R2a and R3a Info...

[Huck Finn]

Doug, I hadn't thought of adding a 50 for the purpose of having an ultra-fast lens in the system. You make an excellent point! The proposed Rollei 50 Planar would not be a candidate for that because it is an f/1.8 lens. However, it would really be something to see Zeiss revive their f/1.5 Sonnar - historically the first of the ultra-fast 50's. On his website, John Lind says that to this day it is the best lens he has ever used! Things get more & more interesting . . .

 

[Kris]

- Stupid question alert -

What kind of effect are you going to see on the picture if you use Sonnar-type lens? I tried to do Google search Planar vs Sonnar and managed to come to this Dante Stella site full of maths on light transmission. 😕

 

[Roger]

Possible Cosina OEM for Zeiss

Possible Cosina OEM for Zeiss

The forthcoming Zeiss camera looks a bit like the two new Cosina-Voigtlanders (R2A/R3A) but with the rangefinder patch window further over to give a longer baseline. You can see that this WOULD have been possible with the R2A and R3A, but hasn't been done. My guess (totally without any inside knowledge) is that Cosina may have created the longer RF baseline camera body for Zeiss having accepted as a condition for this that they would not then be able to market this themselves. Both companies would probably want to avoid a repeat of the Rollie fiasco. (And even there, CV did not produce a similar LOOKING design.)

President Kobayashi runs his company as an OEM centered business, and does very well at it. If my guess is anywhere near the truth, I expect he will make more money creating bodies for Zeiss for use with Zeiss lenses, than marketing them as an "own brand."

Anyway, not long to wait now!

 

[Roger]

Digital back for new Zeiss?

Digital back for new Zeiss?

Since full-frame sensors seem unlikely for a digital RF any time soon, on cost grounds, and seeing that effective focal lengths are multiplied by 1.5 or 1.6 (or even 2.0) depending on which sensor you use, your 50mm lens will function as at least a 75mm, and your 90mm as a 135mm. That's very near the limit of what's actually reliably focusable, if not a wee bit past it--certainly for faster lenses. So maybe the longer baseline is part of an attempt to ease the focusing problem for longer FL lenses when used with a digital back for the new camera. Epson's approach was to use a 1:1 viewfinder. The new Zeiss probably won't do that because of the claim to cover 21mm FL lenses.... that says something more like 0.55:1 for the viewfinder factor. So a long baseline is highly desirable. No? I mean, longer baseline and smaller viewfinder image, desirable for standard 35mm film, essential for digital back?

We'll soon know, anyway!

 

[Huck Finn]

- Stupid question alert -

What kind of effect are you going to see on the picture if you use Sonnar-type lens? I tried to do Google search Planar vs Sonnar and managed to come to this Dante Stella site full of maths on light transmission. 😕

Kris, the Sonnar was a breakthrough lens design back in 1932 because it contolled for flare with little or no coating - at a time when the development of coatings was in a very primitive state. As a result, ultra-fast lenses were able to be developed for the first time. These fast Sonnars are known for their flat field - which I think would be particularly useful when shooting wide open for the purpose of minimizing depth of field. They are also known for edge to edge sharpness although this may vary with aperture & how the design is tweaked in individual cases.

In contrast the Planar couldn't control the problem of flare & as a result didn't come into its own until the development of coatings became more sophisticated. Most high aperture Japanese lenses today are planar designs or a derivative of it.

On Dante Stella's website, read his article "Nikkor Lenses for Leica" for a quick history of Sonnar design development.

His brother, Davidde, has a review: "Zeiss Sonnar Copies."
www.davidde.com

John Lind has extensive information on his website under both the Zeiss Ikon Contax & Rollei 35 sections.
http://johnlind.tripod.com

Finally, you can reference this article for details of Zeiss designs, including both Planar & Sonnar.
www.panix.com/~zone/photo/czlens.htm

 

[Huck Finn]

Kriswhile we're on the topic of Sonnars, I came across this interesting discussion of the Nikkor 50/2 LTM over at photo.net. This lens is a Sonnar design, a derivative of the Zeiss Sonnar - as mentioned in Dante Stella's article on Nion lenses for Leica. One of the posters mentions that high contrast is a characteristic of Sonnars. There are a couple of really nice pictures posted in the discussion.

www.photo.net/bboard/q-and-a-fetch-msg?msg_id=009aHU