What You Need to Make Your Own Fisheye Lens
Peephole. You know when you look through the front door? That’s the same fisheye effect that you get with this lens. If you’re lucky, you can cannibalize one from an old door in the garage or some such. Otherwise, this will be the only expense in this DIY project when you make a trip to your local hardware store. Different size peepholes render different fisheye effects, so experiment with them—or maybe create multiple fisheye lenses to give you even more flexibility. Peepholes can differ in build, so you may have to adjust the directions accordingly—nothing technically difficult.
Rear Lens Cap. An old rear lens cap is your best bet, perhaps a throwoff from another photographer friend, or a broken one of your own. Just make sure that it fits your camera!
Drill. You need to be able to drill a hole the size of your peephole, so make sure you have the appropriate bit. The fit should be snug: a size too small is better than a size too large.
Knife/Box Cutter. You may or may not need one of these to adjust the size of the hole made by the drill.
Glue. This can be anything, hot glue, Gorilla glue, anything as long as it’s strong.
How to Make the Fisheye Lens
First, drill a hole in the center of the rear lens cap that is the size of your peephole mount. Be very careful when you do the drilling to have it as centered as possible. Clamping the rear lens cap to your workbench is a good idea. If the hole is not centered and even, the peephole mount may fit crookedly, which will result in a bit of the interior of this fisheye lens to show up in photos.
Test the fit of the peephole: does it fit? Is it centered? If not, then keep drilling until the peephole can be slid in, centered and snug. You might want to use a sharp knife or box cutter to scrape any extra bits of plastic.
Once the peephole mount fits properly with the peephole itself protruding, then remove the peephole mount and apply glue to the tube of the peephole mount and slide it back into the rear lens cap. Make sure that while drying, this setup is placed in a vertical position so the peephole doesn’t slump into a non-centered position. Wipe away any excess glue before it dries.
The rear lens cap should just be able to screw onto the lens mount of your camera, ready to use.
How to Use Your Homemade Fisheye Lens
The same tips apply to this DIY fisheye lens as to lenses you buy in-store. Manual focus is an absolute must, as your in-camera software probably won’t know how to handle the distorting effects of the lens. Experiment with your particular lens to see the best ways to work with it. Depending on how you made the fisheye lens, you may have to crop images slightly if the peephole was placed in crookedly or too far away from the lens.
Check out some photos taken with a peephole fisheye lens.