Ricoh files a patent for a Pentax 100-300mm f/4 full frame lens

Pentax 100-300mm f:4 full frame lens patent
Ricoh recently filed a patent in a Japan for a 100-300mm f/4 full frame lens that is most likely designed for the Pentax K-1 DSLR camera. Here are the details:

  • Patent No. 2016-80717
  • Published on May 16th, 2016
  • Filing date: October 9th, 2014
  • Zoom ratio: 2.87
  • FNO (aperture): 4.1 – 4.1 – 4.1
  • f (focal length): 102.00 – 200.01 – 293.01
  • L (length): 279.45 – 279.44 – 279.44

Ricoh also had a recent patent for a 200mm f/2.8 full frame lens.

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  • HD10

    This is worth watching. The zoom range is very useful and the aperture is just enough so as not to make the zoom overly big and heavy,

    • SimenO

      I always wondered if making a variable aperture would make a zoom larger or not? For instance f/2,8-4. Isn’t the size defined by the largest aperture at the long end? So 300mm f/4 would be 300/4 = 75mm diameter. If so, the 75mm are more then enough for a 100/2,8 = 36mm diameter. In other words, what holds them back from turning constant aperture lenses like this into variable aperture lenses?

      • Cynog

        Good point. I know nothing about optics, but I imagine it would be perfectly feasible. Perhaps there is some cachet attached to a constant aperture lens? It may be seen as more “professional”, but your guess is as good as mine.

        • Piotr Krochmal

          As far as I know when you are “zooming” you change distance between lenses not shape (or curve) so if you use whole lens surface at one end, at secound you only use part of them.

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