• 0.98 inch 285.7mm2
  • 4.7 megapixels
  • ISO 100 - 1600
  • APS-C 368.2mm2
  • 16.2 megapixels
  • ISO 100 - 6400

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Differences

Sigma SD15 advantages over Nikon D5100

  • Bigger pixels
    ~ 7.84 vs 4.79 microns
    Better low-light and dynamic range (all else equal)
  • Top deck display
    Yes vs No
    Check settings with a screen on top of the camera
  • Pentaprism viewfinder
    Pentaprism vs Pentamirror
    Much better viewfinder picture fidelity
  • Doesn't require an AA filter
    Yes vs No
    A unique sensor design provides sharp photos without moiré

Nikon D5100 advantages over Sigma SD15

  • Lens selection
    Excellent vs Limited
    Better lens selection gives you more options
  • Larger sensor
    APS-C vs 0.98 inch
    More sensor area. Bigger is (generally) better.
  • Tilt-swivel screen
    Tilt-swivel vs none
    Tilt and swivel the screen for maximum shooting flexibility
  • Longer stills battery life
    More info 660 vs 250 shots
    Capture more photos
  • External Mic Jack
    Jack vs No jack
    Improved sound fidelity when shooting video
  • HDMI out
    HDMI out vs None
    Use HDMI output to monitor or review video
  • Shoots 24p video
    Yes vs No
    Gives your movies a big-screen feel
  • More dots on screen
    922k vs 460k dots
    Can mean greater resolution or a brighter screen
  • Shoots 1080p video
    Yes vs No
    You'll want this if you shoot video
  • More pixels
    16.2 vs 4.7 megapixels
    Higher resolution photos
  • More AF points
    11 vs 5
    More AF points improve autofocus
  • Faster JPEG shooting
    3.9 fps vs 3.0 fps
    Faster JPEG shooting (burst mode)
  • Bigger JPEG buffer
    100 vs 21 shots
    Take more JPEG shots before waiting (burst mode)
  • Higher extended ISO
    25600 vs 3200 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
  • Internal flash
    Both provide
    Useful in a pinch for fill flash
  • Hot shoe
    Both provide
    Off-camera flashes open new possibilities
  • Bulb shutter
    Both provide
    Hold the shutter open manually for long exposures

Common Weaknesses

  • Focus peaking
    Neither provide
    Your camera will highlight what's in focus
  • 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
  • In-camera panoramas
    Neither provide
    Stitches multiple shots into a panoramic photo
  • Built-in Wi-Fi
    Neither provide
    Share your photos wirelessly
  • 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
  • On-sensor phase detect
    Neither provide
    Usually improves live view and video AF performance
  • Dual card slots
    Neither provide
    Gives you more storage flexibility
  • Headphone jack
    Neither provide
    Monitor audio recording while you shoot video
  • Slow-motion videos
    Neither provide
    Shoot slow-motion videos

User reviews

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Buy the Nikon D5100
Body Only

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.

  • Read our Nikon D5100 Full Review

The Competition

Compared to Olympus E30

Sigma SD15
Olympus E30
  • $1500
  • 0.98 inch
  • Larger sensor
  • Bigger pixels
  • $1299
  • 4/3
  • Lens selection
  • In-Camera Image Stabilization

Compare Sigma SD15 vs Olympus E30

Nikon D5100
Olympus E30
  • $650
  • APS-C
  • Lens selection
  • Larger sensor
  • $1299
  • 4/3
  • In-Camera Image Stabilization
  • Top deck display

Compare Nikon D5100 vs Olympus E30

Compared to Sony DSLR-A330

Sigma SD15
Sony DSLR-A330
  • $1500
  • 0.98 inch
  • Bigger pixels
  • Top deck display
  • $530
  • APS-C
  • Lens selection
  • Larger sensor

Compare Sigma SD15 vs Sony DSLR-A330

Nikon D5100
Sony DSLR-A330
  • $650
  • APS-C
  • Lens selection
  • Tilt-swivel screen
  • $530
  • APS-C
  • Less expensive
  • In-Camera Image Stabilization

Compare Nikon D5100 vs Sony DSLR-A330

Compared to Sony A55

Sigma SD15
Sony A55
  • $1500
  • 0.98 inch
  • Bigger pixels
  • Top deck display
  • $734
  • APS-C
  • Lens selection
  • Larger sensor

Compare Sigma SD15 vs Sony A55

Nikon D5100
Sony A55
  • $650
  • APS-C
  • Lens selection
  • Tilt-swivel screen
  • $734
  • APS-C
  • In-Camera Image Stabilization
  • In-camera panoramas

Compare Nikon D5100 vs Sony A55

Compared to Olympus E-5

Sigma SD15
Olympus E-5
  • $1500
  • 0.98 inch
  • Larger sensor
  • Bigger pixels
  • $1700
  • 4/3
  • Lens selection
  • In-Camera Image Stabilization

Compare Sigma SD15 vs Olympus E-5

Nikon D5100
Olympus E-5
  • $650
  • APS-C
  • Lens selection
  • Larger sensor
  • $1700
  • 4/3
  • In-Camera Image Stabilization
  • Longer stills battery life

Compare Nikon D5100 vs Olympus E-5

Compared to Sony A57

Sigma SD15
Sony A57
  • $1500
  • 0.98 inch
  • Bigger pixels
  • Top deck display
  • $800
  • APS-C
  • Lens selection
  • Focus peaking

Compare Sigma SD15 vs Sony A57

Nikon D5100
Sony A57
  • $650
  • APS-C
  • Lens selection
  • Tilt-swivel screen
  • $800
  • APS-C
  • Focus peaking
  • In-Camera Image Stabilization

Compare Nikon D5100 vs Sony A57

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