How does a simple little hole work like a lens?

[Jeremy Hughes]

I put a box on my head recently and was intrigued when I saw a small hole in the corner would project an image on the opposite side of the box. It was if the hole was smaller, it would be like a wide angle lens and if it were bigger it would be telephoto. Also, if it were smaller it would be sharper and more focused (but of course a lot darker).

Light's always going in all direction and only with the box on my head I can filter out everything exept for what I saw?

[Curran Giddens]

Did you ever make a pinhole camera in school? I did, but I don't remember any of the science behind it.

[Jeff Kilgroe]

LOL!

OK, I'm laughing... I've got a little pinhole project of my own right now. Maybe I'll share a bit more in a few days. Rather odd, the timing of this post. ;)

[Dominic Jones]

Light's always going in all direction and only with the box on my head I can filter out everything exept for what I saw?

Yup, that's pretty much exactly it! With a lens, glass elements gather the light from various (although obviously fairly close) angles from an object in the scene and focus them onto an imaging plane.

With a pinhole (which is effectively what you've got) all but a very few beams of light from each object can get through to the imaging plane, causing the scene to focus and an image to be projected. That's why the smaller the hole is the sharper the image is. Smaller hole = less bright, deeper (and in the case of a pinhole better) focus. Larger hole = more light, shallower (or likewise, worse) focus. Just like a lens!

[ericyoung]

Wikipedia has a good in depth explanation:
http://en.wikipedia.org/wiki/Pinhole_camera

Blurring is either due to bigger 'circles of confusion' with larger holes and greater pinhole to image plane distance, or diffraction effects with very small pinholes. Pinhole cameras effectively have infinite depth of field as light isn't bent by a lens. They are also 180 degrees angle of view, but the actual useable image angle of view is limited by vignetting by the thickness of the sides of hole the material is punched in. Light rays coming at angles other than 90 degrees to the hole are increasingly shaded by the edges of the hole.

[Hrvoje Simic]

Aren't you talking about "camera obscura" ?

[Dominic Jones]

Yes, pretty much... A camera obscura is a version which you stand inside - so in this case may be a more accurate desciption - whilst a pinhole camera refers to a device which produces a fixed image, usually on photographic paper.

The concept and physics are identical, however.

Btw, thanks for the much better explanation ericyoung, I tried to simplify it in my post and ended up disclosing far less information in a far more confusing fashion!!!

[J. Bernard Vallon]

I've heard of someone making a pinhole camera in winter, placing a single drop of water in the pinhole, wait for it to freeze, and use it like a lens.

According to the legend, the image is RIDICULOUSLY sharp.

I should call mythbusters....

[Jeff Kilgroe]

I've heard of someone making a pinhole camera in winter, placing a single drop of water in the pinhole, wait for it to freeze, and use it like a lens.

According to the legend, the image is RIDICULOUSLY sharp.

I should call mythbusters....

Hmmm... Doubtful. I might try it though. Our cold weather is gone, but I've got extra room in the freezer. I don't see how it would work given that water expands and traps air as it freezes, more so in a slower freeze than a fast one. Also tends to crystalize unless flash-frozen. I suppose I could dial-down the freezer and place the pinhole camera in there for a few hours. Open up the freezer and apply a very tiny drop of water to the pinhole and hope it freezes quick. Then I would have to load it with film and try to take a picture right there before anything melts.

Call me crazy, but I seriously may try it. :nerd:

[Dominic Jones]

The idea is that it will create a meniscus lens. Two potential "mythbusting" comments here:

1) I'm with Jeff - just don't think it will work in practice (but still have a go mate, I'm intrigued to see what happens!).

2) Meniscus lenses aren't actually all that great, and whilst the small "stop" will help with sharpness I don't think you're likely to get an image sharper than a good lens on a good camera. But hey, what do I know?!!

[Jeff Kilgroe]

I don't know if I agree on the meniscus theory. Pinholes are often very small, literally a couple hundredths of an inch at most. I think there's a greater chance of a spherical lens effect, just due to water's own self attraction and surface tension.

I'm also doubtful that a transparent (enough) droplet could form to create a usable lens. Unless it's flash-frozen in some way or we freeze in a vacuum. Water will still crystalize in a vacuum unless frozen very quickly. In a vacuum or environment with very low air pressure, it would be near impossible to keep the small droplet from evaporating before freezing solid.

