TAMRON SP AF 17-50mm f/2.8 XR Di II LD Aspherical [IF] (A16) — Optical Cross-Section & Ray Tracing

Home / Lenses / Tamron / TAMRON SP AF 17-50mm f/2.8 XR Di II LD Aspherical [IF] (A16)TAMRON SP AF 17-50mm f/2.8 XR Di II LD Aspherical [IF] (A16)JP 2007-133138 A↗, Example 2 — Akio Arakawa, Yuichi Muramatsu
16 ELEMENTS / 13 GROUPS
DESIGN f = 17.40–48.50 mm
DESIGN F/2.88
2 ASPHERICAL SURFACES / 2 ELEMENTS
2 HYBRID ASPHERICAL ELEMENTS
Focus MechanismThe patent focuses by moving the negative second group toward the object, but prints spacings only for infinity focus at its three zoom positions. The model therefore shows infinity focus only; the focus control moves no group. The 0.27 m figure is Tamron's marketed minimum focus distance, not a modeled close-focus state.
Optical Elements (16 physical; 18 modeled media)ElementTypeGlass
L211Negative Meniscus847238 dense-flint class
L212Biconvex Positive720503 lanthanum-crown class
L213Positive Meniscus773496 lanthanum-glass class
L221rHybrid Resin Layer (1× Asph)Unmatched (bonded asphere layer; no verified catalog identity)
L221Negative Meniscus773496 lanthanum-glass class
L222Biconcave Negative835427 lanthanum-dense-flint class
L223Biconvex Positive717295 dense-flint class
L224Biconcave Negative773496 lanthanum-glass class
L225Biconvex Positive755275 dense-flint class
L231Biconvex Positive487702 low-index crown class
L232Positive Meniscus487702 low-index crown class
L233Negative Meniscus834372 lanthanum-dense-flint class
L2411rHybrid Resin Layer (1× Asph)Unmatched (bonded asphere layer; no verified catalog identity)
L2411Positive Meniscus487702 low-index crown class
L2421Positive Meniscus487702 low-index crown class
L2422Biconcave Negative834372 lanthanum-dense-flint class
L2423Biconvex Positive497816 low-dispersion crown class
L2424Positive Meniscus487702 low-index crown class

Element	Type	Glass
L211	Negative Meniscus	847238 dense-flint class
L212	Biconvex Positive	720503 lanthanum-crown class
L213	Positive Meniscus	773496 lanthanum-glass class
L221r	Hybrid Resin Layer (1× Asph)	Unmatched (bonded asphere layer; no verified catalog identity)
L221	Negative Meniscus	773496 lanthanum-glass class
L222	Biconcave Negative	835427 lanthanum-dense-flint class
L223	Biconvex Positive	717295 dense-flint class
L224	Biconcave Negative	773496 lanthanum-glass class
L225	Biconvex Positive	755275 dense-flint class
L231	Biconvex Positive	487702 low-index crown class
L232	Positive Meniscus	487702 low-index crown class
L233	Negative Meniscus	834372 lanthanum-dense-flint class
L2411r	Hybrid Resin Layer (1× Asph)	Unmatched (bonded asphere layer; no verified catalog identity)
L2411	Positive Meniscus	487702 low-index crown class
L2421	Positive Meniscus	487702 low-index crown class
L2422	Biconcave Negative	834372 lanthanum-dense-flint class
L2423	Biconvex Positive	497816 low-dispersion crown class
L2424	Positive Meniscus	487702 low-index crown class