f/0.75 lens

Discussion in 'Digital SLR' started by Buy_Sell, Nov 28, 2005.

  1. Buy_Sell

    Buy_Sell Guest

    I have been collecting lenses from old medical machines that have been
    sent to the metal recycling yards. They don't have any apertures but
    they are pretty fast glass. The advantage of buying glass from
    recycling yards is that most lenses sell for less than a dollar.

    I am wondering how hard it would be to make these lenses useful for low
    light photography?
    Has anyone experimented with making their own lens arrays and
    mountings?
    A few of the faster lenses are as follows:

    KOWA 1:0.75 / 42mm
    KOWA 1:0.95 / 33.5mm
    KOWA 1:1.4 / 95mm
    Rodenstock TV-Heligon 1:1.25 / 64mm
    Buy_Sell, Nov 28, 2005
    #1
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  2. Buy_Sell

    Pete D Guest

    "Buy_Sell" <> wrote in message
    news:...
    >I have been collecting lenses from old medical machines that have been
    > sent to the metal recycling yards. They don't have any apertures but
    > they are pretty fast glass. The advantage of buying glass from
    > recycling yards is that most lenses sell for less than a dollar.
    >
    > I am wondering how hard it would be to make these lenses useful for low
    > light photography?
    > Has anyone experimented with making their own lens arrays and
    > mountings?
    > A few of the faster lenses are as follows:
    >
    > KOWA 1:0.75 / 42mm
    > KOWA 1:0.95 / 33.5mm
    > KOWA 1:1.4 / 95mm
    > Rodenstock TV-Heligon 1:1.25 / 64mm


    Have you had a look at what is available in a "T" mount?
    Pete D, Nov 28, 2005
    #2
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  3. Buy_Sell

    Stacey Guest

    Buy_Sell wrote:

    > I have been collecting lenses from old medical machines that have been
    > sent to the metal recycling yards. They don't have any apertures but
    > they are pretty fast glass. The advantage of buying glass from
    > recycling yards is that most lenses sell for less than a dollar.
    >
    > I am wondering how hard it would be to make these lenses useful for low
    > light photography?
    > Has anyone experimented with making their own lens arrays and
    > mountings?
    >


    I've "hacked" some lenses onto medium format cameras and it's not too hard.
    The biggest problem is the focus helix or the lack thereof.

    --

    Stacey
    Stacey, Nov 28, 2005
    #3
  4. Buy_Sell

    Donald Gray Guest

    On 27 Nov 2005 18:54:08 -0800, "Buy_Sell" <>
    wrote:



    >Has anyone experimented with making their own lens arrays and
    >mountings?


    Yes - I am in the process of putting an Olympus OM 10 50MM on my Canon
    20D....

    I had a spare blanking cover for the body - Cut a hole in it that
    would just accept the base of the OM lens. It does have an Iris but
    the auto iris lever on the back of the lens needs to be in the
    'closed' position...

    The blank cover is thickish and sets the lens forward and the furthest
    it focuses is about two feet. I have taken a couple of experimental
    shots and it looks like in might make a reasonable macro setup...

    The main problem I have is working out a way of sticking the lens to
    the blanking cover - I might even try super glue. Hehehehe.... But I
    am going down to the hardware store first and see if I can get some
    tubing that I can fashion an extension barrel !!!!
    Donald Gray, Nov 28, 2005
    #4
  5. Buy_Sell

    wilt Guest

    >>Yes - I am in the process of putting an Olympus OM 10 50MM on my Canon
    20D.... I had a spare blanking cover for the body - Cut a hole in it
    that
    would just accept the base of the OM lens. It does have an Iris but
    the auto iris lever on the back of the lens needs to be in the
    'closed' position... <<

    Or you could buy a proper adapter for about US$50 on eBay
    wilt, Nov 28, 2005
    #5
  6. Buy_Sell

    Gormless Guest

    "Buy_Sell" <> wrote in message
    news:...
    > I have been collecting lenses from old medical machines that have been
    > sent to the metal recycling yards. They don't have any apertures but


    By 'without apertures' I assume you mean they can't be stopped down?
    In which case, the depth of field of such lenses would be absolutely tiny.
    Gormless, Nov 28, 2005
    #6
  7. Buy_Sell

    Donald Gray Guest

    On 28 Nov 2005 07:24:52 -0800, "wilt" <> wrote:

    >>>Yes - I am in the process of putting an Olympus OM 10 50MM on my Canon

    >


    >Or you could buy a proper adapter for about US$50 on eBay



    Yeah - BUT....I don't want to use this lens other than to see if the
    exercise will work....

    At £3 ($5) it is 10 times cheaper...

