• APS-C 369.7mm2
  • 16.2 megapixels
  • ISO 100 - 12,800
  • APS-C 368.2mm2
  • 16.2 megapixels
  • ISO 100 - 6400

Buy From

Differences

Sony A55 advantages over Nikon D5100

  • 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
  • Built-in GPS
    GPS vs None
    Geotag your photos
  • More cross-type AF points
    3 vs 1
    Cross-type AF points improve autofocus performance
  • More viewfinder magnification
    0.73x vs 0.52x
    Get a bigger view of the scene through the eye-level viewfinder
  • More AF points
    15 vs 11
    More AF points improve autofocus
  • Faster JPEG shooting
    9.0 fps vs 3.9 fps
    Faster JPEG shooting (burst mode)

Nikon D5100 advantages over Sony A55

  • Lens selection
    Excellent vs Good
    Better lens selection gives you more options
  • Tilt-swivel screen
    Tilt-swivel vs tilt-only
    Tilt and swivel the screen for maximum shooting flexibility
  • Fast startup
    ~0.50 vs 0.9 sec
    Faster startup lets you catch the moment
  • Higher effective ISO
    1,183 vs 818 iso
    Take photos in low light with less noise
  • Longer stills battery life
    More info 660 vs 330 shots
    Capture more photos
  • Shoots 24p video
    Yes vs No
    Gives your movies a big-screen feel
  • Shoots 1080p video
    Yes vs No
    You'll want this if you shoot video
  • Bigger JPEG buffer
    100 vs 32 shots
    Take more JPEG shots before waiting (burst mode)

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
  • External Mic Jack
    Both provide
    Improved sound fidelity when shooting video
  • 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

  • Focus peaking
    Neither provide
    Your camera will highlight what's in focus
  • Touchscreen
    Neither provide
    Interact with your camera just like your smartphone
  • Built-in Wi-Fi
    Neither provide
    Share your photos wirelessly
  • Built-in Bluetooth
    Neither provide
    Always-on wireless connectivity
  • On-sensor phase detect
    Neither provide
    Usually improves live view and video AF performance
  • Top deck display
    Neither provide
    Check settings with a screen on top of the camera
  • 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

Review Excerpt

  • Side-mounted tilt / swivel LCD screen; same sensor and processing as the Nikon D7000; good speed and battery life; in-camera HDR and filter effects; Full HD video capture with aperture control; audio levels control and external microphone jack.

  • AF-S lens mount doesn't offer autofocus with screw-drive lenses; popup flash isn't the greatest; no built-in wireless flash control; HDR function doesn't microalign source images.

The Competition

Compared to Pentax K-7

Sony A55
Pentax K-7
  • $734
  • APS-C
  • Less expensive
  • In-camera panoramas
  • $1300
  • APS-C
  • Lens selection
  • Fast startup
Nikon D5100
Pentax K-7
  • $650
  • APS-C
  • Tilt-swivel screen
  • Higher effective ISO
  • $1300
  • APS-C
  • In-Camera Image Stabilization
  • Top deck display

Compared to Canon T2i

Sony A55
Canon T2i
  • $734
  • APS-C
  • Larger sensor
  • In-Camera Image Stabilization
  • $692
  • APS-C
  • Lens selection
  • Fast startup
Nikon D5100
Canon T2i
  • $650
  • APS-C
  • Tilt-swivel screen
  • Larger sensor
  • $692
  • APS-C
  • Shoots 60p video

Compared to Sony A33

Sony A55
Sony A33
  • $734
  • APS-C
  • Higher effective ISO
  • Built-in GPS
  • $540
  • APS-C
Nikon D5100
Sony A33
  • $650
  • APS-C
  • Lens selection
  • Tilt-swivel screen
  • $540
  • APS-C
  • In-Camera Image Stabilization
  • In-camera panoramas

Compared to Sony A35

Sony A55
Sony A35
  • $734
  • APS-C
  • Tiltable Screen
  • Built-in GPS
  • $567
  • APS-C
  • Less expensive
  • Longer stills battery life
Nikon D5100
Sony A35
  • $650
  • APS-C
  • Lens selection
  • Tilt-swivel screen
  • $567
  • APS-C
  • In-Camera Image Stabilization
  • In-camera panoramas

Compared to Sony A57

Sony A55
Sony A57
  • $734
  • APS-C
  • Built-in GPS
  • External Mic Jack
  • $800
  • APS-C
  • Focus peaking
  • Longer stills battery life
Nikon D5100
Sony A57
  • $650
  • APS-C
  • Lens selection
  • Tilt-swivel screen
  • $800
  • APS-C
  • Focus peaking
  • In-Camera Image Stabilization
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