• 35mm 855.6mm2
  • 24.3 megapixels
  • ISO 100 - 25,600
  • APS-C 366.6mm2
  • 20.1 megapixels
  • ISO 100 - 51,200

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Differences

Sony A99 advantages over Pentax K-S1

  • Tilt-swivel screen
    Tilt-swivel vs none
    Tilt and swivel the screen for maximum shooting flexibility
  • Larger sensor
    35mm vs APS-C
    More sensor area. Bigger is (generally) better.
  • Bigger pixels
    ~ 5.97 vs 4.29 microns
    Better low-light and dynamic range (all else equal)
  • In-camera panoramas
    Yes vs No
    Stitches multiple shots into a panoramic photo
  • Higher effective ISO
    1,555 vs 1,061 iso
    Take photos in low light with less noise
  • Built-in GPS
    GPS vs None
    Geotag your photos
  • Top deck display
    Yes vs No
    Check settings with a screen on top of the camera
  • External Mic Jack
    Jack vs No jack
    Improved sound fidelity when shooting video
  • More viewfinder magnification
    0.71x vs 0.63x
    Get a bigger view of the scene through the eye-level viewfinder
  • More pixels
    24.3 vs 20.1 megapixels
    Higher resolution photos
  • Dual card slots
    Yes vs No
    Gives you more storage flexibility
  • More AF points
    19 vs 11
    More AF points improve autofocus
  • Headphone jack
    Yes vs No
    Monitor audio recording while you shoot video

Pentax K-S1 advantages over Sony A99

  • 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
  • More cross-type AF points
    9 vs 3
    Cross-type AF points improve autofocus performance
  • Newer
    4 years vs 6 years old
    Newer cameras often support more advanced features
  • Optional anti-aliasing filter
    Optional vs Fixed
    Lets you choose sharper photos or reduced moiré

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
  • HDMI out
    Both provide
    Use HDMI output to monitor or review video
  • Hot shoe
    Both provide
    Off-camera flashes open new possibilities
  • Bulb shutter
    Both provide
    Hold the shutter open manually for long exposures

Common Weaknesses

  • Touchscreen
    Neither provide
    Interact with your camera just like your smartphone
  • 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
  • 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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Buy the Pentax K-S1

Review Excerpt

The Competition

Compared to Nikon D800

Sony A99
Nikon D800
  • $1998
  • 35mm
  • Tilt-swivel screen
  • Focus peaking
  • $1850
  • 35mm
  • Lens selection
  • Fast startup
Pentax K-S1
Nikon D800
  • $399
  • APS-C
  • Less expensive
  • Focus peaking
  • $1850
  • 35mm
  • Larger sensor
  • Higher effective ISO

Compared to Canon 5D Mark III

Sony A99
Canon 5D Mark III
  • $1998
  • 35mm
  • Less expensive
  • Tilt-swivel screen
  • $2520
  • 35mm
  • Lens selection
  • Fast startup
Pentax K-S1
Canon 5D Mark III
  • $399
  • APS-C
  • Focus peaking
  • In-Camera Image Stabilization
  • $2520
  • 35mm
  • Larger sensor
  • Bigger pixels

Compared to Nikon D800E

Sony A99
Nikon D800E
  • $1998
  • 35mm
  • Focus peaking
  • Tilt-swivel screen
  • $2212
  • 35mm
  • Lens selection
  • Fast startup
Pentax K-S1
Nikon D800E
  • $399
  • APS-C
  • Less expensive
  • Focus peaking
  • $2212
  • 35mm
  • Larger sensor
  • Higher effective ISO

Compared to Nikon D3300

Sony A99
Nikon D3300
  • $1998
  • 35mm
  • Focus peaking
  • Larger sensor
  • $438
  • APS-C
  • Lens selection
  • Less expensive
Pentax K-S1
Nikon D3300
  • $399
  • APS-C
  • Focus peaking
  • In-Camera Image Stabilization
  • $438
  • APS-C
  • In-camera panoramas
  • Higher effective ISO

Compared to Pentax K-S2

Sony A99
Pentax K-S2
  • $1998
  • 35mm
  • Larger sensor
  • Bigger pixels
  • $522
  • APS-C
  • Lens selection
  • Less expensive
Pentax K-S1
Pentax K-S2
  • $399
  • APS-C
  • Higher-res screen
  • $522
  • APS-C
  • Tilt-swivel screen
  • Built-in Wi-Fi
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