Mamiya Sekor-C 37mm f/4.5 Fisheye for RB - what a fun lens...

Discussion in 'Medium Format Cameras and Accessories' started by philosomatographer, Mar 29, 2011.

  1. philosomatographer

    philosomatographer Member

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    I've been using this lens for almost a year. from an easthetic and build quality point of view, it has the most gorgeous glass I have ever seen, the front element is absolutely huge, and it weighs a ton.

    I am, however, having a lot more fun with this lens than what I first expected. It's very reawrding to try and compose images which do not have the "fisheye look" to them. These were two recent prints I made (both from Ilford HP5+):

    Dry and Drying
    [​IMG]

    Hand in darkness
    [​IMG]

    As with most good fish-eyes, resolving power and contrast are extraordinary (all elements of the design can be tailored to this, since no distortion correction is necessary) but what I find particularly enjoyable is that this lens cannot be made to flare or produce ghost images, even with the sun right in the frame, or (as per my second shot) a very bright light shining into the lens.

    This is an extremely multi-character lens that I only really learnt to value after a couple of months of use. It has a permanent place in my RB kit now, that's for sure (to the great disdain of my acheing body that has to carry the massive weight!).

    Any other users here?
     
  2. Jeff Kubach

    Jeff Kubach Member

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    I always wanted a fisheye for my RB67 but couldn't afford one right now. I do have an FD fisheye for my Canon FD cameras. I think it is a great lens.

    Jeff
     
  3. hpulley

    hpulley Member

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    Wow, I want that lens for my RB67 Pro S!!! I see the RZ67 version is still for sale new, only $2800, yowzah! I imagine the RB version was similarly expensive when new. Even used I only see one on eBay at the moment but at 500 quid ($780) BIN I think I'll have to hold off.

    I have a Peleng 8mm f/3.5 circular fisheye for Pentax (and Canon adapters). It is fun but the flare is awful, just dreadful, made in Belarus. I see a cheap Ukranian copy is available for Mamiya but wonder if the flare will be as bad? Probably...
     
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  4. Jeff Kubach

    Jeff Kubach Member

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    I lookup KEH sometime ago, the fisheye lens was about $695.

    Jeff
     
  5. EdSawyer

    EdSawyer Member

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    hi Dawid -

    It is a great lens. I have the RZ67 version, and really enjoy it. It's not without some flaws though. Right at the edge of the frame there is a bit of smearing and chromatic aberration, which is just part of the inherent design limitations. (I've had 2 of these, so it's not just a particular copy that does it.). Still, excellent and very sharp. Stopped-down to f/8 or better, it's as sharp in the center and with as much contrast as the ULD 50mm for the RZ, which is saying something. The close-focus capabilities are crazy, you can get down to focusing on things actually touching the front of the lens. Smearing and aberrations get pretty rough around the edges though when it's that close to the subject, but to be expected I suppose.

    It is a heavy gorgeous beast, no question. The front element is so wide and deep it looks like you could go swimming in it. ;-)

    You can also put it on a 4x5 and get round circular fisheye images too. Usually that means removing the petal hood, but that can be done with a spanner wrench (e.g. removable and replacable front section).

    Price-wise usually the RZ version goes for something like $600-1000+, depending on condition. RB versions are usually almost as much. Partly due to rarity and also partly due to the RB version also being pretty easy to use on larger format cameras (due to manual built-in shutter vs. electronic shutter in RZ version).

    -Ed
     
  6. philosomatographer

    philosomatographer Member

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    Hi Ed, good to hear from you! It's great that you also have this lens - you addict you. The optics between the RZ and RB version are identical. I have never seen the edge CA because I only shoot B&W :smile: Enjoy yours, I am enjoying mine...

     
  7. polyglot

    polyglot Member

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    Dammit, I'm still looking for one of these...
     
  8. Neil Grant

    Neil Grant Member

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    I have this lens too - and like you have tried trees as a subject to conceal the distorted image. I've noticed some lateral colour that can be removed from scanned images in PS. Did yours come with a full set of filters? Mine had just the UV. A filter needs to be used at all times or the lens won't quite focus to infinity. I found some 40.5mm contrast filters for b/w and had the mounts thinned on a lathe to allow clearance for the camera's mirror. I also made a R72 IR filter using a stepping ring and a 43mm glass. The fisheye distortion can be removed with software giving a 2:1 aspect ratio. I have seen photos of a number of these lenses and the serial numbers all seem to start 11000. Mine is 11020 - maybe that means it's the 20th one made? What is the serial number on yours?
     
  9. hpulley

    hpulley Member

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    Sounds like a similar design to the Peleng! It also takes rear filters and has a horrible ring of chromatic abberation which is mostly hidden in B&W.
     
  10. EdSawyer

    EdSawyer Member

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    Mine came with the 3 B&W oriented filters (yellow, red, etc.) - I think newer ones come with color-correction filters (81A, etc.). Basically any slim 40.5mm rear-mount filter should work. Polarizers, even... ;-) Agreed that a filter needs to be in place at all times for optical correctness.

    most RZ lens numbers start at I think 10000, though 11000 sounds feasible too. They didn't make too many of these, which accounts for the scarcity.
     
