Abstract: A zoom lens system includes, in order from the object side to the image side, a first, a second, and a third lens groups. The first lens group includes, in order from the object side to the image side, a first and a second lenses. The second lens group is capable of floating to realize an image stabilizating function and includes, in order from the object side to the image side, a third to sixth lenses. The zoom lens system satisfies various formulas, including 0.3<d2a/D2<0.4, wherein d2a is the distance between image-side surfaces of the fifth lens and of the sixth lens, and D2 is a width of the second lens group along an optical axis of the zoom lens system.

Abstract: A wide-angle zoom lens includes a first lens group with positive refraction power, a second lens group with negative refraction power, a third lens group with positive refraction power, and a fourth lens group with positive refraction power. The first lens group, the second lens group, the third lens group, and the fourth lens group move along an optical axis of the zoom lens in focusing. The wide-angle zoom lens satisfies the formulas: 1.6<f3/fw<2.1, where f3 is the effective focal length of the third lens group, and fw is the effective focal length of the wide-angle zoom lens in a wide angle state.

Abstract: A projection lens system includes, in order from the magnified side to the reduced side thereof, a first lens group with negative refractive power, and a second lens group with a positive refracting power. The first lens group includes a first lens having a negative refracting power. The projection lens system satisfies the following condition: 4.5<|F1|/F<6; wherein F1 is the effective focal length of the first lens; F is the effective focal length of the projection lens system.

Abstract: A projection lens system includes, in order from a screen-side to an SLM-side thereof, a first lens group of negative refractive power which includes a first lens, and a second lens group of positive refractive power. The second lens group includes a second to fifth lenses in order from the screen-side to the SLM-side of the projection lens system. The projection lens system satisfies the following condition formulas: 1.95<|F1/Fw|<2.15, 0.5<|f4/Fw|<0.7, and 1.05<|f5/Fw|<1.25, where F1 is the effective focal length of the first lens group, f4 is the focal length of the fourth lens, and f5 is the focal length of the fifth lens, Fw is the effective focal length of the projection lens system which is in the wide-angle state.

Abstract: A zoom lens system includes a first lens group of negative refractive power, a second lens group of positive refractive power and a third lens group of positive refractive power. The zoom lens system satisfies the following condition formulas: 0.78<|f2/f1|<0.91, and 0.72<L2/fT<0.87, where f1 represents an effective focal length of the first lens group, f2 represents an effective focal length of the second lens group, L2 is a displacement of the second lens group when the zoom lens system varies from a wide-angle state to a telephoto state, and fT represents an effective focal length of the zoom lens system which is in the telephoto state.

Abstract: A zoom lens system includes, from the object-side to the image-side thereof, a first lens group, a second lens group, and a third lens group. The first lens group includes a first lens and a second lens. The second lens includes a third lens, a fourth lens, and a fifth lens. The fourth lens and the fifth lens are attached to each other. The third lens group includes a sixth lens. The zoom lens system satisfies the following conditions: 0.35<f2/f3<0.7; 1.8<|f45/Fw|<3; 0.5<|f1|/Ft<0.9; 0.7<f3/Ft<1.2, wherein: f1 is a focal length of the first lens; f2 is a focal length of the second lens; f45 is a focal length of the attached fourth lens and fifth lens; Fw is a focal length of the zoom lens system at a wide-angle end; Ft is a focal length of the zoom lens system in a telephoto state.

Abstract: A wide-angle zoom lens system includes a first lens group with negative refraction power, a second lens group with positive refraction power, and a third lens group with positive refraction power. The first lens group, the second lens group, and the third lens group move along an optical axis of the zoom lens system in focusing. The wide-angle zoom lens system satisfies the formulas: 0.77<|f2/f1|<1.1; and 0.7<L2/fT<1.08; wherein f1 is the effective focal length of the first lens group, f2 is the effective focal length of the second lens group, L2 is a distance of the second lens group moving from a wide-angle state to a telephoto state, and fT is the effective focal length of the wide-angle zoom lens system in the telephoto state.

Abstract: A relay lens is used for an imaging system having a main lens. The main lens has a pupil plane. The relay lens, in the order from the subject side to the image side thereof, includes a first lens of negative refractive power, and a second lens of positive refractive power. The first lens has a first principal plane and a second principal plane. The second lens has a third principal plane and a fourth principal plane. The relay lens system satisfies the following formulas: 0.53<|ƒ1/ƒ2|<0.57; 1.54<?1/?2<3.11; 0.22<D1/D2<0.65, where f1 and f2 are the effective focal lengths of the first and second lenses, v1 and v2 are the Abbe numbers of the first and second lenses, D1 is the distance between the second principal plane and the third principal plane, D2 is the distance between the fourth principal plane and the pupil plane.

Abstract: A projection lens system, in the order from a magnified side to a reduced side, includes a first lens group with negative refraction power and a second lens group with positive refraction power. The projection lens system satisfies the formulas: ?1.55<F1/F2<?1.12; wherein F1 is the effective focal length of the first lens group, and F2 is the effective focal length of the second lens group.

