Archive for January, 2007
Formula for Mounting Your Newly Made Pinhole
by Roger on January 26th, 2007
While browsing through the posts at the F295’s forum. I came across a post by Joe VanCleave, that I found very helpful.
His post was the answer to a question posed regarding the mounting of a Pinhole. The opening “in front” of the pinhole is sometimes overlooked when people start building cameras. That is, until you expose your film/paper and find that you have vignetting around the edges. Unless this hasn’t happened or you haven’t read about it the thought may never occur to you.
So taking the opeing size into consideration, a question comes up. “What should the size of an opening be? Of course you can go really large to be safe, but there must be a way to figure out exactly how much clearance is really needed.
Well thanks to Joe’s post, I have been enlightened. Here it is:
Terminology:
“Projection Distance” = distance from pinhole to center of film
“Film Width” = width of film at its widest point
“Film Height” = height of film at it tallest point
“Front Thickness” = thickness of front of camera (including shutter mechanism) in front of pinhole aperture
Therefore:
Front Opening Width = (Film Width/Projection Distance) x Front Thickness
And:
Front Opening Height = (Film Height/Projection Distance) x Front Thickness
“These results will give you the minimal size opening that will allow the image to not be vignetted at the edge of the film; you may want to add ~10% to the size to ensure that bits of fuzz or wood or cardboard fibers don’t obstruct the view.
This also assumes that the pinhole aperture is centered onto the middle of the film.
I usually make the front opening with the same shape and aspect ratio as the film, rather than just a round hole. This helps to ensure that the corners aren’t vignetted” said Joe.
DSLRs and pinholes made from film: a match made in heaven
by Roger on January 25th, 2007
Earlier in the week I posted an article on making Pinholes and Zoneplates from film. I’m excited to see Photographer Nicolai Grossman run with the process and have some great thoughts about using film pinholes for your DLSR. I encourage you to check out his very informative site.
Creating Perfect Pinholes and Zoneplates Everytime
by Roger on January 20th, 2007
When I first began shooting Zoneplate images, I instantly became interested in creating my own Zoneplates with a variety 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.
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 “film” 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.
Creating a Zoneplate and Pinhole Apertures
What You’ll Need
Computer with “Vector” based software, such as Adobe Illustrator
This Link to a great Zoneplate Calculator
This Link to a Pinhole Calculator
A shop to with an imagesetter to output your digital file to film
The Zoneplate
At Whiz Kid’s site you can learn all about the in’s and out’s 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 8.5×11 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
Figure (A)
Figure (B)
The Pinhole
There are quite a few calculators to determine pinhole diameters. Here are a couple links for you to experiment with.
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 8.5×11 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
Now from the size of the Pinhole or Zoneplate you just created, you can see how much space is left on your 8.5×11 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” capabilities. A sheet of film at 8.5×11 should not cost more than $15, if it does, shop around.
Ask them for a high resolution Film Positive, Right Reading Emulsion Side Down, output at 100% and the final document size to be 8.5×11.
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 razorblade 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.
DIY Shutter Release for your Canon DSLR
by Roger on January 15th, 2007
Here is a very simple diagram for a DIY Shutter Release for your Canon DSLR. See Chris’s Link in the comments section for Pentax instructions.
What you’ll need.
(1) One - 3/32” Stereo Audio Plug (MUST BE STEREO, NOT MONO)
(2) One – Small Toggle Switch
(3) Two – Momentary Switches (SET TO OPEN)
(4) Wire – Small Gauge Insulated wire w/ at least 3 insulated wires within the main outer insulation. (I used 20’ basic telephone wire and only used 3 of the 4 wires in it.) (length depends on how long you would like your shutter release to reach.)
(5) Wire – Small gauge scrap wire, for wiring switches
(6) One – Project housing or Something to mount your switches on
Wiring
The long end that comes out of the bottom of the Audio Plug is where your ground wire (black) needs to be soldered. This wire will go to each of your switches as shown in my diagram.
The audio plug will have 2 small areas for your last 2 wires. The area nearest the plug, is the area where the Auto Focus wire (green) will need to be soldered. The other end will go to one of your Momentary switches.
Next the small area next to the ground tab and below the auto focus area is where you’ll solder the Shutter Release wire (red). This wire will go to both the Toggle switch (blub lock/release) and also the last momentary switch(single release).
Lastly, attach all your switches to a small project housing and you are finished.
It is a pretty simple project and shouldn’t take more than 30 minutes from start to finish. I think I have about 8 bucks wrapped up in mine and it works like a dream.
Latest Camera Build (16×20 Pinhole)
by Roger on January 11th, 2007
I’ve recently finished the build on my latest camera. Before I started, I knew I wanted a camera that will shoot large images for wall display. Well, this “is” a large camera. The beast measures out to be approx 26×24x8. This set up is to shoot a super-wide 16×20 image at around f/335. I will primarily be shooting w/ paper negatives vs. film (because of cost). It is mostly made out of pine (inner frame) and 5mm floor paneling. Below are the basics that went into building this camera. If you are interested in building a camera of your own and you would like to see larger photos you can find them on my flickr page. A great resource to for camera building is F295, these guys are a great help. Hopefully I’ll have some test shots to post soon.
