Re: [Leica] Jupiter lens 'tests'

["Dan Post" <dpost@triad.rr.com>]

Ah! The lovely Summarit feels more and more like a winner all the time!!!
Lovely bokeh, and Leica quality- and cheap compared to the Summilux!!
Once cleaned and collimated, it's not all that bad! Probably why the price
has been creeping up lately!
Dan
- ----- Original Message -----
From: "Dante A Stella" <dante@umich.edu>
To: <leica-users@mejac.palo-alto.ca.us>
Sent: Monday, October 16, 2000 7:57 AM
Subject: Re: [Leica] Jupiter lens 'tests'


>
> Looking at a couple of 20x30 sections, it is interesting that the
> Jupiter-3 and its Japanese equivalent, the Canon/Serenar 50/1.5, which
> has 13-16 blades (I am losing count), both exhibit an odd "donut-bokeh"
> with certain specular highlights (e.g. waxy leaves on trees that are in
> front of the plane of focus). It is interesting because the 1936 50/1.5
> Sonnar does not exhibit this.  Maybe the Opton Sonnar does.  I would
> guess that this difference is attributable to the coatings.  If I can
> get my scanner hooked up again (damn SCSI to USB connections), I can
> email you parts of the prints.  The coatings don't seem to add much to
> the on-axis performance of this lens, like you said because there are
> few air-glass surfaces.  I think in practical terms the contrast
> difference on a sunny day is 1/2 grade.
>
> As for the astigmatism, there is little - there is a lot more in the
> 50/2 Jupiter-8, which likes to make teardrops at down to about f/4.
>
> The 50/1.5 is a good performer if your  other choice is shelling out
> megabucks for a Summilux or other 50/1.2 lens.  But the Jupiter-3 has
> some practical shortcomings that make life interesting
>
> -- extensive use of aluminum, including a lens barrel that deforms
> easily and binds
> -- collimation via a raw aluminum disc, which is subject to compression
> -- lack of click stops, meaning that you have to periodically check the
> aperture ring
> -- extremely soft lens coatings (is a Jupiter-3 free of scratches when
> it leaves the factory?!)
> -- finish that seems to scratch up very handily
> -- filter threads are not quite today's 40.5mm size.
>
> Careful handling can overcome these problems, but they are all things to
> look for in buying a new one.
>
> The Canon version of the Sonnar has a brass barrel and click stops (to
> f/16, not f/22 like the Jupiter), suffers from a similar fragility of
> its coatings, and sometimes is seen with blistered chrome.  The extra
> sharpness, I think, justifies its price, which is now around $250.  This
> is in part because the Jupiter-3 is getting (relatively) expensive,
> hitting $150 and up on some popular auction sites.
>
>
> "Stanislaw B.A. Stawowy" wrote:
>
> > Hello!
> >
> > Thank you for these tests. Indeed, Russian
> > lenses have very pleasant unsharphess (contradiction?)
> >
> > Jupiter 3 have many aperture blades, this may make
> > good out-of-focus-lights reproduction (bokeh?
> > Does anyone believe in bokeh? ), also design is
> > somewhat symmetrical - look at drawing of Sonnar 1.5/50,
> > this may help to make this design considerably rectilinear.
> > One more - Jupiter have only six air-to-glass surfaces.
> > If we add also that all surfaces are coated or multicoated
> > (true? Marc, help please..), we have a design which has
> > remarkable contrast and is resistant to flare. Even if
> > flare appears, this is only one-two spot, even pleasant.
> > Bad point of this design is single, strongly curved front
> > element, making Jupiter 3 prone to astigmatism. I haven't
> > tested Juipiter 3 for this, but, judging by my photos
> > ( www.geocities.com/Stanislaw_Stawowy - I promise to add
> > more photos as fast as I will have some time - now I am
> > too much absorbed by working with Alastair on FOM2 website),
> > astignatism is minimal.
> >
> > Please, whoever have something to add, write this.
> > I am currently looking for people' opinion about Russian
> > lenses and will finally put some compilation of this
> > on my website (of course asking for rights to publish first :-)
> >
> >                                             St6.
> >
> >                                 St.
> >                      (Stanislaw B.A. Stawowy)
>
>