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

Buy From

Differences

Nikon D5100 advantages over Olympus E-M5 III

  • 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)
  • Longer stills battery life
    More info 660 vs 310 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 26 shots
    Take more JPEG shots before waiting (burst mode)

Olympus E-M5 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
  • Built-in Bluetooth
    Yes vs No
    Always-on wireless connectivity
  • On-sensor phase detect
    Yes vs No
    Usually improves live view and video AF performance
  • Thinner
    49 mm vs 79 mm
    Thinner
  • Newer
    5 years vs 14 years old
    Newer cameras often support more advanced features
  • More viewfinder magnification
    0.68x vs 0.52x
    Get a bigger view of the scene through the eye-level viewfinder
  • 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
  • Lacks anti-aliasing filter
    No Filter vs Filter
    Enjoy sharper photos
  • Longer exposure
    60 vs 30 sec
    Long exposures for night shots
  • Faster JPEG shooting
    30.0 fps vs 3.9 fps
    Faster JPEG shooting (burst mode)
  • Faster RAW shooting
    30.0 fps vs 4.0 fps
    Faster RAW shooting in burst mode
  • Bigger RAW buffer
    23 vs 13 shots
    Larger buffer for RAW shots (burst mode)
  • Slow-motion videos
    Yes vs No
    Shoot slow-motion videos
  • 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 GPS
    Neither provide
    Geotag your photos
  • 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

User reviews

Buy From

Your purchases support this site

Buy the Nikon D5100

Your purchases support this site

Buy the Olympus E-M5 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.

  • Improved image quality; Very good dynamic range & high ISO performance for a modern MFT sensor; Very fast AF; Excellent image stabilization; 4K video recording; Weather-sealed build quality.

  • Below average battery life; Small size can be awkward with long, heavy lenses; One SD card slot.

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-M5 III
Sony A55
  • $924
  • 4/3
  • Tilt-swivel screen
  • Lens selection
  • $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
  • Less expensive
  • In-Camera Image Stabilization
Olympus E-M5 III
Sony A33
  • $924
  • 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-M5 III
Sony A57
  • $924
  • 4/3
  • Tilt-swivel screen
  • Lens selection
  • $800
  • APS-C
  • Larger sensor
  • Bigger pixels

Compared to Panasonic G100

Nikon D5100
Panasonic G100
  • $650
  • APS-C
  • Larger sensor
  • Bigger pixels
  • $599
  • 4/3
  • Focus peaking
  • Shoot 4K video
Olympus E-M5 III
Panasonic G100
  • $924
  • 4/3
  • In-Camera Image Stabilization
  • High resolution composite
  • $599
  • 4/3
  • Less expensive
  • In-camera panoramas

Compared to Olympus E-M10 IV

Nikon D5100
Olympus E-M10 IV
  • $650
  • APS-C
  • Tilt-swivel screen
  • Larger sensor
  • $630
  • 4/3
  • Focus peaking
  • In-Camera Image Stabilization
Olympus E-M5 III
Olympus E-M10 IV
  • $924
  • 4/3
  • Tilt-swivel screen
  • High resolution composite
  • $630
  • 4/3
  • Less expensive
  • Longer video battery life
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