DIY hack: reduce infrared hotspot caused by overly focused IR nightvision LEDs

The Before & After picture. Top left triangle shows the infrared hotspot that so many security cameras have - they do this to increase the claimed "nightvision distance" but overexposes the center of the picture and doesn't spread infrared out enough over the scene. Bottom right shows the result of this hack - a nice smooth IR field.
This hotspot effect is REALLY bad if someone is in front of the camera. All the IR light will light up their face like a ghost and you can't make out facial features.

Pretty standard security camera: camera lens in the middle, and IR LEDs around it. You just need to measure the inner diameter and outer diameter of where the LEDs are.

I used Photoshop and the ellipse tool centered on guides. There are probably a million other ways this could be done.

I have two cameras, hence the different shapes. I made an extra donut for each just in case but didn't use the extras.

Print out the tracing guide, trace it with a marker. Use scissors to cut it out - easier then using an exacto blade.

The material is just some spare "privacy window film" I had lying around. It gives glass that frosted look, and was pretty useful in keeping my dog from barking at everything that passed the house.

(If I was smart, I would have traced the side of the material that is discarded for a cleaner look, but it still works great.)

Apply to the glass just like the window film - wet it with a sponge, and just put it in place. Normally with window film you don't want bubbles because it looks bad - but with this I suspect the splotchy bubble pattern helps diffuse the IR even more.