Olympus filed a patent application for a modular DSLR camera. Here is the description of the system:
"The present invention relates to an optical unit to which an imaging optical system is detachably attached, an imaging unit, an imaging body, and an imaging device.
There is known a camera capable of exchanging an imaging element with another imaging element of a different size according to the purpose (refer to Patent Document 1). This camera has a horizontally-long box-like camera body and a photographing lens for silver salt single-lens reflex camera... Further, this camera has a configuration allowing exchange of a CCD substrate and thus different types of digital cameras can be realized by one camera body.
The shutter is disposed between the attachment/detachment portion and the intermediate image.
An imaging body according to a second aspect of the present invention includes: an attachment/detachment portion to which an optical unit is detachably attached; an imaging element; a conversion optical system; and a finder optical system, wherein the conversion optical system is designed to form an intermediate image, the finder optical system has an optical path folding member, the optical path folding member is disposed opposite to the imaging element with respect to the attachment/detachment portion, the direction of a reflecting surface of the optical path folding member is set such that the optical axis of the folded optical path is parallel to the optical axis of the conversion optical system, and another optical system is disposed on the folded optical path."