Making a Pinhole lens for a Canon Rebel XT
By Ryan Raz, July 2005
Depth of Field - Infinite
Equivalent focal length - 50mm
Resolution - very poor!
Speed - slower then you can imagine.
Cost - cheapest Canon lens (the main component is a Canon part)
Making the Pinhole Lens
- Canon camera body cap. Canon caps because they
have a thread are claimed to be light tight. I brought an used
cap, so technically this is a used Canon lens. Test out the light
tightness of the cap by placing it on the camera body and exposing a
shot directly into the sun for 5 seconds or so. The exposure should be
completely dark. This test is good for other models and makes of
- Quality aluminum foil
- Plastic film with self adhesive backing. I used the clear
3m film that they apply to the front of automobiles to prevent
rocks from chipping the paint.
- Hollow tip 32 gage needle. I used a new insulin pen needle.
- Sharp craft knife or razor blade
- Cutting board as a work surface
- Small piece of dense stiff foam such as styrofoam
- 3/16" drill
- Drill a 3/16" hole in the inside center of the cap. Use a
piece of wood as a backing so that the hole will be fairly round.
Use the knife to clean and deburr the edge of the hole.
- Cut a donut shaped piece of plastic film 3/4" OD. - 3/16" ID.
a 1/2" disc out of the aluminum foil.
the foil by
placing on a hard flat surface and rubbing the foil with a
piece of cork (drink the wine first). Be careful not to
damage the foil.
- Place the 1/2" foil disc on the backside of the cap, centered over the 3/16" hole.
- Remove the backing to expose the adhesive on the plastic film donut.
- Place the film donut sticky-side down centered over the foil, use
your fingers or the knife edge to seal the foil between the film and
the cap. Make sure the foil is flat and sealed around the complete
circumference. Note there should be only foil covering the center of
- Place a the cap face up with the bottom of the cap and the foil supported by a small piece of dense stiff foam.
- Very carefully puncture the center of the foil with
the 32 gage needle. The motion of the needle should be straight up and
down., any sideways motion or too deep of a penetration will distort
- Have fun!
Alternative Way to Make the Pinhole
Before the foil is installed in the cap just after step 4:
- Once again the foil must be supported by some dense stiff foam such as styrofoam
- Make the pinhole as in step 9
- Repeat step 4 the foil flattening step
- Inspect the hole to make sure the edges have not been pushed back into hole by the flattening of the foil
- Install the foil as before
Using this method allows you to practice making pinholes and also
allows you to inspect the hole before installation. Note that the
needle can only be used a few times before it will get dull and has to
Each different pinhole will have its own unique qualities, ideally the
pinhole should be perfectly round, perfectly flat and as thin as
possible. This is impossible without buying a manufactured hole (yes
you can buy a hole) . Unfortunately my microscope is on loan
so I can not actually inspect the pinhole except by holding it up to a
light bulb. Hopefully I will update the page with actual hole details
when I get the microscope back.
- I originally used plastic tape instead of the film. But it
took a couple of trys to get a good (nearly centered) pinhole, I
found it was very difficult to remove the gummy residue from the tape
backing, I tried soap and water but that did not work. I tried a cleaning
fluid but as you can see in the pictures it attacked the plastic
cap and messed up the finish. The plastic film has an adhesive that stays with the film even
after you remove the film from the cap, this makes replacing the pinhole an
- Dimensions except for the pinhole are approximate.
- Many of the pictures have some contrast lose, some even
have a rainbow effect.
This could be caused by light leakage, a
ragged irregular pinhole edge or most likely from the large
amount of light that comes through pinhole outside the FOV (field of
view) of camera sensor. This light is reflected and diffused onto the
sensor. If I shield the lens from off angle light the effect goes
away see below for a partial solution..
low resolution of the lens is mostly related to physics. The pinhole is
around 0.3 - 0.4mm diameter and a pixel on the camera sensor is many
times smaller. The only way to get higher resolution would be to have
the camera sensor area much larger, lets say as large as a
large format camera. No way on a proconsumer camera! There is also both a diffraction limit and equivalent F stop light limitation on the minimum pinhole size.
a lense hood I brought an inexpensive rubber hood and glued it on with
Gloop. The hood allows about a 90° field of view which is
still too wide for the pinhole lens.