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Thread: Rm3d

  1. #1
    Member Chris Barrett's Avatar
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    Rm3d

    Finally got enough of a breather to put some words and pics together after a couple months with the new toy...

    Explicit Camera Porn HERE!

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    Senior Member Quentin_Bargate's Avatar
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    Re: Rm3d

    Disgusting!!!!!!!!!! It made my wallet tremble

    Quentin
    Quentin Bargate
    Director of Bargate Murray, Law Firm of the Year 2012 - 2017, ”leading individual”, Chambers HNW guide, 2017, Photographer

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    Re: Rm3d

    seems like a beauty, looks like arca got way into your pockets!
    no matter how many revs you have for the helicoid, isn't the gg focusing still limited by the registration of the back compared to the gg? how well is that done?

  4. #4
    Member Chris Barrett's Avatar
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    Re: Rm3d

    Quote Originally Posted by jlm View Post
    seems like a beauty, looks like arca got way into your pockets!
    No argument there.

    Quote Originally Posted by jlm View Post
    no matter how many revs you have for the helicoid, isn't the gg focusing still limited by the registration of the back compared to the gg? how well is that done?
    Absolutely and I've heard about hit and miss results with various manufacturers. My stuff seems to line up pretty nicely.

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    Re: Rm3d

    Hi Chris, What is in the cold shoe in the very last picture? Thanks, John

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    Re: Rm3d

    Hi Chris. 1) In your experience..which method works best for focusing with this camera : tape measure, focus with the GG and a loupe or "live view" with a laptop ? Maybe this is not clear in your reviw or I dont understand it very well. ( I am a non English speaker )

    2 ) In what scenarios do you prefer to use the R or M-2 camera ?

    Thanks a lot

    Luis
    Last edited by celina20; 21st July 2010 at 13:46.

  7. #7
    Member Chris Barrett's Avatar
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    Re: Rm3d

    John, I asked Arca to fabricate that for me, it slides into the mount for the Vario Finder, which I don't use.

    Luis, I usually focus by ground glass and then fine tune that via captures on the laptop. Live View on the P65 still sucks. I'm using the M2 more for long lens work. I don't have the 90, 135 or 180 mounted for the R (so those only go on the M2). I often find that when I'm shooting with those long lenses that I am also employing more movement than the Rm3d has, so the M2 is perfect in those applications.

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    Re: Rm3d

    Quote Originally Posted by Chris Barrett View Post
    John, I asked Arca to fabricate that for me, it slides into the mount for the Vario Finder, which I don't use.
    Hi Chris, I still don't see what it is. What exactly are you using in the cold shoe?

  9. #9
    Member Chris Barrett's Avatar
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    Re: Rm3d

    Quote Originally Posted by David Klepacki View Post
    Hi Chris, I still don't see what it is. What exactly are you using in the cold shoe?
    Oh, I've got a Profoto radio slave mounted there.

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    Re: Rm3d

    Chris --

    Please elaborate on the focusing mechanism and lens calibration you mention in your report.

    Thanks,

    Dave.

    "... The focus ring on the R makes nearly 5 full rotations, that’s about 1720° of focus adjustment from infinity to closeup… much, much more adjustment than the other style or my view camera have. The ring is indexed and all the lenses come with a cheat sheet that tells you what index number to set the focus at for a given distance. I have tried this method using a tape measure and it is extremely accurate. ..."

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    Re: Rm3d

    Quote Originally Posted by delled View Post
    Please elaborate on the focusing mechanism and lens calibration you mention in your report.
    I do not mean to hijack Chris' thread, but I can help answer your question. I use the RM3D on occasion and am very familiar with using it.

    Each lens is calibrated by Arca-Swiss in order to compensate for (very) small variations in their registration distance to the sensor plane. Unlike other camera systems where the focusing helicoid is part of the lens, on the RM3d the focusing helicoid is part of the camera body. This allows the helicoid ring to be much larger in diameter than on the lens. The larger the helicoid diameter, the finer the sensitivity you have in focusing. (As a side note, a larger diameter helicoid also minimizes internal flare, resulting in greater realized contrast.)

    For example, on a standard lens helicoid for a wide angle lens the amount of focusing between 10 meters and infinity is about 15 degrees of angular movement on the lens helicoid. With the RM3d helicoid, there is close to 600 degrees of angular movement, which is a huge difference in focusing sensitivity. With this much sensitivity, it is possible to achieve "perfect" focus (in the sense that your eyes cannot perceive any better on the GG) by simply measuring the distance to your focus point, for example with a good laser measurement tool. Arca-Swiss provides a small laminated "focus table" for each lens that shows the helicoid setting as a function of distance from the sensor.

    It is a very strange feeling to get extremely sharp images without focusing with your eyes ... but it works. Insecure beings that we are, we always choose to shoot tethered with live preview just to make sure we get the shot. However, if for whatever reason you cannot do this, you can safely rely on the distance method. Composing the shot can be done either with an external viewfinder or on the GG.

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    Re: Rm3d

    David --

    So Arca have already done the calibration for each individual lens -- very nice. Took a bit to sink in.

    Thanks,

    Dave.

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    Re: Rm3d

    "It is a very strange feeling to get extremely sharp images without focusing with your eyes ... but it works. "

    +1

    and at the end of the day, your eyes aren't tired !

    I'm in love with my RM3D also !

  14. #14
    Member Chris Barrett's Avatar
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    Re: Rm3d

    Well said, David, thank you.

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