    My way is more fun & satisfying....
    Donald Gray, Nov 28, 2005
    #7
  8. In article <>,
    "Buy_Sell" <> wrote:

    > I have been collecting lenses from old medical machines that have been
    > sent to the metal recycling yards. They don't have any apertures but
    > they are pretty fast glass. The advantage of buying glass from
    > recycling yards is that most lenses sell for less than a dollar.
    >
    > I am wondering how hard it would be to make these lenses useful for low
    > light photography?


    B.S.-

    Also consider obtaining a cheap lens for a particular camera and using it
    to house the glass from one of your salvaged lenses. If you can manage
    it, there would be an aperture adjustment and a focusing mechanism.

    Bear in mind that the f/stops are determined by aperture diameter and lens
    focal length. To use the f/0.75 42mm, you would need an old lens with a
    maximum aperture of at least 56mm. For example, suppose you found an old
    250mm f/4 lens. That would have a maximum aperture of 62.5mm.

    You might even figure out a way to use the existing AF motor. Talk about
    a challenge!

    One thing you may find, is that these salvaged lenses were used for a
    different purpose than you want. For example they might be designed to
    provide a flat-field image of a flat-field subject, rather than
    flat-from-spherical as commonly used in photography.

    Fred
    Fred McKenzie, Nov 28, 2005
    #8
  9. Buy_Sell

    DoN. Nichols Guest

    According to Donald Gray <>:
    > On 28 Nov 2005 07:24:52 -0800, "wilt" <> wrote:
    >
    > >>>Yes - I am in the process of putting an Olympus OM 10 50MM on my Canon

    > >

    >
    > >Or you could buy a proper adapter for about US$50 on eBay

    >
    >
    > Yeah - BUT....I don't want to use this lens other than to see if the
    > exercise will work....


    O.K. Then *I* would use a lathe to thread the body cap to fit
    the lens' mounting thread.

    Or -- most such lenses come with a mounting ring of matching
    thread, which attaches to the lens board (or in this case, the body cap)
    with three equally-spaced screws.

    > At £3 ($5) it is 10 times cheaper...


    O.K.

    > My way is more fun & satisfying....


    That I can understand.

    I've got a 50mm f/0.95 lens (in C-mount) which I may experiment
    with someday.

    Enjoy,
    DoN.

    --
    Email: <> | Voice (all times): (703) 938-4564
    (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
    --- Black Holes are where God is dividing by zero ---
    DoN. Nichols, Nov 28, 2005
    #9
  10. Buy_Sell

    DoN. Nichols Guest

    According to Fred McKenzie <>:
    > In article <>,
    > "Buy_Sell" <> wrote:
    >
    > > I have been collecting lenses from old medical machines that have been
    > > sent to the metal recycling yards. They don't have any apertures but
    > > they are pretty fast glass. The advantage of buying glass from
    > > recycling yards is that most lenses sell for less than a dollar.
    > >
    > > I am wondering how hard it would be to make these lenses useful for low
    > > light photography?

    >
    > B.S.-
    >
    > Also consider obtaining a cheap lens for a particular camera and using it
    > to house the glass from one of your salvaged lenses. If you can manage
    > it, there would be an aperture adjustment and a focusing mechanism.


    Hmm ... you can't put the aperture just *anywhere*. It must be
    put at the nodal point of the lens assembly. Anywhere else will result
    in varying vignetting as you stop down. Placing this properly may
    require quite a bit of detailed (and precision) construction.

    > Bear in mind that the f/stops are determined by aperture diameter and lens
    > focal length. To use the f/0.75 42mm, you would need an old lens with a
    > maximum aperture of at least 56mm. For example, suppose you found an old
    > 250mm f/4 lens. That would have a maximum aperture of 62.5mm.
    >
    > You might even figure out a way to use the existing AF motor. Talk about
    > a challenge!


    An interesting one. Part of the problem is that most AF lenses
    are designed to move only one or two elements which takes a lot less
    force than moving a focus collar to move an entire lens. (Of course,
    part of that it the grease used in the focus threads for manual focus
    lenses to provide a smoother feel to the focus.

    > One thing you may find, is that these salvaged lenses were used for a
    > different purpose than you want. For example they might be designed to
    > provide a flat-field image of a flat-field subject, rather than
    > flat-from-spherical as commonly used in photography.


    If they have "APO" as part of their names, this is quite likely.
    (Though those would not tend to be f/0.75, so these are more likely to
    be used for low-light surveillance cameras.)

