Author Topic: Dummy Question: how relevant is the IR cut-off filter in front of sensor?  (Read 3359 times)

PeterN

  • NG Member
  • *
  • Posts: 1125
The advantage of breaking something in my camera is to pay attention to things I never paid attention to. In this case, the IR cut-off filter in front of the sensor. The repair service removed the broken glass of the IR-filter and we agreed to first test the camera (Olympus PEN-F) before deciding about replacing the entire sensor house (easy to do but quite expensive). I did a quick test (click and check LCD screen) and expected to see less-natural colors but I did not. I always thought that IR light messes up the color separation.

May I ask the more knowledgeable people here (that's basically everyone) how removing the IR cut-off filter influences the image ( color reproduction, resolution, dynamic range, etc.) ? And perhaps also how I could test the impact?

Thank you!
Peter

Birna Rørslett

  • Global Moderator
  • **
  • Posts: 5287
  • A lesser fierce bear of the North
The sensor is many times more sensitive to IR than visible light. Thus you will note blacks becoming reddish and for "full-spectrum" cameras, in which all filters in front of the sensor are removed, the colour rendition is overlaid by reds unless an appropriate filter is put over the lens.


PeterN

  • NG Member
  • *
  • Posts: 1125
Thank you. I did some test and noticed a color shift. Now I am pondering what to do. Besides replacing the entire sensor unit that includes the IR-cut filter (costing around 400 euros, oeps). Another option is to purchase screw-in IR cut filters (I need 46mm and 37mm and saw that B+W has those. Doing this also enables me to add an IR-pass filter for IR photography. Would this be a viable solution? Are there any drawbacks?
Thanks!
Peter