Timmers Loc: San Antonio Texas.

A bellows? I don't understand what you mean. I've seen bellows cameras made into pinhole cameras, not too often though.

newtoyou Loc: Eastport

Would adjusting the pinhole to sensor or film distance make a difference in focus?
Bill

Timmers Loc: San Antonio Texas.

Bill, one of the things about pinhole images and cameras is that the image is 'always in focus'. Changing the distance of the pinhole from the sensitive surface can and will effect the images sharpness. The ideal sharpness (making it look more in focus) has several factors, mostly the size of the pinhole and the perfection of the hole that makes the pinhole.

One of the biggest factors in all of the practical side of this is to not have a spur left behind as you make the pinhole. Most makers of pinholes use extremely thin shim brass, then they sand the rear of the hole with extremely fine emery paper. You can get all of this at a hobby shop (Michel's, Hobby Lobby).

In the world of practical making of a pinhole to put on a digital camera here is what we did with students at the Southwest School of Art. You can get a body cap for your camera and using a iron for marking leather (plugs into 110 wall outlet) and burn out most of the plastic cover flat area where the name is. If not an iron, you can drill out the majority of the front. Don't be shy, remove as much as you can.

You can cut a toilet paper roll at different heights, but first spray paint the tube with cheap matt black paint, barring that, darken the paper with black ink. Using wood glue, glue to one end a flat blackened card board blank that you have punched a hole in close to the center. You can use a 1/4 inch hole punch, shape and size does not really matter.

Tape a tube length to the camera body cap that has your flat front glued to it, tis is your pinhole lens mount. Make different heights of these from only 1/4 inch deep to 1 inch deep. Better to make several to try out to see which one you like the results from.

Get out the roll of aluminum foil and using one layer you will make a single hole in the aluminum foil. This you will tape (any tape will do) the pinhole over the hole in the cardboard flat of your lens holder.

Making the pinhole, here is where the 'art' of craftsmanship happens. Get a soft quantity of news paper, DO NOT FOLD it, just cut a dozen to dozen layers and tape these down to a discarded soft cloth, this is the 'bed' to hold the aluminum when you prick the aluminum foil shard.

Cut several pieces of over sized pieces of aluminum foil (the size is so you can handle it easily during the making). Select a NEW number 10 (ten) SHARP needle. On the eye end put some tape to help you hold the needle. You only need the one needle and get a No. 10, it is the best for doing this work.

Hold the needle lightly! Hover over one slip of aluminum, try to stay as close to upright as you can with no fidgeting or shakes (for goodness sake, it's a slip of a piece of aluminum, make a bunch of them!)

Now bring the needle down and prick the aluminum foil. Do this over and over on a new shard of aluminum foil, each will be a pinhole, the more force you use the bigger the hole you will be making. Notice that with each pricking that you will be making different size holes, that is the idea! Make different size holes. I recommend that you give each a number written on the aluminum edge with a fine permanent parker pen.

Now you take this out side in the full sunny view and make some exposures with the camera. Stick to one ISO, say begin with 100 or 1000. KISS!, Keep It Simple Stupid! Then vary your times. Forget the pen and paper. Just look at what happens. You will find something like 4 seconds with number 16 looks good. Set it aside and look at the holes that look about the same size. Now try each of them for four seconds. Do get to detailed. Get it down to three or four of the bests and then start getting into best results/fine tune.

Additional note, tap the trimmed down pinhole with but one piece of tape during the tests. Leave the tap on the pinholes. I recommend electrical tape. When you find the great pinholes you can put tape all around the aluminum but don't get it too close to your pinhole. One layer on the front of the aluminum, later you can put tape on the layer of tape to affix the pinhole to the tube to mount that tube to the body mount. The body mount is singular, the tubes will have one attached pinhole and you change the pinhole held cardboard tube to the body mount.

Finaly, each tube gets a name, snow ball, raffles, sharp!, and so on and each goes into a zip lock bag with air in it so the pinhole lens is protected from crushing and dust. AGAIN KISS, in on the pinhole mount put a note ISO 100 4 seconds, winter). Into a larger zip lock bag goes the body cap, (in its own zip lock bag), and all your new lenses.