    Enjoy,
    DoN.
    --
    Email: <> | Voice (all times): (703) 938-4564
    (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
    --- Black Holes are where God is dividing by zero ---
    DoN. Nichols, Nov 28, 2005
    #10
  11. Buy_Sell

    Buy_Sell Guest

    These lenses were retrieved from scrapped medical machines that looked
    similar to X-ray machines. I first got interested in collecting used
    optics when I saw the Frazier lens on the Discovery Channel on
    television. Frazier has since lost his patent for mis-representation
    but Hollywood still rents these units from Panavision for about $2,000
    per day. The Frazier lens has an incredible depth of field that would
    allow a person to photograph an object very close up while keeping
    something very far away in perfect focus.

    http://patft.uspto.gov/netacgi/nph-...,727,236.WKU.&OS=PN/5,727,236&RS=PN/5,727,236

    I have also collected several interesting mirrors that appear to be
    gold plated but when held up to the sun, they look kind of purple as
    you look thru them. You can find very interesting optics, if you look
    in the right places. I am trying to make use of these optics and the
    Frazier lens would be an interesting project to try to duplicate.

    ----------------------------------------------------
    Buy_Sell

    I have been collecting lenses from old medical machines that have been
    sent to the metal recycling yards. They don't have any apertures but
    they are pretty fast glass. The advantage of buying glass from
    recycling yards is that most lenses sell for less than a dollar.

    I am wondering how hard it would be to make these lenses useful for low
    light photography?
    Has anyone experimented with making their own lens arrays and
    mountings?
    A few of the faster lenses are as follows:

    KOWA 1:0.75 / 42mm
    KOWA 1:0.95 / 33.5mm
    KOWA 1:1.4 / 95mm
    Rodenstock TV-Heligon 1:1.25 / 64mm
    Buy_Sell, Nov 29, 2005
    #11
  12. Buy_Sell

    zeitgeist Guest


    > I have been collecting lenses from old medical machines that have been
    > sent to the metal recycling yards. They don't have any apertures but
    > they are pretty fast glass. The advantage of buying glass from
    > recycling yards is that most lenses sell for less than a dollar.
    >
    > I am wondering how hard it would be to make these lenses useful for low
    > light photography?
    > Has anyone experimented with making their own lens arrays and
    > mountings?
    > A few of the faster lenses are as follows:
    >
    > KOWA 1:0.75 / 42mm
    > KOWA 1:0.95 / 33.5mm
    > KOWA 1:1.4 / 95mm
    > Rodenstock TV-Heligon 1:1.25 / 64mm
    >


    you see them on ebay all the time, usually in a nikon mount. two problems,
    they are macro focus only, and fixed at that. and softer than butter left
    out all day.

    so what were they used for anyway, originally, I've always wondered.
    zeitgeist, Dec 7, 2005
    #12
  13. Buy_Sell

    Tony Polson Guest

    "zeitgeist" <> wrote:
    >
    >you see them on ebay all the time, usually in a nikon mount. two problems,
    >they are macro focus only, and fixed at that. and softer than butter left
    >out all day.
    >
    >so what were they used for anyway, originally, I've always wondered.



    X-rays. The reason that so many are available at this time is that
    radiography, like photography, is rapidly going digital.
    Tony Polson, Dec 7, 2005
    #13
  14. In article <>, Tony Polson
    <> writes
    >"zeitgeist" <> wrote:
    >>
    >>you see them on ebay all the time, usually in a nikon mount. two problems,
    >>they are macro focus only, and fixed at that. and softer than butter left
    >>out all day.
    >>
    >>so what were they used for anyway, originally, I've always wondered.

    >
    >
    >X-rays. The reason that so many are available at this time is that
    >radiography, like photography, is rapidly going digital.
    >
    >

    I don't think so; X-rays are almost undeviated by refraction. Virtually
    the only way to bring them to a focus is to use mirrors with a very
    small grazing angle (1 degree or less), often augmented by interference
    coatings.

    David
    --
    David Littlewood
    David Littlewood, Dec 8, 2005
    #14
  15. Buy_Sell

    Rich Guest

    On Thu, 8 Dec 2005 00:43:58 +0000, David Littlewood
    <> wrote:

    >In article <>, Tony Polson
    ><> writes
    >>"zeitgeist" <> wrote:
    >>>
    >>>you see them on ebay all the time, usually in a nikon mount. two problems,
    >>>they are macro focus only, and fixed at that. and softer than butter left
    >>>out all day.
    >>>
    >>>so what were they used for anyway, originally, I've always wondered.

