Help Building Pinhole Camera

[u/todo_code]

Hello,

I'm trying to build a pinhole camera that is easy to operate with my 4 year old. He really likes taking photos. We have a kids digital camera, and one that prints using heat paper (all black and white). I thought he would enjoy making one as a project

Does anyone have experience building one? I'm not sure how small a box i can get. I'm going to take a trip to Office Depot and UPS. But my main question is does the film width/height impact the F-Stop?

Basically I will have f-length probably something like 4-8 inches depending what is available and then the diameter of a pin. However, there might be a lot of empty space along the back wall where the film medium is. I'm going to run a regular film cartridge through on each end so I can do the trick where one film cartridge can roll the each other in and out.

So my question is if a 4-8 inch deep camera is too large, along with the back wall being much larger than the film frame is a problem?

[u/teqogan]

We built a two sided, balsa wood one in college but used photo paper as the film and then made a contact print. It was kind of normal on one side and wide angle on the other so the divider was 1/3 of the way from one end and 2/3 from the other. We used pins with ball tops to mark the sight lines on the outside of the camera so you would line up the pins based on your film size.

[u/metaviewROC]

For that age, put a body cap with a hole in the center, and a piece of metal with the pinhole, onto a film camera, auto meter P, DSLR, motor drive. 36-exposures without a trip to the dark room.

Your child can have a great time, shooting nature and architecture, and even people shots.

I did this in college photo school with a Nikkormat EL-W, while everybody else was using oatmeal boxes and cut sheet film. I made a series of nudes, printed and hung a show, and sold all but one (my favorite, which I still own).

[u/Aeri73]

why use a pinhole camera?

the kids is too young to understand the difference or appreciate it, and the long exporure times means it won't be able to actually hold the camera as it's making them... why make it soo hard?

give the kid an old compact... save the technical stuff for when he/she is old enough to understand and appreciate?

[u/SandpaperTeddyBear]

But my main question is does the film width/height impact the F-Stop?

The technical answer is yes, but the practical answer is no.

Mightn’t it be more fun for your kid if you made a room into a camera obscura? It’s the same idea, but more real-feeling.

[u/Dragon-Teeth]

Ok, pinhole cameras are great. Just about any box can be turned into a pinhole camera. They don't really "focus" the way that you may be thinking of, and exposure is very much a question of try it and see, it's not exactly precision engineering.

A good way into it is to look at the light spots and shadows cast by a bush or tree in the sun. Especially during an eclipse when it's really clear that the bright spots are the same shape as the sun.

You can do a similar demonstration with a colander or just about anything with holes, but be careful not to look directly at the sun with a naked eye. You knew that already didn't you.

This shows how light rays travel in straight lines, and opens the way to explain how a pinhole camera projects many pinhole shaped dots onto the paper, or film.

I'd suggest cutting a moderately large window in your box, and poking the pinhole in a piec6of kitchen foil and then you can glue or tape that piece of foil over the affore mentioned window. Make a few sections of foil and poke a hole in each one, then you can pick the "best", and it's not too critical if you mess up a few. I'd also try to set it up so you can have a sheet of tracing paper across the back. This allows the child to see the image projected from the pinhole, and see how all those tiny pinhole shaped dots blend together just like the pixels on the digital camera. I know that's a dramatic oversimplification but it's close enough for most kids to understand.

If you have a "good" pinhole (very small and no tearing or creasing) you'll probably be looking at an exposure of several minutes, it's an exercise in patience for a youngster.

You'll also need to think about how you intend to "develop" the images. Often the pictures are clear enough to view directly as long as you don't use very bright light, and of course the image will degrade overtime if you don't treat it. I have heard of people who have "developed" pictures by leaving the media overnight in orange juice. The chemistry works, kinda, but it's a bit hit and miss, and for a kid who wants to see results that might be a bit much.

You could also consider using the digital camera to photograph the results d preserve them that way. You have some clever options for adjusting the contrast etc then.

You've also got options to talk about different ways people used to take pictures through history.

Another interesting exercise might be to look at "tumeric prints".

[u/Dragon-Teeth → u/Dragon-Teeth]

https://thegraphicsfairy.com/turmeric-sun-printing/

This is a fairly comprehensive description of the "tumeric printing" process. You might even be able to use this technique to make a sensitive paper for your pinhole camera, fix it with baking soda and then take a digital picture to invert it from negative to positive.

[u/ApatheticAbsurdist]

For 35mm film 8 inches is a bit much. That’s like 200mm. People have made them with matchboxes on the very small end.

If possible paint the inside matte black, use a liberal amount of black tape to make sure no light leaks in from the corners and seams.

The size and focal length will be the main control of your f/stop. If you can measure the size of your pin/pinhole you can use this calculator: https://mrpinhole.com/calcpinh.php people who get really serious about pinholes will get thin sheets of brass, paint them black, and then they can pierce a clean hole and control the size of it.