[Leica] Leica response to Tri Ermar (28/35/50) is retrofocus?

[Paul Roark]

This is a review that includes a cut-away of the MATE optics here:

https://www.stevehuffphoto.com/2010/11/11/the-leica-mate-lens-review-medium-angle-tri-elmar-by-ashwin-rao/


Paul
www.PaulRoark.com

On Wed, Feb 19, 2020 at 12:43 PM Ken Iisaka <ken at iisaka.com> wrote:

> I think there is more to it.
>
> Tri-Elmar 28-50 is basically a zoom lens with two groups: a positive
> focusing lens group closer to the film, and a negative group up front. The
> distance between them is what determines the effective focal length of the
> lens.
>
> To have a negative group up front and having a positive group in the back
> is the definition of a retrofocus design.
>
> At 28mm, the centre of the lens is well ahead of the focal plane, certainly
> further than 28mm. This indicates that it is effectively a retro focus
> lens. At 50mm, it is less so.
>
> On Wed, 19 Feb 2020 at 11:21, Frank Filippone via LUG <lug at leica-users.org
> >
> wrote:
>
> >  It is not considered a retrofocus design.
> >
> > That's it folks.... Final answer
> >
> > Frank Filippone
> > BMWRed735i at gmail.com
> >
> > _______________________________________________
> > Leica Users Group.
> > See http://leica-users.org/mailman/listinfo/lug for more information
> >
>
>
> --
> Ken Iisaka
> first name at last name dot org or com
>
> _______________________________________________
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>