  11. philosomatographer

    philosomatographer Member

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    The Serial number on my 37mm is 10619, so I don't think yours was the 20th one made, unfortunately :smile:
     
  12. Pumalite

    Pumalite Subscriber

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    Fantastic lens. Top of the morning!
     
  13. philosomatographer

    philosomatographer Member

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    Two recent-ish prints from this lens (12x16in), in both cases trying very hard to conceal the fish-eye distortion. The more I use this lens, the more I realise how extremely "natural" this kind of distortion is, even for interiour architecture. In many ways, I prefer this to the stretched corners of an ultra-ultra-wide (think 110ยบ or more) rectilinear lens.

    [​IMG]
    (Mamiya RB67, Sekor-C 37mm, Ilford Pan F at ISO32)

    [​IMG]
    (Mamiya RB67, Sekor-C 37mm, Ilford Pan F at ISO32)
     
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  15. Jeff Kubach

    Jeff Kubach Member

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    I'll give an arm and a leg for that lens.

    Jeff
     
  16. fmajor

    fmajor Member

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    The real question, Jeff, is *whose* "arm and a leg for that lens"? ;-)
     
  17. Jeff Kubach

    Jeff Kubach Member

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    I know what you mean, I don't really care I just love to have that lens!

    Jeff
     
  18. NJS

    NJS Member

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    anyone compared it to Pentax67 35mm fisheye?
     
  19. philosomatographer

    philosomatographer Member

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    I'd venture a guess that very few will be lucky to own more than 6x7cm fisheye :smile:

    The focal length difference is interesting: The Mamiya RB67 is actually an 8x8cm camera, and all the RB lenses cover (at least) this format. This is probably why they went with a slightly longer focal length (37mm) for the 180-degree fisheye in this format, possibly allowing a bit of corner clipping if you're one of the few people shooting 6x8cm in an RB67.

    I'd love to participate in a comparative test - who has a Pentax 35mm? And unfortunately I'm in South Africa :-(
     
  20. Steve Smith

    Steve Smith Subscriber

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    I don't understand this. Could you explain it?


    Steve.
     
  21. philosomatographer

    philosomatographer Member

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    If I may jump in here - as you probably know, the filters for the 37mm screw in at the rear of the lens (impossible to have flat filters in front of a fisheye lens). See attached lens diagram.

    As far as I understand, the optical design of the lens was calculated to take into account the presence of a flat element at the rear (the filter), and if this is not present, it slightly changes the paths of the rays as they travel through the lens, causing them to converge at a slightly different point (in front of the film surface), hence the impossibility of achieving infinity focus. I do believe it's very slight, though (never bothered to waste a frame of 6x7cm film to see the effect) - almost looks in focus through the viewfinder.

    C-37mm-f4.51.jpg
     
  22. Steve Smith

    Steve Smith Subscriber

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    So it's designed to focus correctly with a filter in place, so to compensate for not having a filter, a flat piece of glass needs to be there instead.

    Was it supplied with a (non) filter?

    Also, the depth of field would be huge. I assume it's only really an issue when used wide open.


    Steve.
     
  23. philosomatographer

    philosomatographer Member

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    Mamiya supplies the lens with a couple of filters yes - including a (clear) UV filter. One of them always needs to be in place. I'd also just like to address your last statement, which is a bit of a misconception - the field (in front of the lens, in subject space) is indeed very deep, but the focus (at the film plane) is extremely shallow. Wide angle lenses are much less tolerant of any inaccuracy of distance between the lens and the film. A slight problem behind a 37mm lens will mean a great deal more than the same problem behind a 200mm lens.

    Think about it - focusing, say, a 21mm lens on a 35mm camera from infinity down to a 1 metre moves the lens assembly less than 3mm - imagine how sensitive this space is to inaccuracies! Compared to, say, a 200mm lens, that has to move a great deal (a couple of centimeters) to achieve the same focus distance.

    Lenses with a deep depth of field (wide angle lenses) have shallow depth of focus at the film, and lenses with a shallow depth of field (e.g. telephoto lenses) have a deep depth of focus at the film. Mamiya 37mm lenses have awesome depth of awesomeness all 'round :cool:
     
  24. frobozz

    frobozz Subscriber

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    I've got the version for the 645 - the 24/4.0. It's got a built-in filter turret, so there is always a piece of glass in place and there's no chance of misplacing the UV one. It is one gorgeous piece of glass, and takes amazing pictures.

    Duncan


    [​IMG]


    [​IMG]


    [​IMG]


    [​IMG]


    [​IMG]
     
  25. dodphotography

    dodphotography Member

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    do you think there is a noticeable difference between the C and newer KL version?
     
  26. EdSawyer

    EdSawyer Member

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    better coatings, at the very least.