Damn I'm geeking out. I need to get some sleep... I'm going to try this though. Like I said, I already have a small pinhole project under way. I need to find a place where I can get color sheet film *AND* the proper chemical process kit for developing. No one in town (that I've found) stocks the chemicals and none of the online vendors will ship due to current hazmat and security restrictions. I can't justify the process of packing up undeveloped sheets and taking them somewhere and it seems I can only find chem cartridges for developer machines in town in stock. I suppose, I could retro-fit a Poloroid compliant film holder into my pinhole rig. Then I could use their instant color sheets.... But I've never used their instant sheets... Anyone know how to "activate" them? Is it like their smaller consumer instant films where the sheets have to pass through the pressurized rollers on the way out of the film holder to open and spread the chemicals? Maybe I just pull the film out in the darkroom and give it a few rolls with a rolling pin. I've got B&W film covered, but I want to give some color shots a try... I can use 8x10 sheets, but 5x7 is better... I think Poloroid only makes 4x5 and 8x10 instant though. 4x5 is too small.

Now I'm rambling...

[J. Bernard Vallon]

People are getting rid of a lot of 4x5 film. I went to my old photography school a while ago and a former profession of mine tried to unload a BOX of the stuff on me. He said kodak, or some scientific organization gave it to him free, and he couldnt get the students to shoot the stuff. Newbs.

[Jeremy Hughes]

Wow I actually never heard of a pinhole camera before. Here I know everything about RED and I don't even know what a pinhole camera is.

[Jeff Kilgroe]

People are getting rid of a lot of 4x5 film. I went to my old photography school a while ago and a former profession of mine tried to unload a BOX of the stuff on me. He said kodak, or some scientific organization gave it to him free, and he couldnt get the students to shoot the stuff. Newbs.

Yep... I've had some people try to give me various film stock and supplies over the past couple years. I've had no use for such things myself until I started this little project last week. Finding the right film and supplies has been a challenge. I don't know which is more annoying... Going to a local shop only to find they no longer sell what I need and/or don't know what it is. Or they do still have some, after I find the right person who knows what I'm asking for, but then he wants to play 20-questions as to why I want it.

[Jeff Kilgroe]

Wow I actually never heard of a pinhole camera before. Here I know everything about RED and I don't even know what a pinhole camera is.

The very first cameras ever made by man were pinhole cameras. Pinhole photography has a huge cult following and is a hobby enjoyed by many. I first got hooked on photography when I was bout 8 years old and my mom signed my brother and I up for a "science camp" at the Denver Museum of Natural History (now the ..."Museum of Nature and Science"). Anyway, it was a multi-day event and one of the days had all us kids making and shooting pinhole cameras. I never did much of anything with pinhole cameras after that, I kept the one I made and played with it off and on for a while after. Anyway, I decided to try something last week and it's working out quite well... Pretty cool really. The biggest challenge of it all has been finding the film to shoot.

[Petr Dvorak]

Camera obscura - invented circa 1000 years ago by Abu Ali Al-Hasan Ibn al-Haitham and also probably used by Vermeer.

Darken completely your room and make pinhole in window area and watch your neighbourhood on opposite wall :)

[chuck colburn]

Jeff,

Polaroid use to offer up a 20x24 camera complete with processor, lenses and technician. I think it was $100.00 a shot.

[Jeff Kilgroe]

...It is rumored that officers in Napoleon's army would use the camera obscura technique from within their tents to monitor their own troops at camp. Supposedly even had magnifying lenses they would hang inside the tent a couple feet in front of the pinhole to invert the light so the pinhole projection would be right-side-up.

[Jeremy Hughes]

Did they ever use it for rotoscoping and tracing images? I would think they would.

[Kenn Christenson]

Did they ever use it for rotoscoping and tracing images? I would think they would.
There's been quite the controversy in the artistic community regarding that very notion - that some of the great masters would "project" their subject onto their canvases. Saw an interesting story about it on 60 minutes a while ago. The argument for the use of the process was very compelling - although, I'm pretty certain they used some form of lens to do the trick.

[Jeff Kilgroe]

Jeff,

Polaroid use to offer up a 20x24 camera complete with processor, lenses and technician. I think it was $100.00 a shot.

I was not aware of that... But I've found some info on it now that I've looked it up. I've also run across some links saying they had an 80x40 format too! Or at least that seems to be the case. I can't seem to find any real info on it though or even direct confirmation that it really existed.

