It’s been my experience that I enjoy working with things more when I create them myself. And, for the sake of argument, we’ll say you feel the same way, too. Which is why I can only imaging that you would enjoy photography that much more if you crafted your own gear.
Instructables user bertwert has been looking for an excuse to break out the duct tape and incorporate it into photography in a manner that didn’t result in the Mounties being called. Using a toilet paper roll, some old glass, and a little measuring, he was able to construct a usable homemade camera lens that yielded some hauntingly beautiful results.
- Old lens (from a magnifying glass, broken camera lens, old film/slide projector, etc.)
- An empty oilet paper/paper towel roll
- Duct tape
- Camera mount (he used a telescope adapter to attach it to his camera)
- Tape measure
Now, the key to all of this is making sure that your lens is the proper distance from the sensor. So, here we break out a little math… The Bert offers some insight:
You can do this by standing on the other side of a big room from a point of light, in my case sun shining through a window.
Next measure the distance between the centre of the lens and the image focused on a surface. In my case it was around 120 mm.
Now you need the flange distance of your camera. This wikipedia article can help with that: https://en.wikipedia.org/wiki/Flange_focal_distance. For a Pentax mount it is around 45mm (45.46mm to be exact).
After finding the flange distance, subtract that from the lens focal length to find the distance to put the lens from the camera mount.
Put It All Together
After getting all of your measurements, begin constructing the lens…which basically amounts to wrapping a crap-ton of duct tape around it like you did with that hooker in Vegas.
Make a tube (toilet roll, duct tape, …) the length of the final distance calculated in the last step but if you are attaching it to an adapter make sure it fits and if the adapter lengthens the flange distance, take that into account.
Then, attach the lens using a little (or a lot) more duct tape.
To get a complete list of step-by-step instructions, check out the tutorial on Instructables.