
Single-lens translucent (SLT) is a
Sony
is a Japanese multinational conglomerate (company), conglomerate headquartered at Sony City in Minato, Tokyo, Japan. The Sony Group encompasses various businesses, including Sony Corporation (electronics), Sony Semiconductor Solutions (i ...
proprietary designation for
Sony Alpha
is a Japanese multinational conglomerate (company), conglomerate headquartered at Sony City in Minato, Tokyo, Japan. The Sony Group encompasses various businesses, including Sony Corporation (electronics), Sony Semiconductor Solutions (i ...
cameras which employ a
pellicle mirror
A pellicle mirror is an ultra-thin, ultra-lightweight Transparency (optics), semi-transparent mirror employed in the light path of an optical instrument, splitting the light beam into two separate beams, both of reduced light intensity. Splitting t ...
,
electronic viewfinder
An electronic viewfinder (EVF) is a camera viewfinder where the image captured by the lens is displayed on a small screen (usually LCD or OLED) which the photographer can look through when composing their shot. It differs from a live preview sc ...
, and
phase-detection autofocus system. They employ the same
Minolta A-mount as Sony Alpha DSLR cameras.
Sony SLT cameras have a semi-transparent fixed mirror which diverts a portion of incoming light to a sensor, while the remaining light strikes a motherboard. The image sensor feeds the electronic viewfinder and also records still images and video on command. The utility of the SLT design is to allow full-time phase-detection autofocus during electronic viewfinder,
live view, and video recording operation. With the advent of digital image sensors with integrated phase-detection, the SLT design is no longer required to accomplish this goal, as evidenced by cameras such as the Sony NEX-5R, Fujifilm X-100s, and
Nikon 1,
although the SLT design avoids having pixels unavailable for image formation due to their space on the sensor being occupied by a dedicated phase detection autofocus sensor.
The term "
translucent
In the field of optics, transparency (also called pellucidity or diaphaneity) is the physical property of allowing light to pass through the material without appreciable light scattering by particles, scattering of light. On a macroscopic scale ...
" is a misnomer for the actual SLT design, which employs a
pellicle mirror
A pellicle mirror is an ultra-thin, ultra-lightweight Transparency (optics), semi-transparent mirror employed in the light path of an optical instrument, splitting the light beam into two separate beams, both of reduced light intensity. Splitting t ...
that is not translucent. Pellicle mirrors have been used in
single-lens reflex camera
In photography, a single-lens reflex camera (SLR) is a type of camera that uses a mirror and prism system to allow photographers to view through the lens and see exactly what will be captured. SLRs became the dominant design for professional a ...
s from at least the 1960s (see
Canon Pellix) and in the Pentax EI2000/Hewlett Packard 912 digital SLR of 2000 which used an optical viewfinder and on-sensor contrast-detection focusing.
List of SLT cameras

All of the above cameras record 1920x1080 video at 60i/30p (NTSC regions) or 50i/25p (PAL regions), in
MPEG-4
MPEG-4 is a group of international standards for the compression of digital audio and visual data, multimedia systems, and file storage formats. It was originally introduced in late 1998 as a group of audio and video coding formats and related ...
,
AVCHD
AVCHD (Advanced Video Coding High Definition) is a file-based format for the digital recording and playback of high-definition video. It is H.264 and Dolby AC-3 packaged into the MPEG transport stream, with a set of constraints designed around cam ...
or
H.264 formats. The Alpha 65 and 77 also records video at 50p or 60p, and the Alpha 99II records 4k video at 100 Mbit/s (using XAVC S) with full sensor read-out.
Source: summarised from th
full comparison table at DP Review
See also
*
Digital single-lens reflex camera
A digital single-lens reflex camera (digital SLR or DSLR) is a digital camera that combines the optics and mechanisms of a single-lens reflex camera with a solid-state image sensor and digitally records the images from the sensor.
The reflex des ...
*
Sony ILCA camera
References
{{photography