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MInolta bellows III: conversion to MFT

Discussion in 'Adapted Lenses' started by Austrokiwi, Apr 21, 2016.

  1. Austrokiwi

    Austrokiwi Mu-43 Regular

    46
    Mar 19, 2016
    I suspect some people reading this will have clicked on this thread just to see why any one would bother converting a bellows to MFT. There are plenty of Adapters that will allow us to couple a MFT camera to a bellows supposedly without in need to convert those bellows to the MFT mount.
    To begin with some background. Most of my photography interest developed from my main hobby coin collecting. In wanting to produce good pictures of my coins and later high resolution pictures for Journal articles I developed a real interest in Macro photography. My interest coincided with the development of mirror-less cameras and I went the full frame route with Sony. However over the last year I started to realize a bigger sensor may not actually be the best approach. With a Full frame sensor I was being forced to focus stack ( using the cognisys stackshot system). The issue was that to fill the full frame sensor with the image of the coin I had to use high magnification resulting in shallow depth of field. With an MFT sensor I knew that I would use much lower magnifications with a corresponding increase in the DOF.

    DSC03406.JPG


    Before I purchased my MFT camera I already had a macro rig set up( vibration resistant) and two Minolta Bellows III. This particular model is very well made and it has the advantage of being tilt-shift. Also both the front and rear bellows standards move so you can mount the bellows and not have the bellows rail extending in front of the lens( which can be very annoying when you need to focusing close to the subject).

    As soon as I started mounting the MFT camera to on of these bellows I ran into a problem. The adapter needed Minolta MD-MFT added far too much extension. With the adapter there was 85mm between the lens and the camera sensor As can be seen here:

    DSC03419.JPG

    This meant I was getting shots like this at zero Bellows extension:


    mil.
    I had recently discovered that the Minolta MD/MC camera mount on the bellows could be easily removed so I contacted RAF Camera in Belarus and asked if he could make a replacement mount for the Bellows. As a result today I received the replacement mount. Fitting it was reasonably simple. I first un-clipped the bellows from the front standard.

    DSC03407.JPG


    I then removed the bellows from the rear standard, this involved unscrewing four tiny screws (inside the bellows) once the bellows was off the rear mount I could access the retaining ring that holds the MD/MC mount in place.

    DSC03409.JPG
    (You can see the four small screw holes that are used to hold the bellows in place)
    The new mount made by RAF camera is machined so that it uses that same retaining ring. It was just a simple matter of swapping the original mount with the RAF made MFT mount and then I reassembled the bellows( total time of disassembly and reassembly was just over 6 minutes)


    This is what the finished conversion looks like

    DSC03411.JPG


    DSC03416.JPG




    And this is what the bellows can produce with the reduced gap between the sensor and lens( now 65mm)

    P4210002.
    Here is the modified bellows mounted on my rig( note the lens is a Schneider Kreuznach APO 45/4 HM

    DSC03418.JPG

    I can still do high magnification work with the modified bellows and the conversion is reversible. This conversion can also be performed on the Minolta Bellows IV( which is non-tilt shift)
     

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    Last edited: Apr 21, 2016
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  2. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    Looks like a Kaiser 4x5 enlarger in it's copy stand guise? The older enlargers are great for it as the cast iron damps vibrations...

    Good result :)
     
  3. MAubrey

    MAubrey Photographer

    Jul 9, 2012
    Bellingham, WA
    Mike Aubrey
    The OM-10II does focus stacking in camera, too, right?
     
  4. Austrokiwi

    Austrokiwi Mu-43 Regular

    46
    Mar 19, 2016
    Good guess but slightly off target. The macro stand was originally a kaiser enlarger stand. now the only part that remains of that enlarger stand is the mount that connects the column to the base board. Every thing else was replaced, some of the replacements were kaiser parts purchased new. The baseboard is a 600mm X 600mm X 30 mm slab of granite ( weighs 29kg). The column is now a Kaiser 4476 which has weight compensation, and the camera arm mount can be locked into place on the column. The camera arm is a Kaiser RA 101 which is is only 45mm in length against the standard 100mm. I then use a series of Swiss arca clamps and rails to change how the camera is mounted. This includes two small panorama clamps that are used to adjust level( Chinese made arca rails are not that accurately machined). The macro stand sits on Sorbothane feet ( to dampen vibration). Underneath a bench style table sits on two 15 kg concrete slabs. What you can't see in the picture is the stack-shot focusing rail( hidden behind the camera in the pictures)

    Correct but the Cameras stacking system is too much of a "black box" for my purposes. With the stack shot I can adjust how many microns the focus moves between each shot. Also, although the Oly 60mm macro is a nice lens it just doesn't match the performance of other lenses( which can't use the cameras stacking) I have. In fact I would rate the Oly ED 50mm F2 Macro lens ( which can't use the cameras focusing stacking feature) as a much better performer than the 60mm. It would be really nice if Olympus actually reissued the ED 50mm in MFT format, improving that lenses focusing system in the process.
     
    Last edited: Apr 23, 2016
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  5. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    Sounds like a really nice setup, close but no dice with the guessing game. I find using well thought out and setup equipment actually makes the job more enjoyable.

    I also agree about the performance of native lenses compared to the potential of adapted lenses, I'm holding onto a set of Rodenstock APOs just in case (40mm, 50mm, 75mm, 135mm. their ebay value doesn't match their real world potential imo).
     
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  6. Austrokiwi

    Austrokiwi Mu-43 Regular

    46
    Mar 19, 2016
    In regards to the guessing game I assume you mean Oly's focusing stacking feature. I agree I don't like guessing. I have my own DOF calculator that consists of a Microscope calibration slide mounted at 45 degrees. When setting up a shot I image the calibration slide, measure how much is in focus and then using pythagoras calculate how much vertical focus movement is required in the stack, which is then programed into the stack shot controller. I am envious of the collection of APO Rodenstock optics, brilliant lenses for macro work.

    Edit: ON the guessing game/"black box", I was really disappointed with Olympus, I did approach them and ask for the information that would take the guessing game out of using their focus stacking feature but they won't release the info necessary as they regard it as commercially sensitive. As a result, for me the Olympus focus stacking feature is a waste of time. I have started making a table relating depth of field in Microns to magnification and F stop... but I doubt i will ever finish it.
     
    Last edited: Apr 23, 2016