Archived posting to the Leica Users Group, 1997/05/14

[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]

Subject: Re: Unscientific lens testing (somewhat off topic).
From: Willem-Jan Markerink <w.j.markerink@a1.nl>
Date: Wed, 14 May 1997 23:23:06 +0000

On 14 May 97 at 8:28, David Young wrote:

> I bought the MTO, despite it's bulk, because of the superior performance,
> reasonable price tab and the funky wooden case it came in (complete with 4
> - 77mm filters!).

You mean real wood, as in those things with branches and leaves?!?
Never seen boxes like that. 
They probably ran out of cardboard....;-))
 
> Three questions, for those who are still reading...
> 
> [1] Though engraved as a 500 f8 on the lens, the addendum sheet with it
> says it's a 548mm f8.8.  Is this sort of variation normal?

I believe both ISO and DIN allow 10% deviation either way. Well within 
spec....;-))
If not, then it is fully compliant with a Russian certification....:-))
Related detail: the spec's for the Horizon 202 panorama camera are 
more honest than for the German Noblexes. The Horizon lists a 
horizontal and vertical angle of view separately, all Noblexes only a 
diagonal angle. 
PS: for those interested in more panorama spec's, and a link to the 
Noblex site (Marc, I think you might find some interesting stuff on their 
site too), check my homepage:
http://www.a1.nl/phomepag/markerink/mainpage.htm

> [2] All three lenses, as well 500/8's by Minolta, Leica, Nikon and my
> 1000/11 Celestron all focus to beyond infinty.  Does anyone where know the
> reason Mirror lenses do not have an infinity stop?

To compensate both both temperature expansion/contraction and sloppy 
adaptors. On some cameras with build-in flash this comes in quite 
handy, as you must turn the M42 adaptor loose to clear the prism.
 
> [3] The MTO rsults were virtually as good as the Nikkor's or Celestron's.
> Yet the booklet lists resolution as "Central - 32 lines/mm" and "Peripheral
> - 20 lines/mm".  The MTO seems much better than such numbers would
> indicate.  Can anybody tell me why?

I believe this is common for many Russian lenses, glass lenses 
included. 


 

- -- 
Bye,

Willem-Jan Markerink


      The desire to understand 
is sometimes far less intelligent than
     the inability to understand


<w.j.markerink@a1.nl>
[note: 'a-one' & 'en-el'!]