Final technical note, it is winter, it will take the longest exposure at sea level, in summer you will get an increase of 3/4 of a stop or ISO increase. At 5,000 foot above sea level you get another 3/4 ISO or f stop increase. If in a big city, you will loose 1/3 stop to pollution!

Have fun!

topcat Loc: Alameda, CA

Very nice

newtoyou Loc: Eastport

I have both editions. I got a price list and autograph in the second Ed.
I will not argue what is or is not art. I will say that I would not be satisfied, or even publish some of his 'art'. Adults taking a photo with a Quaker Oats can camera MAY create art, but I doubt it. That said, it is interesting and has a place. I bought a laser drilled Canon cap pinhole. Ten dollars. I made a few based on caps. Not worth the effort except as an exercise. The commercial ones are sealed and more precise than I could make.
I do see now, how the pinhole is in focus. The only change is the percent of picture on a given area of viewing.
I would like to build an exotic hardwood camera based on Polaroid film and holder. More for the looks than utility. The problem is time. My DSLR cameras take a lot of that. When technology works to your benifit, why be a Luddite?
The pinhole has an area where it stands out, tho. Long exposure in darkness can allow some interesting effects with a strobe and flashes. You can 'stack' images.
Bill

Timmers Loc: San Antonio Texas.

A great friend and collogue of mine just passed away. She worked extensively with pinhole images and Polaroid 665 film when it was still in existence! For her birthday a few years after the demise of Polaroid a friend gave me several cases of 665 film. The shear delight on her face as she discovered the content of that heavy box wrapped present was such a pleasure!

I helped her print six images on mural paper, taller than she was! What a blast it was those three days! The Polaroid 665 film was an amazing film.

A lot of Polaroid products were just amazing. I remember when Eric visited he also got hooked on his Polaroid Pack camera that Melanie and Eric built in the workshop portion of his week with us. An amazing persons both he and his wife.

If you build a Polaroid pinhole use an old derelict Polaroid Pack Camera, Fuji still makes the Pack Size film and the Polaroid Project insists that they will introduce Pack film in the near future. The critical thing for a Polaroid product are the stainless steel rollers in the back of the camera.

larryepage Loc: North Texas area

Mostly adjusting the bellows for P to F (pinhole to film) distance would change image size...effectively changing the focal length of the lens er the camera. Shifts could fine tune the image area without having to reorient the camera. Sharpness would be affected too. As the length is increased, each virtual "dot" would get bigger, reducing sharpness.

Bipod

The recommendations for optimum pinhole size all take projection distance into account. Therefore, that
does not account for the differences in the recommendations, which vary by at least 35%:
https://photo.stackexchange.com/questions/46489/how-to-calculate-the-optimal-pinhole-size

Pinhole's extreme depth-of-field means that most subjects are at or beyond the pinhole's hyperfocal distance.
Therefore, differences. in distance to the object cannot account for the different recommendations.

Lord Rayleigh declared that Josef Petzval's theory "can hardly be regarded as sound" ("On Pinhole Photography", 1891)
and his recommended optimal pinhole is larger than Petzval's and even larger than George Airy's. But both give a
sharper image than Rayleigh's. Contemporary recommendations cover an even wider ground. This is a real
disagreement between experts and should not be dismissed without further investigation.

While it important that a pinhole be round, there is no reason for extreme precision. And mechanical machining
can be quite precise. (Take a look inside a Rollex watch.) I use a watchmakers drill to make pinholes, and the
result looks smooth under a 10x binocular microscope.

Zone plates are often produced photographically, by reducing a larger image, then printing a transparency.
The same method can be used to create pinholes.

NASA does not use pinholes to take photographs in visible light--nobody does except photographers.
Pinholes (and zone plates) are used in scientific instruments to image with wavelengths that are too
short for lenses: X-rays and even gamma rays.

Lasers are "high tech", but don't necessarily punch a smooth hole. The shape of a laser beam depends on
how it is produced. They are not naturally round with a smooth edge (as you can verify by shining a
solid state laser, such as a laser pointer, onto a wall--it produces a very messy pattern). Lasers of all
times have to passed though an aperture to become round and smooth -- and that of course produces
diffraction. It is rather difficult to produce a perfectly round, coherent beam with a smooth edge.

