TAMRON SP AF 28-75mm f/2.8 XR Di LD Aspherical [IF] MACRO — Optical Cross-Section & Ray Tracing

Home / Lenses / Tamron / TAMRON SP AF 28-75mm f/2.8 XR Di LD Aspherical [IF] MACROTAMRON SP AF 28-75mm f/2.8 XR Di LD Aspherical [IF] MACROUS 7,075,731 B1↗ — Yasuharu Yamada
16 ELEMENTS / 14 GROUPS
DESIGN f = 28.87-72.65 mm
DESIGN F/2.91
0.33 m MFD
4 ASPHERICAL SURFACES
Focus MechanismCONSTRAINED_RECONSTRUCTION: the patent specifies G2-only inner focusing but no close-focus spacings. Close states are code-solved at Tamron's 0.33 m MFD with only G2 translating, d6+d16 conserved, and the image plane fixed; telephoto magnification computes to about 1:3.923 versus the marketed 1:3.9.
Optical Elements (16 physical; 20 modeled media)ElementTypeGlass
L1Negative Meniscus847238 class (vendor unresolved)
L2Biconvex Positive697555 class (vendor unresolved)
L3Positive Meniscus773496 class (vendor unresolved)
L4rHybrid Resin Layer (1× Asph)Unmatched (hybrid/aspheric layer; nd=1.53610, νd=41.2)
L4Negative Meniscus804466 class (vendor unresolved)
L5Biconcave Negative804466 class (vendor unresolved)
L6Biconvex Positive805254 class (vendor unresolved)
L7Biconcave Negative487702 class (vendor unresolved)
L8Biconvex Positive805254 class (vendor unresolved)
L9Positive Meniscus497816 class (vendor unresolved)
L10rHybrid Resin Layer (1× Asph)Unmatched (hybrid/aspheric layer; nd=1.53610, νd=41.2)
L10Positive Meniscus487702 class (vendor unresolved)
L11Positive Meniscus497816 class (vendor unresolved)
L12Negative Meniscus847238 class (vendor unresolved)
L13Positive Meniscus487702 class (vendor unresolved)
L14Biconvex Positive497816 class (vendor unresolved)
L15Biconcave Negative834372 class (vendor unresolved)
L15rHybrid Resin Layer (1× Asph)Unmatched (hybrid/aspheric layer; nd=1.53610, νd=41.2)
L16Biconvex Positive581408 class (vendor unresolved)
L16rHybrid Resin Layer (1× Asph)Unmatched (hybrid/aspheric layer; nd=1.53610, νd=41.2)

Element	Type	Glass
L1	Negative Meniscus	847238 class (vendor unresolved)
L2	Biconvex Positive	697555 class (vendor unresolved)
L3	Positive Meniscus	773496 class (vendor unresolved)
L4r	Hybrid Resin Layer (1× Asph)	Unmatched (hybrid/aspheric layer; nd=1.53610, νd=41.2)
L4	Negative Meniscus	804466 class (vendor unresolved)
L5	Biconcave Negative	804466 class (vendor unresolved)
L6	Biconvex Positive	805254 class (vendor unresolved)
L7	Biconcave Negative	487702 class (vendor unresolved)
L8	Biconvex Positive	805254 class (vendor unresolved)
L9	Positive Meniscus	497816 class (vendor unresolved)
L10r	Hybrid Resin Layer (1× Asph)	Unmatched (hybrid/aspheric layer; nd=1.53610, νd=41.2)
L10	Positive Meniscus	487702 class (vendor unresolved)
L11	Positive Meniscus	497816 class (vendor unresolved)
L12	Negative Meniscus	847238 class (vendor unresolved)
L13	Positive Meniscus	487702 class (vendor unresolved)
L14	Biconvex Positive	497816 class (vendor unresolved)
L15	Biconcave Negative	834372 class (vendor unresolved)
L15r	Hybrid Resin Layer (1× Asph)	Unmatched (hybrid/aspheric layer; nd=1.53610, νd=41.2)
L16	Biconvex Positive	581408 class (vendor unresolved)
L16r	Hybrid Resin Layer (1× Asph)	Unmatched (hybrid/aspheric layer; nd=1.53610, νd=41.2)