• APS-C 366.6mm2
  • 24.4 megapixels
  • ISO 100 - 51,200
  • 35mm 847.3mm2
  • 24.2 megapixels
  • ISO 100 - 51,200

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Differences

Pentax K-3 advantages over Sony A9

  • Lens selection
    Excellent vs Good
    Better lens selection gives you more options
  • Fast startup
    ~0.90 vs 1.2 sec
    Faster startup lets you catch the moment
  • 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
  • Less shutter lag
    0.14 vs 0.22 sec
    Focus and take a photo quickly (wide angle)
  • Optional anti-aliasing filter
    Optional vs Fixed
    Lets you choose sharper photos or reduced moiré

Sony A9 advantages over Pentax K-3

  • Larger sensor
    35mm vs APS-C
    More sensor area. Bigger is (generally) better.
  • Bigger pixels
    ~ 5.93 vs 3.91 microns
    Better low-light and dynamic range (all else equal)
  • 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
  • Tiltable Screen
    Tiltable vs Fixed
    Tilt the screen for shooting flexbility
  • 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
  • Higher effective ISO
    3,517 vs 1,216 iso
    Take photos in low light with less noise
  • On-sensor phase detect
    Yes vs No
    Usually improves live view and video AF performance
  • Newer
    8 years vs 11 years old
    Newer cameras often support more advanced features
  • More viewfinder magnification
    0.78x vs 0.63x
    Get a bigger view of the scene through the eye-level viewfinder
  • Faster JPEG shooting
    20.0 fps vs 7.1 fps
    Faster JPEG shooting (burst mode)
  • Bigger JPEG buffer
    364 vs 75 shots
    Take more JPEG shots before waiting (burst mode)
  • Faster RAW shooting
    20.0 fps vs 7.1 fps
    Faster RAW shooting in burst mode
  • Bigger RAW buffer
    240 vs 24 shots
    Larger buffer for RAW shots (burst mode)
  • Slow-motion videos
    Yes vs No
    Shoot slow-motion videos
  • Faster shutter
    1/32000 vs 1/8000 sec
    Shoot wide open in bright light
  • Higher extended ISO
    204800 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

  • 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
  • Built-in GPS
    Neither provide
    Geotag your photos

User reviews

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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

  • New sensor offers incredible performance; Excellent image quality at low & high ISOs; Very good dynamic range; Phenomenal 20fps burst speed & deep buffer; Very good battery life for a mirrorless; 4K video; Dual card slots.

  • Slow buffer clearing; Only one card slot is UHS-II compatible; Touchscreen underutilized; No lossless RAW compression option; No 4K/60p option.

  • Read our Sony A9 Review

The Competition

Compared to Nikon D7100

Pentax K-3
Nikon D7100
  • $699
  • APS-C
  • Focus peaking
  • In-Camera Image Stabilization
  • $690
  • APS-C
  • Fast startup
  • Longer stills battery life

Compare Pentax K-3 vs Nikon D7100

Sony A9
Nikon D7100
  • $2995
  • 35mm
  • Focus peaking
  • Larger sensor
  • $690
  • APS-C
  • Lens selection
  • Less expensive

Compare Sony A9 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 A9
Nikon D5300
  • $2995
  • 35mm
  • Focus peaking
  • Larger sensor
  • $549
  • APS-C
  • Lens selection
  • Less expensive

Compare Sony A9 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 A9
Nikon D7200
  • $2995
  • 35mm
  • Focus peaking
  • Larger sensor
  • $1016
  • APS-C
  • Lens selection
  • Less expensive

Compare Sony A9 vs Nikon D7200

Compared to Leica SL (Typ 601)

Pentax K-3
Leica SL (Typ 601)
  • $699
  • APS-C
  • In-Camera Image Stabilization
  • Longer stills battery life
  • $3802
  • 35mm
  • Larger sensor
  • Bigger pixels

Compare Pentax K-3 vs Leica SL (Typ 601)

Sony A9
Leica SL (Typ 601)
  • $2995
  • 35mm
  • Less expensive
  • In-Camera Image Stabilization
  • $3802
  • 35mm
  • Built-in GPS
  • Top deck display

Compare Sony A9 vs Leica SL (Typ 601)

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 A9
Sony A9 II
  • $2995
  • 35mm
  • Less expensive
  • $4498
  • 35mm
  • Newer

Compare Sony A9 vs Sony A9 II

Compare Other Cameras?