[Leica] M8 and the WAR now diopter lenses

[henningw at archiphoto.com (Henning Wulff)]

>ELPRO's?
>
>Them's LEICA TALK.
>But more than one element.
>
>"Leica ELPRO 2 close focus attachment"
>
>
>mark@rabinergroup.com
>Mark William Rabiner
>
>

ELPRO's are achromats. They are 'close up lenses' with two elements, 
one positive and one negative. Like Nikon's 3D to 6D, or Canon's 250D 
and 500D.

The Rollei thing would be the opposite. They would be a filter with a 
negative diopter grind to correct for a specific film's peak 
sensitivity.

Wandering a bit further off topic (but then, this IS the LUG...) 
slight positive and negative diopters are very useful in large format 
photography if your lens coverage isn't quite right.

Just screw in a +1 diopter, and what you are doing is basically 
shortening the total focal length (which is how the close-up thing 
works), so now your 4x5 lens has a slightly wider field of view. Stop 
down a bit more, and everything works fine. I always carry something 
like this when I take a light field camera out and have a big gap to 
the next shorter focal length.

A negative diopter (which is a lot rarer) would increase the focal 
length a bit, but that isn't as important in LF photography, because 
cropping a little gets you the same thing, and usually with better 
quality.



>
>>  From: Douglas Sharp <douglas.sharp@gmx.de>
>>  Reply-To: Leica Users Group <lug@leica-users.org>
>>  Date: Sat, 14 Jun 2008 10:30:24 +0200
>>  To: Leica Users Group <lug@leica-users.org>
>>  Subject: Re: [Leica] M8 and the WAR
>>
>>  Anastigmats?
>>
>>  Alastair Firkin wrote:
>>>  Correction lens?
>>>
>>>  --- mark@rabinergroup.com wrote:
>>>
>>>  From: Mark Rabiner <mark@rabinergroup.com>
>>>  To: Leica Users Group <lug@leica-users.org>
>>>  Subject: Re: [Leica] M8 and the WAR
>>>  Date: Sat, 14 Jun 2008 00:04:30 -0400
>>>
>>>  Well you're not supposed to call those close up filters filters.
>>>  You're supposed to call thems something else.
>>>  I forgot what.
>>>  Dioptors maybe.
>>>
>>>
>>>
>>>  mark@rabinergroup.com
>>>  Mark William Rabiner
>>>
>>>
>>>
>>>
>>>>  From: Henning Wulff <henningw@archiphoto.com>
>>>>  Reply-To: Leica Users Group <lug@leica-users.org>
>>>>  Date: Fri, 13 Jun 2008 19:58:56 -0700
>>>>  To: Leica Users Group <lug@leica-users.org>
>>>>  Subject: Re: [Leica] M8 and the WAR
>>>>
>>>>
>>>>>  The kind of really smart and cool stuff we expect from Rollei usually.
>>>>>  But I feel like to be correct we should not be referring to it as a
>>>>>  "filter".
>>>>>
>>>>>
>>
>
>
>
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    *            Henning J. Wulff
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