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Re: Eclair Cameras: Zeiss Zoom T3 vs. Zeiss T2

I know you said that the T* coated 10-100 and 11-110 are optically
equivalent.  That aside, however, let me entertain another idea:

Do you think the 11-110 has a 1.1x converter added by Zeiss?  After all,
the 1.2x converter added by Optex gives you 0.4 of a stop more (T2.4).
The 1.15x converter that Van Diemen used to perform gave you 0.3 of a
stop more (T2.3).  I would think it would reason that Zeiss is simply
adding a 1.1x convertor to the 10-100 T2 in order to make it an 11-110
with 0.2 of a stop added (T2.2).  However, I am only postulating and
have no idea if this is the case.  Do you know if this is correct or
incorrect?  If it is incorrect why does the Super-16 11-110 have an
increased focal scale and T-stop?

Mike Welle

Hi Mike.

Zeiss have reconstruct the rear elements on the 11-110 mm zoom lens.
If you shall cover a larger area, super-16, you have to increase the focal
length, if not reconstruct the hole lens. If the light coming in to the lens
shall cover a larger area the intensity will be less, according to the
optical and psychical laws.

Cooke made the same with the Varo-Kinetal 9-50 mm T2.5, and got a super-16
lens 10,8-52 mm T2.8. by chanced 4 lens element in the rear unit, as Barry
Billington, at Cooke Optics, told me today.

OpTex convert the Cooke 9-50 mm T2.5 to a super 16 lens 11-60 mm T3.0 by
adding a extender to the back of the lens. As soon you start adding lens
element you are loosing quality.

All the best Hans Hansson, FSF, Sweden

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