Abstract: An image lens for imaging an object on an image plane, in the order from the object side to the image side thereof, includes: a first lens with negative refraction power, a second lens with positive refraction power, a third lens with negative refraction power, a fourth lens with positive refraction power, and a fifth lens. The image lens satisfies the following formula: 0.9<F2/F<1.4; wherein F2 is focal length from the second lens to the fourth lens, F is focal length of the image lens.

Abstract: A wide-angle zoom lens system includes a first lens group with negative refraction power, a second lens group with positive refraction power, and a third lens group with positive refraction power. The first lens group, the second lens group, and the third lens group move along an optical axis of the zoom lens system in focusing. The wide-angle zoom lens system satisfies the formulas: 0.77<|f2/f1|<1.1; and 0.7<L2/fT<1.08; wherein f1 is the effective focal length of the first lens group, f2 is the effective focal length of the second lens group, L2 is a distance of the second lens group moving from a wide-angle state to a telephoto state, and fT is the effective focal length of the wide-angle zoom lens system in the telephoto state.

Abstract: A zoom lens system includes, in order from the object side to the image side, a first, a second, and a third lens groups. The first lens group includes, in order from the object side to the image side, a first and a second lenses. The second lens group is capable of floating to realize an image stabilizating function and includes, in order from the object side to the image side, a third to sixth lenses. The zoom lens system satisfies various formulas, including 0.3<d2a/D2<0.4, wherein d2a is the distance between image-side surfaces of the fifth lens and of the sixth lens, and D2 is a width of the second lens group along an optical axis of the zoom lens system.

Abstract: A projection lens system includes, in order from a screen-side to an SLM-side thereof, a first lens group of negative refractive power which includes a first lens, and a second lens group of positive refractive power. The second lens group includes a second to fifth lenses in order from the screen-side to the SLM-side of the projection lens system. The projection lens system satisfies the following condition formulas: 1.95<|F1/Fw|<2.15, 0.5<|f4/Fw|<0.7, and 1.05<|f5/Fw|<1.25, where F1 is the effective focal length of the first lens group, f4 is the focal length of the fourth lens, and f5 is the focal length of the fifth lens, Fw is the effective focal length of the projection lens system which is in the wide-angle state.

Abstract: A projection lens system includes, in order from the magnified side to the reduced side thereof, a first lens group with negative refractive power, and a second lens group with a positive refracting power. The first lens group includes a first lens having a negative refracting power. The projection lens system satisfies the following condition: 4.5<|F1|/F<6; wherein F1 is the effective focal length of the first lens; F is the effective focal length of the projection lens system.

Abstract: A projection lens system, in the order from a magnified side to a reduced side, includes a first lens group with negative refraction power and a second lens group with positive refraction power. The projection lens system satisfies the formulas: ?1.55<F1/F2<?1.12; wherein F1 is the effective focal length of the first lens group, and F2 is the effective focal length of the second lens group.

Abstract: A projection lens includes, in order from the magnification end to the minimization end thereof: a first lens group of a negative refractive power; and a second lens group of a positive refractive power. The projection lens satisfies the formula: 0.061<F/L<0.078; where F represents the effective focal length of the projection lens and L represent the total length of the projection lens.

Abstract: Provided is a zoom lens for imaging an object on an imaging surface. The zoom lens includes, in the order from an object side to an image side thereof, a first lens group with positive refraction power, a second lens group with negative refraction power, a third lens group with positive refraction power, and a fourth lens group with positive refraction power. The first lens group includes a first surface. The zoom lens satisfies the formula: 0.15<|L3|/Lt<0.25, where L3 is a distance of the movement of the third lens group along an optical axis of the zoom lens when the zoom lens is switched between a wide-angle state and a telephoto state, and Lt is a distance from the first surface to the imaging surface.

Abstract: A zoom lens system includes a first lens group of negative refractive power, a second lens group of positive refractive power and a third lens group of positive refractive power. The zoom lens system satisfies the following condition formulas: 0.78<|f2/f1|<0.91, and 0.72<L2/fT<0.87, where f1 represents an effective focal length of the first lens group, f2 represents an effective focal length of the second lens group, L2 is a displacement of the second lens group when the zoom lens system varies from a wide-angle state to a telephoto state, and fT represents an effective focal length of the zoom lens system which is in the telephoto state.

Abstract: A projection lens system includes, in order from the magnified side to the reduced side thereof, a first lens group with negative refractive power, a second lens group with a positive refracting power, and a spatial light modulator. The projection lens system satisfies the following condition: 3.478<BFL/F<3.528. Wherein: BFL is a back focal length of the projection lens system; F is an effective focal length of the projection lens system.

Abstract: An image lens for imaging an object on an image plane, in the order from the object side to the image side thereof, includes: a first lens with negative refraction power, a second lens with positive refraction power, a third lens with negative refraction power, a fourth lens with positive refraction power, and a fifth lens. The image lens satisfies the following formula: 0.9<F2/F<1.4; wherein F2 is focal length from the second lens to the fourth lens, F is focal length of the image lens.