Native M4/3 Sigma 35mm/f2 lens coming soon?

Discussion in 'Native Lenses' started by DeeJayK, Jun 17, 2015.

  1. DeeJayK

    DeeJayK Mu-43 Hall of Famer

    Feb 8, 2011
    Pacific Northwest, USA
    Keith
    Everyone's favorite rumors site has a post about a patent Sigma recently received for a 35mm f/2 lens. According to the source the image circle of this lens just covers the 4/3 sensor (and not APS) which would make this the first Sigma lens designed exclusively for :mu43:, which is maybe the most interesting part of this rumor.

    Unfortunately, the source is in Japanese (which I can't read) so details are pretty sparse. Also, when I tried to search the patent number provided (2015-102559) my search turns up something completely different. Not sure what that means...likely that I don't know what I'm doing when it comes to searching patents.

    From what details are available, it seems this lens may be slightly longer (physically) than the Sigma 60mm/2.8. It seems that there is some speculation that the optical design will be similar to the Panasonic 42.5/1.7. The lens also apparently would have built-in OIS.

    If any of this comes to pass, it's at least an interesting lens that perhaps fills a small gap in the available lens lineup. The 70mm 135mm equivalent focal length is a bit unusual, but I'd rather see this than another 42.5/45mm offering if just for variety.
     
  2. b_rubenstein

    b_rubenstein Mu-43 All-Pro

    Mar 20, 2012
    Melbourne, FL
    There is no direct connection between patents and products. Companies come up with new designs and then protect their intellectual property with a patent. If a profitable business case can't be made for that lens it won't be produced.
     
  3. tkbslc

    tkbslc Mu-43 Hall of Famer

    35mm would seems like an odd focal length for a m4/3 native lens.

    Is it 35mm effective?
     
  4. b_rubenstein

    b_rubenstein Mu-43 All-Pro

    Mar 20, 2012
    Melbourne, FL
  5. tkbslc

    tkbslc Mu-43 Hall of Famer

    Which would be extremely odd. Too long for normal, kinda short for a portrait prime. Unless it's a reincarnation of their 70mm macro or something.

    I'm holding out a small sliver of hope that it's 35mm effective and we can finally get an outstanding lens at that focal length (with stabilization!).

    Too bad it's not a 50mm f1.4. That's what I really want. Sigma knows how to make a good one (although their SLR ones are quite huge).
     
  6. DeeJayK

    DeeJayK Mu-43 Hall of Famer

    Feb 8, 2011
    Pacific Northwest, USA
    Keith
    Obviously this is true. Perhaps the most interesting thing that we can learn from this patent is that it appears to be evidence that Sigma has devoted at least some technical resources to thinking about :mu43:-centric designs.
    I agree that's not among the "holy" focal lengths that seem to have been delivered on stone tablets by some optical higher power, i.e. 28mm, 35mm, 50mm, 85mm, 135mm, etc. (speaking in terms of 135mm equivalence). However, I don't really see that as a bad thing since we already have lenses available that hit most of those points. I wouldn't necessarily rush out to buy a 35mm lens, but more dviersity of choice seems like a good thing. On the other hand, Sigma may very well come to the same conclusion you have before they green light this lens for production.
     
  7. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    Sigma designed and holds the patents for several lenses subsequently released by Olympus(some are commonly thought as some of the best lenses), I wouldn't be surprised if the lens turns up in some form or another. :)

    A few examples: https://www4.j-platpat.inpit.go.jp/eng/tokujitsu/tkbs_en/TKBS_EN_GM101_Top.action (Second field, publication of patent)
    Patent number 2015-075501, covers the 25mm f1.8 (also covers half a dozen minor changes to it which could result in an f1.2 and f1.9 version etc, same optical design).
    Patent number 2013-161076, covers the 75mm f1.8 (and half a dozen small changes, all f1.8 however).
     
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  8. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    Also fwiw; no real difference from the usual however the rumors site was completely wrong on almost all the details they posted...

    ...it's far from the first, or second, or third, or 12th... you would be amazed at how many lenses Sigma has designed for other companies.
     
  9. EdH

    EdH Mu-43 Top Veteran

    631
    Jul 14, 2014
    Devon, UK
    Ed
    Two of my favourite legacy lenses are 35mm(ish) – the Olympus Pen F 38mm f1.8 and the Nikon Nikkor-O 35mm f2. I don't find it a difficult focal length at all on m4/3.
     
