts from the previous design I was able to keep, like the:
distance from pinhole to frame
and that is basically it. Everything else sooner or later needed a rework. The key component of The Tinhole Camera XL are the gears and knobs, that allow forwarding the film. I was looking at conventional cameras and they had one advantage: The lever or gear that would forward the film was in film axis. For The Tinhole Camera XL that was turned 90°. Which is why I had to use beveled gears. Much to my surprise they were quite easy to print and given that they are made out of PLA or PETG they were quite strong. I really tried a lot to get a print in place solution, but eventually had to give up and find a different way to connect the knobs with the gears. This is when I found female nut threads. They are basically threads you can push or force into any material you would like, to allow a screw to go in. And again fortunately as I found out through some fellow 3D printing enthusiasts it is extremely easy to push those female nut threads into PLA or PETG with a soldering iron. I think this is the moment now where I moved away from the ease of printing and use in favor of the possibility to shoot a full roll of 35mm film.
There was one further issue I could not figure out for a long time: Light reflections on the frame. I was looking for the reason everywhere. I checked every piece for light safety, I printed the cover with 100% infill. Nothing seems to be able to remove the reflections on the images. Until I realized one thing, that was different from the previous model of "The Tinhole Camera". It was screws. The film holder in The Tinhole Camera XL is screwed onto the frame. And when there was light entering the camera it was reflecting on the screws causing light reflection on the film. To block them out I made a cylinder, that would cover all external light to fall onto the film.
The other parts, like the holder for the film, or the empty spool holder were pretty straightforward and I do not want to go into that much detail here on that topic. I recommend my video series about the development of The Tinhole Camera and The Tinhole Camera XL where I explain in detail how the design was made.
Building a pinhole camera is a lot of fun. I am still surprised that a small hole works like a lens and allows to take sharp pictures. And there are a lot of different pinhole cameras that people have designed. Some even for panorama photos. It is incredible how beautiful sometimes the wooden versions look. The pinhole photography and analog photography community in general is generally helpful and most enthusiastic about this topic. Without the help of them, this project would definitely have not been possible. And this is why I also encourage you to build your own pinhole camera. Reddit is a great source for help in this regard. And if you want to print your own Tinhole Camera or Tinhole Camera XL take a look at my Etsy store, where you can find the STL files. If you do not have a 3D printer and would like to purchase an already printed Tinhole Camera XL just send me an email: firstname.lastname@example.org . Below you find some pictures I have taken with The Tinhole Camera and The Tinhole Camera XL.
Thank you very much for reading and have a great day.