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]
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. 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.
| Model | Announcement | Megapixels | Sensor | Screen | Built-in flash | |
|---|---|---|---|---|---|---|
| 2010 | 14 MP | 3" articulated | (pop-up) | |||
| 2011 | 16 MP | 3" fixed | (pop-up) | |||
| 2012 | 16 MP | 2.7" tilting | (pop-up) | |||
| 2010 | 16 MP | 3" articulated | (pop-up) | |||
| 2012 | 16 MP | 3" articulated | (pop-up) | |||
| 2013 | 20 MP | 2.7" tilting | (pop-up) | |||
| 2011 | 24 MP | 3" articulated | (pop-up) | |||
| 2015 | 24 MP | 2.7" tilting | (pop-up) | |||
| 2011 | 24 MP | 3" fully articulated | (pop-up) | |||
| 2014 | 24 MP | 3" fully articulated | (pop-up) | |||
| 2012 | 24 MP | 3" fully articulated | ||||
| 2016 | 42 MP | 3" fully articulated |
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.