Zoom lens system and image pickup apparatus

A zoom lens system comprising:

• a first lens group having a positive refractive power;
• a second lens group having a negative refractive power;
• a third lens group having a positive refractive power;
• a fourth lens group having a positive refractive power;
• and
• a fifth lens group having a positive refractive power, which are arranged in an order from an object side,
• wherein:
• the first lens group comprises a lens having a negative refractive power, a reflector for changing an optical path, and a lens having a positive refractive power;
• when zooming is performed from a wide angle position to a telephoto position, the second lens group and the fourth lens group move, the fifth lens group does not move, and
• the zoom lens system satisfies:
• 6.5≦Lt/L2≦7.5, and 3.0≦F1/(Ft/Fw)≦3.9;
• where
• Lt represents an overall length of the zoom lens system at the telephoto position;
• L2 represents an amount of movement of the second lens group when zooming is performed from the wide angle position to the telephoto position;
• F1 represents a focal length of the first lens group;
• Fw represents a focal length at the wide angle position of the zoom lens system;
• and
• Ft represents a focal length at the telephoto position of the zoom lens system.

An image pickup apparatus comprising

• a zoom lens system;
• and
• an imaging device for receiving an image formed by the zoom lens system, wherein:
• the zoom lens system comprises a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a positive refractive power, and a fifth lens group having a positive refractive power, which are arranged in an order from an object side;
• the first lens group comprising one or more lenses having a negative refractive power, a reflector for changing an optical path, and one or more lenses having a positive refractive power
• the first lens group comprises one or more lenses having a negative refractive power, a reflector for changing an optical path, and one or more lenses having a positive refractive power;
• when zooming is performed from a wide angle position to a telephoto position, the first lens group, the third lens group and the fifth lens group remain fixed and the second lens group and the fourth lens group move, and
• the zoom lens system satisfies:
• Nd>1.94, 6.5≦Lt/L2≦7.5, and 3.0≦F1/(Ft/Fw)≦3.9;
• where
• Nd represents a refractive index of the one or more lenses having a negative refractive power in the first lens group;
• Lt represents an overall length of the zoom lens system at the telephoto position;
• L2 represents an amount of movement of the second lens group when zooming is performed from the wide angle position to the telephoto position;
• F1 represents a focal length of the first lens group;
• Fw represents a focal length at the wide angle position of the zoom lens system;
• and
• Ft represents a focal length at the telephoto position of the zoom lens system.

An image pickup apparatus comprising:

• a zoom lens system;
• and
• an imaging device for receiving an image formed by the zoom lens system, wherein:
• the zoom lens system comprises a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a positive refractive power, and a fifth lens group having a positive refractive power, which are arranged in an order from an object side;
• the first lens group comprises a lens having a negative refractive power for changing an optical path, and a lens having a positive refractive power;
• when zooming is performed from a wide angle position to a telephoto position, the second lens group, the fourth lens group move, the fifth lens group does not move, and
• the zoom lens system satisfies:
• 6.5≦Lt/L2≦7.5, and 3.0≦F1/(Ft/Fw)≦3.9;
• where
• Lt represents an overall length of the zoom lens system at the telephoto position;
• L2 represents an amount of movement of the second lens group when zooming is performed from the wide angle position to the telephoto position;
• F1 represents a focal length of the first lens group;
• Fw represents a focal length at the wide angle position of the zoom lens system;
• and
• Ft represents a focal length at the telephoto position of the zoom lens system.