Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
179 words
A compact zoom lens comprising: a first group having a positive refractive power, including a cemented positive lens of a negative lens and a positive lens, and a positive lens, and movable for focusing; a second group having a negative refractive power, comprising a negative lens and a cemented negative lens of a negative lens and a positive lens, and movable for variation of magnification; a third group having a positive refractive power, comprising a cemented positive lens of a positive lens and a negative lens, and movable for compensation along with the second group; and an image forming lens having a positive refractive power, positioned to the rear of the third group on an optical axis, and consisting of fourth and fifth groups, said fourth group including, from front to rear, at least one positive lens with its front surface covex toward the front, and a negative lens; and said fifth group consisting of, from front to rear, a negative meniscus lens of rearward convexity, and a positive lens, said zoom lens satisfying the following conditions: 0.7<φ4,5/φ4<0.85 (1)
Claim 2
Dependent Claim
179 words
A compact zoom lens comprising: a first group having a positive refractive power, including a cemented positive lens of a negative lens and a positive lens, and a positive lens, and movable for focusing; a second group having a negative refractive power, comprising a negative lens and a cemented negative lens of a negative lens and a positive lens, and movable for variation of magnification; a third group having a positive refractive power, comprising a cemented positive lens of a positive lens and a negative lens, and movable for compensation along with the second group; and an image forming lens having a positive refractive power, positioned to the rear of the third group on an optical axis, and consisting of fourth and fifth groups, said fourth group including, from front to rear, at least one positive lens with its front surface covex toward the front, and a negative lens; and said fifth group consisting of, from front to rear, a negative meniscus lens of rearward convexity, and a positive lens, said zoom lens satisfying the following conditions: 0.7<φ4,5/φ4<0.85 (1)
Claim 3
Dependent Claim
112 words
5<φ4s/φ4,5<2.2 (2) N4n>N4p (3) 1.76<N5n<1.85 (4) 30<ν5p<45 (5) where φ4 is the refractive power of said fourth group; φ4,5 is the overall refractive power of said fourth and fifth groups; φ4s is the refractive power of the first surface of the positive lens of said fourth group; N4p is the refractive index of the positive lens in said fourth group (when the positive lens is plural in number, the average value thereof); N4n is the refractive index of the negative lens in said fourth group; N5n is the refractive index of the negative lens in said fifth group; and ν5p is the Abbe number of the positive lens of said fifth group.
Claim 4
Dependent Claim
112 words
5<φ4s/φ4,5<2.2 (2) N4n>N4p (3) 1.76<N5n<1.85 (4) 30<ν5p<45 (5) where φ4 is the refractive power of said fourth group; φ4,5 is the overall refractive power of said fourth and fifth groups; φ4s is the refractive power of the first surface of the positive lens of said fourth group; N4p is the refractive index of the positive lens in said fourth group (when the positive lens is plural in number, the average value thereof); N4n is the refractive index of the negative lens in said fourth group; N5n is the refractive index of the negative lens in said fifth group; and ν5p is the Abbe number of the positive lens of said fifth group.
Claim 5
Dependent Claim
55 words
A compact zoom lens as described in claim 1, further satisfying following conditions: 0.15<|f2/ft|<0.17 (1) 1.78<N2p<1.85 (2) where f2: the focal length of said 2nd group; N2p: the refractive index of the positive lens in the cemented negative lens of said second group; and ft: the longest focal length of the zoom lens entire system.