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Thread: Caldwell Photographic 120mm f/4.5 Macro UV-IR Apochromat

  1. #1
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    Caldwell Photographic 120mm f/4.5 Macro UV-IR Apochromat


  2. #2

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    Re: Caldwell Photographic 120mm f/4.5 Macro UV-IR Apochromat

    A wonderful lens.

    At 1:1, where the image circle will be presumably double what they state, it's still a bit small for Large Format, no ?

  3. #3

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    Re: Caldwell Photographic 120mm f/4.5 Macro UV-IR Apochromat

    Quote Originally Posted by Ken Lee View Post
    A wonderful lens.

    At 1:1, where the image circle will be presumably double what they state, it's still a bit small for Large Format, no ?
    It is, indeed. Unless you put on the back of your LF camera a RF holder 6x9 (why not a 6x7?) and then we can start, once again, the lengthy theories about what is LF photography. Wonderful, isn't it?

  4. #4

    Re: Caldwell Photographic 120mm f/4.5 Macro UV-IR Apochromat

    Dr Brian Caldwell, the optics designer whom I have the honor to know, did (again) a fantastic job for this multispectral lens, which is intended for a special monochrome digital scan back to scan ancient documents, the http://www.mega-vision.com/cultural_heritage.html

    (image (c) Dr Brian Caldwell)
    Klaus

    http://www.macrolenses.de for macro and special lens info
    http://www.pbase.com/kds315/ for UV Images and lens/filter info
    http://photographyoftheinvisibleworld.blogspot.com/ my UV diary

  5. #5

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    Re: Caldwell Photographic 120mm f/4.5 Macro UV-IR Apochromat

    Re: Caldwell Photographic 120mm f/4.5 Macro UV-IR Apochromat

    From Dr. Klaus:

    >Dr Brian Caldwell, the optics designer whom I have the honor to know, did (again) a fantastic job for this multispectral lens, which is intended for a special monochrome digital scan back

    Actually, the lens is designed not for a scan back, but for an area capture. MegaVision's current E6 39 megapixel monochrome is due to be updated with the company's 50 megapixel E7 offering, next month. This monochrome setup is designed to take advantage of the 12 separate bands of LED illumination by dispensing with the greenish IR filtration (worth a stop-and-a-thrid) and the Bayer pattern (an additional stop-and-a third). This design ethic results in close to a 1,000 times less light volume on the cultural treasure-- some treasures are limited to 50 lux which is quite dim. Removing the two glass surfaces reduces the internal flare and optimizes Brian's design. Brian's lens provides marked resolution improvement in the UV wavelengths. Brian's patent pending clocking mechanism provides improved center-to-corner resolution compared to the Schneider and Rodenstock designs. Brian's floating front element is a first for a view camera optic and his use of an aspheric rear element avoids the need for costly quartz glass in a multi-spectral optic (like the Coastal 60). All in all, quite a lens. Brian is to be commended for thinking out of the box.

    From Ken Lee:

    >At 1:1, where the image circle will be presumably double what they state, it's still a bit small for Large Format, no ?

    Brian's lens was not designed for large format film. It was always specifically designed for a multi-spectral LED illuminant used for imaging a 6.8 micron and smaller pixel, in a 37mm x 49mm image area. Film is not an acceptable landing area for scientific imaging in these modern times. Brian's lens will make a first class film imager, but that was not the original intent.

    GPS wrote:

    >and then we can start, once again, the lengthy theories about what is LF photography

    It may be practical to consider the native size of a 39 megapixel sensor-- 18 x 24 inches @ 300 pixels per inch. A 50 megapixel sensor is 20 x 27 without enlarging.

    Richard Chang

  6. #6

    Re: Caldwell Photographic 120mm f/4.5 Macro UV-IR Apochromat

    Where can one go about buying this lens, as I cannot find any info anywhere on how to contact Caldwell etc.

    Thanks

    M

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