• APS-C 366.6mm2
  • 24.4 megapixels
  • ISO 100 - 51,200
  • 35mm 847.3mm2
  • 12.1 megapixels
  • ISO 80 - 102,400

Buy From

Differences

Pentax K-3 advantages over Sony A7S III

  • Lens selection
    Excellent vs Good
    Better lens selection gives you more options
  • Internal flash
    Internal flash vs None
    Useful in a pinch for fill flash
  • Top deck display
    Yes vs No
    Check settings with a screen on top of the camera
  • More pixels
    24.4 vs 12.1 megapixels
    Higher resolution photos

Sony A7S III advantages over Pentax K-3

  • Larger sensor
    35mm vs APS-C
    More sensor area. Bigger is (generally) better.
  • Tilt-swivel screen
    Tilt-swivel vs none
    Tilt and swivel the screen for maximum shooting flexibility
  • Bigger pixels
    ~ 8.40 vs 3.91 microns
    Better low-light and dynamic range (all else equal)
  • Shoot 4K video
    No vs 1080p
    Make sure you have a fast computer
  • Touchscreen
    Touch vs No touch
    Interact with your camera just like your smartphone
  • In-camera panoramas
    Yes vs No
    Stitches multiple shots into a panoramic photo
  • Built-in Wi-Fi
    Wi-Fi vs None
    Share your photos wirelessly
  • NFC
    Yes vs No
    Simplifies pairing your camera with supported phones
  • Built-in Bluetooth
    Yes vs No
    Always-on wireless connectivity
  • Newer
    4 years vs 11 years old
    Newer cameras often support more advanced features
  • Higher-res screen
    480k vs 346k pixels
    More detail on the screen lets you judge focus and composition
  • More viewfinder magnification
    0.90x vs 0.63x
    Get a bigger view of the scene through the eye-level viewfinder
  • Slow-motion videos
    Yes vs No
    Shoot slow-motion videos
  • Higher extended ISO
    409600 vs 51200 ISO
    Higher extended ISO can give more low-light flexibility

Similarities

Common Strengths

  • Focus peaking
    Both provide
    Your camera will highlight what's in focus
  • Eye-level viewfinder
    Both provide
    You'll be able to frame photos even when the sun is out
  • In-Camera Image Stabilization
    Both provide
    Reduces the effects of camera shake at slower shutter speeds
  • 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
  • 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

  • Built-in GPS
    Neither provide
    Geotag your photos
  • On-sensor phase detect
    Neither provide
    Usually improves live view and video AF performance

User reviews

Buy From

Your purchases support this site

Buy the Pentax K-3
Body Only
  • Body Only
  • Kit with 18-135mm Lens
All K-3 Deals

Your purchases support this site

Buy the Sony A7S III
Body Only
All A7S III Deals

Review Excerpt

  • Top-notch image quality; Great ergonomics in a compact body; Unique on-demand low-pass filtering; Broad sensitivity range; Large and bright viewfinder for an APS-C camera; Dual card slots; Optional Wi-Fi remote control

  • AE Lock button is poorly located; Below-average battery life for a DSLR; Rather dated-looking menu system; Requires a different battery grip accessory than its predecessors; Less third-party support than some rivals

  • Read our Pentax K-3 Review

The Competition

Compared to Nikon D7100

Pentax K-3
Nikon D7100
  • $699
  • APS-C
  • Focus peaking
  • In-Camera Image Stabilization
  • $745
  • APS-C
  • Fast startup
  • Longer stills battery life

Compare Pentax K-3 vs Nikon D7100

Sony A7S III
Nikon D7100
  • $3348
  • 35mm
  • Tilt-swivel screen
  • Focus peaking
  • $745
  • APS-C
  • Less expensive
  • Lens selection

Compare Sony A7S III vs Nikon D7100

Compared to Nikon D5300

Pentax K-3
Nikon D5300
  • $699
  • APS-C
  • Focus peaking
  • In-Camera Image Stabilization
  • $549
  • APS-C
  • Tilt-swivel screen
  • Fast startup

Compare Pentax K-3 vs Nikon D5300

Sony A7S III
Nikon D5300
  • $3348
  • 35mm
  • Focus peaking
  • Larger sensor
  • $549
  • APS-C
  • Less expensive
  • Lens selection

Compare Sony A7S III vs Nikon D5300

Compared to Nikon D7200

Pentax K-3
Nikon D7200
  • $699
  • APS-C
  • Focus peaking
  • In-Camera Image Stabilization
  • $1016
  • APS-C
  • Fast startup
  • Built-in Wi-Fi

Compare Pentax K-3 vs Nikon D7200

Sony A7S III
Nikon D7200
  • $3348
  • 35mm
  • Focus peaking
  • Larger sensor
  • $1016
  • APS-C
  • Less expensive
  • Lens selection

Compare Sony A7S III vs Nikon D7200

Compared to Sony A9 II

Pentax K-3
Sony A9 II
  • $699
  • APS-C
  • Lens selection
  • Internal flash
  • $4498
  • 35mm
  • Larger sensor
  • Bigger pixels

Compare Pentax K-3 vs Sony A9 II

Sony A7S III
Sony A9 II
  • $3348
  • 35mm
  • Less expensive
  • Tilt-swivel screen
  • $4498
  • 35mm
  • On-sensor phase detect
  • More pixels

Compare Sony A7S III vs Sony A9 II

Compared to Canon R6

Pentax K-3
Canon R6
  • $699
  • APS-C
  • More telephoto lens reach
  • Internal flash
  • $2149
  • 35mm
  • Larger sensor
  • Tilt-swivel screen

Compare Pentax K-3 vs Canon R6

Sony A7S III
Canon R6
  • $3348
  • 35mm
  • Slower slow-motion
  • Bigger pixels
  • $2149
  • 35mm
  • Less expensive
  • On-sensor phase detect

Compare Sony A7S III vs Canon R6

Compare Other Cameras?