Archived posting to the Leica Users Group, 2007/05/23

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Subject: [Leica] Leica IR Filter vs. B&W 486 IR Filter
From: len-1 at comcast.net (Leonard Taupier)
Date: Wed May 23 05:07:16 2007
References: <1BA737B0-A39E-41E5-AA93-59769A48728F@mac.com>

Hi Bob,

Yes the B+W 486 filter is stronger then the Leica UV/IR. This is  
pretty much not a problem at all with lenses longer then 50mm. The  
only issue is WB on non-coded lenses. If you take outdoor photos  
using the filter and Daylight WB, the photos will have a more green  
look. This is corrected easily in the Photoshop raw converter or by  
using Auto WB. The color temperature using either filter is about  
7000 deg K rather then the Daylight setting of 5650 deg.

Wide angle lenses are a different story. This is especially true with  
focal lengths between 16mm and 21 or 24mm. If you use a filter with  
these lenses you should use a coded lens and the DET + UV/IR setting.  
The problem of course is cyan creep in the corners and edges. I'm  
using the Leica filter holder for my WATE. The 67mm Leica filter for  
it is not yet available. When using the B+W 486, the cyan creep is  
not fully corrected as the M8 firmware was written to correct for the  
weaker Leica filter. The WATE is nearly unusable with this filter. It  
takes a lot of work in CS2 to correct it. Instead I use the Tiffen  
filter. It is much weaker then the B+W filter  so the M8 totally  
eliminates cyan creep. It actually slightly over compensates for the  
cyan and you now see a very slight pinkish cast in the corners. At  
the 16mm setting this is totally corrected by telling the M8 the lens  
is set to 18mm instead of 16mm. The slightly less cyan correction at  
the 18mm setting is perfect for 16mm. When the lens and M8 are set to  
the same 18mm and 21mm settings, the pink cast is insignificant.

Regards,
Len


On May 23, 2007, at 1:36 AM, Robert Rose wrote:

> My 46mm IR filter came today from Leica.  They did not ship the  
> 60mm for the Noctilux, however.
>
> I already have another 46mm B&W 486 filter, so I was able to make  
> some very interesting observations:
>
> 1.  The Leica filter is much "paler" than the B&W; that is to say  
> that the "hot mirror" red effect is much less evident on the Leica  
> filter.
> 2.  The B&W filter has a thinner frame.  This is not a slim version  
> (which is thinner still).
> 3.  The Customs declaration states that the filter is made in JAPAN.
> 4.  The camera does not seem to correct the cyan vignette unless it  
> has a coded lens.
>
> So, it is evident that the Leica filter is different from the B&W  
> filters.  I don't have any information on how this affects the  
> images, if at all.
>
> Bob Rose
>
> _______________________________________________
> Leica Users Group.
> See http://leica-users.org/mailman/listinfo/lug for more information


In reply to: Message from robert.rose at mac.com (Robert Rose) ([Leica] Leica IR Filter vs. B&W 486 IR Filter)