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

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Subject: [Leica] How IR filters affect M8 B&W
From: imagist3 at mac.com (Lottermoser George)
Date: Tue Jun 17 15:02:51 2008
References: <469309.58596.qm@web82107.mail.mud.yahoo.com> <E4DFA006-E4FC-4729-BAA0-025079645639@mac.com> <p06230903c47db1231156@[10.1.16.146]>

What you say makes sense.
Yet, at the same time, it would seem that being digital data, and  
with all the manipulation that can be achieved in post processing  
software, that some of those manipulations could also be achieved in  
firmware.
I don't know enough about software/firmware to make any claims in  
these regards.

Fond regards,
George
george@imagist.com
www.imagist.com
http://www.imagist.com/blog
Picture A Week - www.imagist.com/paw_07



On Jun 17, 2008, at 1:34 PM, Henning Wulff wrote:

>> I'd assume that the firmware setting of whether the IR filter is  
>> on or off may have an effect on the camera interpolation as well -  
>> yes? no?
>>
>> Fond regards,
>> George
>> george@imagist.com
>> www.imagist.com
>> http://www.imagist.com/blog
>> Picture A Week - www.imagist.com/paw_07
>>
>
> George, the only things that the firmware setting does is  
> compensate for cyan drift and vignetting. It can't compensate for  
> spectral responses beyond the usual white balance corrections, ie,  
> global changes.
>
> So setting the firmware 'incorrectly' will cause vignetting  
> oddities which will be readily evident for lenses which show  
> significant vignetting, and slight tonal difference due to spectral  
> response differences in the corners, again with wide angle lenses,  
> but not other effects.
>
> Just as too high IR response due to shooting without an IR filter  
> cannot be corrected completely in post-processing in colour shots,  
> neither can tonal changes such as Peter has shown be compensated  
> for in firmware, which is of course a type of post processing.
>
> BTW, I've tried some of the same kind of shots as Peter, and gotten  
> exactly the same results to my satisfaction. They weren't really  
> processed for posting, but gave me enough to cause me to leave the  
> IR blocking filter on unless I really want the high-red/IR look.  
> You can enhance it substantially by using an orange, or even red  
> filter.
>
>
> -- 
>    *            Henning J. Wulff
>   /|\      Wulff Photography & Design
>  /###\   mailto:henningw@archiphoto.com
>  |[ ]|     http://www.archiphoto.com
>
> _______________________________________________
> Leica Users Group.
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Replies: Reply from henningw at archiphoto.com (Henning Wulff) ([Leica] How IR filters affect M8 B&W)
In reply to: Message from rgacpa at yahoo.com (Bob Adler) ([Leica] How IR filters affect M8 B&W)
Message from imagist3 at mac.com (Lottermoser George) ([Leica] How IR filters affect M8 B&W)
Message from henningw at archiphoto.com (Henning Wulff) ([Leica] How IR filters affect M8 B&W)