If a laser is used to punch a hole in metal, it melts it way though, producing a spawled edge. Commerciaal
pinholes are images on plastic, for the most part.

Eric Renner's book is the best available, but it does not even attempt to settle the question of optimum
pinhole size for objects at infinity. Nor does contain any measurements of the tolerances of pinholes
manufactured by different means. It would be really nice to have something written by an optical engineer
or a physicist. It would be nice to have a mechanical engineer weigh in on the best means of manufacturing
small, smooth holes.

Bipod

Pinhole body caps are available for Canon EF-mount and Nikon F-mount, among others.
However, these cameras are all miniature format ("full-frame") or smaller. As the posted
images show, the best pinhole photos on FF are exceedingly unsharp.

Large format cameras can produce remarkably sharp pinhole images. Ryan Raz, 8 x 10":
http://farm3.static.flickr.com/2346/2066282002_2f2d8b8f5e.jpg

Smaller formats require smaller pinholes. Smaller pinholes produce more diffraction.

Remember, diffraction is based on physical aperture size. The same f-number has a smaller
diameter on a smaller format camera, because the pinhole or lens is located closer to the film
or sensor.

Format loosely determines pinhole-to-film (image projection) distance, which determines
optimum pinhole size (for a given wavelength of light), which determines amount of diffraction,
which limits image resolution
and acutance.

Bipod

A hawk? A handsaw?

Timmers Loc: San Antonio Texas.

Pinhole cameras are one of the interesting parts of the photographic experience. There was a post in the forum about exposure. It was interesting to see all the responses. In mine, which got jumped on by the 'boys' about how full of do-do was just the same ol' same ol'. I still hold that there are two types of posters here, those who make photographs and those who just talk about photography.

I am of course that jack ass who holds that when you are creating meaningful images, one truly needs to KISS (Keep It Simple Stupid!). Doing math is NOT doing photography, at least not for myself. I could give a fig about f stops, they are just those numbers and I could care less about those 'things'.

Now, with that said, there are arts issues that are far more critical than the mechanics of all this distracting side line 'stuff' that is fine by me but has nothing to do with making a practical and especially a creative image.

Zone plates are NOT pinholes, in fact if one understands making creative images they are of little creative potential. I say this because of a deeper understanding of the potential in optics. No, not all the silly optical bench stuff that distracts from a much greater understanding of optics as the potential for a broad range of possibilities for image making.

Yes, I am being obtuse. It is obtuse because so many of those babbling about mechanics, engineering and mechanical parts of the techno side of photography have no large 'picture' of the range that photography has. I am not attacking optical engineering, it is just that real photographers grasp the old Ansel Adams stance that he stated again and again, that he would rather look at a well conceived idea that was fuzzy than have to look at a boring empty image that had all the marks of technical accomplishment.

There is a reason why Henri Cartier-Bresson used a view finder 35mm camera rather than an SLR. He never would have evolved the philosophy of the 'decisive moment' to reflect his notion of making photographs. There are many other photographers who used equipment to create because the gear was in support of their creative vision.

This is crazy Summa at it again. Here is a simple thing to ponder with regards to pinhole cameras but more about optics and photography gear in particular. If one understands optics, I mean truly grasps the notion of optics as image making devices, then this question should be incredibly simple. What is the opposite of a pinhole lens?

Yes it is a trick question and it does have a vary precise solution. It has that infuriating quality that is in Alice in Wonderland where Alice is asked "How is a writing desk like a raven?"

Now, I will be that smart guy know it all that pisses everyone off. You know how I love a good train wreck, this will be the one that gets everyone talking, I hope it gets some people on here to come around to the poetic and creative camp. Pinhole imaging is one of the book ends in photography, so what is the other optical bookend? Hint, zone plates are the poor step child. No, not yet, you don't know what the opposite to a pinhole image is? The answer to that question is a pinspeck image. A what? Find it in the 1974 addition of the publication Scientific American, armature scientist editorial, I believe it was the May addition. Real quick, Pinspeck is pure and simple forms of diffraction and interference imaging. Do not call B&H, they don't have any Pinspeck lens/cameras.

