SIGMA 50mm f/2.8 (Sigma DP3 Merrill)

JP 2014-126652 A — Noriyuki Ogasawara

10 ELEMENTS / 8 GROUPS
f ≈ 48.7 mm
F/2.91 (design)
2ω ≈ 32.1°
1 ASPHERICAL SURFACE

Focus Mechanism

Unit focus — G1 (L1–L6 with aperture stop) extends toward the object; G2 and sensor are stationary. Only d11 (L6-rear to L7-front gap) changes during focusing.

Optical Elements (10 physical)

ElementTypeGlass
L1Positive MeniscusS-LAH58 (OHARA)
L2Biconvex PositiveFCD515 (HOYA)
L3Biconcave NegativeNBFD15 (HOYA)
L4Biconcave NegativeS-LAH95 (OHARA)
L5Biconvex PositiveS-LAH55 (OHARA)
L6Biconvex PositiveNBFD10 (HOYA catalog equivalent; production supplier unspecified)
L7Negative MeniscusE-F2 (HOYA catalog-equivalent; production supplier unspecified)
L8Positive MeniscusSF57 (Schott) / S-TIH53 (Ohara) — exact match
L9Negative MeniscusS-LAH65 (OHARA)
L10Biconvex Positive (1× Asph)MC-NBFD135 (HOYA catalog-equivalent; production supplier unspecified)