[Leica] M8 with UV-IR filters

[pklein at threshinc.com (Peter Klein)]

Ken:  Use the filters and set the M8 "Lens Detection" menu item to "On + 
UV/IR."

My experience is that lenses of 50mm and longer don't need to be coded.

35mm is a toss-up.  You can do without coding, and the vast majority of the 
time you won't notice the difference.  But if the picture contains some 
uniform areas of white, grey, or a pale color, you may notice that things 
get a little cyan-ish towards the corners.

28mm and wider, you really do need the coding.  The cyan corners are quite 
noticeable without it.

There's a distinction between needing the filters and needing the 
coding.  You need the filters at any focal length, or the IR component 
changes some subject colors. It's not just black synthetics--green grass 
and some leaves are yellower, for example.  Even in B&W, the IR component 
slightly smears the image, because the IR rays come to focus at a slightly 
different distance than visible rays.

All the M8 does with the coding is to apply a bit of graduated color and 
general vignetting correction to the image, getting stronger towards the 
corners.  And it puts the focal length into the EXIF.

--Peter


At 06:08 PM 12/19/2008 -0800, you wrote:
>From: Ken Lassiter <kenlass@gate.net>
>Subject: [Leica] M8 with  UV-IR filters
>To: lug@leica-users.org
>Message-ID: <494C510D.9090903@gate.net>
>Content-Type: text/plain; charset=us-ascii; format=flowed
>
>I received my free UV-IR filters directly from Leica in Germany via Fed
>Ex today.  I read the little instruction sheet in each filter and it
>says, "Leica 6-bit coded lenses are necessary for the use of this filter
>with the Leica M8."
>
>I do not have any of my lenses coded yet. Should I use the filters or
>not?  In the menu, one cannot turn on using the UV-IR filter without
>turning on lens detection.
>
>What has been the experience of  LUGgers in using their UV-IR filters
>without coded lenses?  Good idea or not?
>
>Thanks for your advice... Ken Lassiter, Boynton Beach, FL