Optical system having intermediate image formed therein

An optical system composed of a first optical subsystem disposed on an enlargement side and a second optical subsystem disposed on a reduction side with an intermediate image in between,

• wherein the first optical subsystem includes:
• a first lens group that is disposed on the enlargement side of a first stop with a first distance that includes a spacing in which no other lenses are disposed, and the first lens group includes, on the enlargement side of the first lens group, a first component with negative refractive power, and
• a second lens group that has positive refractive power, is disposed on the reduction side of the first stop with a second distance that includes a spacing in which no other lenses are disposed, and forms the intermediate image so as to be adjacent on the reduction side of the second lens group and so as to be tilted toward the enlargement side;
• wherein the second optical subsystem includes:
• a third lens group that is disposed on the enlargement side of a second stop at a third distance that includes a spacing in which no other lenses are disposed, and the third lens group includes, on an enlargement side of the third lens group, a third component with negative refractive power;
• and
• a fourth lens group that has positive refractive power and is disposed on the reduction side of the second stop with a fourth distance that includes a spacing in which other lenses could be disposed but no other lenses are disposed;
• wherein the third component of the third lens group is disposed adjacent to the intermediate image and includes, in order from the enlargement side, a lens that has positive refractive power and is closest to the intermediate image and two lenses with negative refractive power;
• wherein the first distance SP1, the second distance SP2 and an effective diameter SD1 of the first stop satisfy following conditions:
• 0.5<SP1/SD1 <1.7,
• 0.5<SP2/SD1 <1.7, and
• wherein the third distance SP3, the fourth distance SP4, and an effective diameter SD2 of the second stop satisfy following conditions:
• 0.4<SP3/SD2 <1.5,
• 0.4<SP4/SD2 <1.5.

An optical system composed of a first optical subsystem disposed on an enlargement side and a second optical subsystem disposed on a reduction side with an intermediate image in between,

• wherein the first optical subsystem includes:
• a first lens group that is disposed on the enlargement side of a first stop with a first distance that includes a spacing in which no other lenses are disposed, and the first lens group includes, on the enlargement side of the first lens group, a first component with negative refractive power, and
• a second lens group that has positive refractive power, is disposed on the reduction side of the first stop with a second distance that includes a spacing in which no other lenses are disposed, and forms the intermediate image so as to be adjacent on the reduction side of the second lens group and so as to be tilted toward the enlargement side;
• wherein the second optical subsystem includes:
• a third lens group that is disposed on the enlargement side of a second stop at a third distance that includes a spacing in which no other lenses are disposed, and the third lens group includes, on an enlargement side of the third lens group, a third component with negative refractive power;
• and
• a fourth lens group that has positive refractive power and is disposed on the reduction side of the second stop with a fourth distance that includes a spacing in which other lenses could be disposed but no other lenses are disposed;
• wherein the second optical subsystem includes a zoom group including one or more lenses that move during zooming;
• wherein the zoom group includes:
• a first zoom lens group including one or more lenses of the third lens group;
• and a second zoom lens group including one or more lenses of the fourth lens group;
• wherein the first distance SP1, the second distance SP2 and an effective diameter SD1 of the first stop satisfy following conditions:
• 0.5<SP1/SD1 <1.7,
• 0.5<SP2/SD1 <1.7, and
• wherein the third distance SP3, the fourth distance SP4, and an effective diameter SD2 of the second stop satisfy following conditions:
• 0.4<SP3/SD2 <1.5,
• 0.4<SP4/SD2 <1.5.