1. A zoom lens, consisting of sequentially from an object side:
a first lens group having a positive refractive power and a focusing function;
a second lens group having a negative refractive power and having a variator function of performing zooming;
a third lens group having a positive refractive power and a diaphragm;
a fourth lens group having a positive refractive power, and having a compensator function of correcting a position of an imaging plane at the time of zooming; and
a fifth lens group having a positive or negative refractive power,
wherein the second lens group is moved to the imaging plane side from the object side along an optical axis, and the fourth lens group is moved along the optical axis, in a state of fixing the first lens group, the third lens group, and the fifth lens group at the time of zooming from a wide angle end to a telephoto end, and only the first lens group is moved along the optical axis at the time of focusing.
2. The zoom lens according to claim 1, wherein the first lens group is composed of three or more lenses including at least one concave lens, and the following conditional formula (1) is satisfied:
0.45<ftf1<0.6\u2003\u2003(1)
wherein
f1: focal distance of the first lens group
ft: focal distance of a total lens system at the telephoto end.
3. The zoom lens according to claim 1, wherein the fourth lens group includes at least two lenses, and the following conditional formulas (2) to (5) are satisfied:
1<f4|f2|<2.5\u2003\u2003(2)
0.83<f3f4<3\u2003\u2003(3)
0.5<\u03b2t4\u03b2w4<1.7\u2003\u2003(4)
\u03b2t4<0.6\u2003\u2003(5)
wherein
f2: focal distance of the second lens group
f3: focal distance of the third lens group
f4: focal distance of the fourth lens group
\u03b2w4: lateral magnification of the fourth lens at the wide angle end
\u03b2t4: lateral magnification of the fourth lens at the telephoto end.
4. The zoom lens according to claim 1, wherein the fifth lens group includes at least three lenses, and the object side two lenses of at least the three lenses of the fifth lens group are configured as a cemented lens composed of a positive lens and a negative lens sequentially from the object side, and the following formula (6) is satisfied:
n5B<n5A\u2003\u2003(6)
wherein
n5A: d line refractive index of the positive lens included in the cemented lens of the fifth lens group
n5B: d line refractive index of the negative lens included in the cemented lens of the fifth lens group.
5. The zoom lens according to claim 1, wherein the fourth lens group includes at least two lenses, and the fifth lens group includes at least three lenses, and the object side two lenses of at least the three lenses of the fifth lens group are configured as a cemented lens composed of a positive lens and a negative lens sequentially from the object side, and the following conditional formulas (2) to (6) are satisfied:
1<f4|f2|<2.5\u2003\u2003(2)
0.83<f3f4<3\u2003\u2003(3)
0.5<\u03b2t4\u03b2w4<1.7\u2003\u2003(4)
\u03b2t4<0.6\u2003\u2003(5)
n5B<n5A\u2003\u2003(6)
wherein
f2: focal distance of the second lens group
f3: focal distance of the third lens group
f4: focal distance of the fourth lens group
\u03b2w4: lateral magnification of the fourth lens group at the wide angle end
\u03b2t4: lateral magnification of the fourth lens group at the telephoto end
n5A: d line refractive index of the positive lens included in the cemented lens of the fifth lens group
n5B: d line refractive index of the negative lens included in the cemented lens of the fifth lens group.
6. The zoom lens according to claim 1, wherein the first lens group is composed of three or more lenses including at least one concave lens, and the fourth lens group includes at least two lenses, and the fifth lens group includes at least three lenses, and the object side two lenses of at least the three lenses of the fifth lens group are configured as a cemented lens composed of a positive lens and a negative lens sequentially from the object side, and the following conditional formulas (1) to (6) are satisfied.
0.45<ftf1<0.6\u2003\u2003(1)
1<f4|f2|<2.5\u2003\u2003(2)
0.83<f3f4<3\u2003\u2003(3)
0.5<\u03b2t4\u03b2w4<1.7\u2003\u2003(4)
\u03b2t4<0.6\u2003\u2003(5)
n5B<n5A\u2003\u2003(6)
wherein
f1: focal distance of the first lens group
ft: focal distance of a total lens system at the telephoto end
f2: focal distance of the second lens group
f3: focal distance of the third lens group
f4: focal distance of the fourth lens group
\u03b2w4: lateral magnification of the fourth lens group at the wide angle end
\u03b2t4: lateral magnification of the fourth lens group at the telephoto end
n5A: d line refractive index of the positive lens included in the cemented lens of the fifth lens group
n5B: d line refractive index of the negative lens included in the cemented lens of the fifth lens group.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of tire testing comprising:
applying a drive torque to a tire and a wheel assembly about an axis of rotation to drive the tire and wheel assembly and a rotatable drum with the tire in rolling contact with the rotatable drum;
controlling a load pressure of the tire against the rotatable drum; and
adjusting a lateral position of the tire across a surface of the rotatable drum, such that the surface of the rotatable drum is substantially evenly used after conclusion of a test.
2. The method of claim 1, wherein tire testing includes the use of a programmable lateral position waveform.
3. The method of claim 1, wherein a non-linear ramp rate of the tire back and forth across the abrasive surface of the rotatable drum is performed.
4. The method of claim 1, wherein said rotatable drum includes a surface comprised of at least two different abrasive materials.
5. (canceled)
6. The method of claim 2, wherein said waveform has between 10 and 1000 points
7. The method of claim 2, wherein said waveform varies in accord with the tread width of the tire.
8. The method of claim 4 wherein said two different abrasive materials comprise a high microcontent surface and a high macrocontent surface
9. The method of claim 1, wherein tracks are not created in the surface of a rotatable drum.
10. (canceled)
11. A method of tire testing comprising:
applying a drive torque to a tire and a wheel assembly about an axis of rotation to drive the tire and wheel assembly and a rotatable drum with the tire in rolling contact with the rotatable drum;
controlling a load pressure of the tire against the rotatable drum; and
adjusting a lateral position of the tire across a surface of the rotatable drum according to a programmable lateral position waveform which optimizes wear of the surface of the rotatable drum based on width of the surface and width of a tire footprint.
12. A method of tire testing comprising:
applying a drive torque to a tire and a wheel assembly about an axis of rotation to drive the tire and wheel assembly and a rotatable drum having a surface comprised of at least two different abrasion materials with the tire in rolling contact with the rotatable drum;
controlling a load pressure of the tire against the rotatable drum; and
adjusting a lateral position of the tire across a surface of the rotatable drum.