Sony/Zeiss are getting closer

Discussion in 'General Technical Discussion' started by Iliah, Sep 11, 2005.

  1. Iliah

    Iliah

    Jan 29, 2005
    nowhere
    to the sensor.

    The distance between rear lens element and the sensor plane in R1 is about 2mm. Corner sharpness is said to be excellent. Lens seems to be 14-72 (optically). Classic lens designs always took benefit of the close placement of the lens to the film plane - this helped increasing resolution. If the limitations of the angle of incidence for WA lenses are not an issue with R1, we may see several nice things in a year or too.
     
  2. Yeah, I read about it HERE. Pretty interesting stuff.
     
  3. TOF guy

    TOF guy

    208
    Mar 11, 2005
    I agree with you, Iliah, this is the beginning of a very interesting development.

    Now add the ability of interchangeable lenses, and you have an extremely useful tool.

    My question is :confused: : because of the close proximity between sensor and lens, the focusing on a "traditional" dSLR lens (read Minolta-Konica's lens :wink: ) would not work right away on such a body (the focusing element which have been designed to focus the image on a "film" further away may not have the proper motion range to focus the image on a "film" a few mm from the lens back element at least for part of the distance range). Therefore Sony and Konica-Minolta would (with Zeiss's help ?) have to come up with newly designed lenses to create a camera / interchangeable lenses system. Am I correct :Angel: ?

    Thierry
     
  4. Iliah

    Iliah

    Jan 29, 2005
    nowhere
    Dear Thierry,

    Many of rangefinder lenses have very small back focus distance. (I use back focus here in its original meaning of back focal distance, that is distance from tip of the rear lens element to the plane where the image is focused.) Hologon 16/8 has it at less then 7mm, Biogon 21/2.8 and 28/2.8 - at 12mm and 13 mm respectively (Contax G mount). Medium format lens Biogon 38/4.5 (90 degrees FoV) has back focus at 19mm (yes, it is a fixed lens, still there is enough room for focusing to work:) ). Non-retrofocus designs are cheaper, more symmetrical (better bokeh), have smaller front elements (flare). And for some lens designs it is possible to use internal focusing (IF).
     
  5. TOF guy

    TOF guy

    208
    Mar 11, 2005
    Hi Iliah,

    Thank you for the reply.

    But I didn't word my question very well :frown: .

    Basically I'd like to see Sony building on the R1 design and next offer a similar body - with short backfocus distance - but with interchangeable lenses. And I am asking the question: what does Sony need to do to get there ?

    We know that Sony has an alliance with Konica-Minolta (KM). So I may think that it would be enough to make a body similar to the R1, but with the current lens mount found in KM's (d)SLRs, and voila, one has a system with interchangeable lenses with the current KM lenses offering - no need to design new lenses. My thought is that this would not work: a lens with a focusing element designed to focus on a plane "far away" from the back lens element would not work without modifications on a body with short backfocusing distance simply because the focusing element is not designed for the correct displacement. So Sony - either through its new alliance with KM or the old one with Zeiss - would have to design a new lens system to work with this body. Am I right ?

    As you've pointed out, this has already been done with rangefinder's camera but maybe in a different way ? I mean the absence of a mirror box allowed Zeiss engineers to design a lens with a back optical element protruding inside the camera and fit very close from the film plane. By constrast in the R1 it is the sensor plane which is displaced towards the lens.

    Thierry
     
    Last edited by a moderator: Sep 12, 2005
  6. As quoted from DPR Preview of Cyber-shot DSC-R1 :
    "This is the first all-in-one digital camera to utilize a large (APS size) sensor, to be precise a 10.3 megapixel CMOS unit measuring 21.5 x 14.4 mm which is essentially a slightly smaller version of the sensor used in the Nikon D2X."

    Have we here what might be the D200 sensor ?
     
  7. Iliah

    Iliah

    Jan 29, 2005
    nowhere
    Dear Thierry,

    Some lenses I have are recessed so that the distance from the film plane is less then 7mm. Those lenses do not protrude further back when focusing. They use internal focusing, or front focusing (Vario-Sonnar is the type with front focusing, as far as I know). I'm not seeing Sony as a manufacturer of pro-grade rangefinders, but ZM Zeiss Icon with M mount can use Sony sensor. The Zeiss line of lenses is known for very good and even field coverage, that is why even for FF Canon dSLRs folks are queuing for months to get 21mm Distagon ( see comparison here http://www.16-9.net/ultrawides ) For rangefinders, new Zeiss lenses were tested to give better flatness and corner resolution than Leitz. So, the question for me is - are there any modifications in the sensor, or in the lens, or both - that allow such a close placement? In other words, is there any major progress in the lens array that is achieved, or it is lens design that provides highly parallel beam? And if it is lens design, how much the ideas behind Biogon, Distagon, Planar, Tessar, Sonnar, and other classical designs should be compromised to get to that parallel beams?
     
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