[0001]
The present invention is most suitable for digital cameras, silver salt cameras, video cameras, etc., and is particularly suitable for a mirrorless camera having an angle of view of about 80 ° to 100 °, a small size, and a short back focus. Regarding the optical system.
[0002]
In recent years, the market share of mirrorless cameras has been increasing in interchangeable lens digital cameras. Mirrorless cameras tend to be smaller than single-lens reflex cameras by using a short flange back. There is a demand for miniaturization of interchangeable lenses to match the miniaturization of camera bodies. Since the mirrorless camera has a short flange back, a product with a shorter optical length and a shorter back focus than a lens for a single-lens reflex camera is required in order to reduce the size.
[0003]
Further, as mirrorless cameras have become widespread, the moving image function has become more important. It is necessary to keep the drive sound associated with autofocus small so that sound does not enter the image when shooting a movie, and considering the need for miniaturization of the lens body, the motor can not be made large, so the parts that drive during focus are lightweight. Is required.
[0004]
However, while miniaturization is desired, it is also desired to increase the diameter and performance of the interchangeable lens in order to increase the number of pixels of the output device and differentiate it from the smartphone camera.