An objective lens configured by multiple lenses each consisting of a single lens has a retro ratio of 1.5 or higher. The multiple lenses configure a substantially afocal first lens group and a positive second lens group arranged in this order from a magnification side. The first lens group includes a 1a lens group having a negative power and a 1b lens group having a positive power which are arranged in this order from the magnification side. Provided that a focal length of the first lens group is represented by f(Gr1) and a focal length of a whole system of the objective lens is represented by f(total), a condition of |f(Gr1)/f(total)|>10 is satisfied. The second lens group includes a 2a lens group having a negative power and a 2b lens group having a positive power which are arranged in this order from the magnification side.

An objective lens configured by multiple lenses each consisting of a single lens has a retro ratio of 1.5 or higher. The multiple lenses configure a substantially afocal first lens group and a positive second lens group arranged in this order from a magnification side. The first lens group includes a 1a lens group having a negative power and a 1b lens group having a positive power which are arranged in this order from the magnification side. Provided that a focal length of the first lens group is represented by f(Gr1) and a focal length of a whole system of the objective lens is represented by f(total), a condition of |f(Gr1)/f(total)|>10 is satisfied. The second lens group includes a 2a lens group having a negative power and a 2b lens group having a positive power which are arranged in this order from the magnification side.

Provided are a rear converter lens and an imaging apparatus capable of achieving favorable optical performance and an appropriate back focal length with high magnification. The rear converter lens RCL consists of, in order from the object side, four lens-groups of positive, negative, negative, and positive lens-groups. In order from the object side, a first lens-group RG1 consists of a negative lens RL11 and a positive lens RL12, a second lens-group RG2 consists of a negative lens RL21 and a positive lens RL22, a third lens-group RG3 consists of a negative lens RL31, a positive lens RL32, and a negative lens RL33, and a fourth lens-group RG4 consists of a biconvex lens RL41 and a negative lens RL42. Here, 0.22<cf/f12<1 is satisfied, where f12 is a composite focal length of the first lens-group RG1 and the second lens-group RG2, and cf is a focal length of the rear converter lens RCL.

Provided are a rear converter lens and an imaging apparatus capable of achieving favorable optical performance and an appropriate back focal length with high magnification. The rear converter lens RCL consists of, in order from the object side, four lens-groups of positive, negative, negative, and positive lens-groups. In order from the object side, a first lens-group RG1 consists of a negative lens RL11 and a positive lens RL12, a second lens-group RG2 consists of a negative lens RL21 and a positive lens RL22, a third lens-group RG3 consists of a negative lens RL31, a positive lens RL32, and a negative lens RL33, and a fourth lens-group RG4 consists of a biconvex lens RL41 and a negative lens RL42. Here, 0.22<cf/f12<1 is satisfied, where f12 is a composite focal length of the first lens-group RG1 and the second lens-group RG2, and cf is a focal length of the rear converter lens RCL.

Provided are a rear converter lens and an imaging apparatus capable of achieving favorable optical performance and an appropriate back focal length with high magnification. The rear converter lens RCL consists of, in order from the object side, four lens-groups of positive, negative, negative, and positive lens-groups. In order from the object side, a first lens-group RG1 consists of a negative lens RL11 and a positive lens RL12, a second lens-group RG2 consists of a negative lens RL21 and a positive lens RL22, a third lens-group RG3 consists of a negative lens RL31, a positive lens RL32, and a negative lens RL33, and a fourth lens-group RG4 consists of a biconvex lens RL41 and a negative lens RL42. Here, 0.22<cf/f12<1 is satisfied, where f12 is a composite focal length of the first lens-group RG1 and the second lens-group RG2, and cf is a focal length of the rear converter lens RCL.

Provided are a rear converter lens and an imaging apparatus capable of achieving favorable optical performance and an appropriate back focal length with high magnification. The rear converter lens RCL consists of, in order from the object side, four lens-groups of positive, negative, negative, and positive lens-groups. In order from the object side, a first lens-group RG1 consists of a negative lens RL11 and a positive lens RL12, a second lens-group RG2 consists of a negative lens RL21 and a positive lens RL22, a third lens-group RG3 consists of a negative lens RL31, a positive lens RL32, and a negative lens RL33, and a fourth lens-group RG4 consists of a biconvex lens RL41 and a negative lens RL42. Here, 0.22<cf/f12<1 is satisfied, where f12 is a composite focal length of the first lens-group RG1 and the second lens-group RG2, and cf is a focal length of the rear converter lens RCL.