Large magnification factor zoom lens
AssigneeTamron Co., Ltd.
InventorsYuuichi Muramatsu, Akio Arakawa
Life of this patent
Estimating the term…
Abstract
This large magnification factor zoom lens includes, in an order arranged from an object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens group having a positive refractive power. The third lens group includes, in an order arranged from the object side, a positive lens, a positive lens, a positive meniscus lens having a larger radius of curvature on an image surface side, and a negative lens. The positive lens has an aspherical surface on an object side.
Claims9
A large magnification factor zoom lens comprising:
- a first lens group having a positive refractive power;
- a second lens group having a negative refractive power;
- a third lens group having a positive refractive power;
- and
- a fourth lens group having a positive refractive power,
- wherein
- the first lens group, the second lens group, and the third lens group are arranged in an order from an object side, and
- the large magnification factor zoom lens is configured so as to satisfy the following conditional expressions including
- 0.35≦f1/ft≦0.45
- 0.6≦|f2|/fw≦0.8
- 0.15≦f3/ft≦0.3
- 6.08≦2ω(t)≦7.82
- where f1 represents a focal length of the first lens group, f2 represents a focal length of the second lens group, f3 represents a focal length of the third lens group, ft represents the focal length of an entire zoom lens system at a telephoto end, fw represents a focal length of the entire zoom lens system at a wide-angle end, and 2ω(t) represents angle of view of the entire zoom lens system at the telephoto end.
Dependencies are inferred from the claim text.