• APS-C 355.7mm2
  • 14.2 megapixels
  • ISO 100 - 3200
  • APS-C 369.7mm2
  • 24.3 megapixels
  • ISO 100 - 16,000

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Differences

Nikon D3100 advantages over Sony A77

  • Lens selection
    Excellent vs Good
    Better lens selection gives you more options
  • Less expensive
    $700 vs $2000 (MSRP)
    Save money for lenses or accessories
  • Bigger pixels
    ~ 5.01 vs 3.95 microns
    Better low-light and dynamic range (all else equal)
  • Fast startup
    ~0.40 vs 0.8 sec
    Faster startup lets you catch the moment
  • Higher effective ISO
    919 vs 801 iso
    Take photos in low light with less noise
  • Lighter weight
    777g vs 1363g
    Lighter weight
  • Bigger JPEG buffer
    100 vs 17 shots
    Take more JPEG shots before waiting (burst mode)

Sony A77 advantages over Nikon D3100

  • Tilt-swivel screen
    Tilt-swivel vs none
    Tilt and swivel the screen for maximum shooting flexibility
  • Focus peaking
    Peaker vs Non-peaker
    Your camera will highlight what's in focus
  • In-Camera Image Stabilization
    Yes vs No
    Reduces the effects of camera shake at slower shutter speeds
  • In-camera panoramas
    Yes vs No
    Stitches multiple shots into a panoramic photo
  • More dynamic range
    13.2 vs 11.2 evs
    Retain detail in highlight and shadows
  • Built-in GPS
    GPS vs None
    Geotag your photos
  • Top deck display
    Yes vs No
    Check settings with a screen on top of the camera
  • External Mic Jack
    Jack vs No jack
    Improved sound fidelity when shooting video
  • More cross-type AF points
    11 vs 1
    Cross-type AF points improve autofocus performance
  • More dots on screen
    922k vs 230k dots
    Can mean greater resolution or a brighter screen
  • Less shutter lag
    0.12 vs 0.28 sec
    Focus and take a photo quickly (wide angle)
  • More viewfinder magnification
    0.73x vs 0.53x
    Get a bigger view of the scene through the eye-level viewfinder
  • More pixels
    24.3 vs 14.2 megapixels
    Higher resolution photos
  • Shoots 60p video
    Yes vs No
    A faster framerate can give you more editing options
  • More AF points
    19 vs 11
    More AF points improve autofocus
  • Wider angle kit lens
    24 mm vs 27 mm
    Capture more of the scene with the included lens
  • Faster JPEG shooting
    11.6 fps vs 2.9 fps
    Faster JPEG shooting (burst mode)
  • Faster shutter
    1/8000 vs 1/4000 sec
    Shoot wide open in bright light

Similarities

Common Strengths

  • Eye-level viewfinder
    Both provide
    You'll be able to frame photos even when the sun is out
  • Internal flash
    Both provide
    Useful in a pinch for fill flash
  • HDMI out
    Both provide
    Use HDMI output to monitor or review video
  • Hot shoe
    Both provide
    Off-camera flashes open new possibilities
  • Bulb shutter
    Both provide
    Hold the shutter open manually for long exposures

Common Weaknesses

  • Touchscreen
    Neither provide
    Interact with your camera just like your smartphone
  • Built-in Wi-Fi
    Neither provide
    Share your photos wirelessly
  • NFC
    Neither provide
    Simplifies pairing your camera with supported phones
  • Built-in Bluetooth
    Neither provide
    Always-on wireless connectivity
  • On-sensor phase detect
    Neither provide
    Usually improves live view and video AF performance
  • Dual card slots
    Neither provide
    Gives you more storage flexibility
  • Headphone jack
    Neither provide
    Monitor audio recording while you shoot video
  • Slow-motion videos
    Neither provide
    Shoot slow-motion videos

User reviews

Buy From

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Your purchases support this site

Buy the Sony A77

Review Excerpt

  • Very fast top frame rate; full-time phase-detect autofocus; Full 60p HD video; Excellent kit lens; Very good high-resolution sensor.

  • Heavy; EVF appears dim when used in bright light; AF tracking in Movie mode was unreliable in our testing.

The Competition

Compared to Sony DSLR-A380

Nikon D3100
Sony DSLR-A380
  • $700
  • APS-C
  • Lens selection
  • Less expensive
  • $849
  • APS-C
  • In-Camera Image Stabilization
  • Tiltable Screen
Sony A77
Sony DSLR-A380
  • $1899
  • APS-C
  • Tilt-swivel screen
  • Focus peaking
  • $849
  • APS-C
  • Less expensive
  • Bigger pixels

Compared to Canon 7D

Nikon D3100
Canon 7D
  • $700
  • APS-C
  • Bigger pixels
  • Lighter weight
  • $1499
  • APS-C
  • Longer stills battery life
  • More telephoto lens reach
Sony A77
Canon 7D
  • $1899
  • APS-C
  • Tilt-swivel screen
  • Focus peaking
  • $1499
  • APS-C
  • Lens selection
  • Fast startup

Compared to Sony A33

Nikon D3100
Sony A33
  • $700
  • APS-C
  • Lens selection
  • Fast startup
  • $540
  • APS-C
  • In-Camera Image Stabilization
  • In-camera panoramas
Sony A77
Sony A33
  • $1899
  • APS-C
  • Focus peaking
  • Tilt-swivel screen
  • $540
  • APS-C
  • Less expensive
  • Bigger pixels

Compared to Pentax K-r

Nikon D3100
Pentax K-r
  • $700
  • APS-C
  • Less expensive
  • Higher effective ISO
  • $850
  • APS-C
  • In-Camera Image Stabilization
  • Fast startup
Sony A77
Pentax K-r
  • $1899
  • APS-C
  • Tilt-swivel screen
  • Focus peaking
  • $850
  • APS-C
  • Lens selection
  • Less expensive

Compared to Sony A77 II

Nikon D3100
Sony A77 II
  • $700
  • APS-C
  • Lens selection
  • Bigger pixels
  • $1198
  • APS-C
  • Focus peaking
  • Tilt-swivel screen
Sony A77
Sony A77 II
  • $1899
  • APS-C
  • Built-in GPS
  • $1198
  • APS-C
  • Built-in Wi-Fi
  • NFC
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