Attachment optical system and image pickup apparatus

An image pickup apparatus comprising:

• an attachment optical system, to which an imaging lens is attachable on an object side of the attachment optical system, the attachment optical system including two bending optical systems arranged in parallel;
• and
• an image sensor configured to capture optical images formed by the two bending optical systems,
• wherein each of the two bending optical systems includes a first reflective member and a second reflective member,
• wherein each of the two bending optical systems includes, in order from the object side to an image side, a front unit and a rear unit, which are separated by a maximum air gap on an optical axis in each bending optical system, and
• wherein at least one of the first reflective member and the second reflective member is disposed between a surface having refractive power and disposed closest to an object in the rear unit and a surface having refractive power and disposed closest to an image plane in the rear unit of each bending optical system,
• wherein the following inequality is satisfied:
• -
• 0.75
• <
• β
• <
• -
• 0.25
• where β is a lateral magnification of each bending optical system.

An attachment optical system, to which an imaging lens is attachable on an object side of the attachment optical system, the attachment optical system comprising two bending optical systems arranged in parallel,

• wherein each of the two bending optical systems includes a first reflective member and a second reflective member,
• wherein each of the two bending optical systems includes, in order from the object side to an image side, a front unit and a rear unit, which are separated by a maximum air gap on an optical axis in each bending optical system, and
• wherein at least one of the first reflective member and the second reflective member is disposed between a surface having refractive power and disposed closest to an object in the rear unit and a surface having refractive power and disposed closest to an image plane in the rear unit of each bending optical system,
• wherein the following inequality is satisfied:
• 0.2
• <
• fF
• /
• ❘
• "\[LeftBracketingBar]"
• fR
• ❘
• "\[RightBracketingBar]"
• <
• 2.
• where fF is a focal length of the front unit, and fR is a focal length of the rear unit.

An attachment optical system, to which an imaging lens is attachable on an object side of the attachment optical system, the attachment optical system comprising two bending optical systems arranged in parallel,

• wherein each of the two bending optical systems includes a first reflective member and a second reflective member,
• wherein each of the two bending optical systems includes, in order from the object side to an image side, a front unit and a rear unit, which are separated by a maximum air gap on an optical axis in each bending optical system, and
• wherein at least one of the first reflective member and the second reflective member is disposed between a surface having refractive power and disposed closest to an object in the rear unit and a surface having refractive power and disposed closest to an image plane in the rear unit of each bending optical system,
• wherein the front unit includes three or four spherical lenses.

An attachment optical system, to which an imaging lens is attachable on an object side of the attachment optical system, the attachment optical system comprising two bending optical systems arranged in parallel,

• wherein each of the two bending optical systems includes a first reflective member and a second reflective member,
• wherein each of the two bending optical systems includes, in order from the object side to an image side, a front unit and a rear unit, which are separated by a maximum air gap on an optical axis in each bending optical system, and
• wherein at least one of the first reflective member and the second reflective member is disposed between a surface having refractive power and disposed closest to an object in the rear unit and a surface having refractive power and disposed closest to an image plane in the rear unit of each bending optical system,
• wherein the front unit includes a set of cemented lenses.