Patent ID: 7593163

Claim:
A rear converter lens apparatus, comprising: a master lens device-side mount portion for mounting a master lens device thereon, a camera body-side mount portion for mounting a camera body thereon, and a converter lens portion having generally negative refracting power so as to obtain a lens system having a focal length longer than that of said master lens device by mounting said master lens device, wherein: said converter lens portion consists of, in order from an object side that is said master lens device side, a first lens group of positive refracting power, a second lens group of positive refracting power and a third lens group of negative refracting power; there is a spacing between the respective lens groups; said first lens group and said second lens group are located such that an axial air space between said first lens group and said second lens group is largest in axial air spaces in said converter lens portion; and one each lens group comprises a positive lens element and a negative lens element.