Archived posting to the Leica Users Group, 2007/04/06

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Subject: [Leica] M8 picture in magenta light
From: davison_m at (MARK DAVISON)
Date: Fri Apr 6 22:23:05 2007

>It maybe just physics, but in many cases I bet most people wouldn't see any
>difference unless it was pointed out to them. Or it was such an obvious
>shift of colour it would easily be seen.
>I'm not arguing that there isn't an IR problem, I just think a number of
>people are over reacting to the problem. Yep it's there and in some cases
>obvious. However is it obvious in every frame shot and is it as big a
>"problem" as some folks make out? I think not.

The effect of IR contamination in unfiltered M8 shots is obvious in every 
frame I have shot which has IR rich illumination and synthetic fibers, pale 
skin, and/or green foliage, just as physics would predict.  100% of the 
people that I have shown comparisons to notice the effect immediately.

I would definitely recommend that you use an IR blocking filter on the M8 if 
you intend to shoot social events in color.  The bride might remember the 
exact shade she chose for those bride's maids gowns in synthetic fabrics.  
Your preference for warm flesh tones may not amuse her. You will have a lot 
of Photoshop retouching to do.  The IR blocking filters are cheaper than the 
labor involved.

The real point of the example I posted is that the synthetic green sweater 
has turned slightly magenta grey--and no known custom color profile has any 
chance of mapping it back to green.  Not to mention that the shadowed area 
of the sweater is hardly affected at all.  Mixed light brings a form of 
differential IR contamination which will drive you completely nuts to try to 
remove in post processing.

My overall recommendation--if you shoot color with the M8, you should at 
least buy one IR blocking filter and try the comparison yourself, to see if 
it makes a difference in the shooting that you do.  No amount of internet 
debate by others will settle the issue for your shooting and your eye.

If you want to have some fun you should buy a filter which passes IR and 
blocks visible frequencies and go out and have some fun with the M8.  You 
will find that it is so sensitive to IR that you can easily shoot those 
dreamy IR shots hand held--and moreover the exposure meter is sufficiently 
sensitive to IR that you can use it to meter, possibly with a +1 exposure 

One very positive side effect of the M8 IR controversy for me has been that 
I discovered that my Nikon D2h is rather sensitive to IR as well, and using 
an IR blocking filter with that camera improves its color rendition quite a 
bit.  I now understand why I got such weird and inconsistent colors from 
synthetic sports uniforms.  Earlier reports on Nikon forums of unatural skin 
tones and magenta color shifts in synthetics were dismissed  by the Nikon 
partisans as due to uncalibrated monitors, gross incompetence, and/or 
insufficient faith.

Mark Davison

In reply to: Message from tedgrant at (Ted Grant) ([Leica] M8 picture in magenta light)