• APS-C 369.7mm2
  • 12.4 megapixels
  • ISO 200 - 6400
  • 4/3 224.9mm2
  • 12.3 megapixels
  • ISO 200 - 12,800

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Differences

Pentax K-x advantages over Olympus E-P3

  • Larger sensor
    APS-C vs 4/3
    More sensor area. Bigger is (generally) better.
  • Less expensive
    $650 vs $900 (MSRP)
    Save money for lenses or accessories
  • Eye-level viewfinder
    Eye-level vs Rear display only
    You'll be able to frame photos even when the sun is out
  • Bigger pixels
    ~ 5.53 vs 4.29 microns
    Better low-light and dynamic range (all else equal)
  • Fast startup
    ~0.60 vs 0.9 sec
    Faster startup lets you catch the moment
  • Higher effective ISO
    811 vs 536 iso
    Take photos in low light with less noise
  • More dynamic range
    12.5 vs 10.1 evs
    Retain detail in highlight and shadows
  • Longer stills battery life
    More info 420 vs 330 shots
    Capture more photos
  • Shoots 24p video
    Yes vs No
    Gives your movies a big-screen feel
  • Less shutter lag
    0.10 vs 0.22 sec
    Focus and take a photo quickly (wide angle)
  • Faster JPEG shooting
    4.3 fps vs 3.1 fps
    Faster JPEG shooting (burst mode)
  • Faster shutter
    1/6000 vs 1/4000 sec
    Shoot wide open in bright light

Olympus E-P3 advantages over Pentax K-x

  • Thinner
    34 mm vs 69 mm
    Thinner
  • HDMI out
    HDMI out vs None
    Use HDMI output to monitor or review video
  • Lighter weight
    490g vs 791g
    Lighter weight
  • More dots on screen
    614k vs 230k dots
    Can mean greater resolution or a brighter screen
  • Shoots 60p video
    Yes vs No
    A faster framerate can give you more editing options
  • Longer exposure
    60 vs 30 sec
    Long exposures for night shots

Similarities

Common Strengths

  • In-Camera Image Stabilization
    Both provide
    Reduces the effects of camera shake at slower shutter speeds
  • Internal flash
    Both provide
    Useful in a pinch for fill flash
  • 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
  • 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
  • Top deck display
    Neither provide
    Check settings with a screen on top of the camera
  • External Mic Jack
    Neither provide
    Improved sound fidelity when shooting video
  • Dual card slots
    Neither provide
    Gives you more storage flexibility
  • Headphone jack
    Neither provide
    Monitor audio recording while you shoot video
  • Slow-motion videos
    Neither provide
    Shoot slow-motion videos

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Review Excerpt

  • Extremely fast autofocus; Pop-up flash and AF-assist lamp; Full HD recording; wisely limited focus for touchscreen; excellent print quality results; removable grip.

  • Larger than some competitors (see E-PL3 if you prefer a smaller camera); strong noise suppression; touchscreen easily activated by mistake; list of options is overwhelming; shoulder strap D-rings are noisy.

The Competition

Compared to Sony DSLR-A380

Pentax K-x
Sony DSLR-A380
  • $702
  • APS-C
  • Lens selection
  • Less expensive
  • $849
  • APS-C
  • Tiltable Screen
  • HDMI out
Olympus E-P3
Sony DSLR-A380
  • $561
  • 4/3
  • Lens selection
  • Thinner
  • $849
  • APS-C
  • Larger sensor
  • Eye-level viewfinder

Compared to Pentax K-7

Pentax K-x
Pentax K-7
  • $702
  • APS-C
  • Less expensive
  • Higher effective ISO
  • $1300
  • APS-C
  • Longer stills battery life
  • Top deck display
Olympus E-P3
Pentax K-7
  • $561
  • 4/3
  • Less expensive
  • Thinner
  • $1300
  • APS-C
  • Larger sensor
  • Eye-level viewfinder

Compared to Olympus E-P2

Pentax K-x
Olympus E-P2
  • $702
  • APS-C
  • Less expensive
  • Larger sensor
  • $1100
  • 4/3
  • Thinner
  • HDMI out
Olympus E-P3
Olympus E-P2
  • $561
  • 4/3
  • Less expensive
  • Fast startup
  • $1100
  • 4/3
  • Eye-level viewfinder

Compared to Pentax K-r

Pentax K-x
Pentax K-r
  • $702
  • APS-C
  • Less expensive
  • Shoots 24p video
  • $850
  • APS-C
  • Fast startup
  • External Mic Jack
Olympus E-P3
Pentax K-r
  • $561
  • 4/3
  • Thinner
  • HDMI out
  • $850
  • APS-C
  • Larger sensor
  • Eye-level viewfinder

Compared to Olympus E-PL3

Pentax K-x
Olympus E-PL3
  • $702
  • APS-C
  • Larger sensor
  • Eye-level viewfinder
  • $700
  • 4/3
  • Tiltable Screen
  • Thinner
Olympus E-P3
Olympus E-PL3
  • $561
  • 4/3
  • Fast startup
  • Internal flash
  • $700
  • 4/3
  • Less expensive
  • Tiltable Screen
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