Q&A: 6×8 on the RB67?

Image courtesy of Chemical Cameras

Somewhere during the Pro-S years Mamiya introduced a way of shooting 6×8 on the RB67. Several different components are needed to shoot 6×8 and in the end you will end of with a 5.6cmx7.5cm (compared with the 5.6cm by 6.8cm negative for the normal 6×7 back). However, the 6×8 frame size will only be used when the back is rotated to portrait.

From my notes on RB67 6×8; To have a full 6×8 setup, first start with a Pro-S or Pro-SD body (the Pro body can be used with some work), then add the following.

  • a 6×8 power back.
  • a 6×8 light baffle–which lies between the revolving adapter and the body. You can tell what sort of baffle you have by taking off the current revolving adapter. There is a flat black baffle held in by four screws, if this says “8” or “6×8” you are ready to go.
  • Pro-SD 6×8 revolving adapter
  • a 6×8 Matte screen to get full 6×8 view(optional)

If all the pieces are assembled, you should have a 5.6cm x 7.5cm frame size. APUG user jtcliff was able to test different configurations of the above components and the resulting frame size.

  • RB67 Pro Body + RB67 Pro revolving adapter + 6×8 power back:  5.6cm x 7.2cm negative.
  • RB67 Pro Body + RB67 Pro-SD revolving adapter + 6×8 power back: 5.6cm x 7.3cm negative
  • RB67 Pro Body + RB67 Pro-SD revolving adapter+ 6×8 power back + “8” light baffle: 5.6cm x 7.5cm negative

In the end, you have to wonder if all the work is really worth it for an extra .7cm…


  • August 28, 2011 - 4:07 am | Permalink

    I recently found a 645 back for the RB ProSD. I posted some shots of it on chemical cameras. Then today I brought home a left handed grip which I haven’t photographed yet but will do so soon. Combined with the prism finder it transforms the RB into the most monstrous hand held rig I’ve ever seen!! Some day I might even try it out with some film.

    • jodys
      August 28, 2011 - 6:01 am | Permalink

      I have the left handed grip and prism, as well. I think I would need to be a weightlifter to use it handheld like a SLR–the prism alone is like ~3 lbs. Handholding using a waist-level finder and cradling it with two hands is reasonably doable be mere mortals such as myself.

  • December 8, 2011 - 6:00 pm | Permalink

    Thanx for posting about the 6×8 conversion. I wasn’t aware of it prior.

    Do you know if there is a change in the number of frames you would get out of a roll of film?

    Glad I found your site, I have the 67 Pro myself, not too heavy hand held, for me anyway. Use a Mono-Pod if you need to.

    A lot of woman shot with the RB professionally before digital and plastic body cameras came to be the norm. With a Digital back, RB’s kick butt. I love mine.

    • jodys
      December 10, 2011 - 7:26 am | Permalink

      I’m glad you appreciate the site! I have the Pro-SD and find it to be one of the most usable cameras I own. Enough heft to keep it steady, everything in the right place and enough to do to keep you involved in every shot.

    • Ronald Gordon
      February 3, 2020 - 12:54 pm | Permalink

      I have a mint RB67 kit with 5 lenses and 2 oil backs, which digital back would you recommend for my RB67 Pro SD

  • jodys
    December 10, 2011 - 7:18 am | Permalink

    The number of frames for 6×8 is: 9 exposures with 120 roll film or 18 exposures with 220 roll film

  • T Kamiya
    August 23, 2012 - 8:17 am | Permalink

    Using 6×8 motorized back on Pro-SD, top of the image has not so well defined border. All other borders are sharply defined. Looks more like there was an obstruction along the light path. The image height is exactly 7.5cm.

    Since it is a Pro-SD body, Mamiya says (I called) the light baffle is capable of this size and it is NOT supposed to have the “8” imprinted on it.

    Is this how it works??

  • Ken Pratt
    April 25, 2013 - 2:24 pm | Permalink

    I bought a 6X8 back and I don’t understand the term “power pack”. In the battery compartment it would appear that four AA batteries are what is needed. Is that what is meant by the Power Pack?

    • jodys
      May 2, 2013 - 8:05 pm | Permalink

      There is only the 6×8 power back which is the whole 6×8 film back with integral battery compartment. The much older Pro-S generation motor backs required additional power packs. Hope that clarifies things.

  • Panoramic PEI
    July 19, 2013 - 5:19 pm | Permalink

    I recently ordered a Mamiya Pro SD with a 6×8 Back & 50mm C Lens for one specific reason, Panoramic Format Photography on 35mm film with the help of some adaption of course. With my Bronica ETRSi & Panoramic W 135mm Backs my final result is a 24mm x 54mm negative or transparency or 2.25 x the width to the height. The Mamiya RB SD will render 24mm X 75mm or 3.1 x the width to the height which will better a 6×17 Panoramic Camera for the Panoramic Ratio. In my case, extra width of exposed film is welcomed.
    The downfall is I would prefer to photograph 6×7 when I load the camera with 120 film, I’ll be stuck with the 6×8 format.

    • jodys
      July 22, 2013 - 5:20 am | Permalink

      Please, keep us posted with your results and details on what you used to allow the use of 35mm film.

      Recall that the RB67 has removable film backs. While 6×8 requires specific parts, those parts are compatible with 6×7 film backs as well. So if your modifications are limited to just the film back you can always carry two backs, one for panoramic and for 6×7 and swap them whenever the situation needs it.

  • Panoramic PEI
    August 3, 2013 - 12:51 pm | Permalink

    Unfortunately I hit a snag with 35mm Film & the 6×8 Motorized Back, the Back will stop at #1 with 120 Film but will just keep going with 35mm Film & not stop at #1, doesn’t matter if the Back is on 120 or 220 side or Motorized or Manual Mode. KEH is sending me another Back due to the fact the Lock- Open Latch was broken & missing, hopefully that Back has other differences to recognize the fact that 35mm Film is loaded & it will stop at #1.

    • Panoramic PEI
      August 7, 2013 - 9:15 am | Permalink

      It seems the problem is the the 35mm Cassette sits on the Roller therefore jams the Roller or Cog (which activates the counter)) once taped to the main Roller will not turn either.
      I will need to find a Pro S 220 6×7 Back, the 35mm Cassette will not interfere with the Roller due to the different design (where the loaded film sits) compared to any SD Back.

      • Panoramic PEI
        September 8, 2013 - 5:38 am | Permalink

        It seems the earlier 6×8 Motorized Backs where designed with the larger RB-S Rollers therefore now I am able to load 35mm Film into a 6×8 Back (the newer SD version is impossible to load 35mm due to the thinner rollers, the 35mm film will not advance correctly). The results are excellent, 24 x 76mm format, without a paper leader I get 13 images from a 35mm 36 exposure roll, with perfect spacing between frames.
        Considering how heavy this equipment is to carry on the field, to come back with 13 excellent images, mission accomplished.

  • Eulalio Silva
    January 10, 2018 - 4:45 pm | Permalink

    I have a PRO SD and a PRO SD adapter…so I realize that I can only use the portrait/vertical orientation so if I use the landscape/horizontal format – what would happen? Would it simply vignette on the sides? corners?

    Kindly have a link for samples please? Thanks much and love you all, RB community!

  • November 2, 2018 - 9:42 am | Permalink

    You will lose a tiny bit of the corners. If you scan the negative that easy correctable in PS. It is different for each lens though. The 75mm Shift lens covers the total format. The 140mm Macro almost does the job.

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