    Last edited: Jun 18, 2015
  10. tkbslc

    tkbslc Mu-43 Hall of Famer

    I guess one man's odd is another man's normal.... :2thumbs:

    I could see 35mm being a nice mid point between a 15 or 17mm and a 75mm.
     
  11. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    I've read through the patent and it wasn't one designed for Olympus (not surprising with the optical stabilization), I can't say for certain however there's wording missing from the patent which suggests to me it was designed for a compact camera and not m4/3 at all.
     
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  12. DeeJayK

    DeeJayK Mu-43 Hall of Famer

    Feb 8, 2011
    Pacific Northwest, USA
    Keith
    Here's a machine translation of the patent in case anyone else is interested in the nitty gritty details.

    I'm not an optical engineer nor do I speak patentese, so I'm not sure what else I can glean from this, but I also don't see any mention of 4/3 in the patent. I do see this: "image-height Y 10.82" which may mean that the image circle is not large enough to cover the 4/3 sensor which measures 13mm vertically, if I'm not mistaken.

    However, the prospect of a 35mm lens with a 55+mm depth in a compact camera with a 1" sensor (or thereabouts) seems hard to imagine.
     
  13. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    It's easily enough to cover m4/3, it will probably 'cover' APS-C however only just and the corners will probably be rubbish - most designs go for 12-15mm (13.6mm is a common aim fwiw).

    Think of image height as the radius of a circle, it extends in both directions from the centre. You normally need half the normal lens in coverage at a small fstop (coverage increases at large fstops, this is why some compact cameras have fixed apertures and you can only shoot them wide open, infinite dof with small sensors can make up for this). I know it's weird given the size of the lens however there's jargon missing which screams to me that it's not a lens designed for the m4/3 system itself.
     
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  14. DeeJayK

    DeeJayK Mu-43 Hall of Famer

    Feb 8, 2011
    Pacific Northwest, USA
    Keith
    I knew I was likely missing something. Only an engineer (or attorney) could have a convention as confusing as referring to a lens' image circle radius as the "image height".
    Can you elaborate? What sort of jargon would you expect to be included were this a 4/3 lens?
     
  15. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    4/3 and m4/3 are a standard, there's conventions that all lenses for the system must adhere to so that they fall within the system.

    While this lens is a standard Sigma design that has been pulled off the shelf and tweaked to produce the desired focal length and probably meets the standard however it's missing all of the jargon outlining the cleverness that went into designing the lens to fit exactly those criteria. The buzz words for 4/3 are things relating to the image stabilization and dust removal (essentially parts of lens design that need to be met for them to function reliably under different conditions, the technical name for it is image side (or space) telecentricity, they generally use fancy wording describing the field angle of their approach vs the traditional and such rather than the end goal however), m4/3 generally includes the 4/3 features as well as referencing traditional cameras with a mirror and the design choices made available by reducing the flange focal distance.

    This patent looks more like a claim so that no one else can use the design than anything, it might be that it was designed then another design was chosen over it however the patent was still taken out to keep the IP rights.

    On a sort of related to the lens however really not interesting note this lens doesn't do much for me, I would be much more interested in a 100mm f1.2 - anyone with me on that one? :)
     
  16. tkbslc

    tkbslc Mu-43 Hall of Famer

    It would be a monster!

    Maybe a 135mm f2 on a speedbooster? Gives about 96mm f1.4
     
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  17. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    Yeap, it would be a monster indeed, one of the design goals is that it would still take an 86mm filter (if you like filters or not they're very useful with fast lenses to reduce shutter speed using an ND filter as people are strangely fond of shooting wide open in broad daylight).

    A monster of a lens indeed :)
     
  18. tkbslc

    tkbslc Mu-43 Hall of Famer

    Canon 85 1.2L uses a 72mm filter. 100mm would need 17% larger diameter, so it would be close to 86mm using that design as a reference point.
     
  19. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    Rather than using other lenses as examples just do the math, a 100mm f1.2 lens would need an 83.3mm front element at the absolute minimum (The canon needed 70.8 and used 72, it fits). It doesn't allow for much wiggle room however given the narrow angle of view it's right on the limit of what's achievable, the problem comes more when people use filters with a rim such as the popular B+H XS-Pro series (the thin black painted rim is 2mm wide, it would cause a slight reduction in effective aperture compared to a different filter purpose designed with less rim).

    The other option is drop in filters however for various reasons this is not as attractive.