Variable ND filter for Vis/IR

[Nate]

I had purchased a variable ND for video work in the past

 

https://www.amazon.com/Concept-Variable-Neutral-Adjustable-Cleaning/dp/B00JL4INW8?source=ps-sl-shoppingads-lpcontext&ref_=fplfs&psc=1&smid=A3JK7NEF4ES3E9 

 

It was collecting dust until I saw Andrea's adjustable IR filter topic and I decided to test my variable ND with a full spectrum camera.

I think there are probably one's that block IR but this one passes both, but cuts the visible a lot on the max on the dial. 

 

I made a short video clip of this inside at night with ambient light being a non IR emitting bulb, Filter on MIN, WB on grey ptfe tape.

Object is a Playstation media remote that becomes transparent in IR.

Slowly turn the filter to max, and ambient light gets cut quite a bit. Camera picks up a regular incandescent bulb in another room, but not too bright.

I then turn on the 940nm torch to see through the remote.

 

I think this is kinda cool, but probably not much use in sunlight because of all the IR

 

 

 

 

[colinbm]

Good one Nate.
Yes many black plastics are transparent to IR as you have found.
Black garbage bags etc are clear in IR.

[Nate]

Thanks Colin, I found the pen I take notes the ink disappears when I turn dial to max also. I think this setup might have some uses for photos/videos in monochrome as WB needs done for every light source.

[Unscenerie]

This is fascinating

[Andrea B.]

Yes, I loved seeing that remote go transparent in IR!

 

Thanks for an interesting demo, Nate.