Hi! I have made pinhole cameras with my high school photography class. We are using oatmeal containers and photo paper for the "film". We have painted them black used black tape on lid, and used a thumbtack for the pinhole. We are getting mixed results. Is it better to be in the sun or shade? So far around 4-5 seconds has been the best time.
Pinhole Camera Mixed Results
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It would help to provide help if you would show examples of "mixed results". IMO the quality of the pinhole plays a big role, and one made with a thumbtack is unlikely to be optimum. Then again, this is a totally blind comment.
Hi! By "mixed" I mean sometimes it works & sometimes, we get a totally overexposed image. Some of them have gone down to a 1 second exposure.
The hole may be to big, use a needle. Also did you make the pinhole in the cardboard of the oatmeal box or something else? I use very thing brass "shim stock" from a auto parts store.
I use soda can metal.
If you're looking for more consistent results, maybe try getting some laser drilled pinholes with a known diameter? If you have a bit of budget, fireseller66 on ebay sells some for less than $5. Then you can calculate the f-stop and other exposure variables. Mr. Pinhole has a nice calculator online. Justin Quinnell also has some good DIY pinhole projects, including how to make a solargraph.
Easiest and cheapest way to ensure quality pinholes is to scan them on a flatbed after to ensure consistent sizing and roundness. You can go cheap and use soda can metal and just discard the poor ones.
to me, what you are explaining is part of the pinhole charge. what is your desired result?
Not sure what oatmeal containers you are using. I just pulled a "quaker oats" cardboard can out of the kitchen cupboard and it is 5 inches in diameter. For a can that size, I'd expect the basic exposure in full sun ( EV 15 @ISO100 ) to be something like 20 to 30 seconds for the paper I often use: pre-flashed Adorama house brand paper. Without pre-flashing, it's not quite twice as slow, so something close to 45 seconds or a minute. If you're getting exposures much shorter than that, the pinhole is probably too big. ( But that doesn't mean it's not worth trying to see what you get... as long as the exposures are long enough that you can control them! )
Ilford MV IV paper is a little slower, maybe add 1/2 or 2/3 of a stop. Without pre-flashing and/or yellow filters, in bright sunlight, paper negatives can have pretty harsh contrast, which can be good or bad depending on the subject. Overcast days, cloudy days, early morning and late afternoon sun can be good... a low angle sun will fool a light meter, I think it's better just to add an extra stop of exposure if the sun's getting low, and an extra 2 if it's nearly sunset.
I disagree about the importance of having a perfect pinhole in razor-thin material. For me part of the charm and fun of pinhole photography is keeping it simple and being amazed that you can make a photograph at all with light going directly though a little hole and directly onto the photo paper. If the pinhole is not a perfect circle, what will happen is that there will be a little more resolution in one direction or the other ( e.g. vertical or horizontal ) at the center of your image, and it will fall off differently in different directions on the image. This can look really cool, and each handmade pinhole has a certain "characteristic look" to the images it makes, maybe there is a tiny burr that reflects some light just so, or maybe the edge is slightly thinner in one place ( and that does affect diffraction ). If you make a bunch of them, over time, some will become your favorites, and you won't be able to reproduce "why" they are your favorites, but that's part of the fun. I think it's more fun to just make the pinhole - don't worry about it much or fuss around with it-- just check that it's "in the ballpark". +/- 10 or 15% is perfectly fine, and you can tell that by holding it next to a mm-marked ruler and looking through a simple magnifying glass... and once you've made a few ( or a few dozen
you'll be able to judge the size just by looking at it with your eyes. I think the pinhole should be judged by whether you like the images it makes, not by anything else, and I don't think any of my favorites are necessarily the ones that are more perfect.
For example, if your pinhole calculation says you need a pinhole that is 0.23 mm, then choose one that looks like it's between .20 and .25 mm. Or even between .2 and .3. They'll all make images and they'll all be just fine for what you're doing.
