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To filter or not to filter, IR is the question


bonjac

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Hi folks. My name is Jack and I am new to the M8 and RF cameras. I bought a used M8 and finally have it working well. Bought a Minolta rokkor 40mm f/2 lens. I have read quite a bit about the IR filter issue/M8 design flaw. But, I must admit to some confusion. Specifically, is an IR filter requiredfor all focal lengths or just for the "wider" lenses (35mm and below). I also wanted to add how great I think this site is. Your helpful attitude is really special. Thanks

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The IR issue (or , better, the "UVIR" issue) is lens-indipendent : it depends on the reflectivity properties of the subjects taken in the picture, with the consequence that materials like fabrics (above all) and foliage show a wrong color (the famed "magenta cast", the most easy to spot is when you take a pic of a black cotton or synthetic dress); with foliage there can be also a certain effect of unsharpness probably due to UVIR ghost image that focus on a different plane (to say, the phenomenon of chromatic abherration).

So, the UVIR filter is someway a must for any focal... most M8 users (me included) simply keep their lenses with a filter always mounted on.

 

The problem of wideangles is that the UVIR filter has a side effect... very angled lightrays, passing through the filter, tend to cause color fringing at the borders: this issue is managed into M8 software WHEN THE CAMERA RECOGNIZES THE LENS, which is through the 6 bit code on the modern Leica lenses (and when one sets the camera to "Lens recognition ON+UVIR").

This makes the lens coding almost a must with wideangles (35mm and smaller focals, about), while in teles, which do not suffer the color fringing issue, it's much less important (the lens recognition registers also the lens used on the EXIF file... useful but not fundamental)

Having a 40 (uncoded) you can be rather comfortable... but is better you take a UVIR filter (known also as "486" filter in B+W coding system) : I do not remember which is the filter size of the Rokkor 40... its Leitz brother (Summicron 40) was problematic about for it used a filter size (40,5 mm, unthreaded, kept in position by hood) that has been abandoned.

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Always use an IR filter (B&W 486) on any lens. Make sure your lenses of 28 and shorter are coded, either Leica or any of the alternatives to be found in this forum. You may well be able to get away with uncoded 35 lenses. Or use Cornerfix, a handy little program. Only take the filter off if there is a good reason to do so (e.g. strong specular highlights at night)

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There's an article in LFI 8/2010 on going without for black-and-white.

 

Best example of why not to use the filter (as Jaap said) is the following shot, originally posted at http://www.l-camera-forum.com/leica-forum/leica-m8-forum/38394-nastiest-filter-reflection-ive-ever-seen.html.

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

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There's an article in LFI 8/2010 on going without for black-and-white.

 

Best example of why not to use the filter (as Jaap said) is the following shot, originally posted at http://www.l-camera-forum.com/leica-forum/leica-m8-forum/38394-nastiest-filter-reflection-ive-ever-seen.html.

 

And for all these years I have believed that vampires could not be photographed! :D

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You know, the sad thing about Walt's picture (I wish he had stuck around) is that to repair it, he had to suck the blood out of it--he posted this in the thread with the original:

 

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

 

 

And come to think of it, Walt himself disappeared from the forum soon after starting the thread. Hmm. I wonder... :confused:

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You know, the sad thing about Walt's picture (I wish he had stuck around) is that to repair it, he had to suck the blood out of it...

 

And come to think of it, Walt himself disappeared from the forum soon after starting the thread. Hmm. I wonder... :confused:

 

Hmmm... could be that now he can go around ONLY by night... :confused:;)... not the optimum to take pictures, expecially if you have more vital issues to manage...

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Always use an IR filter (B&W 486) on any lens. Make sure your lenses of 28 and shorter are coded, either Leica or any of the alternatives to be found in this forum. You may well be able to get away with uncoded 35 lenses. Or use Cornerfix, a handy little program. Only take the filter off if there is a good reason to do so (e.g. strong specular highlights at night)

 

Ditto. Well said.

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