• APS-C 368.2mm2
  • 16.2 megapixels
  • ISO 100 - 6400
  • 4/3 226.2mm2
  • 20.4 megapixels
  • ISO 200 - 25,600

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Differences

Nikon D5100 advantages over Olympus E-M1 Mark III

  • Less expensive
    $650* vs $2499
    Save money for lenses or accessories
  • Larger sensor
    APS-C vs 4/3
    More sensor area. Bigger is (generally) better.
  • Bigger pixels
    ~ 4.79 vs 3.36 microns
    Better low-light and dynamic range (all else equal)
  • 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

Olympus E-M1 Mark III advantages over Nikon D5100

  • 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 (DCI) vs 1080p
    Make sure you have a fast computer
  • Touchscreen
    Touch vs No touch
    Interact with your camera just like your smartphone
  • High resolution composite
    Yes vs No
    Combine multiple shots to form a super hi-res version
  • Built-in Wi-Fi
    Wi-Fi vs None
    Share your photos wirelessly
  • On-sensor phase detect
    Yes vs No
    Usually improves live view and video AF performance
  • Newer
    5 years vs 14 years old
    Newer cameras often support more advanced features
  • More pixels
    20.4 vs 16.2 megapixels
    Higher resolution photos
  • Shoots 60p video
    Yes vs No
    A faster framerate can give you more editing options
  • Dual card slots
    Yes vs No
    Gives you more storage flexibility
  • Headphone jack
    Yes vs No
    Monitor audio recording while you shoot video
  • Lacks anti-aliasing filter
    No Filter vs Filter
    Enjoy sharper photos
  • Longer exposure
    60 vs 30 sec
    Long exposures for night shots
  • Faster shutter
    1/32000 vs 1/4000 sec
    Shoot wide open in bright light

Similarities

Common Strengths

  • Tilt-swivel screen
    Both provide
    Tilt and swivel the screen for maximum shooting flexibility
  • Eye-level viewfinder
    Both provide
    You'll be able to frame photos even when the sun is out
  • 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

  • In-camera panoramas
    Neither provide
    Stitches multiple shots into a panoramic photo
  • NFC
    Neither provide
    Simplifies pairing your camera with supported phones
  • Built-in Bluetooth
    Neither provide
    Always-on wireless connectivity
  • Built-in GPS
    Neither provide
    Geotag your photos
  • Top deck display
    Neither provide
    Check settings with a screen on top of the camera
  • Slow-motion videos
    Neither provide
    Shoot slow-motion videos

User reviews

Buy From

Your purchases support this site

Buy the Olympus E-M1 Mark III

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 Sony A55

Nikon D5100
Sony A55
  • $650
  • APS-C
  • Lens selection
  • Tilt-swivel screen
  • $734
  • APS-C
  • In-Camera Image Stabilization
  • In-camera panoramas
Olympus E-M1 Mark III
Sony A55
  • $1699
  • 4/3
  • Lens selection
  • Focus peaking
  • $734
  • APS-C
  • Larger sensor
  • Bigger pixels

Compared to Sony A33

Nikon D5100
Sony A33
  • $650
  • APS-C
  • Lens selection
  • Tilt-swivel screen
  • $540
  • APS-C
  • In-Camera Image Stabilization
  • In-camera panoramas
Olympus E-M1 Mark III
Sony A33
  • $1699
  • 4/3
  • Lens selection
  • Focus peaking
  • $540
  • APS-C
  • Larger sensor
  • Bigger pixels

Compared to Sony A57

Nikon D5100
Sony A57
  • $650
  • APS-C
  • Lens selection
  • Tilt-swivel screen
  • $800
  • APS-C
  • Focus peaking
  • In-Camera Image Stabilization
Olympus E-M1 Mark III
Sony A57
  • $1699
  • 4/3
  • Lens selection
  • Tilt-swivel screen
  • $800
  • APS-C
  • Larger sensor
  • Bigger pixels

Compared to Panasonic G95

Nikon D5100
Panasonic G95
  • $650
  • APS-C
  • Larger sensor
  • Bigger pixels
  • $848
  • 4/3
  • Focus peaking
  • In-Camera Image Stabilization
Olympus E-M1 Mark III
Panasonic G95
  • $1699
  • 4/3
  • High resolution composite
  • On-sensor phase detect
  • $848
  • 4/3
  • Less expensive
  • In-camera panoramas

Compared to OM System OM-1

Nikon D5100
OM System OM-1
  • $650
  • APS-C
  • Larger sensor
  • Bigger pixels
  • $2200
  • 4/3
  • Focus peaking
  • In-Camera Image Stabilization
Olympus E-M1 Mark III
OM System OM-1
  • $1699
  • 4/3
  • $2200
  • 4/3
  • Newer
  • Higher-res screen
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