I'm probably going to make another pinhole camera this weekend. It's going to have 3 or 4 pinholes, and I'm sure what I'll do is take a piece of soda can metal, some 600 grit emery paper, and a needle.. and I'll probably make 6 or 7 pinholes and then cut out the 3 or 4 that look similar to each other and about the right diameter. And if they are a little different from each other, it will make my results distinctive and I'll be happy.
By the way your photopaper, even if it is VC, will be mostly sensitive to blue and UV light. If you use one of the formulas to get an idea of the right pinhole size, choose a wavelength like 480 or 490 nm. I usually use a constant quite a bit lower than Rayleigh's 1.9. I usually use 1.65 or 1.6 or sometimes 1.55 ( I tend to err on the side of a smaller pinhole, for a few reasons that are too much to go into here.... )
TLDR: I agree, use a needle for a smaller pinhole and have fun with you pinhole cameras! Don't forget you can slap the negative onto a fresh sheet of photopaper and make a contact print, that's part of the fun too.
Ilford MV IV paper is a little slower, maybe add 1/2 or 2/3 of a stop. Without pre-flashing and/or yellow filters, in bright sunlight, paper negatives can have pretty harsh contrast, which can be good or bad depending on the subject. Overcast days, cloudy days, early morning and late afternoon sun can be good... a low angle sun will fool a light meter, I think it's better just to add an extra stop of exposure if the sun's getting low, and an extra 2 if it's nearly sunset.
I disagree about the importance of having a perfect pinhole in razor-thin material. For me part of the charm and fun of pinhole photography is keeping it simple and being amazed that you can make a photograph at all with light going directly though a little hole and directly onto the photo paper. If the pinhole is not a perfect circle, what will happen is that there will be a little more resolution in one direction or the other ( e.g. vertical or horizontal ) at the center of your image, and it will fall off differently in different directions on the image. This can look really cool, and each handmade pinhole has a certain "characteristic look" to the images it makes, maybe there is a tiny burr that reflects some light just so, or maybe the edge is slightly thinner in one place ( and that does affect diffraction ). If you make a bunch of them, over time, some will become your favorites, and you won't be able to reproduce "why" they are your favorites, but that's part of the fun. I think it's more fun to just make the pinhole - don't worry about it much or fuss around with it-- just check that it's "in the ballpark". +/- 10 or 15% is perfectly fine, and you can tell that by holding it next to a mm-marked ruler and looking through a simple magnifying glass... and once you've made a few ( or a few dozen
you'll be able to judge the size just by looking at it with your eyes. I think the pinhole should be judged by whether you like the images it makes, not by anything else, and I don't think any of my favorites are necessarily the ones that are more perfect.For example, if your pinhole calculation says you need a pinhole that is 0.23 mm, then choose one that looks like it's between .20 and .25 mm. Or even between .2 and .3. They'll all make images and they'll all be just fine for what you're doing.
I'm probably going to make another pinhole camera this weekend. It's going to have 3 or 4 pinholes, and I'm sure what I'll do is take a piece of soda can metal, some 600 grit emery paper, and a needle.. and I'll probably make 6 or 7 pinholes and then cut out the 3 or 4 that look similar to each other and about the right diameter. And if they are a little different from each other, it will make my results distinctive and I'll be happy.
By the way your photopaper, even if it is VC, will be mostly sensitive to blue and UV light. If you use one of the formulas to get an idea of the right pinhole size, choose a wavelength like 480 or 490 nm. I usually use a constant quite a bit lower than Rayleigh's 1.9. I usually use 1.65 or 1.6 or sometimes 1.55 ( I tend to err on the side of a smaller pinhole, for a few reasons that are too much to go into here.... )
TLDR: I agree, use a needle for a smaller pinhole and have fun with you pinhole cameras! Don't forget you can slap the negative onto a fresh sheet of photopaper and make a contact print, that's part of the fun too.
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Thank you for the response! I found out Pringles chip cans work perfect!!! So I made a bunch of them for my classes.
MattKing
Moderator
And if you have a bunch of young students, you probably have no trouble getting a supply of empty chip cans!Thank you for the response! I found out Pringles chip cans work perfect!!! So I made a bunch of them for my classes.
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