Rodenstock Imagon 120mm f4.5 Soft-Portrait Lens

Discussion in 'Medium Format Cameras and Accessories' started by gr82bart, Jan 8, 2005.

  1. gr82bart

    gr82bart Subscriber

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    Anyone know where I can get more info on this lens? Specifically, I need instructions.

    I picked this lens up at a flea market of all places. The guy selling it had in a Hassey 500CM and it gives this soft-like appearance using these disks with holes. The guy selling it had no clue how to use the lens or the camera. It was obvious since he had it on sale as a package for $650 CAD. I had to show him how to wind the camera and what to do after it reached 12. All I wanted was the lens, which I bartered him down, for the lens only. I figured it was worth a lot more.

    Any help would be appreciated.

    Regards, Art.
     
  2. bobfowler

    bobfowler Subscriber

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  3. gr82bart

    gr82bart Subscriber

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    HELP!

    OK, So what I have is a Rodenstock Imagon 120mm f4.5 lens that's attached to a Prontor Professional 1 shutter, it looks like, that's attached to a Hasselblad converter that appears to have a focusing ring. Plus I have a lens hood, a filter of some sort labelled 4x and three snap-on disks labeled H=4.5/H=5.8, H=5.8/H=7.7, & H=7.7/H=9.5.

    How the HECK does this thing work with my Hassey?

    The converter doesn't have the cocking mechanism in it, so it looks like I have to hold and cock the mirror up and then depress the shutter some how. What I can't do is focus because the shutter is always closed and I can't figure out how to open the shutter long enough to focus.

    I probably need a very fancy cable release of some sort as well in order to time this thing properly.

    HELP!

    Regards, Art.
     
  4. rbarker

    rbarker Member

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    The shutter should have a bulb (B) setting. If you have a locking shutter cable, you should be able to use that to focus. The Prontor shutter itself, unlike many LF shutters, is "self cocking" - that is, depressing the cable release cocks and then releases the shutter.
     
  5. gr82bart

    gr82bart Subscriber

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    Thanks Ralph,

    I got this procedure from the Hassey User's Group:
    --------------------
    With a 500 series body you can in theory make due with one cable release on the Prontor, but it would be easier with two, the second for your body's release.

    The procedure would be like this:
    1. Open the Prontor shutter (B exposure) with cable release and lock.
    2. Focus.
    3. Close Prontor shutter by unlocking the release, and set proper/desired exposure.
    4. With a second release open the body's aux shutter by pressing the release, or alternatively, prefire the body (mirror prefire).
    5. With the aux shutter open then release the Prontor shutter using the cable release.
    6. Release the body's shutter or unlock the cable release on the body to close the body's aux shutter.
    --------------------

    I guess I would add the disks after focussing and see which one gives me the effect I like.

    One more question - which f-stop do I use? If the disk has an f-stop of f7.7 and the shutter an f-stop of 5.6, I assume the f5.6 f-stop prevails, right?

    And with Bob's links I think I've got the whole idea of this thing. Now to give it a whirl.

    Regards, Art.
     
  6. bobfowler

    bobfowler Subscriber

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    Nope, the smaller f/stop is the one that prevails. Think about it for a minute... if the disk has a stop of f/7.7 and the lens is f/5.6, how would the lens get more light than the disk allows?
     
  7. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    I think the idea with an Imagon is always to use the aperture wide open and use the disks to control exposure.

    The principle of the "sink strainer" aperture is that the softness is created by spherical aberration, or the difference in focus between rays that enter at the edge of the lens as opposed to rays than enter near the lens axis. Normally this would be corrected as you stop down, because you are reducing the contribution of light from the edge of the lens, but the disk allows you to reduce the amount of light entering the camera while still using the rays from the edge. Some soft focus lenses achieve this effect by using a star-shaped diaphragm, rather than a round diaphragm.
     
  8. steve

    steve Member

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    I own this exact lens. There should be two cable releases. One interfaces with the shutter release on the Hasselblad camera body to the Imagon, and the other with the lens shutter. Through a really convoluted mechanism (works about 50% of the time), the Imagon will trip the mirror in the body when the shutter on the Imagon is released. In practice, its way easier to manually trip the mirror lockup on the camera body.

    For the softest effects, the f/stop on the lens must be wide open. As you stop down the lens iris, the lens will become sharper and sharper, until you notice no soft focus effect. Use the the lens wide open, and the discs to control the effect. You should notice that the discs also turn so that some of the apertures through the disc are blocked. This controls the amount of effect you get from the lens and exposure.

    In use, what I do is focus the lens, manually trip the mirror lockup on the camera and then expose with the shutter release on the lens. This takes some practice, and use on a tripod - but, the lens is far from hand holdable anyway. BTW - the price you paid is really a good deal.

    When I got my lens, I paid $1450 USD (employee price!) in 1994. The lens was not being imported into the US and I got it through a friend who's a representative for HP Marketing. The president of HP hand carried the lens back from Germany on one of his trips to the Rodenstock factory. You have a very low production lens that is no longer available. They work great - have fun using it. Search on photo.net, Bob Solomon (VP of HP Marketing) posted extensive instructions about 4-5 years ago on exactly how to use the lens to best effect.
     
  9. gr82bart

    gr82bart Subscriber

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    D'oh! You are absolutely correct. Photography Basics 101 again! Bigger number - smaller opening. Thanks.

    Regards, Art.
     
  10. gr82bart

    gr82bart Subscriber

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    Thanks Steve,

    I will look on Photo.net some more.

    Holy cow! I paid $200CAD for the lens combination - lens, shutter, neutral density filter, 'sink strainer' disks, and Hasselblad converter.

    Reading through some more online literature, I might need a one of these fancy shutter accessories (it's a monster of precision German engineering!): http://www.skgrimes.com/prontor/

    Thanks again, everyone, for all your help.

    Regards, Art.
     
    Last edited by a moderator: Jan 12, 2005