Making a weeeery, weeeery small hole

[xwhatsit]

Wei wei,

I'm playing around with pin-hole cameras and fun stuff like that. Anyway, there's a mathematical equation to what is the best size of pinhole to use for a certain distance from film to hole. For my chosen 8cm focal length, it works out that for the best quality, I really need a hole just a shade under 0.4mm. A poke with a needle really doesn't cut it (unless you're Disco Dan's shag -- or so he hopes ;)).

So, what's the best way to punch a 0.4mm hole into a piece of thin aluminium (paint can if you must know)? Preferably without burrs, and remaining as close to perfectly circular as you can get.

[Gremlin]

nail?

grr fucken blah

[Sam I Am]

hey i know just a little about this the main trick is use the thinnest metal you can aluminum foil is thicker than you need i think they may even use gold leaf?

you can buy the perfect thing ..just the hole in metal on the web some were ? maybe ebay ( sort of out of sprit of making a camera )

yes just tape your thin metal ( with pre punched hole ) over a larger hole in your box/tin

and yes its a tiny hole

but i didn't think distance of lens had anything to do with it just the smaler the hole the more depth of field you get and longer exposures

best of luck

oh also if you want large pinhole prints wheelie bins make wicked portable pinhole cameras

[xwhatsit]

Well ideally you tailor the size of the hole to how far away the film/paper is from the aperture. The image has more resolution/definition if you get the size of the hole right. Pinhole lenses by their very nature have infinite depth of field (apart from super-close objects), so that's not an issue -- but if you use a much too big size hole for the distance between film and lens, you get a blurry image without definition (everything's blurry, nothing's in focus). On the other hand if the hole is much too small for the distance you chose, I believe the image will be very dark and equate to a huge f-stop, meaning you'll have to leave it to expose for a few hours if it's cloudy.

I'll look around for this pre-punched stuff.

I'd like to make the hole myself, directly in the pain tin though, mainly for robustness and simplicity. If possible.

[Steam]

... in the pain tin ...
A pain tin... is that the same as a can of whoop-arse? I'll have a gross please.

[BMW]

use tin fool and pope that hole using a grade of wire.

[twinkle]

So, what's the best way to punch a 0.4mm hole into a piece of thin aluminium (paint can if you must know)? Preferably without burrs, and remaining as close to perfectly circular as you can get.

Ring a model shop, they have stupidly small drill bits for exactly this sort of thing :done: I needed one to drill the brake disks in my model Ducati.

[The Stranger]

Wei wei,

I'm playing around with pin-hole cameras and fun stuff like that. Anyway, there's a mathematical equation to what is the best size of pinhole to use for a certain distance from film to hole. For my chosen 8cm focal length, it works out that for the best quality, I really need a hole just a shade under 0.4mm. A poke with a needle really doesn't cut it (unless you're Disco Dan's shag -- or so he hopes ;)).

So, what's the best way to punch a 0.4mm hole into a piece of thin aluminium (paint can if you must know)? Preferably without burrs, and remaining as close to perfectly circular as you can get.

I used to purchase jet drills in .05mm increments from an engineers supplier at the bottom of Nelson St in the central city. Not sure if they are still there, however I am sure that some engineers supplies outfits will have these available.

[Donor]

Ring a model shop, they have stupidly small drill bits for exactly this sort of thing

Errr... what they said! :niceone:

[Bass]

The commonest way of drilling REALLY small holes uses a spark eroder. You just need some fine enough wire and some money - less than 0.1mm is possible. If you are really keen, PM me. I can refer you to people who can do this kind of stuff

[vifferman]

Wei wei,

I'm playing around with pin-hole cameras and fun stuff like that. Anyway, there's a mathematical equation to what is the best size of pinhole to use for a certain distance from film to hole. For my chosen 8cm focal length, it works out that for the best quality, I really need a hole just a shade under 0.4mm. A poke with a needle really doesn't cut it (unless you're Disco Dan's shag -- or so he hopes ;)).

So, what's the best way to punch a 0.4mm hole into a piece of thin aluminium (paint can if you must know)? Preferably without burrs, and remaining as close to perfectly circular as you can get.
It's a pin-hole camera - use a pin, or it won't be authentic.

[Usarka]

bloody perverts!

make sure you post the footage :whistle:

[bungbung]

Dome out a piece of aluminium using a rounded off punch, then sand back the dome using wet and dry until you break through enough to make a hole of the correct size. This will give a hole with nice sharp edges, but easy to handle.

[xwhatsit]

I'm liking these miniature drill bits! I just better purchase about three of them, otherwise *snap* (didn't I do that at one of Justin's workshop nights?).

