[rollei_list] Re: Tell the tales of Triotars
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <rollei_list@xxxxxxxxxxxxx>
- Date: Sun, 5 May 2013 11:33:00 -0700
----- Original Message -----
From: "Jerry Lehrer" <glehrer@xxxxxxxxxx>
To: <rollei_list@xxxxxxxxxxxxx>
Sent: Sunday, May 05, 2013 10:09 AM
Subject: [rollei_list] Re: Tell the tales of Triotars
Richard,
I hate to quibble (he lied), but the fast Ektar lens for
the Miniature Speed Graphic was f3.7, not f3.8.
According to experts it was the same glass as the Medalist
100mm f3.5 AND the first Hasselblad
80mm f2.8. Different glass element spacing, but I find it
hard to reconcile that.
Jerry Lehrer
Yes, f/3.7, my memory is not always exact. I doubt its
the same glass elements with only a change in spacing. If
someone has both they could perhaps measure element
diameters which might answer the question (or not). Element
spacing is important to the corrections. This was a deluxe
lens intended to have extremely good performance. Both are
variations of the Heliar based on a patent By Altman of
Kodak. The same basic design was used in the Kodak Enlarging
Ektar of 50 and 75 mm focal lengths and some other lenses.
The whole Ektar series was designed to have very good color
correction to promote the use of color film, from which
Kodak made a lot of money. The Commercial Ektar is very
nearly apochromatic.
--
Richard Knoppow
Los Angeles
WB6KBL
dickburk@xxxxxxxxxxxxx
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