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US 4,647,160 AGranted
Small-sized wide angle zoom objective
AssigneeCanon Kabushiki Kaisha
InventorKeiji Ikemori
Life of this patent
Estimating the term…
Abstract
A small-sized wide angle zoom objective comprising, from front to rear, a 1st lens unit of negative power, a 2nd lens unit of positive power and a 3rd lens unit, wherein the 1st and 2nd units are made axially movable to effect zooming.
Claims19
A wide angle zoom objective of reduced size comprising:
- a first lens unit, a second lens unit, and a third lens unit arranged from the object side;
- said first lens unit being divergent, said second lens unit being convergent, and said third lens unit being stationary during zooming;
- and
- a diaphragm for controlling a light flux passing through the zoom objective,
- said first lens unit and said second lens unit moving for zooming along the optical axis and said diaphragm being associated with said second lens unit.
2 more elements
A wide angle zoom objective of reduced size comprising:
- a first lens unit, a second lens unit, and a third lens unit arranged from the object side;
- said first lens unit being divergent, said second lens unit being convergent, and said third lens unit being stationary during zooming;
- and
- letting f.sub.I denote the focal length of said first lens unit and f.sub.T the longest focal length of the entire lens system, the following condition is satisfied:
- .vertline.f.sub.I .vertline..ltoreq.f.sub.T.
2 more elements
A wide angle zoom objective of reduced size comprising:
- a first lens unit, a second lens unit, and a third lens unit arranged from the object side;
- said first lens unit being divergent, said second lens unit being convergent, and said third lens unit being stationary during zooming;
- and
- the following condition is satisfied:
- 0.04.ltoreq.t/f.sub.T .ltoreq.0.25
- where t is the thickness from the front-most lens surface of the third lens unit to the rear-most lens surface.
3 more elements
A wide angle zoom objective of reduced size comprising:
- a first lens unit, a second lens unit, and a third lens unit arranged from the object side;
- said first lens unit being divergent, said second lens unit being convergent, and said third lens unit being stationary during zooming and being composed of a single lens.
A wide angle zoom objective or reduced size comprising:
- a first lens unit, a second lens unit, and a third lens unit arranged from the object side;
- said first lens unit being divergent, said second lens unit being convergent, and said third lens unit being stationary during zooming and being composed of a cemented lens.
A wide angle zoom objective of reduced size comprising:
- a first lens unit, a second lens unit, and a third lens unit arranged from the object side;
- said first lens unit being divergent, said second lens unit being convergent, and said third lens unit being stationary during zooming and being composed of a negative single lens, and a positive single lens, separated by air from said negative lens.
A wide angle zoom objective of reduced size comprising:
- a first lens unit, a second lens unit, and a third lens unit arranged from the object side;
- said first lens unit being divergent, said second lens unit being convergent, and said third lens unit being stationary during zooming and being composed of a single lens and a cemented lens separated by airs from said single lens.
Dependencies are inferred from the claim text.