Sony SLT camera

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The Sony SLT design features a pellicle mirror which allows light to strike both the digital image sensor (parallel to the lens mount, behind mirror) and phase-detection autofocus sensor (perpendicular to the mount) at all times. Sony Alpha Mount Camera.jpg
The Sony SLT design features a pellicle mirror which allows light to strike both the digital image sensor (parallel to the lens mount, behind mirror) and phase-detection autofocus sensor (perpendicular to the mount) at all times.

Single-lens translucent (SLT) is a Sony proprietary designation for Sony Alpha cameras which employ a pellicle mirror, electronic viewfinder, and phase-detection autofocus system. They employ the same Minolta A-mount as Sony Alpha DSLR cameras. [1]

Contents

Sony SLT cameras have a semi-transparent fixed mirror which diverts a portion of incoming light to a phase-detection autofocus sensor, while the remaining light strikes a digital image sensor. 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. [2] [3] 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, [4] [5] 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" is a misnomer for the actual SLT design, which employs a pellicle mirror that is not translucent[ citation needed ]. Pellicle mirrors have been used in single-lens reflex cameras 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 focussing.

List of SLT cameras

Sony Alpha 55 Sony SLT-A55 01s5.jpg
Sony Alpha 55
ModelAnnouncementMegapixelsSensorScreenBuilt-in flash
Sony Alpha 33 201014 MP APS-C 3" articulatedYes check.svg (pop-up)
Sony Alpha 35 201116 MP APS-C 3" fixedYes check.svg (pop-up)
Sony Alpha 37 201216 MP APS-C 2.7" tiltingYes check.svg (pop-up)
Sony Alpha 55 201016 MP APS-C 3" articulatedYes check.svg (pop-up)
Sony Alpha 57 201216 MP APS-C 3" articulatedYes check.svg (pop-up)
Sony Alpha 58 201320 MP APS-C 2.7" tiltingYes check.svg (pop-up)
Sony Alpha 65 201124 MP APS-C 3" articulatedYes check.svg (pop-up)
Sony Alpha 68 201524 MP APS-C 2.7" tiltingYes check.svg (pop-up)
Sony Alpha 77 201124 MP APS-C 3" fully articulatedYes check.svg (pop-up)
Sony Alpha 77 II 201424 MP APS-C 3" fully articulatedYes check.svg (pop-up)
Sony Alpha 99 201224 MP Full-frame sensor 3" fully articulatedDark Red x.svg
Sony Alpha 99 II 201642 MP Full-frame sensor 3" fully articulatedDark Red x.svg

All of the above cameras record 1920x1080 video at 60i/30p (NTSC regions) or 50i/25p (PAL regions), in MPEG-4, AVCHD 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 the full comparison table at DP Review.

See also

Related Research Articles

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<span class="mw-page-title-main">Autofocus</span> Sensor-controlled optical focus

An autofocus optical system uses a sensor, a control system and a motor to focus on an automatically- or manually-selected point or area. An electronic rangefinder has a display instead of the motor; the adjustment of the optical system has to be done manually until indication. Autofocus methods are distinguished as active, passive or hybrid types.

<span class="mw-page-title-main">Digital single-lens reflex camera</span> Digital cameras combining the parts of a single-lens reflex camera and a digital camera back

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<span class="mw-page-title-main">APS-C</span> Image sensor format

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<span class="mw-page-title-main">Pellicle mirror</span> Light, semi-transparent mirror

A pellicle mirror is an ultra-thin, ultra-lightweight 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 the beam allows its use for multiple purposes simultaneously. The thinness of the mirror practically eliminates beam or image doubling due to a non-coincident weak second reflection from the nominally non-reflecting surface, a problem with mirror-type beam splitters. The name pellicle is a diminutive of pellis, a skin or film.

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<span class="mw-page-title-main">Mirrorless camera</span> Compact camera with a user-removable and replaceable lens

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<span class="mw-page-title-main">Sony E-mount</span> Lens mount designed by Sony for their camcorders and mirrorless cameras

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<span class="mw-page-title-main">Sony Alpha 55</span> Camera model

The Sony α55 is a midrange-level SLT camera, released in August 2010.

<span class="mw-page-title-main">Sony Alpha 77</span> Camera model

The Sony α77 was the flagship for Sony's midrange Alpha SLT camera line.

<span class="mw-page-title-main">Sony Alpha 37</span> Camera model

The Sony α37 or Sony Alpha 37 is a single-lens reflex style digital camera that replaced the SLT-A35 in 2012. However, the Alpha 37 camera features an electronic viewfinder and a translucent mirror. The main advantage of a translucent mirror is that it needn't flip up out of the way when taking a picture in order to expose the sensor, but the camera can focus and capture images simultaneously. Also the viewfinder can be used while video recording or stills/video playback, which is useful for example in bright sunlight. The camera's 15-point autofocus system can be set to single, continuous or automatic and is arranged towards the centre. The 7 fps burst mode is available only in "speed priority" mode but can reach up to 5.5 fps burst rate in combination with any other settings. The A37 is compatible with Sony Bravia Televisions.

<span class="mw-page-title-main">Sony Alpha 57</span> Camera model

The Sony Alpha 57 is a Digital single-lens reflex camera that replaced the A55 in 2012. The camera features an electronic viewfinder and a translucent mirror. The main advantage of a translucent mirror is that it needn't flip up out of the way when taking a picture in order to expose the sensor, but the camera can focus and capture images simultaneously. The camera's 15-point autofocus system can be set to single, continuous or automatic and is arranged towards the centre. The 12-fps burst mode is available only in "speed priority" mode but can reach up to 5.5 fps burst rate in combination with any other settings.

<span class="mw-page-title-main">Sony Alpha 99</span> Digital camera model

The Sony Alpha 99 was announced by Sony on September 12, 2012. It was the flagship Sony DSLR camera and of the Sony Alpha SLT line until late 2016 when it was replaced by the Sony α99 II.

In Sony digital cameras, the acronym ILCE stands for "Interchangeable Lens Camera with E-mount". In August 2013, Sony announced the first model of the ILCE mirrorless camera with E-mount, electronic viewfinder, contrast-detection autofocus and Multi Interface Shoe, the ILCE-3000. In October 2013, two full-frame E-mount cameras were announced, the ILCE-7 and ILCE-7R.

<span class="mw-page-title-main">Sony Alpha 65</span> Digital camera model

Announced by Sony on August 24, 2011, and launched alongside its brother the Sony Alpha 77, the Sony Alpha 65 is the top-tier for Sony's midrange Alpha SLT camera line.

<span class="mw-page-title-main">Sony Alpha 77 II</span> Camera model

The Sony Alpha 77 II (ILCA-77M2), stylized as the Sony α77 II, is an interchangeable-lens camera aimed at the advanced amateur. It replaced the Sony Alpha 77 model in June 2014. It is similar in design to its predecessor, including the use of a SLT transparent mirror and electronic viewfinder.

References

  1. "Lenses for Translucent Mirror cameras". Sony.com.
  2. "Sony Single-Lens Translucent Cameras". KolariVision.com.
  3. "Mirrorless Cameras: A Primer". December 15, 2011.
  4. "Fujifilm's phase detection system explained". Digital Photography Review .
  5. Mike Tomkins. "Nikon V1, J1: Two new compact system cameras for Nikon's mirrorless debut". Imaging Resource.