    >>
    >>
    >>X-rays. The reason that so many are available at this time is that
    >>radiography, like photography, is rapidly going digital.
    >>
    >>

    >I don't think so; X-rays are almost undeviated by refraction. Virtually
    >the only way to bring them to a focus is to use mirrors with a very
    >small grazing angle (1 degree or less), often augmented by interference
    >coatings.
    >
    >David


    True. X-Ray telescope optics look like nested cylinders that are
    aluminized on the inside.
    -Rich
    Rich, Dec 8, 2005
    #15
  16. In article <>, Rich
    <> writes
    >On Thu, 8 Dec 2005 00:43:58 +0000, David Littlewood
    ><> wrote:
    >
    >>In article <>, Tony Polson
    >><> writes
    >>>"zeitgeist" <> wrote:
    >>>>
    >>>>you see them on ebay all the time, usually in a nikon mount. two problems,
    >>>>they are macro focus only, and fixed at that. and softer than butter left
    >>>>out all day.
    >>>>
    >>>>so what were they used for anyway, originally, I've always wondered.
    >>>
    >>>
    >>>X-rays. The reason that so many are available at this time is that
    >>>radiography, like photography, is rapidly going digital.
    >>>
    >>>

    >>I don't think so; X-rays are almost undeviated by refraction. Virtually
    >>the only way to bring them to a focus is to use mirrors with a very
    >>small grazing angle (1 degree or less), often augmented by interference
    >>coatings.
    >>
    >>David

    >
    >True. X-Ray telescope optics look like nested cylinders that are
    >aluminized on the inside.
    >-Rich


    Plus there is the fact that diagnostic radiographs are actually
    shadowgraphs; the X-rays pass directly from the tissue to the sensor
    (which AFAIK is indeed far more likely to be a digital one now) with no
    "optics" in between.

    David
    --
    David Littlewood
    David Littlewood, Dec 9, 2005
    #16
  17. David Littlewood wrote:

    >
    > Plus there is the fact that diagnostic radiographs are actually
    > shadowgraphs; the X-rays pass directly from the tissue to the sensor
    > (which AFAIK is indeed far more likely to be a digital one now) with no
    > "optics" in between.
    >
    > David


    The lenses could by from hybrid digital systems where a cesium iodide
    scintillator panel captures the x-rays as they exit the patient and
    converts them to light. Then a lens is used to focus the image on a
    conventional CCD light sensor.
    gbuchana(a)rogers(dot)com, Dec 10, 2005
    #17
  18. In article <>,
    "gbuchana(a)rogers(dot)com" <"gbuchana(a)rogers(dot)com"@?.?.invalid>
    writes
    >David Littlewood wrote:
    >
    >> Plus there is the fact that diagnostic radiographs are actually
    >>shadowgraphs; the X-rays pass directly from the tissue to the sensor
    >>(which AFAIK is indeed far more likely to be a digital one now) with
    >>no "optics" in between.
    >> David

    >
    >The lenses could by from hybrid digital systems where a cesium iodide
    >scintillator panel captures the x-rays as they exit the patient and
    >converts them to light. Then a lens is used to focus the image on a
    >conventional CCD light sensor.


    Interesting; thanks.

    David
    --
    David Littlewood
    David Littlewood, Dec 10, 2005
    #18
  19. Buy_Sell

    Buy_Sell Guest

    There appears to be a lot of speculation as to where these lenses came
    from. Since I was the person who retrieved them, let me provide some
    information as to what I saw. These lenses were from discarded medical
    machines. I saw some sort of video camera installed behind these
    lenses. I initialled retrieved a few of these cameras but they looked
    very old compared to todays technology, so I discarded the video
    cameras.

    ----------------------------------------------------
    Buy_Sell

    I have been collecting lenses from old medical machines that have been
    sent to the metal recycling yards. They don't have any apertures but
    they are pretty fast glass. The advantage of buying glass from
    recycling yards is that most lenses sell for less than a dollar.

    I am wondering how hard it would be to make these lenses useful for low
    light photography?
    Has anyone experimented with making their own lens arrays and
    mountings?
    A few of the faster lenses are as follows:

    KOWA 1:0.75 / 42mm
    KOWA 1:0.95 / 33.5mm
    KOWA 1:1.4 / 95mm
    Rodenstock TV-Heligon 1:1.25 / 64mm
    Buy_Sell, Dec 10, 2005
    #19
  20. In article <>,
    Buy_Sell <> writes
    >There appears to be a lot of speculation as to where these lenses came
    >from. Since I was the person who retrieved them, let me provide some
    >information as to what I saw. These lenses were from discarded medical
    >machines. I saw some sort of video camera installed behind these
    >lenses. I initialled retrieved a few of these cameras but they looked
    >very old compared to todays technology, so I discarded the video
    >cameras.
    >

    In the light of this and the comment of the previous poster, it seems
    Tony may have been right (and I therefore wrong). Still, I learned
    something.

    David
    --
    David Littlewood
    David Littlewood, Dec 10, 2005
    #20
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