Leica UV/IR Filters

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kelrik13

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:confused: Hello to all,

Just received 2 free filters from leica for the problem they where having with the color black chaging when using the m8. my question is would you guys and girls use them as a lens protector or would you go with another type of filter like a b+w or a heliopan for general use.
 
For M8, I have to use it to correct the black-to-magenta problem. Why not leave it on? It also serves well as a protector!
 
If you plan to use the lens with film (especially color) - then you should remove the IR filters.
 
kelrik13 said:
:confused: Hello to all,

Just received 2 free filters from leica for the problem they where having with the color black chaging when using the m8. my question is would you guys and girls use them as a lens protector or would you go with another type of filter like a b+w or a heliopan for general use.
Click to expand...

It's not just black but many other colors which are affect. The greens of folage because of their hi ir content are also affected. Just shot a color chart under sunlight and you see other colors are changed.
 
johnastovall said:
Why? B+W show the spectral transmission diagram for their 486 and it's not impacting visual light and they suggest it can be used with film.
Click to expand...
What the filter manufacturer's data sheets don't tell you is how the spectral transmission of the filter changes with angle of incidence. The graphs are shown for light rays normal to the filter's surface. As the rays become more oblique the "IR cut" moves into the red end of the spectrum resuting in a cyan cast/drift towards the corners of wide angle photographs. That's one reason why Leica recommends coding for lenses 35mm and wider when using the IR cut filters. The cyan corners can then be corrected in camera. I also believe the Leica 67mm filter for the Wide Angle Tri Elmar is specified differently to the other filters in an attempt to minimise this problem.

The change in transmission characteristics with angle of incidence is why the filters look colorless when viewed straight on but show a red reflection when viewed obliquely. In the straight on view infrared is being reflected but as the angle changes the reflection moves towards shorter wavelengths - red.

Bob.
 
Last edited:
kelrik13 said:
:confused: Hello to all,

Just received 2 free filters from leica for the problem they where having with the color black chaging when using the m8. my question is would you guys and girls use them as a lens protector or would you go with another type of filter like a b+w or a heliopan for general use.
Click to expand...

In my experience these past 7 months, an IR filter is mandatory unless you are prepared to scrutinize every shot for possible subjects that will come out with a weird color (including outdoor foliage...the IR problem goes far beyond the "black synthetic fabric" as expressed in Leica's official position). Or, unless prepared to do handstands in photoshop trying to selectively correct the aberrant colors without skewing the ones that are OK.

Since the IR filters are essential and also very expensive, I do carry a couple spares w/stepping adaptors, just in case I ruin one somehow. But since I already had the B+W MRC plain UV filters beforehand, I just put them back on in front of the IR filter (due to the M8's cropping, vignetting isn't a problem except on the 15mm, where I have only the IR filter). I never noticed any reflections or ill-effects from them in the past, so I can't see how they would detract on top of an IR filter. OTOH the IR filters don't seem to be as well multicoated, so occasionally they do pose some reflections, even without the UV in front.
 
johnastovall said:
Why? B+W show the spectral transmission diagram for their 486 and it's not impacting visual light and they suggest it can be used with film.
Click to expand...

In addtion to Bob Parsons' comments above, there are B&W films with spectral sensitivity that extends into the cut range of that BW filter. The significance would depend on the film, but there is an impact.

For most people this is a greater concern for color film, which brings the shifts we are all familiar with.
 
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