Zoom lens of rear focus type
AssigneeCanon Kabushiki Kaisha
InventorHiroyuki Hamano
Life of this patent
Estimating the term…
Abstract
A zoom lens of the rear focus type is disclosed, comprising, in order from an object side to an image side, a first lens unit of positive refractive power, a second lens unit of negative refractive power, a third lens unit of positive refractive power, a fourth lens unit of positive refractive power and a fifth lens unit of negative refractive power, wherein at least the second lens unit and the fourth lens unit are moved to vary magnification and the fourth lens unit is moved to effect focusing, and wherein the third lens unit comprises, in order from the object side to the image side, a positive lens and a negative lens having a strong concave surface facing the image side.
Claims2
A zoom lens comprising, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, a fourth lens unit having a positive refractive power, and a fifth lens unit having a negative refractive power, wherein said second lens unit and said fourth lens unit are moved to vary magnification and said fourth lens unit is moved to effect focusing, wherein said third lens unit comprises, in order from the object side to the image side, a positive lens and a negative lens having a strong concave surface facing the image side, and wherein said first lens unit, said third lens unit, and said fifth lens unit are stationary during zooming.
Dependencies are inferred from the claim text.