Telephoto lens system having an improved focusing capability

Claim 2

In a telephoto lens system having improved focusing capabilities, the improvement comprising; a front lens group of an overall positive refractive power; and a rear lens group of an overall negative refractive power including a first negative lens component on the object side of the rear lens group and a second positive lens component on the image side, the second positive lens component being movably mounted relative to other lens elements for focusing the lens system on close objects as it is moved towards the object side.

Claim 3

The invention of claim 1 wherein the rear lens group consists only of the first negative lens component and the second positive lens component.

Claim 4

The invention of claim 1 wherein the absolute value of the composite focal lengths, f M , of the front lens group and the first negative lens component is greater than 1.2f.

Claim 5

The invention of claim 3 wherein the absolute value of the radius of curvature, r F , of the object side end surface of the second positive lens component is greater than the absolute value of the radius of curvature, r R , of the image side end surface of the second positive lens component.

Claim 6

The invention of claim 4 wherein the focal length, f 2 , of the second positive lens component is less than 0.8f.

Claim 7

The invention of claim 5 wherein the rear lens group further includes a third negative lens component adjacent the image side of the second positive lens component.

Claim 8

The invention of claim 6 wherein the third negative lens component is fixidly mounted relative to the front lens group and the first negative lens component is movably mounted toward the object side with a lower differential speed ratio than the second positive lens component during a focusing mode of operation.

Claim 9

In a telephoto lens system having improved focusing capabilities, the improvement comprising; a front lens group of an overall positive refractive power; and a rear lens group of an overall negative refractive power including a first negative lens component on the object side of the rear lens group, a second positive lens component on the image side of the first negative lens component, and a third negative lens component adjacent to the image side of the second positive lens component, the second positive lens component being movably mounted relative to the other lens elements for focusing the lens system on close objects as it is moved towards the object side, the first negative lens component being also movably mounted, the first negative lens component being mounted to provide a lower differential speed ratio than that of the second positive lens component during a focusing mode of operation.

Claim 10

In a telephoto lens system having improved focusing capabilities, the improvement comprising; a front lens group of an overall positive refractive power; and a rear lens group of an overall negative refractive power including a first negative lens component on the object side of the rear lens group, a second positive lens component on the image side of the first negative lens component, and a third negative lens component adjacent to the image side of the second positive lens component, the second positive lens component being movably mounted relative to the other lens elements for focusing the lens system on close objects as it is moved towards the object side, the first negative lens component being also movably mounted, the first negative lens component being mounted to provide a lower differential speed ratio than that of the second positive lens component during a focusing mode of operation.

Claim 11

An improved telephoto lens system having a simplified focusing mode of operation comprising the following design parameters: Table 5 __________________________________________________________________________ Embodiment 3 f = 100 F No.: 6.3 2ω = 4° 13' Telephoto Ratio: 0.684 Photographing Distance: ∞- Axial Refractive Abbe Radius of Curvature Distance Index Number __________________________________________________________________________ ##STR25## 28.799 25.206 d.sub.1 = 0.855 n.sub.1 = 1.5168 ν.sub.1 = 64.0 d.sub.2 = 0.427 ##STR26## 22.613 -36.991 d.sub.3 = 2.632 n.sub.2 = 1.4339 ν.sub.2 = 95.0 d.sub.4 = 1.381 ##STR27## -34.414 125.075 d.sub.5 = 0.684 n.sub.3 = 1.757 ν.sub.3 = 47.7 d.sub.6 = 1.776 ##STR28## 24.738 ∞ d.sub.7 = 1.538 n.sub.4 = 1.5038 ν.sub.4 = 66.8 d.sub.8 = 29.414 (variable) ##STR29## -9.001 -33.714 d.sub.9 = 0.256 n.sub.5 = 1.689 ν.sub.5 = 49.4 d.sub.10 = 1.775 (variable) ##STR30## 36.83 -10.809 d.sub.11 = 0.547 n.sub.6 = 1.5168 ν.sub.6 = 64.0 d.sub.12 = 0.369 (variable) ##STR31## -18.978 6.589 ∞ d.sub.13 = d.sub.14 = 0.256 0.615 n.sub.7 = 1.6583 n.sub.8 = 1.5955 ν.sub.7 = 57.3 ν.sub.8 = 39.4 __________________________________________________________________________

Claim 12

An improved telephoto lens system having a simplified focusing mode of operation comprising the following design parameters: Table 5 __________________________________________________________________________ Embodiment 3 f = 100 F No.: 6.3 2ω = 4° 13' Telephoto Ratio: 0.684 Photographing Distance: ∞- Axial Refractive Abbe Radius of Curvature Distance Index Number __________________________________________________________________________ ##STR25## 28.799 25.206 d.sub.1 = 0.855 n.sub.1 = 1.5168 ν.sub.1 = 64.0 d.sub.2 = 0.427 ##STR26## 22.613 -36.991 d.sub.3 = 2.632 n.sub.2 = 1.4339 ν.sub.2 = 95.0 d.sub.4 = 1.381 ##STR27## -34.414 125.075 d.sub.5 = 0.684 n.sub.3 = 1.757 ν.sub.3 = 47.7 d.sub.6 = 1.776 ##STR28## 24.738 ∞ d.sub.7 = 1.538 n.sub.4 = 1.5038 ν.sub.4 = 66.8 d.sub.8 = 29.414 (variable) ##STR29## -9.001 -33.714 d.sub.9 = 0.256 n.sub.5 = 1.689 ν.sub.5 = 49.4 d.sub.10 = 1.775 (variable) ##STR30## 36.83 -10.809 d.sub.11 = 0.547 n.sub.6 = 1.5168 ν.sub.6 = 64.0 d.sub.12 = 0.369 (variable) ##STR31## -18.978 6.589 ∞ d.sub.13 = d.sub.14 = 0.256 0.615 n.sub.7 = 1.6583 n.sub.8 = 1.5955 ν.sub.7 = 57.3 ν.sub.8 = 39.4 __________________________________________________________________________