Low total track length for large sensor format including seven lenses of +−+−++− refractive powers
Lens assemblies comprising from an object side to an image side, seven lens elements numbered L1-L7; an optical window; and an image sensor having a sensor diagonal length (SDL), wherein an exemplary lens assembly has a total track length TTL that includes the optical window an effective focal length EFL and a field of view (FOV), wherein TTL/EFL<1.100, wherein TTL/SDL<0.64, wherein FOV<90 degrees, wherein a normalized thickness standard deviation constant T_STD of at least four of the seven lens elements complies with T_STD<0.035, and wherein a focal length f 1 of lens element L1 fulfills f 1 /EFL<0.95.
1. A lens assembly comprising: from an object side to an image side,
a) only seven lens elements numbered L1-L7;
b) an optical window; and
d) an image sensor having a sensor diagonal length (SDL),
wherein the lens assembly has a total track length TTL that includes the optical window, an effective focal length EFL and a field of view (FOV)<90 degrees, wherein TTL/EFL<1.100, wherein TTL/SDL<0.64, wherein a normalized thickness standard deviation constant T_STD of four of the seven lens elements complies with T_STD<0.035, and wherein a focal length f 1 of lens element L1 fulfills f 1 /EFL<0.95.
2. The lens assembly of claim 1 , wherein D/2 is an aperture radius and wherein a sign of z(r) from z(0.85*D/2) to z(D/2) is positive for surfaces LO 1 , LI 1 of L1 and surfaces LO 2 , LI 2 of L2, and negative for surfaces LO 4 , LI 4 of L4, LO 5 , LI 5 of L5 LO 6 , LI 6 of L6 and LO 7 , LI 7 of L7.
3. The lens assembly of claim 1 , wherein each element has a clear aperture (CA) and wherein a CA of lens elements L3 or L4 is the smallest of all CAs in the lens assembly.
4. The lens assembly of claim 1 , wherein TTL/EFL<1.090.
5. The lens assembly of claim 1 , wherein TTL/EFL<1.083.
6. The lens assembly of claim 1 , wherein TTL/SDL<0.63.
7. The lens assembly of claim 1 , wherein TTL/SDL<0.61.
8. The lens assembly of claim 1 , wherein lens element L1 is convex on the object side.
9. The lens assembly of claim 1 , wherein the lens elements have, starting with lens element L1, a power sign sequence of positive-negative-positive-negative-positive-positive-negative.
10. The lens assembly of claim 1 , wherein a central thickness CT of at least 6 of the 7 lens elements complies with CT/TTL<0.07.
11. The lens assembly of claim 1 , wherein the T_STD of at least 5 of the 7 lens elements complies with T_STD<0.05.
12. The lens assembly of claim 1 , wherein the T_STD of at least 5 of the 7 lens elements complies with T_STD<0.06.
13. The lens assembly of claim 1 , wherein T_STD<0.03.
14. The lens assembly of claim 1 , wherein f 1 /EFL<0.9.
15. The lens assembly of claim 1 , wherein fi/EFL<0.85.
16. The lens assembly of claim 1 , wherein a focal length f 5 of lens element L5 fulfills |f 5 /EFL|>4.0.
17. The lens assembly of claim 1 , wherein a focal length f 5 of lens element L5 fulfills |f 5 /EFL|>6.0.
18. The lens assembly of claim 1 , wherein a focal length f 5 of lens element L5 fulfills |f 5 /EFL|>8.0.
19. The lens assembly of claim 1 , wherein a focal length f 6 of lens element L6 fulfills f 6 /EFL|>15.0.
20. The lens assembly of claim 1 , wherein a focal length f 6 of lens element L6 fulfills f 6 /EFL|>30.0.
21. The lens assembly of claim 1 , wherein a focal length f 6 of lens element L6 fulfills f 6 /EFL|>45.0.
22. The lens assembly of claim 1 , wherein a normalized gap standard deviation constant G_STD of a gap between lens elements L1 and L2 complies with G_STD<0.006.
23. The lens assembly of claim 1 , wherein a normalized gap standard deviation constant G_STD of a gap between lens elements L1 and L2 complies with G_STD<0.01.
24. The lens assembly of claim 1 , wherein a normalized gap standard deviation constant G_STD of a gap between lens elements L1 and L2 complies with G_STD<0.007.
25. The lens assembly of claim 1 , wherein SDL=12 mm and wherein FOV<82.1 degrees.