• APS-C 369.7mm2
  • 14.6 megapixels
  • ISO 100 - 3200
  • APS-C 369.7mm2
  • 16.1 megapixels
  • ISO 100 - 16,000
  • Detailed specifications
  • Samsung GX-20
  • Sony Alpha SLT-A57
Links
Prices:    
Manufacturer URL: Manufacturer website Manufacturer website
Predecessor:    
Successor:    
General
Model Number: GX-20 A57
Alternate Model Number(s):    
Camera Format: Pro SLR SLR
Currently Manufactured: No No
Retail Price: $1399.95 $799.99
Street Price:    
Date Available: 2008-03-30 2012-04-15
Tripod Mount: Yes Yes
Weight: 25.2 oz (714 g) 29.2 oz (828 g)
includes batteries, kit lens
Size: 5.6 x 4.0 x 2.8 in.
(142 x 102 x 70 mm)
5.2 x 3.8 x 3.2 in.
(132 x 98 x 81 mm)
Waterproof: No No
Waterproof Depth: n/a n/a
Image Sensor
Sensor Type: CMOS CMOS
Sensor Manufacturer:   Sony
Effective Megapixels: 14.6 16.1
Sensor Format: APS-C APS-C
Sensor size: 369.72mm2 (23.7mm x 15.6mm) 369.72mm2 (23.7mm x 15.6mm)
Approximate Pixel Pitch: 5.07 microns 4.82 microns
Focal Length Multiplier: 1.5x 1.5x
Aspect Ratio: 3:2 3:2
Color Filter Type: RGBG RGBG
Anti Aliasing Filter: Fixed Fixed
Self-Cleaning: Yes Yes
Sensor shift image stabilization: Yes Yes
On-Sensor Phase Detect: No No
DxO Sensor Score: 68 75
DxO Color Depth Score (bits): 23.1 23.4
DxO Dynamic Range Score (evs): 11.2 13.0
DxO Maximum Effective ISO Score (iso): 714 785
Image Capture
Image Resolution: 4672 x 3104 (14.5 MP, Other),
3872 x 2592 (10.0 MP, Other),
3008 x 2000 (6.0 MP, 3:2),
1824 x 1216 (2.2 MP, 3:2)
4912 x 3264 (16.0 MP, 3:2),
4912 x 2760 (13.6 MP, 16:9),
3568 x 2368 (8.4 MP, Other),
3568 x 2000 (7.1 MP, 16:9),
2448 x 1624 (4.0 MP, Other),
2448 x 1376 (3.4 MP, 16:9),
12416 x 1856 (23.0 MP, Other),
5536 x 2160 (12.0 MP, Other),
8192 x 1856 (15.2 MP, Other),
3872 x 2160 (8.4 MP, Other),
7152 x 1080 (7.7 MP, Other),
4912 x 1080 (5.3 MP, Other),
1920 x 1080 (2.1 MP, 16:9)
Image File Format: JPEG (EXIF 2.21), RAW (.PEF, .DNG), 14-bit JPEG, MPO, RAW (12-bit ARW 2.3), RAW+JPEG
Continuous-mode frames/second: n/a 10.0
Video Capture
Can take movies: No Yes
Movie Resolution: 1920x1080 (60p(PS)/​60i(FX)/​60i(FH)/​24p(FX)/​24p(FH))
1440x1080 (30p)
640x480 (30p)
Movie File Format:   AVCHD 2.0/MP4 (Audio: Dolby Digital (AC-3)/MPEG-4 AAC-LC)
Composite Video Out: Yes No
NTSC/PAL Switchable Video: Yes n/a
Video Usable as Viewfinder: No n/a
HD Video Out: No Yes
HD Video Connection: HDMI
Lens & Optics
Lens Mount: Pentax K (KA/KAF/KAF2) Sony Alpha (Minolta A)
Lens: n/a Sony 18-55mm f/3.5-5.6 DT SAM
Focal Length (35mm equivalent):   27 - 83mm
Focal Length (actual):   18 - 55mm
Zoom Ratio:   3.06x
Aperture Range:   f/3.5 - 22 (W), f/5.6 - 36 (T)
Integrated ND Filter: No No
Normal Focus Range:   25 cm to Infinity
9.8 in to Infinity
Macro Focus Range:    
Filter Thread: n/a 55.0mm
Thread Type: n/a n/a
Optical Image Stabilization: No No
Digital Zoom: No Yes
