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ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

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  1. has530

    Light throughput equation

    Not every manufacturer, the Nikon WX did not make such a compromise (although even that somewhat did as the 7x50 has a markedly smaller FOV than the 10x50) and could be yours for a mere 4-5k over in the classifieds! Or a handful of older Japanese UWA 7x50 but some have pretty poor image quality...
  2. has530

    Light throughput equation

    It is the nature of the larger objective lenses. As the objective lens diameter grows you typically also get a longer focal length to keep a reasonable f/ and image quality. Then in turn you need a longer focal length eyepiece in order to keep the focal ratio (i.e. magnification) low. As you...
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