Optical assembly for a wide field of view point action camera with low astigmatism

1. An optical assembly for a point action camera having a wide field of view, comprising multiple lens elements, including an aspheric surface, configured to provide a field of view in excess of 150 degrees that comprises a longitudinal astigmatism of 0.3 mm or less,

wherein the optical assembly comprises from object end to image end a first optical group and a second optical group, wherein the first optical group is configured to collect light at said wide field of view and said second optical group is configured to correct distortion error, and

wherein at least one of said multiple lens elements is configured with an aspheric departure to correct astigmatism error, and

wherein said longitudinal astigmatism comprises multiple orders including fifth order astigmatism.

2. The optical assembly of claim 1 , wherein the longitudinal astigmatism comprises approximately 0.2 mm or less.

3. The optical assembly of claim 1 , wherein the longitudinal astigmatism comprises approximately 0.1 mm or less.

4. The optical assembly of claim 3 , wherein said second optical group comprises an aspheric lens element.

5. The optical assembly of claim 4 , comprising an aperture stop between said first and second optical groups.

6. The optical assembly of claim 4 , wherein one or both of an ultimate or penultimate lens element of the second optical group comprises an aspheric lens element.

7. The optical assembly of claim 6 , wherein said ultimate lens element comprises an aspheric lens element.

8. The optical assembly of claim 7 , wherein said ultimate lens element comprises an object facing side and an image facing side, and wherein said object facing side comprises an aspheric lens surface.

9. A digital camera, comprising

an optical assembly as in claim 1 ; and

an image sensor disposed approximately at a focal plane of the optical assembly; and

a digital camera housing including electronics and a user interface, and containing said optical assembly and said image sensor in optically effective relative disposition.

10. The digital camera of claim 9 , wherein the optical assembly comprises a longitudinal astigmatism of approximately 0.2 mm or less.

11. The digital camera of claim 9 , wherein the optical assembly comprises a longitudinal astigmatism of approximately 0.1 mm or less.

12. The digital camera of claim 11 , wherein said second optical group comprises an aspheric lens element.

13. The digital camera of claim 12 , wherein the optical assembly comprises an aperture stop between said first and second optical groups.

14. The digital camera of claim 12 , wherein one or both of an ultimate or penultimate lens element of the second optical group comprises an aspheric lens element.

15. The digital camera of claim 14 , wherein said ultimate lens element comprises an aspheric lens element.

16. The digital camera of claim 15 , wherein said ultimate lens element comprises an object facing side and an image facing side, and wherein said object facing side comprises an aspheric lens surface.

17. An optical assembly for a point action camera having a wide field of view, comprising multiple lens elements, including an aspheric surface, configured to provide a field of view in excess of 150 degrees that comprises a longitudinal astigmatism of 0.3 mm or less,

wherein the optical assembly comprises from object end to image end a first optical group and a second optical group, wherein the first optical group is configured to collect light at said wide field of view and said second optical group is configured to correct distortion error, and

wherein at least one of said multiple lens elements is configured with an aspheric departure to correct astigmatism error, and

wherein said optical assembly comprises seven lens elements.

18. A digital camera, comprising

an optical assembly as in claim 17 ; and

an image sensor disposed approximately at a focal plane of the optical assembly; and

a digital camera housing including electronics and a user interface, and containing said optical assembly and said image sensor in optically effective relative disposition.

19. An optical assembly for a point action camera having a wide field of view, comprising multiple lens elements, including an aspheric surface, configured to provide a field of view in excess of 150 degrees that comprises a longitudinal astigmatism of 0.3 mm or less,

wherein the optical assembly comprises from object end to image end a first optical group and a second optical group, wherein the first optical group is configured to collect light at said wide field of view and said second optical group is configured to correct distortion error, and

wherein at least one of said multiple lens elements is configured with an aspheric departure to correct astigmatism error, and

wherein said second optical group comprises four lens elements.

20. A digital camera, comprising

an optical assembly as in claim 19 ; and

an image sensor disposed approximately at a focal plane of the optical assembly; and

a digital camera housing including electronics and a user interface, and containing said optical assembly and said image sensor in optically effective relative disposition.

21. An optical assembly for a point action camera having a wide field of view, comprising multiple lens elements, including an aspheric surface, configured to provide a field of view in excess of 150 degrees that comprises a longitudinal astigmatism of 0.3 mm or less,

wherein the optical assembly comprises from object end to image end a first optical group and a second optical group, wherein the first optical group is configured to collect light at said wide field of view and said second optical group is configured to correct distortion error, and

wherein at least one of said multiple lens elements is configured with an aspheric departure to correct astigmatism error, and

wherein said second optical group comprises from object side to image side, a first singlet, a doublet and a second singlet.

