Re: [ATM] Glass type

["Thomas Janstrom" <thomas@moiler.com>]

Hi Richard Et Al,

I've just a quick Q regarding this thread. I have been unable to find
any real numbers for BSC2 (of which I have two 4" X 3/8" blanks) so I
was wondering how it would work with NF11 of which I have one 4.5" by
5/8" blank (one side is concave...)?

I have most of the melt data on the NF11, but next to nothing on the
BSC2. I know that the two blanks are very thin, but how about doing two
halves of the one lens with the half way line being a flat surface
between the two BSC2 blanks? Sort of like this:

/||\ \\
|||| || <-this is the flint
\||/ //

^ ^ Two halves of the crown element.

Would this work?

Cheers Thomas.


-----Original Message-----
From: atm-bounces@atmlist.net [mailto:atm-bounces@atmlist.net] On Behalf
Of Richard F.L.R. Snashall
Sent: Friday, 13 January 2006 4:32 PM
To: atm@atmlist.net
Subject: Re: [ATM] Glass type

Richard F.L.R. Snashall wrote:

>
>Surf     Radius   Thickness     Glass   Diameter       Conic
>
> STO   Infinity   -2.421525                  106           0
>   2     581.31           8    N-SK16      114.3   0.1600132
>   3    215.086         2.1                114.3           0
>   4    209.059        14.9   S-FPL51      114.3           0
>   5   -8636.89    1578.593                114.3           0
> IMA   -537.637                         44.51772           0
>
>
But, if you're going to add new glass to glass of unknown
quality, you may as well do something really funky -- maybe
a 106 mm f/7.5 split corrector camera:


Surf    Radius   Thickness    Glass  Diameter

 STO  Infinity   -5.058366                106
   2   280.188         9.2   N-SK16     114.3 -- stop down to 106 mm
   3   112.918        5.75              114.3
   4   120.716        23.7     CAF2     114.3
   5  -1220.03      102.68              114.3
   6  -159.394        10.6    N-BK7     114.3
   7  -130.433      546.31              114.3 -- here too
   8   -161.48         7.2    N-BK7        90
   9  -353.191    95.77639                 90
 IMA  Infinity                        90.5488

Oh, yeah... they don't make 6x7 film anymore;-)


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