@bungbung, how do I know when the hole is big enough?

[bungbung]

Print a 0.4mm sized dot on a laser printer, use a 0.5mm mechanical pencil as a guide, 0.3/0.25 drafting pen. Steel rule with 0.5mm grads. What else do you have around home?

[bungbung]

A combination of drill bit and the doming/thinning operation would be the best of both ideas. Dome it, drill it, thin it. Don't forget the matte black interior.

[Steam]

How about... drill a small hole in a can, then put a small pencil lead in it, then paint around the 0.5mm mechanical pencil lead, then remove the lead once the paint is dry. You should have a nice 0.5mm hole. But that's too big. What else is less than .5? Can you get pencil leads thinner than that? A needle! Use a needle and paint around that.

[hospitalfood]

the thickness of the can will affect the shot, not a lot of point in being fussy with hole size without being fussy about sheet thickness, the thiner the better as the light will reverse faster and cleaner ( i know this sounds strange but i am a photographer by day and i know strange stuff like this )
I would put a big hole in the can , maybe 10mm, then tape the foil over that hole.
for an experement you could use something thick and something thin with the same hole size an see the difference.

cheers

[xwhatsit]

Ahh... didn't think about sheet thickness either. That could be a tricky one.

That's another reason why the doming/punching method might work a little better. Oh well, just more things to experiment and play with, it's not like paint cans are expensive. Bloody suitable photographic paper is though -.-''

I'm not going to paint the interior black; part of the reason for using a paint tin in the first place is the interest in the distortion produced. The photographic paper will be mounted on a curve (putting the hole in the side of the tin), giving barrel distortion, and I've seen some interesting effects with unpainted mint tins. If it looks like arse (just heaps of stray light) then I'll paint it matte black.

[bungbung]

Painting the interior black is going to minimise fogging from stray light bouncing about. If you want the sharpest image then a bit of black paint is going to help.

[xwhatsit]

Here's a shot using a similar design to what I want to build.

[Manxman]

bloody perverts!

make sure you post the footage :whistle:

^ ...like he said. I can't believe that it took 12 posts to query his motive;).

Does this mean that:
1) there are 11 pervs :dodge:, or just
2) 11 'innocent' engineer-types trying to be helpful:whistle:; or
3) the above options are one and the same...:clap: :eek5:

[Ocean1]

Most engineering supply shops will have small drills, ask them about pin chucks while you're there. They're just a tiny chuck on the end of a small knurled spindle, you just use your fingers.

Clamp a piece of brass, 'bout 18 or 22swg (0.7 - 0.9mm) nice and snug against both sides of the paint tin and drill away. The brass cuts easily and cleanly and supports the drill as it enters the tin. It also helps prevent break-through burrs on the exit side.

Take your time, when you're through remove the brass bits and clean up the faces of the tin around the hole with wet & dry, p'raps 800. Nice clean crisp hole.

[xwhatsit]

Thanks for the advice, guys. Sometimes I wish I had attended the sort of school that has metal-work/wood-work sort of classes, I'm missing a complete set of skills in life (it's only been since I got a bike that I've acquired a set of ring spanners, for instance).

For the people making `pervert' comments -- you'd be pretty silly to build a spy-cam to snap nudey shots out of a pinhole camera :lol: Perhaps you're confused with a camera the size of a pinhole?

[Steam]

How about this for a nice pinhole camera, from artist Wayne Martin Belger (http://www.boyofblue.com/cameras.html)

http://www.boyofblue.com/cameras/3rd_eye/3rd_eye-front.jpg

http://www.boyofblue.com/cameras/3rd_eye/3rd_eye-side.jpg

or this http://www.boyofblue.com/cameras/hiv/hiv_left.jpg

[Pixie]

I'm liking these miniature drill bits! I just better purchase about three of them, otherwise *snap* (didn't I do that at one of Justin's workshop nights?).

@bungbung, how do I know when the hole is big enough?

Drilling small holes without breaking the bit is best done with a rotary tool like a Dremel.
Cheap versions are available from the warehouse

[bungbung]

Dremel or pin vice

http://www.simrantools.com/jeweller_watchmaker/pin_vices.html

[deanohit]

Yea, dremels are a very handy tool. I got a proper Dremel which cost over $250 5 years back for engraving, one of the cheapies from the warehouse would do though. They're great for so many small jobs. Just think of the savings from not having to go to the dentist for fillings!

[Artifice]

you could just put a sheet or two of paper between the tinfoil and a stainless bench, Then just push the needle tip through the tin, you should be able to calibrate the size of the hole by the number of sheets of paper underneath the tin when you push the needle or pin into it.