Kowa 65mm f/0.75 X-Ray Lens Mounted on a Nikon D90

Flickr member scenery_and_fish found a Kowa 65mm f/0.75 x-ray lens, and mounted it to a Nikon D90 by using macro extension tubes and epoxy. The lens is fixed focus, lacks an iris, and is one beastly piece of glass.

Here’s a sample photo taken with the lens:

If you want to see more sample photos, here’s a Flickr set dedicated to this unique combo.

Image credits: Kowa 65mm f/0.75 and Sign of Spring by scenery_and_fish and used with permission

  • Josh Ladella

    WOW. That’s some intense light-gathering capacity! But all the images seem so soft. Is it a lens defect or the fact that there’s little depth of field? From what I gather, this lens should theoretically have more depth of field than a 300mm 2.8 though.

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  • Steve

    Can you please tell me what an X-ray lens is? X-rays cannot be focussed with glass lenses!!

  • Andy Wong

    Assuming one can focus X-Rays with glass, the reason this is so blurry is probably because it isn’t corrected for chromatic aberration, as the X-rays should be about the same wavelength.

  • Roger Moore

    The X-rays can’t be focused with a glass lens, but they can be used to generate visible light through X-ray fluorescence. If you put a screen covered with a fluorescing agent in the place of a regular x-ray film, you can look at x-ray results in real-time- including moving pictures rather than static ones. To minimize the x-ray dose, you want to use the most sensitive possible imaging system to record the image on the screen. That means making ultra-fast lenses like this f/0.75 beast.

    There are, or were, similar applications for ultra-fast lenses in recording other faint optical traces. Before modern recording oscilloscopes, the only way of recording a trace was to photograph the screen using an ultra-fast oscilloscope lens. ISTR that some laser rangefinders also use ultra-fast lenses to pick up faint reflected light signals.

  • Roger Moore

    That looks like bad spherical aberration, which makes sense. The faster a lens is, the harder it is to correct for aberrations. The only way to make an ultra-fast lens like this one work is to design it for a fixed magnification, e.g. 1/25 life size, which might be appropriate for chest x-rays. As you move away from the designed magnification, the aberrations will get worse. By the time you get close to life size, the aberrations will be bad enough to make the picture very soft. Combine that with ultra-narrow DOF from the fast lens and high magnification, and you get a soft in focus image and everything out of focus blurred into a smear.

  • Anonymous

    Maybe that’s what the Nikon AFS G N 50 1.2 will look like !

  • migo

    i have a d90 to but can some one explain to me how this got mounted on it? it says in the caption that he used a macro extension tube and epoxy, can the build be posted here or somewhere please? i’m quite interested in doing this i think its AWESOME! =D more so the only kowa 65mm f0.75 i can find is an eos mount, so that kinda throws me off a bit…