Help with Tiffen IR Neutral Density HM (Hot Mirror) ApeX 3.0 Filter - colour issue

Discussion in 'Accessories' started by BradS, Jun 17, 2017.

  1. BradS

    BradS Mu-43 Regular

    56
    Mar 9, 2017
    Newcastle NSW
    Hi,

    I an using a Tiffen IR Neutral Density HM (Hot Mirror) ApeX 3.0 Filter on my EM1 MK2 and having problems with the colour of the resulting image.

    The filter is described here: Tiffen 52mm XLE Series apeX Hot Mirror IRND 3.0 Filter . Cannot find the filter on the Tiffen site :confused:

    Am trying to work how to avoid or minimise this colour issues or is it a fault with the faulty filter. Is it the WB that I need to adjust?

    I am not too confident in Lightroom and would rather get it right in camera then fix post. Having said that would be grateful for any tips to correct in Lightroom.

    Image below showing the colour issue I am getting.

    Any assistance would be greatly appreciated.

    Regards,

    Brad

    P6120045.JPG
     
  2. Petrochemist

    Petrochemist Mu-43 Top Veteran

    730
    Mar 21, 2013
    N Essex, UK
    Mike
    I assume you realise this filter is intended for Full spectrum converted cameras. If yours is not one of these then that will explain the blue colour cast, as it will be removing some of the red signal!

    Even with a converted camera getting the right colours with an external hot mirror will need a CWB.
    There are many variations in the spectral transmission of hot mirrors particularly on the border between red & NIR. So it is extremely unlikely any hot mirror you get will match that of the cameras hot mirror so proportions of light reaching the channels will differ. A CWB will correct that.
     
    • Informative Informative x 1
  3. BradS

    BradS Mu-43 Regular

    56
    Mar 9, 2017
    Newcastle NSW
    Hi Mike,

    Thanks for the quick response.

    Do you think I bought the wrong filter? Of is this an issues I was always going to get?

    I have looked again at the image and I had adjusted the white balance to 7500K, playing around without really knowing that I was doing.

    So choosing another temperature WB values would be the way to go when shooting?

    Bit disappointed in this filter then as paid extra for the hot mirror being lead to believe it would have a least colour issues....
     
  4. Petrochemist

    Petrochemist Mu-43 Top Veteran

    730
    Mar 21, 2013
    N Essex, UK
    Mike
    It does specifically say it's for cameras without an internal IR filter. Most ND filters transmit IR at a much higher proportion than the visible light, so they don't work too well for IR sensitive cameras. If your camera has not been IR converted then this filter is solving an issue you don't have & causing other issues in the process.

    I've never been too impressed with the results of using any of the three external hot mirrors I've tried on my converted camera, they are much closer to normal than shots taken without but they do always give a colour cast, so I carry a non converted camera in my bag as well. In the summer months probably about half my shots are using IR.

    Selecting a prerecorded WB with a higher temperature will reduce the blue but it looks to me as if there might be a green element as well... Setting a custom WB using a grey card target (or similar neutral target) , should get all three channels right. An alternative is simply to tweak it in post, but it can sometimes take a while to get the look right.
     
  5. BradS

    BradS Mu-43 Regular

    56
    Mar 9, 2017
    Newcastle NSW
    Hi,

    Seriously appreciate your feedback.

    I am a bit out of my depth here which is fine, always learning, and I will investigate the WB issue more.

    To confirm- the EM1 MK2 is an IR converted camera and therefore has an internal IR filter?

    Do you have any advice on "Setting a custom WB using a grey card target (or similar neutral target)". Will definitely have to google this lol

    Thanks again for you time
     
  6. Petrochemist

    Petrochemist Mu-43 Top Veteran

    730
    Mar 21, 2013
    N Essex, UK
    Mike
    The standard EM1 (like any other normal camera) is not IR converted, and so has an internal IR filter. Conversion involves removing the Internal IR filter (AKA 'hot mirror' or 'ICF') Typically getting an camera converted will cost $250 and will invalidate any warantee, but will give the camera near infra red (700-1100nm) response similar to it's initial the visual response. It's a rather a niche form of photography which can give very surreal images. If you had a converted camera you would know!
     
    • Informative Informative x 1
  7. BradS

    BradS Mu-43 Regular

    56
    Mar 9, 2017
    Newcastle NSW
    Thank you