Ricoh Patent for Pentax 18mm f/1.8 Macro Lens

Ricoh filed a patent for a Pentax 18mm f/2.8 Macro lens in Japan. The new patent describes a Pentax 18mm f/1.8 lens designed for mirrorless cameras with 1/1.7-inch-type sensors.

The lens offers a wide-angle focal length of 18mm but when used with the 1/1.7-inch sensor cameras it will become a 35mm equivalent of about 84mm focal length.

More details for the patented Pentax 18mm f/1.8 lens aimed at Q-mount cameras can be seen below.

Pentax 18mm f/1.8 Macro Lens Patent

pentax-18mm-f2.8-macro-lens

Explanation self interpretation of patent literature

  • Patent Publication No. 2015-4717
    • Published 2015.1.8
    • Filing date 2013.6.19
  • Example
    embodiment
    Example Fno. Focal distance Magnification Angle of view Full length Lens constitution ED Fluorite / Super ED
    One 2.8 18.00 18.75 19.18 0.000 -0.217 -0.333 15.8 13.0 11.6 50.70 55.89 58.67 9 groups 10 sheets Two Two
    Two 2.8 22.00 22.30 22.46 0.000 -0.217 -0.333 12.9 10.8 9.8 51.80 56.44 58.92 9 groups 10 sheets One Two
    Three FNO. 2.8 3.1 3.2 20.00 20.29 20.43 0.000 -0.150 -0.217 14.2 12.8 12.2 49.97 53.42 54.96 9 groups 10 sheets Two One
    Four 2.8 20.00 20.53 20.82 0.000 -0.217 -0.333 14.2 11.8 10.7 50.80 55.87 58.57 9 groups 10 sheets One Two
    Five 2.8 20.00 20.74 21.08 0.000 -0.150 -0.217 14.3 12.5 11.7 50.00 53.65 55.28 8 groups nine 0 One
    Six 2.8 20.00 20.50 20.78 0.000 -0.217 -0.333 14.2 11.7 10.6 50.80 55.86 58.56 9 groups 10 sheets Three 0

    Image height Y = 5.00mm, BF = 1.00mm

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via Egami