Resources Contact Us Home
Zoom lens

Image Number 11 for United States Patent #6646815.

A zoom lens, comprises: three lens groups including a first lens group having a negative refracting power, a second lens group having a positive refracting power and a third lens group having a positive refracting power arranged serially in this order from the object side. The second lens group comprises a positive lens, a cemented lens including a positive lens and a negative lens and one lens arranged serially in this order from the object side. The following conditional expression is satisfied;where f.sub.2 represents a focal length of the second lens group and f.sub.w represents a focal length of the total optical system at a wide-angle end.

  Recently Added Patents
Tire tread
Visual physician office systems and methods
Cleaning device, and image forming apparatus, process cartridge, and intermediate transfer unit each including the cleaning device
Reducing energy and increasing speed by an instruction substituting subsequent instructions with specific function instruction
System and method for improving cache efficiency
System and method for organizing, processing and presenting information
Position and orientation measurement apparatus, position and orientation measurement method, and storage medium
  Randomly Featured Patents
Tag communication apparatus, tag communication apparatus control method, and tag communication apparatus control program
Monitoring stage alignment and related stage and calibration target
Hand dryer
Prefabricated retroreflective sign
Clostridium perfringens vaccine
Road surface detection apparatus and apparatus for detecting upward/downward axis displacement of vehicle-mounted radar
Multiple alternate path pipelined microsequencer and method for controlling a computer
Gas grill with insect deterrent
System and method for transmitting /receiving a signal in a mobile communication system using a multiple input multiple output adaptive antenna array scheme
Simplified detection implement