PENTAX HD D FA* 50mm f/1.4 SDM AW

US 2019/0250367 A1 Example 1 — Murayama

15 elements / 9 groups
f = 49.57 mm design
F1.45 design / F1.4 nominal
2ω = 47°
2 aspherical surfaces

Focus Mechanism

Rear-group unit focusing. The first group is stationary; the complete second group translates toward the object. Patent Example 1 changes D11 from 10.407 mm to 1.012 mm and the folded air-equivalent back focus from 39.628974 mm to 49.024974 mm.

Optical Elements (15)

ElementTypeGlass
L11Weak Biconvex PositiveF5-class dense flint (HOYA E-F5 / Schott F-type equivalent)
L12Biconcave NegativeS-NBM51 / N-KZFS4 class (613443)
L13Biconvex PositiveTAFD35 (HOYA, 911353; patent rounds νd to 35.2)
L14Negative MeniscusS-NBM51 / N-KZFS4 class (613443)
L21Biconcave NegativeNiobium dense flint class (OHARA S-NBH8 class)
L22Biconvex PositiveS-PHM52 (OHARA, 618634)
L23Biconvex PositiveS-LAH55 / TAFD5F class (835427)
L31Positive MeniscusOHARA S-LAH89 class
L32Biconvex PositiveOHARA S-FPM2 / ED fluorophosphate class
L33Negative MeniscusF5-class dense flint (HOYA E-F5 / Schott F-type equivalent)
L41Negative MeniscusF5-class dense flint (HOYA E-F5 / Schott F-type equivalent)
L42Biconvex PositiveOHARA S-FPM2 / ED fluorophosphate class
L43Positive MeniscusS-LAH58 / TAFD30 class (883408)
L44Biconcave NegativeOHARA S-TIL26 class
L51Biconvex Positive (2× Asph)773495 - moldable lanthanum crown class (patent nd=1.77250, νd=49.5)

Analysis

Detailed analysis available in the interactive viewer above.