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  1. #111

    Join Date
    Mar 2008
    Large Format
    new update, Xenotar 2.8/150 on Byron

    RF housing not yet mounted.

  2. #112

    Join Date
    Mar 2008
    Large Format
    Finally, I made it!

  3. #113

    Join Date
    Oct 2011
    Santa Paula, California
    Multi Format
    Too Cool! A true Milestone in 4x5 Polaroid 110B tecnology.

    You are the Zen Master of the Big, Big Xenotar!

    I have customers that want a 150mm Xenotar conversion, they will be in touch with you soon, Xenotar Mania Lives!

    Myself, Noah, Dean and Nate have beaten down the Grinch in New York! So Glad he has not bothered you, he must know his arse is beat!

    Now if I could just get a few more of those 135mm f3.5 Xenotars.........

  4. #114

    Join Date
    Mar 2013
    Instant Films
    Quote Originally Posted by salihonba View Post
    Basic concept is clear, so we conclude the steps of calibration as following..

    1. Zeroing: set the lens to infinity, and make sure the mirror arm is attached with cam, on the mark line.
    2. Align overlay image at infinity object.
    3. Align overlay image at closer object.

    That are all steps we will follow, then here comes the detail...

    1. Byron camera with prime lens, ground glass panel, magnifying loupe, tripod.

    2. Screw drivers, one tiny flat head, one normal philips head.

    3. A sunny day and clear view
    Choose a contrasty object as infinity target, like a high-voltage tower, about 2 km away from my house.

    4. A high contrast object for close focusing
    What I pick is a Big number calender panel. Hang it on wall, at the same height of the tripod, parallel with camera.

    Step 1. RF housing removal

    * Byron uses two screws to hold the RF housing, one is beneath the cold shoe, you need to remove tiny screw on top, and peel apart the plastic sheet to reveal the screw.

    * Another one is in the side plate of film chamber, this screw need a long neck driver, or you can temporary take off the sliding tooth set for easier un-screwing.

    * Once two screws are removed, carefully take the housing off, and put it aside.

    * Now the RF mechanical parts are revealed, what we will adjust later are three parts, as explained at beginning, they are fixed screw, mirror, and lens cam (from left to right).

    Step 2. Zeroing
    Now we are going to calibrate infinity end, this is no extension for rail, so called zeroing.

    * Mount Byron onto the tripod, face the infinity object. (high voltage tower)
    * Mount on your prime lens, here is a Ysarex 4.7/127mm lens as example, if your prime lens is 150mm, mount it on.
    * Pull the front standard to the correspond infinity stop, engage the groove. Byron engraves lens length for each infinity stop, so it is easy to distinguish.

    * Set shutter to B, and with a cable release lock, make the lens shutter keep opening, and the aperture to full opening.
    * Make sure that rail is not extended, distance scale marked on infinity. You can check with loupe on ground glass panel.
    * Check lens cam, mirror arm should engage cam curve at the engraved line, adjust the cam by loosing locking screw if necessary.
    * View through the RF eye window, align the tower in the center, observe the overlaying image, do necessary adjustments, till images align with each other.
    * (In this step, we use two screws on mirror for adjustment)

    Step 3. Close distance calibration

    * After zeroing, turn camera to close distance object (calender), adjust camera distance to object about 4 feet, about the nearest distance the lens can focus.
    * with loupe and ground glass panel, turn the focus knob to focus the object, after focus is set, DO NOT TOUCH THE KNOB ANYMORE!
    * View through the RF eye window, align the object in center, observe the overlaying image, do necessary adjustments, till images align with each other.
    * (In this step, we use fixed screw for adjustment)

    Step 4. Re-check, further adjustment

    * Both infinity and close ends are calibrated, we re-check the result by turning back to face the infinity, to see if images in eye window keep align or not.
    * If overlay images keep align, then the calibration is done, and you can put back the RF housing.
    * If overlay images are not aligned with each other, then it may caused by wrong cam curve section. By loose the cam locking screw and turn the cam a bit, to make overlay images align again.
    * Repeat step 1~3, make necessary adjustments, till overlay images keep align on both end.

    These are steps for calibration, I hope this answer some questions concerning about the RF adjustments.

    And for Byron whose prime lens is set to 150mm, the original 127mm lens cam is replaced by custom made 150mm lens cam, they look alike, but curve is little bit different. (left: 150mm cam, right: 127mm cam)

    Sometimes new cam needs a little bit of filing to match the lens, because each lens got its own character! That belongs to advanced fine tuning...
    First I'd just like to say you do beautiful work, some of the best back and rail systems I've seen, super clean and smooth. The info here was very informative as I'm having a small issue coupling the rangefinder on my 900. I'm using a 150mm Calumet Caltar Type-S f/5,6 on a home made standard from hard woods. I'm still working to get the 150mm into infinity due to the stop won't reach far enough back. I've installed a 600SE release for removable backs and this is what( I truly believe) has caused the problems as it to far off to reach because the 900s infinity stop only goes back to the focus wheel. All I need is about 5mm more but have not found a way around this due to there is a need for the standard to clip into the bracket from all the weight up there. I've been trying to come up with some sort of other clip for the Mamiya backs (these are my favorite films, cheap, easy to find on trips and I get 120, cut film, small wet plates and Impossible films as well) but nothing that's stable enough so far to trust out in the field. As i'm sure you know the bracket for the film backs is fairly thick and if there was another way to not use piece I would. I've tried my 210mm but of coarse this is way to much. I've been looking for some time now to find a better way, It was all put together and out taking beautiful shots with it but of coarse I was dependent on the ground glass till this issue is resolved, so it has been disassembled until a way is found but as you could guess I'm really excited to get it back together to go out and play. If you have any suggestions i'd be open to anything, all I have is limited tools and most the work is done by hand so I'm limited by this.
    Last edited by swardo; 03-16-2013 at 03:31 AM. Click to view previous post history.

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