22. The optical assembly of claim 21 , wherein said first singlet comprises a biconvex or plano-convex or quasi-plano-convex lens.

23. The optical assembly of claim 22 , wherein said second singlet comprises a biconvex, or convexo-plano or convexo-quasi-plano lens.

24. The optical assembly of claim 23 , wherein said first optical group comprises two or more convexo-concave or meniscus lenses.

25. The optical assembly of claim 24 , wherein said first optical group further comprises a biconvex lens.

26. The optical assembly of claim 21 , wherein said doublet comprises, from object side to image side, a biconcave lens and a biconvex lens.

27. A digital camera, comprising

an optical assembly as in claim 21 ; and

an image sensor disposed approximately at a focal plane of the optical assembly; and

a digital camera housing including electronics and a user interface, and containing said optical assembly and said image sensor in optically effective relative disposition.

28. The digital camera of claim 27 , wherein said first singlet comprises a biconvex or plano-convex or quasi-plano-convex lens.

29. The digital camera of claim 28 , wherein said second singlet comprises a biconvex, or convexo-plano or convexo-quasi-plano lens.

30. The digital camera of claim 29 , wherein said first optical group comprises two or more convexo-concave or meniscus lenses.

31. The digital camera of claim 30 , wherein said first optical group further comprises a biconvex lens.

32. The digital camera of claim 27 , wherein said doublet comprises, from object side to image side, a biconcave lens and a biconvex lens.

33. An optical assembly for a point action camera having a wide field of view, comprising multiple lens elements, including an aspheric surface, configured to provide a field of view in excess of 150 degrees that comprises a longitudinal astigmatism of 0.3 mm or less,

wherein the optical assembly comprises from object end to image end a first optical group and a second optical group, wherein the first optical group is configured to collect light at said wide field of view and said second optical group is configured to correct distortion error, and

wherein at least one of said multiple lens elements is configured with an aspheric departure to correct astigmatism error, and

wherein the optical assembly further comprises a third optical group disposed between the first and second optical groups.

34. The optical assembly of claim 33 , wherein the third optical group comprises a biconvex lens.

35. The optical assembly of claim 33 , wherein the lateral chromatic aberration is less than approximately three pixels.

36. The optical assembly of claim 35 , wherein the lateral chromatic aberration is less than approximately two pixels.

37. The optical assembly of claim 33 , wherein the lateral chromatic aberration is less than approximately five microns.

38. The optical assembly of claim 37 , wherein the lateral chromatic aberration is less than approximately three microns.

39. The optical assembly of claim 33 , comprising a single aspheric lens element, which is the only aspheric lens element within the optical assembly.

40. The optical assembly of claim 39 , wherein lens elements other than the single aspheric lens element comprise spherical or planar lens surfaces, or both, each without significant aspheric departures.

41. The optical assembly of claim 39 , wherein the single aspheric lens element comprises a single aspheric lens surface, which is the only aspheric lens surface within the optical assembly.

42. A digital camera, comprising

an optical assembly as in claim 33 ; and

an image sensor disposed approximately at a focal plane of the optical assembly; and

a digital camera housing including electronics and a user interface, and containing said optical assembly and said image sensor in optically effective relative disposition.

43. The digital camera of claim 42 , wherein the third optical group comprises a biconvex lens.

44. The digital camera of claim 42 , wherein the lateral chromatic aberration of the optical assembly is less than approximately three pixels.

45. The digital camera of claim 44 , wherein the lateral chromatic aberration is less than approximately two pixels.

46. The digital camera of claim 42 , wherein the lateral chromatic aberration of the optical assembly is less than approximately five microns.

47. The digital camera of claim 46 , wherein the lateral chromatic aberration is less than approximately three microns.

48. The digital camera of claim 42 , wherein the optical assembly comprises a single aspheric lens element, which is the only aspheric lens element within the optical assembly.

49. The digital camera of claim 48 , wherein lens elements other than the single aspheric lens element comprise spherical or planar lens surfaces, or both, each without significant aspheric departures.

50. The digital camera of claim 48 , wherein the single aspheric lens element comprises a single aspheric lens surface, which is the only aspheric lens surface within the optical assembly.

51. The digital camera of claim 50 , wherein the longitudinal astigmatism of the optical assembly comprises approximately 0.2 mm or less.

52. The digital camera of claim 51 , wherein the longitudinal astigmatism comprises approximately 0.1 mm or less.