[chuck colburn]

I was not aware of that... But I've found some info on it now that I've looked it up. I've also run across some links saying they had an 80x40 format too! Or at least that seems to be the case. I can't seem to find any real info on it though or even direct confirmation that it really existed.

HOLY FONG!

80x40? Inches? I wanna see the lens!

[Adrian T.]

Polaroid use to offer up a 20x24 camera complete with processor, lenses and technician.

I still have that technician in my closet. :sarcasm:

[Paris Remillard]

For any all digital folks out there who want to try some hot pinhole action, try this:

http://www.calumetphoto.com/item/PY2120.html

There are also other home made how-tos online if you just search "slr pinhole" or "canon pinhole" or similar.

Also, on the subject of the Masters tracing from camera obscura images, I remember watching some news type show recently that was questioning if the Shroud of Turin was actually a primitive photograph made using the same technique. They coated a similarly sized piece of cloth with photo-sensitive materials (sorry, I can't remember what they were) and then placed it on the wall where a camera obscura image of a man was being projected and left it to expose for many hours (the ASA was quite low : )) I don't actually remember what the outcome was. I'm gonna have to go find out now.

Oh, and one more thing. Here's the info on the 20x24 polaroid.

http://www.polaroid.com/studio/20x24/rental/index.html

-or-

http://www.mammothcamera.com/index.html

[Paris Remillard]

These are interesting as well.

http://www.legacyphotoproject.com/index2.php

http://www.fotoart.gr/photography/history/historyphotos/onephotoonestory/thelargestcamera.htm

Check out the lens in the second link.

[chuck colburn]

I still have that technician in my closet. :sarcasm:

Are you waiting for him to come out? chorttle chorttle snarf snork.
Sorry about that, I couldn't help my self.
Do you still have Prince Albert in the can?

[J. Bernard Vallon]

when i first got my fuji s3, i punched a hole in my body cap, made a pinhole, and added a plastic lens out of a disposible camera. i ended up with about an f90 50mm lens, that was sharpest at about 5 inches from the aperture.

these are the images i made
http://www.bigevilmonsterrobot.com/macro/index.html

i tried to make a few extras and sell them on ebay. no takers. that was a few years ago though

[Terry_Lasater]

Here's a complete pinhole camera kit (http://www.freestylephoto.biz/sc_prod.php?cat_id=&pid=6275&sc=23016) for $40.

[Jeff Kilgroe]

$40 for a kit? Yikes.... Actually it's not a bad price considering it includes photo paper and chemicals, trays, etc..

[Hannes Isaksson]

http://shop.lomography.com/paperpinhole/
Super deluxe! :)

[chuck colburn]

Looks like the typical image quality you get out of one of those 35mm lens adapters for home camcorders. Wonder if that was the instant before the end of that Honda car!

[Jeff Kilgroe]

http://shop.lomography.com/paperpinhole/
Super deluxe! :)

Er... Seems like a lot of work to put that thing together. You could build a pinhole camera that takes photos that nice (maybe better) with just a simple cardboard box, a pop can, some tape and about 30 minutes.

I kinda like making them out of paint cans or oatmeal boxes. You get that groovy circular distortion going on. As for sharpness/clarity of the image, the smaller the pinhole, the sharper the image (and longer exposure). I've found the cleanest holes are made from aluminum can material and it works best to drill the hole with the tip of a standard #11 x-acto blade. Trying to poke it with a needle doesn't make a clean hole and it's hard to find a needle that small that you can do a drilling motion with.

I'm really not a pinhole camera nut... I just jumped into a pinhole project about a week ago. The last time I did pinhole cameras, I was a kid.

[Petr Dvorak]

http://shop.lomography.com/paperpinhole/
Super deluxe! :)

Bah they want to squeeze money from everthing.
Here is free layout of our famous pinhole paper camera from times of deep cold war - Dirkon (near translation - Pinkon like Pinhole Nikon) :bleh:

http://pinhole.cz/en/index.php
http://pinhole.cz/en/pinholecameras/dirkon_01.html
http://www.pinhole.cz/downloads/dirkon_en.pdf

http://kweerious.com/projects/itp/notes/design/final-pinhole-photography

Loks like its quite popular around the world
http://images.google.cz/images?hl=cs&q=dirkon&btnG=Hledat+obr%C3%A1zky&gbv=2

enjoy