Macro lens system
AssigneePentax Ricoh Imaging Company, Ltd.
InventorMasakazu Saori
Life of this patent
Estimating the term…
Abstract
A macro lens system includes a positive first lens group, and a positive or negative second lens group, in that order from the object side, wherein at least the first lens group moves toward the object side when focusing on an object at infinity to an object at a close distance, wherein the second lens group includes a negative first sub-lens group and a positive second sub-lens group, in that order from the object side, wherein the following condition (1) is satisfied: −5.0<f2A/fi<−0.8 (1), wherein f2A designates the focal length of the first sub-lens group, and fi designates the focal length of the entire the macro lens system when focusing on an object at infinity.
Claims20
A macro lens system comprising a positive first lens group, and a positive or negative second lens group, in that order from the object side, wherein at least said first lens group moves toward the object side when changing from focusing on an object at infinity to focusing on an object at a close distance, and each lens group being defined such that a distance between adjacent lens elements of adjacent lens groups changes as focusing is performed
- wherein said second lens group includes a negative first sub-lens group and a positive second sub-lens group, in that order from the object side, wherein the following condition is satisfied:
- −5.0<f2A/fi<−0.8, wherein
- f2A designates the focal length of said first sub-lens group, and
- fi designates the focal length of the entire said macro lens system when focusing on an object at infinity.
A macro lens system comprising a positive first lens group, and a positive or negative second lens group, in that order from the object side, wherein at least said first lens group moves toward the object side when changing from focusing on an object at infinity to focusing on an object at a close distance
- wherein said second lens group includes a negative first sub-lens group and a positive second sub-lens group, in that order from the object side,
- wherein said first sub-lens group comprises a negative single lens element, and wherein the following condition is satisfied:
- −5.0<f2A/fi<−0.8, wherein
- f2A designates the focal length of said first sub-lens group, and
- fi designates the focal length of the entire said macro lens system when focusing on an object at infinity.
A macro lens system comprising a positive first lens group, and a positive or negative second lens group, in that order from the object side, wherein at least said first lens group moves toward the object side when changing from focusing on an object at infinity to focusing on an object at a close distance, and
- wherein said second lens group includes a negative first sub-lens group and a positive second sub-lens group, in that order from the object side,
- wherein said second sub-lens group comprises a positive lens element having a convex surface on the image side, and a negative lens element having concave surface on the object side, in that order from the object side, and wherein the following condition is satisfied:
- −5.0<f2A/fi<−0.8, wherein
- f2A designates the focal length of said first sub-lens group, and
- fi designates the focal length of the entire said macro lens system when focusing on an object at infinity.
Dependencies are inferred from the claim text.