Bipod

"jack ass"
"silly optical bench stuff"
"pinhole lens"
"I could give a fig about f-stops"
"those babbling about mechanics, engineering and mechanical parts"
"Henri Cartier-Bresson used a view finder 35mm camera"

Timmers Loc: San Antonio Texas.

But, you left out pinspeck, the important item!

Bipod

No. Pinholes do not have a focal distance per se--although in some ways they act as if they did!
(It's one of those "dolphins are not fish" things.)

For a given pinhole and format, if you change the pinhole-to-film distance, the biggest change is to
the angle-of-view. A short projection distance can create a very wide angle view. However, you
will have to change to a different diameter pinhole to get the sharpest image.

It's common to talk about a pinhole "focal distance" or "back focus", but this simply refers to the
maximally-sharp pinhole-to-film distance. Light is not being focused. At other distances, there is
no defocus. It's just not optimally sharp.

Lenses have a focal distance because two rays emitted by the same point in an object that follow
different paths and strike the lens at different places, are refracted so that they converge on the
same point in image. That's how the lens forms an image, while "gathering light" to do it.

Pinholes also make an image, but in a different way. A pinhole does not gather light. It simply blocks
all the rays except those passing though a very small aperture. The only way two rays emitted from the
same point can sneak though is if the angle between them is very small. The net effect of all such rays
is the circle-of-confusion that represents that object point.

For objects at infinity, the circle-of-confusion is simply the diameter of the pinhole. Simple!

Finally, pinholes have a hyperfocal distance (just as lenses do): any object from that distance to infinity
will be "acceptably sharp". With lenses, what's "acceptably sharp" is up to the photographer, and
usually depends on the resolution of the film or sensor, or on the viewing distance for the final image,
or some such practical consideration.

With pinholes there is a lot more diffraction, and making the circle-of-confusion (predicted by geometric
optics) smaller than the Airy disk buys you nothing. So as soon the object is far enough away so that the
circle-of-confusion is smaller than the Airy disk, it's always "acceptable". So that's the hyperfocal distance.
If you're willing to tolerate a larger circle-of-confusion, the the hyperforcal distance will be even less.

I perfer to define the hyperfocal distance of the pinhole as the distance for which one would expect an
circle-of-confusion the same size as the Airy disk (the center of the Airy pattern). Everything beyond
this distance is equally sharp (or if you prefer, equally unsharp).

So in practice pinhole cameras are somewhat similar to use to fixed-focus cameras--except that the hyperfocal
distance is much shorter (a few feet to a few inches).

BTW, this is not the way it's explained in most books, because in geometric optics there is a "camera model"
used for explanatory purposes, which excludes infinity. In theory, infinity (collimated rays) is a special case.
But in pinhole practice, most subjects effectively at infinity.

A pinhole has no aberrations or distortion. The only source of unsharpness is diffraction--which is a completely
different animal than defocus. If only there were some distance at which diffraction went away! But that airy
disk extends from the pinhole at a fixed angle, and the only way to reduce that angle is to use a larger pnhole
(which means a bigger circle-of-confusion) or a shorter wavelength of light.

If a blue filter makes the pinhole image sharper, then the pinhole is limited by diffraction (the right size or too small).
If it doesn't then the pinhole is too big.

Timmers Loc: San Antonio Texas.

What a totally bright presentation. I will be perfectly honest, I read what you wrote and it all makes perfect sense. It is all quite correct it appears, and is ever so in the moment as an explanation. You have done a perfectly grand explanation. Even the part were you assert that "Light is not being focused", that also with in the context of your explanation can be useful, but only in the context of that explanation.

For me, stating that a pinhole is a lens has to do with some rather simplistic criteria. "Light is not being focused" is extremely misrepresenting the notion of a lens, any lens. A pinhole lens does the same thing that any and all lenses do, that is, the pinhole inverts the view, switches right left in opposite directions from the scene and alters the position of objects forward and back words.

That is the stuff of optics, but a lens/optic has one more property that all optical system have, it compresses time. But this last quality of an optic is not investigated as yet, so we never speak to such things.