• 0.98 inch 285.7mm2
  • 4.7 megapixels
  • ISO 100 - 1600
  • APS-C 366.6mm2
  • 24.1 megapixels
  • ISO 100 - 6400

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Differences

Sigma SD15 advantages over Nikon D7100

  • Bigger pixels
    ~ 7.84 vs 3.92 microns
    Better low-light and dynamic range (all else equal)
  • Doesn't require an AA filter
    Yes vs No
    A unique sensor design provides sharp photos without moiré
  • Bigger JPEG buffer
    21 vs 12 shots
    Take more JPEG shots before waiting (burst mode)

Nikon D7100 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.
  • Longer stills battery life
    More info 950 vs 250 shots
    Capture more photos
  • External Mic Jack
    Jack vs No jack
    Improved sound fidelity when shooting video
  • More cross-type AF points
    15 vs 1
    Cross-type AF points improve autofocus performance
  • 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
    1229k 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 viewfinder magnification
    0.63x vs 0.53x
    Get a bigger view of the scene through the eye-level viewfinder
  • More pixels
    24.1 vs 4.7 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
  • More AF points
    51 vs 5
    More AF points improve autofocus
  • Headphone jack
    Yes vs No
    Monitor audio recording while you shoot video
  • Faster JPEG shooting
    5.8 fps vs 3.0 fps
    Faster JPEG shooting (burst mode)
  • Faster shutter
    1/8000 vs 1/4000 sec
    Shoot wide open in bright light
  • 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
  • Top deck display
    Both provide
    Check settings with a screen on top of the camera
  • Pentaprism viewfinder
    Both provide
    Much better viewfinder picture fidelity
  • 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
  • Tilt-swivel screen
    Neither provide
    Tilt and swivel the screen for maximum shooting flexibility
  • 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
  • Tiltable Screen
    Neither provide
    Tilt the screen for shooting flexbility
  • 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
  • Slow-motion videos
    Neither provide
    Shoot slow-motion videos

User reviews

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Your purchases support this site

Buy the Nikon D7100

Review Excerpt

  • Solid, ergonomic body design; Stunning, highly detailed photos, thanks to 24.1MP sensor upgrade and removal of optical low-pass filter; Cool 1.3x crop mode extends reach to nearly 2x the full-frame equivalent; Records Full 1080p HD video at up to 30fps with full-time AF; Many pro-level features packed into a consumer-friendly body at reasonable price.

  • Shallow buffer that hampers continuous burst shooting; AF slightly slower than average for its class; No real-time aperture control while in Movie mode (among other quirks); More noticeable moire patterns and aliasing artifacts (but only found when shooting fabrics with strong, distinct patterns).

The Competition

Compared to Canon 70D

Sigma SD15
Canon 70D
  • $1500
  • 0.98 inch
  • Bigger pixels
  • Doesn't require an AA filter
  • $1149
  • APS-C
  • Tilt-swivel screen
  • Lens selection
Nikon D7100
Canon 70D
  • $745
  • APS-C
  • Less expensive
  • Fast startup
  • $1149
  • APS-C
  • Tilt-swivel screen
  • Touchscreen

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
Nikon D7100
Olympus E30
  • $745
  • APS-C
  • Lens selection
  • Larger sensor
  • $1299
  • 4/3
  • In-Camera Image Stabilization
  • Tiltable Screen

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
Nikon D7100
Sony DSLR-A330
  • $745
  • APS-C
  • Lens selection
  • Fast startup
  • $530
  • APS-C
  • In-Camera Image Stabilization
  • Bigger pixels

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
Nikon D7100
Olympus E-5
  • $745
  • APS-C
  • Lens selection
  • Larger sensor
  • $1700
  • 4/3
  • In-Camera Image Stabilization
  • Tiltable Screen

Compared to Pentax K-3

Sigma SD15
Pentax K-3
  • $1500
  • 0.98 inch
  • Bigger pixels
  • $699
  • APS-C
  • Lens selection
  • Focus peaking
Nikon D7100
Pentax K-3
  • $745
  • APS-C
  • Fast startup
  • Longer stills battery life
  • $699
  • APS-C
  • Focus peaking
  • In-Camera Image Stabilization
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