Digital Zoom Values: n/a Up to 2x Precision, Up to 2x Clear Image Zoom, 1.4x (8.4MP) or 2.0x (4MP) Smart Zoom
Auto Focus
Auto Focus: Yes Yes
Auto Focus Type: 11-point TTL phase-matching (SAFOX VIII) Phase Detection: 15 points (3 points cross type); Wide (auto, 15 points), Zone, Spot, Local; Enhanced Object Tracking
Auto Focus Assist Light? Yes Yes
Manual Focus: Yes Yes
Viewfinder
Viewfinder: Optical / LCD EVF / LCD
Viewfinder Type: SLR type; eye-level pentaprism EVF type; 1.1cm (0.43") 1.44M/1.25M-dot LCD (480K/418K-dot time-multiplexed RGB), 100% coverage, 1.04x/0.97x magnification, 23.1/25.2mm eyepoint, -4 to +3 diopter
Focus Peaking: No Yes
EVF Resolution: n/a  
Viewfinder Magnification (35mm equivalent):   0.69x
Viewfinder Magnification (nominal/claimed):   1.04x
Display
Eye-level Viewfinder: Yes Yes
Rear Display: Yes Yes
Rear Display Size (inches): 2.7 3.0
Rear Display Resolution: 230,000 dots 921,600 dots (307,200 px)
Touchscreen: No No
Articulating Screen: No Yes
Tilt Swivel Screen: No
Selfie Screen: No
Max Playback Zoom: 32.0x 13.6x
Top Deck Display: Yes No
Exposure
Maximum ISO (native): 3200 16000
Minimum ISO (native): 100 100
ISO Settings: Auto, 100, 200, 400, 800, 1600, 3200, 6400 (expanded) Auto (100-3200), 100 - 16000; (Multi-frame NR mode up to ISO 25600)
Auto ISO Mode: Yes Yes
White Balance Settings: Auto, Daylight, Shade, Cloudy, Tungsten, Fluorescent (W, D, N), Flash, Color Temperature Auto, Daylight, Shade, Cloudy, Incandescent, Fluorescent (4), Flash, Custom, Color Temp./ Filter (2500-9900K with 15-step Magenta/Green compensation)
Shutter Speed Range: 1/4000 - 30 sec 1/4000 - 30 sec
Bulb Mode: Yes Yes
Exposure Compensation: +/- 3.0EV in 0.3EV steps +/- 3.0EV in 0.3EV steps
Metering Modes: TTL open-aperture: 16-segment, Center-weighted, Spot 1200-zone Evaluative, Center-weighted, Spot
Program Auto Exposure: Yes Yes
Aperture Priority: Yes Yes
Shutter Priority: Yes Yes
Full Manual Exposure: Yes Yes
Creative Exposure Modes: Sensitivity Priority, Shutter and Aperture Priority Portrait, SportsAction, Macro, Landscape, Sunset, Night scene, Hand-held Twilight (6 shot layering), Night Portrait; Sweep Panorama, 3D Sweep Panorama, Auto Portrait Framing, Picture Effect (Posterization (Color, B/W), Pop Color, Retro Photo, Partial Color (R,G,B,Y), High Contrast Monochrome, Toy Camera, Soft High-key, Soft Focus, HDR Painting, Rich-tone Monochrome, Miniature), Dynamic Range Optimizer (Off/Auto/Level),
Self Timer: 2 or 12 seconds 2 or 10 seconds
Time Lapse (intervalometer):    
High Resolution Composite: No No
Flash
Built-in Flash: Yes Yes
Flash Modes: On, Redeye, Slow Sync, Slow Sync + Redeye, Trailing Curtain Sync, Wireless Auto, Off, Fill-flash, Rear sync, Wireless, High-Speed sync, Slow sync, Red-eye reduction: On/Off
Flash Guide Number (ISO 100): n/a 10.0 m / 32.8 ft.
