• APS-C 355.7mm2
  • 14.2 megapixels
  • ISO 100 - 3200
  • 4/3 226.2mm2
  • 20.3 megapixels
  • ISO 200 - 25,600

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Differences

Nikon D3100 advantages over Olympus E-P7

  • Larger sensor
    APS-C vs 4/3
    More sensor area. Bigger is (generally) better.
  • Eye-level viewfinder
    Eye-level vs Rear display only
    You'll be able to frame photos even when the sun is out
  • Bigger pixels
    ~ 5.01 vs 3.36 microns
    Better low-light and dynamic range (all else equal)

Olympus E-P7 advantages over Nikon D3100

  • 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
  • Shoot 4K video
    4K (UHD) vs 1080p
    Make sure you have a fast computer
  • Touchscreen
    Touch vs No touch
    Interact with your camera just like your smartphone
  • 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
  • Built-in Bluetooth
    Yes vs No
    Always-on wireless connectivity
  • Thinner
    38 mm vs 74 mm
    Thinner
  • More dots on screen
    1037k vs 230k dots
    Can mean greater resolution or a brighter screen
  • More pixels
    20.3 vs 14.2 megapixels
    Higher resolution photos
  • Shoots 60p video
    Yes vs No
    A faster framerate can give you more editing options
  • Longer exposure
    60 vs 30 sec
    Long exposures for night shots
  • Faster JPEG shooting
    8.7 fps vs 2.9 fps
    Faster JPEG shooting (burst mode)
  • Bigger JPEG buffer
    Unlimited vs 100 shots
    Take more JPEG shots before waiting (burst mode)
  • Slow-motion videos
    Yes vs No
    Shoot slow-motion videos
  • Faster shutter
    1/16000 vs 1/4000 sec
    Shoot wide open in bright light
  • Higher extended ISO
    25600 vs 12800 ISO
    Higher extended ISO can give more low-light flexibility

Similarities

Common Strengths

  • 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

  • Tilt-swivel screen
    Neither provide
    Tilt and swivel the screen for maximum shooting flexibility
  • NFC
    Neither provide
    Simplifies pairing your camera with supported phones
  • 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
  • External Mic Jack
    Neither provide
    Improved sound fidelity when shooting video
  • Dual card slots
    Neither provide
    Gives you more storage flexibility
  • Headphone jack
    Neither provide
    Monitor audio recording while you shoot video

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Review Excerpt

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
Olympus E-P7
Sony DSLR-A380
  • $0
  • 4/3
  • Lens selection
  • Focus peaking
  • $849
  • APS-C
  • Larger sensor
  • Eye-level viewfinder

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
Olympus E-P7
Sony A33
  • $0
  • 4/3
  • Lens selection
  • Focus peaking
  • $540
  • APS-C
  • Larger sensor
  • Eye-level viewfinder

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
Olympus E-P7
Pentax K-r
  • $0
  • 4/3
  • Focus peaking
  • Shoot 4K video
  • $850
  • APS-C
  • Larger sensor
  • Eye-level viewfinder

Compared to Nikon D5100

Nikon D3100
Nikon D5100
  • $700
  • APS-C
  • $650
  • APS-C
  • Tilt-swivel screen
  • Higher effective ISO
Olympus E-P7
Nikon D5100
  • $0
  • 4/3
  • Focus peaking
  • In-Camera Image Stabilization
  • $650
  • APS-C
  • Tilt-swivel screen
  • Larger sensor

Compared to Sony A35

Nikon D3100
Sony A35
  • $700
  • APS-C
  • Lens selection
  • Fast startup
  • $567
  • APS-C
  • In-Camera Image Stabilization
  • In-camera panoramas
Olympus E-P7
Sony A35
  • $0
  • 4/3
  • Lens selection
  • Focus peaking
  • $567
  • APS-C
  • Larger sensor
  • Eye-level viewfinder
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