Zoom lens and imaging device using zoom lens
AssigneeSony Corporation
InventorYoshito Iwasawa
Life of this patent
Estimating the term…
Abstract
The present invention is directed to a zoom lens used for image pick-up optical system of digital still camera, or video camera, and is composed, in order from the object side, of a first group GR1 including a reflection member for bending or folding the optical axis and having negative refractive power, a second group GR2 having negative refractive power, a third group GR3 having positive refractive power, and a fourth group GR4 having positive refractive power, wherein a light quantity adjustment member ST1 for adjusting light quantity is fixed during zooming operation.
Claims5
A zoom lens, comprising in order from object side:
- a first lens group comprising a reflection member for bending or folding the optical axis and having negative refractive power, the first lens group being fixed during magnification changing or adjustment operation;
- a second lens group having negative refractive power, the second lens group being movable in the magnification changing or adjustment operation;
- and
- a light quantity adjustment member fixed in the magnification changing or adjustment operation and serving to adjust light quantity,
- wherein the following formula is satisfied:
- 1.6<D12w/fw<5,
- wherein D12w is a distance between a most image side surface of a lens placed next to the reflection member at object side of the reflection member and a most object side surface of an entire second group, at a wide-angle end state, and
- wherein fw is a focal length of an entire system at the wide-angle end state.
An image pick-up apparatus comprising:
- a zoom lens comprising in order from object side:
- a first lens group including a reflection member for bending or folding the optical axis having negative refractive power,
- a second lens group having negative refractive power, the second lens group being movable in the magnification changing or adjustment operation;
- a light quantity adjustment member fixed in the magnification changing or adjustment operation and serving to adjust light quantity,
- wherein the following formula is satisfied:
- 1.6<D12w/fw<5,
- wherein D12w is a distance between a most image side surface of a lens placed next to the reflection member at object side of the reflection member and a most object side surface of an entire second group, at a wide-angle end state, and
- wherein fw is a focal length of an entire system at the wide-angle end state;
- and
- an image pick-up device for converting an optical image formed by zoom lens into an electric signal.
Dependencies are inferred from the claim text.