• 35mm 864.0mm2
  • 22.3 megapixels
  • ISO 100 - 25,600
  • APS-C 361.2mm2
  • 25.7 megapixels
  • ISO 100 - 1,600,000

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Differences

Canon 5D Mark III advantages over Pentax K-3 III

  • Larger sensor
    35mm vs APS-C
    More sensor area. Bigger is (generally) better.
  • Bigger pixels
    ~ 6.25 vs 3.76 microns
    Better low-light and dynamic range (all else equal)
  • More cross-type AF points
    41 vs 25
    Cross-type AF points improve autofocus performance
  • Bigger JPEG buffer
    63 vs 30 shots
    Take more JPEG shots before waiting (burst mode)

Pentax K-3 III advantages over Canon 5D Mark III

  • 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 (UHD) 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
  • Newer
    4 years vs 13 years old
    Newer cameras often support more advanced features
  • Higher-res screen
    540k vs 348k pixels
    More detail on the screen lets you judge focus and composition
  • More viewfinder magnification
    1.05x vs 0.71x
    Get a bigger view of the scene through the eye-level viewfinder
  • More pixels
    25.7 vs 22.3 megapixels
    Higher resolution photos
  • More AF points
    101 vs 61
    More AF points improve autofocus
  • Optional anti-aliasing filter
    Optional vs Fixed
    Lets you choose sharper photos or reduced moiré
  • Faster JPEG shooting
    12.0 fps vs 6.0 fps
    Faster JPEG shooting (burst mode)
  • Higher extended ISO
    1600000 vs 102400 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
  • Top deck display
    Both provide
    Check settings with a screen on top of the camera
  • External Mic Jack
    Both provide
    Improved sound fidelity when shooting video
  • Pentaprism viewfinder
    Both provide
    Much better viewfinder picture fidelity
  • HDMI out
    Both provide
    Use HDMI output to monitor or review video
  • Hot shoe
    Both provide
    Off-camera flashes open new possibilities
  • Dual card slots
    Both provide
    Gives you more storage flexibility
  • Headphone jack
    Both provide
    Monitor audio recording while you shoot video
  • Bulb shutter
    Both provide
    Hold the shutter open manually for long exposures

Common Weaknesses

  • Tilt-swivel screen
    Neither provide
    Tilt and swivel the screen for maximum shooting flexibility
  • In-camera panoramas
    Neither provide
    Stitches multiple shots into a panoramic photo
  • Tiltable Screen
    Neither provide
    Tilt the screen for shooting flexbility
  • NFC
    Neither provide
    Simplifies pairing your camera with supported phones
  • Built-in GPS
    Neither provide
    Geotag your photos
  • On-sensor phase detect
    Neither provide
    Usually improves live view and video AF performance
  • Internal flash
    Neither provide
    Useful in a pinch for fill flash
  • Slow-motion videos
    Neither provide
    Shoot slow-motion videos

User reviews

Buy From

Your purchases support this site

Buy the Canon 5D Mark III

Your purchases support this site

Buy the Pentax K-3 III

Review Excerpt

  • Superb still and video image quality; Powerful, fast, and accurate AF system with loads of cross-type points, loads of configurability and great frame coverage; Rugged, weather-sealed body with great control layout and user-interface configurability.

  • Dynamic range is limited by noise in deep shadows; Somewhat heavy-handed noise suppression and sharpening at default settings. (Shooting RAW avoids both.); No AF illuminator.

The Competition

Compared to Canon 6D

Canon 5D Mark III
Canon 6D
  • $2079
  • 35mm
  • More cross-type AF points
  • Less shutter lag
  • $1699
  • 35mm
  • Less expensive
  • Built-in Wi-Fi
Pentax K-3 III
Canon 6D
  • $1847
  • APS-C
  • Focus peaking
  • In-Camera Image Stabilization
  • $1699
  • 35mm
  • Less expensive
  • Larger sensor

Compared to Canon 5D Mark IV

Canon 5D Mark III
Canon 5D Mark IV
  • $2079
  • 35mm
  • Less expensive
  • Bigger pixels
  • $2249
  • 35mm
  • Shoot 4K video
  • Touchscreen
Pentax K-3 III
Canon 5D Mark IV
  • $1847
  • APS-C
  • Focus peaking
  • Less expensive
  • $2249
  • 35mm
  • Larger sensor
  • Bigger pixels

Compared to Sony A850

Canon 5D Mark III
Sony A850
  • $2079
  • 35mm
  • Lens selection
  • Higher effective ISO
  • $2219
  • 35mm
  • In-Camera Image Stabilization
Pentax K-3 III
Sony A850
  • $1847
  • APS-C
  • Lens selection
  • Focus peaking
  • $2219
  • 35mm
  • Larger sensor
  • Bigger pixels

Compared to Nikon D800E

Canon 5D Mark III
Nikon D800E
  • $2079
  • 35mm
  • Bigger pixels
  • More cross-type AF points
  • $2212
  • 35mm
  • Fast startup
  • Higher effective ISO
Pentax K-3 III
Nikon D800E
  • $1847
  • APS-C
  • Focus peaking
  • In-Camera Image Stabilization
  • $2212
  • 35mm
  • Larger sensor
  • Bigger pixels

Compared to Sony A99

Canon 5D Mark III
Sony A99
  • $2079
  • 35mm
  • Lens selection
  • Fast startup
  • $1998
  • 35mm
  • Focus peaking
  • Tilt-swivel screen
Pentax K-3 III
Sony A99
  • $1847
  • APS-C
  • Lens selection
  • Shoot 4K video
  • $1998
  • 35mm
  • Tilt-swivel screen
  • Larger sensor
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