An objective optical system includes in order from an object side, a front unit having a positive refractive power and a rear unit. The front unit includes in order from the object side, a first lens having a negative refractive power, a second lens having a positive refractive power, and a third lens having a positive refractive power. The rear unit includes one lens or a plurality of lenses and the following conditional expression is satisfied:
|(FLag−FLaC)/FLad|<0.05  (1) where, FLad denotes a focal length for a d-line of the front unit, FLag denotes a focal length for a g-line of the front unit, and FLaC denotes a focal length for a C-line of the front unit.

A projection lens system that projects an image of a reduction side into a magnification side includes a diaphragm, a plurality of positive lenses, and a plurality of negative lenses. The plurality of positive lenses include a first positive lens closer to the magnification side than the diaphragm is and closest to the diaphragm, a second positive lens second closest to the diaphragm after the first positive lens on the magnification side, a third positive lens closer to the reduction side than the diaphragm is and closest to the diaphragm. The plurality of negative lenses include a first negative lens closer to the magnification side than the diaphragm is and closest to the diaphragm, and a second negative lens closer to the reduction side than the diaphragm is and closest to the diaphragm. The lenses have transmittances larger than threshold values, respectively.

A head for a walk-around costume is provided that is adapted for enhanced visibility. The costume head includes an outer shell defining an interior space for receiving a head of a human performer. The outer shell includes an aperture allowing incoming light from an exterior space to enter the interior space, and an eye location for the human performer is spaced apart from the aperture when the head is received in the interior space. To provide an enlarged field of view, the costume head includes an optical viewfinder assembly disposed within the interior space of the outer shell between the aperture and the eye location. The optical viewfinder assembly is adapted for receiving the incoming light and transmitting the incoming light to the eye location to move a viewpoint of the human performer to the aperture to provide a larger field of view of the exterior space.

Disclosed is an interchangeable conversion lens for underwater photography or cinematography able to change from macro to wide angle photographic perspectives and consists of a sequential assembly of optical lens elements. This conversion lens includes an objective lens, a relay lens and a focusing unit which are positioned on an optical axis and are interrelated in their optical performance to one another. The objective lens is to form an intermediate image (reversed and inverted) from wide angle perspective to half the size of the sensor in the camera, this intermediate image is then transmitted through the relay lens and the focusing unit which projects the image through a macro lens into the sensor of a camera. The three parts can be disassembled and reassembled underwater, all three separate parts are waterproof and therefore the optical performance of water is taken into consideration in the optical system. The length of this lens can be extended or reduced, and the three individual parts can be changed according to personal preferences. This provides a flexible underwater optical system that can easily be changed in water between macro and wide angle perspectives, depending on the photographer's needs.

An optical tissue imaging system includes a probe for insertion into a transparent cylindrical capillary. The capillary includes an internal cylindrical channel that extends along a central axis. The capillary is inserted into tissue of a subject, and the probe may rotate and translate within the capillary. The probe may include a mirror configured to reflect light to the tissue outside of the cylindrical capillary.

A system includes a head-mounted display (HMD) device configured to project digital images to a user's eye and a viewing device. The viewing device includes an optical relay unit having a world-facing surface and an eye-facing surface and a holder coupled to the optical relay unit and configured to support the HMD device near the world-facing surface. The optical relay unit is configured to transmit light projected by the HMD device to an eye-facing aperture disposed at the eye-facing surface of the optical relay. The system shifts an eyebox of the HMD by receiving light projected from an optical combiner of the HMD, transmitting the light through the optical relay unit of the viewing device to the eye-facing aperture of the optical relay unit, and outputting the light from the eye-facing aperture such that the light is focused at an eyebox in which a user's eye is located.

An imaging system including a front aperture, two or more refractive lens elements mounted in a lens barrel, and a photosensor. One or more of the components of the imaging system (e.g., the aperture, lenses, lens groups, and/or photosensor) are tilted with respect to each other and/or with respect to a center (or mechanical) axis of the imaging system to compensate for effects including but not limited to keystone distortion, resolution non-uniformity, and gradient blur that result from tilt of an object in the field of view of the camera with respect to the center axis of the camera.

An apparatus and method for imaging includes an imaging system formed of a movable objective stage proximal to a sample and positioned for providing an excitation beam onto and for capturing an emission from the sample. The movable objective stage includes an optical lens apparatus and a turn reflector optically coupled to the imaging optics, where at least one of the optical lens apparatus and the turn reflector are movable relative to one another for scanning the sample, and wherein the movement is achieved while maintaining a substantially fixed optical path length between the optical lens apparatus and a fixed plane in a fixed imaging optics stage.

A low parallax imaging device includes a plurality of imaging lens elements arranged to capture adjacent fields of view. In some examples, adjacent imaging lens elements may contact at datum features to maintain a desired spacing. The spacing may allow for partial overlapping of low-parallax volumes associated with the respective imaging lens elements.

An imaging device, an adjustment method, and an adjustment program can acquire multispectral images having good image quality. The imaging device is disposed on an image side of another optical system, and includes a multispectral camera that acquires images in a plurality of wavelength ranges, a field lens that relays the other optical system to the multispectral camera, and an adjustment mechanism that adjusts a conjugate relationship between an emission pupil position of the other optical system and an incident pupil position of the multispectral camera. The multispectral camera includes: a wavelength polarizing filter unit that includes an optical member disposed at a pupil position or near the pupil position and including a plurality of aperture regions having different centroids, a plurality of optical filters arranged in the aperture regions, and a plurality of polarizing filters arranged in the aperture regions; an imaging element; and a processor.