Flash Range Description: Depends on lens Lens dependent
Max Flash Sync: 1/180 1/160
Flash Exposure Compensation:   +/- 2.0 EV in 0.3EV steps
External Flash Connection: Hot Shoe, X-Sync Socket Hot shoe
Built-In Wireless Flash Control:    
Image Storage
Usable Memory Types: SD / SDHC MS PRO Duo / SD / SDHC / SDXC
UHS Support:    
Other Memory:    
Dual Card Slots: No No
RAW Capture Support: Yes Yes
Uncompressed Format: RAW (.PEF, .DNG), 14-bit RAW (12-bit ARW 2.3), RAW+JPEG
Movie File Format:   AVCHD 2.0/MP4 (Audio: Dolby Digital (AC-3)/MPEG-4 AAC-LC)
Included Memory: No memory included  
Included Memory Type:    
Connectivity
Built-In Wi-Fi: No No
NFC: No No
Bluetooth: No No
Built-In GPS: No No
Microphone Jack: No No
Headphone Jack: No No
External Connections: USB 2.0 High Speed USB 2.0 High Speed
PictBridge Compliant: Yes Yes
DPOF Compliant: Yes Yes
Remote Control: Yes Yes
Remote Control Type: Wired or IR Optional Wireless or Wired
Connections (extended): DC input, wired remote Type-C Mini HDMI (BRAVIA Sync, PhotoTV HD); Wired Remote Terminal, 3.5mm External Stereo Micophone Jack, DC Input
Performance Timing
Cycle time for JPEG shooting in single shot mode (seconds per frame, max resolution):    
Cycle time for RAW shooting in single shot mode (seconds per frame):    
Buffer size for RAW shooting in single shot mode (frames):    
Cycle time for RAW+JPEG shooting in single shot mode (seconds per shot):    
Camera penalizes early shutter press?
JPEG shooting speed in burst mode (fps, max resolution):   10.0
Buffer size for JPEG shooting in burst mode (frames, max resolution):   25
RAW shooting speed in burst mode (fps):    
Buffer size for RAW shooting in burst mode (frames):    
RAW+JPEG shooting speed in burst mode (fps):    
Buffer Size for RAW+JPEG shooting in burst mode (frames):    
Shutter lag (full AF, wide/mid):    
Shutter lag (full AF, tele):    
Shutter lag (full AF, live view - DSLR):    
Shutter lag (prefocused, live view - DSLR):    
Shutter Lag (manual focus):    
Shutter lag (full AF, with flash):    
Shutter Lag (prefocused):    
Shutter Lag (notes):    
Startup Time:    
Play -> Record Time:    
Flash cycle time, full power:    
Power
Battery Life, Stills (CIPA Rating Monitor/Live View):    
Battery Life, Still (CIPA Rating OVF/EVF):   550 shots
Battery Life, Video:    
Battery Form Factor: Proprietary Proprietary
Usable Battery Types: Lithium-ion rechargeable NP-FM500H Lithium-ion rechargeable
Batteries Included: 1 x Proprietary Lithium-ion rechargeable 1 x Proprietary NP-FM500H Lithium-ion rechargeable
Battery Charger Included (dedicated charger or AC/USB adapter): Yes Yes
Dedicated Battery Charger Included: Yes
Internal Charging Supported: No
Software
Included Software:   Sony Software CD-ROM
OS Compatibility:   Windows XP SP3/Vista SP2/7, Mac OS X (v.10.3 +)
Miscellaneous
Notes & Features: SteadyShot INSIDE Sensor-shift Image Stabilization (up to 4.5 EV correction), Full HD 1080p60 Video, Up to 12 fps Burst Mode (Tele-zoom Continuous Advance Priority AE), Enhanced Object Tracking AF, 2x Clear Image Digital Zoom, New Auto Portrait Framing, Tilting 921K-dot LCD, 1.44M-dot EVF.