[rollei_list] Re: Planar, Xenotar, Summicron

  • From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
  • To: <rollei_list@xxxxxxxxxxxxx>
  • Date: Thu, 26 May 2005 15:48:54 -0700

----- Original Message ----- 
From: "Jerry Lehrer" <jerryleh@xxxxxxxxxxx>
To: <rollei_list@xxxxxxxxxxxxx>
Sent: Thursday, May 26, 2005 2:01 PM
Subject: [rollei_list] Re: Planar, Xenotar, Summicron


> Peter,
>
> No, no!  I referred to INTERNAL elements which are never 
> owner
> cleaned. The Leica rumors had this as a 90mm f1.4 
> lightweight lens.
>
> Jerry
>
> "Peter K." wrote:
>
>> Companies like Tokina made molded plastic elements for 
>> some zoom
>> lenses. Not sure of the compsite of plastic material for 
>> a lens
>> element, but they worked well. Of course they were 
>> created via molding
>> and far less expensive. The only problem with them was to 
>> avoid
>> leaving them in the sum or heat for any long time period 
>> and also to
>> avoide cleaning them alcohol.
>>
>> Peter K

   Kingslake discusses plastic lenses to a limited extent. 
Kodak used them in some cameras. Also, its possible to make 
an aspheric surface by cementing a plastic asphere to a 
glass lens. The problem with plastics is that the range of 
index of refraction and dispersion is limited.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx 

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