CANON RF 28-70mm F2 L USM

JP 2020-118807 A Example A — Canon / Kimura

19 ELEMENTS / 13 GROUPS
f = 28.9 – 67.9 mm (patent)
F/2.06 (constant)
2ω = 73.6° – 35.3°
5 ASPHERICAL SURFACES (4 elements)

Focus Mechanism

Inner focusing via Group 3 (probable); ring-type USM. No close-focus data in patent — zoom-only model.

Optical Elements (19)

ElementTypeGlass
L1Negative MeniscusS-NPH1 (OHARA)
L2Positive MeniscusS-LAL18 (OHARA)
L3Positive MeniscusS-LAH66 (OHARA)
L4Neg. Meniscus (1× Asph)S-LAM54 (OHARA)
L5Biconcave NegativeM-TAFD305 (HOYA)
L6Biconvex PositiveS-NPH5 (OHARA)
L7Positive MeniscusS-FSL5 (OHARA)
L8Neg. Meniscus (1× Asph)S-LAH60 (OHARA)
L9Plano-Convex PositiveS-LAL18 (OHARA)
L10Biconvex Pos. (1× Asph)S-LAH65V (OHARA)
L11Biconcave NegativeS-NBH8 (OHARA)
L12Positive MeniscusS-FPL51 (OHARA)
L13Biconvex PositiveS-FPL53 (OHARA)
L14Biconvex PositiveS-FPM2 (OHARA)
L15Biconvex PositiveS-FPL51 (OHARA)
L16Biconcave NegativeS-NBH56 (OHARA)
L17Neg. Meniscus (2× Asph)S-LAH66 (OHARA)
L18Biconcave NegativeS-FSL5 (OHARA)
L19Biconvex PositiveS-NPH2 (OHARA)

Analysis

Detailed analysis available in the interactive viewer above.