Archived posting to the Leica Users Group, 2008/06/17

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Subject: [Leica] How IR filters affect M8 B&W
From: hoppyman at bigpond.net.au (Geoff Hopkinson)
Date: Tue Jun 17 14:22:38 2008
References: <5.1.0.14.2.20080616220709.00bed860@mail.2alpha.com><200806171434.ARO75340@rg4.comporium.net> <C0BA6AF4-A021-48F8-8C3B-DFE5C0C81A9C@cox.net>

Steve, we look forward to seeing results from your testing. Peter's examples
are certainly a worst case. If you are querying sharpness as well as tonal
shift, you will be considering other factors too, in order to reduce
variables (DoF, focus accuracy, focal distance, focus shift, camera and
subject movement, aberration level at large apertures with different
lenses). I just shot some available light family shots. Black T shirts
against black cloth partitions under mixed artificial light. The well known
magenta shift makes a marked difference in tonality of the blacks after BW
conversion (and some to the skin tones). Similar but less predictable
effects on various metal or plastic objects (it was an invention convention
for school kids). Shots made experimentally removing the filter were
noticeably degraded. 

Cheers
Geoff
http://www.pbase.com/hoppyman/e
http://gallery.leica-users.org/v/gh/
-----Original Message-----
Subject: Re: [Leica] How IR filters affect M8 B&W


On Jun 17, 2008, at 7:34 AM, Tina Manley wrote:

> At 02:20 AM 6/17/2008, you wrote:
>> All other things being equal, I prefer to use the IR filter while  
>> shooting B&W with the M8.  However, I have noticed that you can  
>> often gain a half stop more exposure without the filter, especially  
>> in reddish tungsten light.  So if I was shooting at 1/15 or slower,  
>> I might remove the IR filter, figuring that the half-stop faster  
>> shutter speed I'd get might gain me more in clarity than the IR  
>> smearing would take away.
>>
>> --Peter
>
> That's very helpful, Peter, and a greater difference than I thought  
> it would be.  Guess I need to get a couple more filter sizes :-(


  my thoughts too Tina but, I am not totally convinced yet, but  
almost...just need to see this reproduced and carried a bit further,

Steve
>
>
> Tina
>
> Tina Manley
> www.tinamanley.com
>
> _______________________________________________
> Leica Users Group.
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Replies: Reply from kididdoc at cox.net (Steve Barbour) ([Leica] How IR filters affect M8 B&W)
In reply to: Message from pklein at 2alpha.net (Peter Klein) ([Leica] How IR filters affect M8 B&W)
Message from images at comporium.net (Tina Manley) ([Leica] How IR filters affect M8 B&W)
Message from kididdoc at cox.net (Steve Barbour) ([Leica] How IR filters affect M8 B&W)