Optical imaging system

An optical imaging system comprising an image sensor for photoelectric conversion, the optical imaging system further comprising:

• a first lens group having a positive refractive power;
• a second lens group having a negative refractive power;
• a third lens group having one of a positive or negative power;
• and
• a fourth lens group having one of a positive or negative power, wherein the optical imaging system satisfies
• 0.45
• <
• f
• TTL
• <
• 1.01
• ,
• wherein f denotes a synthetic focus distance of die optical imaging system and TTL denotes a distance from an iris surface to an imaging surface;
• wherein a lens located in the first lens group and having at least one aspheric surface;
• and
• one of a thin film filter or an optical filter for restricting the transmission of a portion of light between the second and third lens groups or between the third and fourth lens groups.

An optical imaging system comprising an image sensor for photoelectric conversion, the optical imaging system further comprising:

• a first lens group having a positive refractive power;
• a second lens group having a negative refractive power;
• a third lens group having one of a positive or negative power;
• and
• a fourth lens group having one of a positive or negative power, wherein the first and second lens groups satisfy an optical axis direction size according to
• 0
• <
• d
• 1
• TTL
• <
• 0.26
• ,
• wherein d1 denotes a separated distance between the first lens group and the second lens group on the optical axis and TTL denotes a distance from an iris surface to an imaging surface;
• wherein a lens located in the first lens group and having at least one aspheric surface;
• and
• one of a thin film filter or an optical filter for restricting the transmission of a portion of light between the second and third lens groups or between the third and fourth lens groups.

An optical imaging system comprising an image sensor for photoelectric conversion, the optical imaging system further comprising:

• a first lens group having a positive refractive power;
• a second lens group having a negative refractive power;
• a third lens group having one of a positive or negative power;
• and
• a fourth lens group having one of a positive or negative power, wherein the third and fourth lens groups satisfy an optical axis direction size according to
• 0
• <
• d
• 3
• TTL
• <
• 0.40
• ,
• wherein d3 denotes a separated distance between the third lens group and the fourth lens group on the optical axis and TIL denotes a distance from an iris surface to an imaging surface;
• wherein a lens located in the first lens group and having at least one aspheric surface;
• and
• one of a thin film filter or an optical filter for restricting the transmission of a portion of light between the second and third lens groups or between the third and fourth lens groups.

An optical imaging system comprising an image sensor for photoelectric conversion, the optical imaging system further comprising:

• a first lens group having a positive refractive power closest to a subject;
• a second lens group closest to the first lens group and having a negative refractive power;
• a third lens group having one of a positive or negative power;
• and
• a fourth lens group having one of a positive or negative power,
• wherein each of the first to fourth lens groups comprises an aspheric lens having at least one aspheric surface thereof, and
• wherein the Abbe's numbers of the first and second lens groups G1 and G2 satisfy
• 28.2<υ1−υ2<42.8,
• wherein υ1 and υ2 denote Abbe's numbers representing the distribution characteristics of the first and second lens groups respectively.