Tiffen Hot Mirror?

[Stina3246]

I have a bunch of old screw on filters left over from the film days and was wondering what this one actually does? It screws right onto my 18-55 lens but I don't know what it's supposed to do.
It's a Tiffen Standard 52mm Hot Mirror. It appears to have a pink tint to it but the picturers don't look any different with it on from what I can tell.

[zona5101]

Let me google that for you

[LeeR]

Unless I am mistaken a hot mirror filter blocks Infra Red light. Your camera already has one immediately in front of the CMOS so, yes, adding another would have no noticeable effect. If, on the other hand, you had a camera altered for IR shooting, you would need the hot mirror when you wanted to shoot 'normal.'

[Stina3246]

Originally Posted by LeeR

Unless I am mistaken a hot mirror filter blocks Infra Red light. Your camera already has one immediately in front of the CMOS so, yes, adding another would have no noticeable effect. If, on the other hand, you had a camera altered for IR shooting, you would need the hot mirror when you wanted to shoot 'normal.'

Ah....that's interesting. I wonder why I had one in the first place.

[OsmosisStudios]

Film used to be susceptible to IR (and UV, hence UV blocking filters). Sensors have these filters built in.