• APS-C 366.6mm2
  • 24.3 megapixels
  • ISO 100 - 25,600
  • 4/3 226.2mm2
  • 20.4 megapixels
  • ISO 200 - 25,600

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Differences

Sony A5100 advantages over Olympus E-M1 Mark III

  • Less expensive
    $448 vs $2499
    Save money for lenses or accessories
  • Larger sensor
    APS-C vs 4/3
    More sensor area. Bigger is (generally) better.
  • Bigger pixels
    ~ 3.92 vs 3.36 microns
    Better low-light and dynamic range (all else equal)
  • In-camera panoramas
    Yes vs No
    Stitches multiple shots into a panoramic photo
  • NFC
    Yes vs No
    Simplifies pairing your camera with supported phones
  • Internal flash
    Internal flash vs None
    Useful in a pinch for fill flash
  • Thinner
    35 mm vs 68 mm
    Thinner
  • More pixels
    24.3 vs 20.4 megapixels
    Higher resolution photos
  • Has anti-aliasing filter
    Filter vs No Filter
    Reduces unsightly moiré in photos

Olympus E-M1 Mark III advantages over Sony A5100

  • 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
  • Eye-level viewfinder
    Eye-level vs Rear display only
    You'll be able to frame photos even when the sun is out
  • 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
  • High resolution composite
    Yes vs No
    Combine multiple shots to form a super hi-res version
  • External Mic Jack
    Jack vs No jack
    Improved sound fidelity when shooting video
  • Higher max flash sync
    1/250 vs 1/160 sec
    Reduce the effect of ambient light in flash shots
  • Newer
    5 years vs 10 years old
    Newer cameras often support more advanced features
  • Higher-res screen
    346k vs 230k pixels
    More detail on the screen lets you judge focus and composition
  • Hot shoe
    Hot shoe vs None
    Off-camera flashes open new possibilities
  • 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

  • Focus peaking
    Both provide
    Your camera will highlight what's in focus
  • Touchscreen
    Both provide
    Interact with your camera just like your smartphone
  • Built-in Wi-Fi
    Both provide
    Share your photos wirelessly
  • On-sensor phase detect
    Both provide
    Usually improves live view and video AF performance
  • HDMI out
    Both provide
    Use HDMI output to monitor or review video
  • Bulb shutter
    Both provide
    Hold the shutter open manually for long exposures

Common Weaknesses

  • 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

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Your purchases support this site

Buy the Sony A5100

Your purchases support this site

Buy the Olympus E-M1 Mark III

Review Excerpt

  • Very small and comfortable form factor; Very good image quality for its class; New dual video record function; Quick autofocus and good dynamic range.

  • Lacks an EVF and external mode dial; No hot shoe; JPEG processing at higher ISOs not as good as some competing mid-level models.

The Competition

Compared to Samsung NX1000

Sony A5100
Samsung NX1000
  • $348
  • APS-C
  • Lens selection
  • Focus peaking
  • $416
  • APS-C
  • Higher-res screen
  • Hot shoe
Olympus E-M1 Mark III
Samsung NX1000
  • $1649
  • 4/3
  • Tilt-swivel screen
  • Lens selection
  • $416
  • APS-C
  • Larger sensor
  • Bigger pixels

Compared to Samsung NX1100

Sony A5100
Samsung NX1100
  • $348
  • APS-C
  • Lens selection
  • Focus peaking
  • $450
  • APS-C
  • Higher-res screen
  • Hot shoe
Olympus E-M1 Mark III
Samsung NX1100
  • $1649
  • 4/3
  • Tilt-swivel screen
  • Lens selection
  • $450
  • APS-C
  • Larger sensor
  • Bigger pixels

Compared to Sony A5000

Sony A5100
Sony A5000
  • $348
  • APS-C
  • Touchscreen
  • Higher effective ISO
  • $298
  • APS-C
  • Less expensive
Olympus E-M1 Mark III
Sony A5000
  • $1649
  • 4/3
  • Tilt-swivel screen
  • Lens selection
  • $298
  • APS-C
  • Less expensive
  • Larger sensor

Compared to Panasonic G95

Sony A5100
Panasonic G95
  • $348
  • APS-C
  • Less expensive
  • Larger sensor
  • $848
  • 4/3
  • Lens selection
  • Tilt-swivel screen
Olympus E-M1 Mark III
Panasonic G95
  • $1649
  • 4/3
  • High resolution composite
  • On-sensor phase detect
  • $848
  • 4/3
  • Less expensive
  • In-camera panoramas

Compared to OM System OM-1

Sony A5100
OM System OM-1
  • $348
  • APS-C
  • Larger sensor
  • Bigger pixels
  • $2200
  • 4/3
  • Tilt-swivel screen
  • Lens selection
Olympus E-M1 Mark III
OM System OM-1
  • $1649
  • 4/3
  • $2200
  • 4/3
  • Newer
  • Higher-res screen
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