|With IR Cut Filter Without IR Cut Filter|
|Remote Control Using iPhone Selfie Camera|
|IR Cut Filter on a Webcam Lens|
Once the IR cut filter is removed, replace it with a filter that only passes IR radiation. I use a Wratten #87C filter. Edmund Optics sells one for $175. That is expensive but it would be enough to make many near IR cameras. The filter is large enough to be attached over the lens of the camera. This allows pictures to be taken with and without it for comparison. I chose to place it inside the lens housing of the webcam so it is more secure. I can then use an unmodified webcam for comparison pictures. You can find less expensive Wratten 87C filters on eBay for $30-$40.
|Unexposed, Developed Color Film|
|View of My Classroom Through the Material from a 3.5" Floppy Disk|
|Continuous Spectrum Compared to Spectrum After Pass Through IR Cut, Floppy, Color Negative, and Wratten 87C Filters|
A near IR webcam is very useful in the classroom but awkward for taking around town and country. Many people would have difficulty successfully taking apart a webcam AND putting it back together in working condition. I know I did. Another option that overcomes these obstacles is the Sony Nightshot line of cameras. They have a switch that slides the IR cut filter out of the optical path. They also have IR LEDs to illuminate objects so they can be seen in total darkness. I use a Sony MiniDV Handycam DCRHC40 that I purchased new in 2004. There are usually many inexpensive Sony Nightshot cameras for sale on eBay. To convert a Nightshot camera to a near IR camera all you need to do is place an IR pass filter over the lens. Either a Wratten 87C or one made from developed, unexposed color film works well. I made a card stock holder so I can quickly attach and remove the filter to take near IR/visible comparison pictures. I also cover the IR LEDs with electrical tape although they are useful for some applications.
|My Sony Nightshot Camera With IR Pass Filter Installed and Tape Blocking IR LEDs|
|Fabric in Visible Light Same Fabric in Near IR|
I learned how to convert webcams to near-IR cameras by searching for DIY websites and videos online. This post is an amalgamation of what I have learned from this research and from using near IR cameras for many years. Here are a few websites that I found useful: