PHOTOGRAPHY: Creating Perfect Pinholes and Zoneplates

by RCline

26K606

Intro: PHOTOGRAPHY: Creating Perfect Pinholes and Zoneplates

Zoneplate's and Pinholes are alternative light focusing elements vs. a conventional lens.

When I first began shooting Zoneplate images, I instantly became interested in creating my own Zoneplates with a number of zones and to accommodate a variety of focal lengths. The traditional process of creating Zoneplates, is more work that it needs to be especially if you are concerned w/ the accuracy of your final Zoneplate. Accuracy is also a concern for Pinhole photographers when creating their self-made apertures. You can also use this same process to create pinholes.

Having a background in Graphic arts and the processes involved to create plates (not to be confused w/ Zoneplates) for offset printing presses. I've had plenty of experience in the days before Direct-to-plate technology using a output device called an imagesetter. When creating plates for offset presses accuracy is a must and at the time the imagesetter heeded that call. The imagesetter is still used at many local print shops for both Screen printing and Offset printing.

If you don't know what an imagesetter is check out http://en.wikipedia.org/wiki/Imagesetter.

I'll upload the instructional photos asap, in the meantime, I have all these steps w/ photos here.

STEP 1: What You Will Need!

Creating a Zoneplate and Pinhole Apertures

What You'll Need

Computer with Vector based Illustration software, such as Adobe Illustrator

This Link: Create Zoneplate Design Tool

This Link: Pinhole Size Calculator

STEP 2: THE ZONEPLATE (SKIP THIS STEP IF YOU WANT TO MAKE a PINHOLE INSTEAD)

The Zoneplate

At Whiz Kid's site you can learn all about the ins and outs of Zoneplates. Since the subject is creating them we'll stick to that.

1. Determine the focal length of the camera you would like to use your zone plate on.
2. Use Whiz Kid's Calculator and enter in the information required.
3. Set the output dpi to 9600 in the calculator (this will create an .eps file for you)
4. Download the file
5. Open Illustrator and create an 8.5x11 page. Now open the file you downloaded and bring it into the blank document you just created.
6. If your Zoneplate looks like Figure A, select all and ungroup the selection
7. Deselect the black background and the text at the top and the bottom of the box
8. With only the center images selected, using your align tool, align the image both horizontally and vertically. The zone plate should now look like Figure B.
9. Save your file as an .eps
10. Done

STEP 3: PINHOLE PRODUCTION

The Pinhole

There are quite a few calculators to determine pinhole diameters. Here are a couple links for you to experiment with.

http://www.mrpinhole.com/holesize.phpHere is one of them.

1. Determine the focal length of the camera you would like to use your pinhole on.
2. Use one of the suggested calculators and enter in the information required for the calculator.
3. Open Illustrator and create an 8.5x11 page.
4. When you have the results you can to into Illustrator and draw a black box however large you would like.
5. Now, draw a circle the using the results figured by the Pinhole Calculator
6. Center the Pinhole in the black box.
7. Save your file as an .eps
8. Done

STEP 4: Final Production

Now from the size of the Pinhole or Zoneplate you just created, you can see how much space is left on your 8.5x11 page. Do a variety of Zoneplates with different zones or pinholes experiment with different sizes, shapes or designs till your page is full.

Once you have your files saved you can drop them onto a CD or DVD and take them to a local printer that has film output/imagesetting capabilities. A sheet of film at 8.5x11 should not cost more than $15, if it does, shop around. CALL A LOCAL SCREEN PRINTING SHOP, they should put you in the right direction.

When you give them your file. Ask them for a high resolution Film Positive, Right Reading Emulsion Side Down, output at 100% and the final document size to be 8.5x11.

When you get your Film back it is just like any other film. There is an emulsion side and a carrier side. There are a couple ways to tell which is the emulsion side. The easiest way is to take a razor blade and see if the black will scratch off with very little pressure. If so, that is the emulsion side. The other way is to look at both sides of the film, the emulsion side will be dull and the carrier side will be glossy.

Lastly, when you mount your pinhole or zoneplate to your camera, position the emulsion side towards your paper or film that your are projecting light to.

Now that you have done this process you should have created an ultra-sharp pinhole and a perfect Zoneplate.

If you want more information on mounting your optic. I have some stuff here: http://www.cline-company.com/blog/?p=23

6 Comments

Myself 16 years ago

Some context would be helpful. What is a Zoneplate, why is it capitalized (is it a proper noun?), why would I want to use one, and what are the advantages of making my own over using a store-bought one?

geo 16 years ago

A zone plate is a lens which uses diffraction, rather than refraction, to bend light. Diffraction is the tendency for waves to bend around tight corners, or circular edges in this case. One of the advantages of a zone plate over a lens, is that you don't need a refractive medium (e.g. glass) to bend the light. You just need some opaque stuff and some transparent stuff. Indeed, the transparent stuff can be open space; it doesn't need to be film as in this case. Since you don't need a refractive medium (or even any transparent medium, for that matter), the zone plate is used to focus wavelengths of light which don't easily go through normal glass. Another advantage of the zone plate is that it can be _entirely_ flat. It doesn't need fancy curved surfaces like a lens does. So you can produce it with a lithographic (or in this case, photographic) process, instead of grinding or molding. For this reason, it is used for making incredibly tiny lenses for focusing x-rays, and probably other things. Another way to think about and understand the zone plate is that it is the hologram of an infinitely tiny point source. You already own a device with a zone plate: It is used to focus the light from the laser onto the reflective surface inside a CD or a DVD disc. Also interesting, is the zone plate need not be for light! Any wave which can be diffracted, can be focused using a zone plate. For instance, you can make an acoustic zone plate (to focus sound) out of any acoustic insulator material (plywood, acoustic foam, foam core board, etc). Something to keep in mind when using a zone plate, and RCline didn't discuss this above, is that the focal length of a zone plate is _strongly_ dependent on the wavelength. In particular, the focal length is inversely proportional to wavelength. So, if you want a sharp image from a zone-plate based camera, you should probably pre-filter the light using a colored filter.

CeeJay.dk 16 years ago

Since a zoneplate is highly dependent on the wavelength and we are trying to create a zoneplate with a photographic process can't we make a zoneplate that accounts for different wavelengths, by making several virtual zoneplates for several wavelengths and combine them to make a single zoneplate that would give a sharp image for more than one wavelength ? It's hard to explain , but I hope you understand what I mean. To put it simpler - Don't create a black and white zoneplate - create a multicoloured one. I imagine that the edges of the zoneplate would look like a rainbow if you did this.

RCline 16 years ago

Thank you "Geo". Another reason you may want to produce a zoneplate yourself is thisthis.

Another nice thing about film pinholes & zoneplates are that if you are shooting digital, you don't have to worry about dust making it's way to your sensor.

Ribs 16 years ago

Why would you want to use a zone plate? and what does it have to do with a pinhole camera?