LAOWA 90mm f/2.8 2× Ultra Macro APO — Optical Cross-Section & Ray Tracing

Home / Lenses / Laowa / LAOWA 90mm f/2.8 2× Ultra Macro APOLAOWA 90mm f/2.8 2× Ultra Macro APOCN 116520542 A↗ — Dayong Li
13 ELEMENTS / 10 GROUPS
DESIGN f = 87.06 mm
DESIGN F/2.9
2× MACRO
NO ASPHERES
Focus MechanismFloating focus through the patent's three tabulated states: infinity, 1.0× and 2.0×. G1 (L1) is fixed. G2 (L2–L8 with the stop) moves 25.2 mm toward the object by 1.0× and 42.5 mm by 2.0×. G3 (L9–L13) moves 5.9 mm toward the object by 1.0×, then partly returns, ending 1.2 mm objectward of its infinity position at 2.0×, so the back focus D24 rises and then falls. The 1.0× and 2.0× names are the patent's; the paraxial magnifications of those states are −0.997× and −1.960×. The printed gaps lengthen the track by 0.04 and 0.13 mm and are kept as printed. Positions between the three states are linear interpolations, not a cam law, and the 20 cm end of the slider is the calculated object-to-image distance at 2.0×, not Laowa's stated minimum focus.
Optical Elements (13 physical)ElementTypeGlass
L1Positive MeniscusUnmatched (native nd=1.88403, vd=43.00; no tight six-vendor coordinate match)
L2Biconvex PositiveH-FK61 (CDGM coordinate equivalent; supplier unconfirmed)
L3Positive MeniscusH-FK61 (CDGM coordinate equivalent; supplier unconfirmed)
L4Biconcave Negative717295 — coordinate-equivalent class; supplier unconfirmed
L5Positive Meniscus923209 — coordinate-equivalent class; supplier unconfirmed
L6Negative MeniscusUnmatched (native nd=1.88300, vd=43.00; no tight six-vendor coordinate match)
L7Biconvex PositiveH-FK61 (CDGM coordinate equivalent; supplier unconfirmed)
L8Biconvex Positive904313 — coordinate-equivalent class; supplier unconfirmed
L9Negative MeniscusUnmatched (native nd=1.88177, vd=40.87; no tight six-vendor coordinate match)
L10Biconcave Negative620363 — coordinate-equivalent class; supplier unconfirmed
L11Biconvex PositiveUnmatched (native nd=1.89786, vd=29.88; no tight six-vendor coordinate match)
L12Negative MeniscusUnmatched (native nd=1.83967, vd=43.30; no tight six-vendor coordinate match)
L13Biconvex PositiveH-K9L (CDGM coordinate equivalent; supplier unconfirmed)

Element	Type	Glass
L1	Positive Meniscus	Unmatched (native nd=1.88403, vd=43.00; no tight six-vendor coordinate match)
L2	Biconvex Positive	H-FK61 (CDGM coordinate equivalent; supplier unconfirmed)
L3	Positive Meniscus	H-FK61 (CDGM coordinate equivalent; supplier unconfirmed)
L4	Biconcave Negative	717295 — coordinate-equivalent class; supplier unconfirmed
L5	Positive Meniscus	923209 — coordinate-equivalent class; supplier unconfirmed
L6	Negative Meniscus	Unmatched (native nd=1.88300, vd=43.00; no tight six-vendor coordinate match)
L7	Biconvex Positive	H-FK61 (CDGM coordinate equivalent; supplier unconfirmed)
L8	Biconvex Positive	904313 — coordinate-equivalent class; supplier unconfirmed
L9	Negative Meniscus	Unmatched (native nd=1.88177, vd=40.87; no tight six-vendor coordinate match)
L10	Biconcave Negative	620363 — coordinate-equivalent class; supplier unconfirmed
L11	Biconvex Positive	Unmatched (native nd=1.89786, vd=29.88; no tight six-vendor coordinate match)
L12	Negative Meniscus	Unmatched (native nd=1.83967, vd=43.30; no tight six-vendor coordinate match)
L13	Biconvex Positive	H-K9L (CDGM coordinate equivalent; supplier unconfirmed)