• APS-C 355.7mm2
  • 14.2 megapixels
  • ISO 100 - 3200
  • 35mm 861.6mm2
  • 36.4 megapixels
  • ISO 100 - 25,600

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Differences

Nikon D3100 advantages over Sony A7R

  • Lens selection
    Excellent vs Good
    Better lens selection gives you more options
  • Fast startup
    ~0.40 vs 2.0 sec
    Faster startup lets you catch the moment
  • Longer stills battery life
    More info 550 vs 340 shots
    Capture more photos
  • Internal flash
    Internal flash vs None
    Useful in a pinch for fill flash
  • Has anti-aliasing filter
    Filter vs No Filter
    Reduces unsightly moiré in photos
  • Bigger JPEG buffer
    100 vs 15 shots
    Take more JPEG shots before waiting (burst mode)

Sony A7R advantages over Nikon D3100

  • Focus peaking
    Peaker vs Non-peaker
    Your camera will highlight what's in focus
  • Larger sensor
    35mm vs APS-C
    More sensor area. Bigger is (generally) better.
  • In-camera panoramas
    Yes vs No
    Stitches multiple shots into a panoramic photo
  • Tiltable Screen
    Tiltable vs Fixed
    Tilt the screen for shooting flexbility
  • Built-in Wi-Fi
    Wi-Fi vs None
    Share your photos wirelessly
  • NFC
    Yes vs No
    Simplifies pairing your camera with supported phones
  • Better color depth
    25.6 vs 22.5 bits
    Capture richer, more accurate colors
  • Higher effective ISO
    2,746 vs 919 iso
    Take photos in low light with less noise
  • More dynamic range
    14.1 vs 11.2 evs
    Retain detail in highlight and shadows
  • Thinner
    48 mm vs 74 mm
    Thinner
  • External Mic Jack
    Jack vs No jack
    Improved sound fidelity when shooting video
  • Newer
    5 years vs 8 years old
    Newer cameras often support more advanced features
  • More dots on screen
    922k vs 230k dots
    Can mean greater resolution or a brighter screen
  • More viewfinder magnification
    0.71x vs 0.53x
    Get a bigger view of the scene through the eye-level viewfinder
  • More pixels
    36.4 vs 14.2 megapixels
    Higher resolution photos
  • Shoots 60p video
    Yes vs No
    A faster framerate can give you more editing options
  • Headphone jack
    Yes vs No
    Monitor audio recording while you shoot video
  • Lacks anti-aliasing filter
    No Filter vs Filter
    Enjoy sharper photos
  • Faster JPEG shooting
    4.0 fps vs 2.9 fps
    Faster JPEG shooting (burst mode)
  • Faster shutter
    1/8000 vs 1/4000 sec
    Shoot wide open in bright light
  • Higher extended ISO
    51200 vs 12800 ISO
    Higher extended ISO can give more low-light flexibility

Similarities

Common Strengths

  • Eye-level viewfinder
    Both provide
    You'll be able to frame photos even when the sun is out
  • 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

  • Tilt-swivel screen
    Neither provide
    Tilt and swivel the screen for maximum shooting flexibility
  • In-Camera Image Stabilization
    Neither provide
    Reduces the effects of camera shake at slower shutter speeds
  • Touchscreen
    Neither provide
    Interact with your camera just like your smartphone
  • Built-in Bluetooth
    Neither provide
    Always-on wireless connectivity
  • Built-in GPS
    Neither provide
    Geotag your photos
  • 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
  • Slow-motion videos
    Neither provide
    Shoot slow-motion videos

User reviews

Buy From

Review Excerpt

  • Incredibly small body for a fully-featured, full-frame camera; Resolution that rivals a medium-format camera; Excellent image quality even at very high sensitivities; Decent performance bearing in mind its extremely high resolution; Accepts existing Alpha-mount and E-mount lenses, and can optionally crop to APS-C image circle.

  • Extreme resolution makes focus and lens quality critical; Modest performance; Loud shutter; Lacks hybrid autofocus of the A7; Mediocre battery life when using electronic viewfinder; Slow X-sync; Limited selection of native Sony FE lenses.

The Competition

Compared to Sony A7

Nikon D3100
Sony A7
  • $700
  • APS-C
  • Lens selection
  • Fast startup
  • $798
  • 35mm
  • Focus peaking
  • Larger sensor
Sony A7R
Sony A7
  • $1849
  • 35mm
  • Higher effective ISO
  • More pixels
  • $798
  • 35mm
  • Less expensive
  • Bigger pixels

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 A7R
Sony A33
  • $1849
  • 35mm
  • Focus peaking
  • Larger sensor
  • $540
  • APS-C
  • In-Camera Image Stabilization
  • Fast startup

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 A7R
Pentax K-r
  • $1849
  • 35mm
  • Focus peaking
  • Larger sensor
  • $850
  • APS-C
  • Lens selection
  • In-Camera Image Stabilization

Compared to Nikon D5100

Nikon D3100
Nikon D5100
  • $700
  • APS-C
  • $549
  • APS-C
  • Tilt-swivel screen
  • Higher effective ISO
Sony A7R
Nikon D5100
  • $1849
  • 35mm
  • Focus peaking
  • Larger sensor
  • $549
  • APS-C
  • Lens selection
  • Less expensive

Compared to Sony A7R II

Nikon D3100
Sony A7R II
  • $700
  • APS-C
  • Lens selection
  • Fast startup
  • $1598
  • 35mm
  • Focus peaking
  • Larger sensor
Sony A7R
Sony A7R II
  • $1849
  • 35mm
  • Lighter weight
  • $1598
  • 35mm
  • In-Camera Image Stabilization
  • Shoot 4K video
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