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Sony A7S vs Pentax K-3 Comparison

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Sony A7S

12 MP | Full frame (35.8 x 23.9 mm) CMOS Sensor

Sony A7S
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Pentax K-3

24 MP | APS-C (23.5 x 15.6 mm) CMOS Sensor

Pentax K-3
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Sony A7S vs Pentax K-3 Comparison Overview

Here we are comparing two cameras with different body types: Sony A7S, which was introduced in April 2014 is a Pro Mirrorless camera with a 12.0MP Full frame sensor whereas Pentax K-3, which was introduced in April 2014 is a Advanced DSLR camera with a 24.0MP APS-C sensor. Both A7S and K-3 were launched within the same month so we are expecting this to be a fair comparison regarding age and available technology level.

Despite some fundamental differences of these two body types, Mirrorless cameras are becoming serious alternatives to DSLR cameras thanks to their size/weight advantages and recent improvements in their focus speeds , which makes this comparison even more interesting.

Here is a brief look at the main features of Sony A7S and Pentax K-3 before getting into our more detailed comparison.

Sony A7S Key Specs

  • Announcement Date: 2014-04-06
  • 12MP - Full frame CMOS Sensor
  • ISO 100 - 409600
  • Sony E Mount
  • 3 Tilting Screen
  • 2359k dot Electronic viewfinder
  • 5 fps continuous shooting
  • 4K (UHD) - 3840 x 2160 video resolution
  • 120 fps High-Speed Video
  • Built-in Wireless
  • 489g. 127 x 94 x 48 mm
  • Weather Sealed Body

Pentax K-3 Key Specs

  • Announcement Date: 2014-04-10
  • 24MP - APS-C CMOS Sensor
  • No Anti-aliasing (AA) filter
  • ISO 100 - 51200
  • Pentax KAF2 Mount
  • Sensor-shift Image Stabilization
  • 3.2" Fixed Type Screen
  • Optical (pentaprism) viewfinder
  • 8 fps continuous shooting
  • Full HD - 1920 x 1080 video resolution
  • 800g. 131 x 100 x 77 mm
  • Weather Sealed Body

Sony A7S was replaced by Sony Alpha 7S II. You may also be interested in these comparisons:
Sony Alpha 7S II vs Sony Alpha A7S
Sony Alpha 7S II vs Pentax K-3

Pentax K-3 was replaced by Pentax K-3 II. You may also be interested in these comparisons:
Pentax K-3 II vs Pentax K-3
Pentax K-3 II vs Sony Alpha A7S

Let's read on the following sections in order to better understand in detail how Sony A7S and Pentax K-3 compares and hopefully end up with enough arguments to decide which one is better for you.

Reasons to choose Sony Alpha A7S over Pentax K-3
Wireless Connection
Built-In vs None Better connectivity
LCD Screen
Tilting vs Fixed Type Flexible shooting positions
Viewfinder Magnification
0.71x vs 0.64x Larger Viewfinder
Max ISO
409.600 vs 51.200 700% higher Max ISO
LCD Screen Resolution
1.230k dots vs 1.037k dots 18% higher resolution screen
Weight
489 g vs 800 g 311 g lighter
Color Depth
23.9 vs 23.7 higher color depth
Low Light ISO
3702 vs 1216 better High ISO performance
Sensor Pixel Area
71.24µm2 vs 15.24µm2 367% larger pixel area
Max Video Resolution
3840 x 2160 vs 1920 x 1080 Higher Resolution Video
AE Bracketing Range
±5 EV vs ±2 EV Wide Bracketing range is useful for HDR
NFC Connection
Yes vs No Easy wireless connectivity with compatible devices
Smartphone Remote
Yes vs No Remote control your camera with a smartphone


Reasons to choose Pentax K-3 over Sony Alpha A7S
Image Stabilization
Sensor-shift vs None Sharper images at longer focal lengths and long exposures
Built-in Flash
Yes vs No Useful in low-light
Max Sensor Resolution
24 MP vs 12 MP 100% more pixels
Number of Focus Points
27 vs 25 2 more focus points
LCD Screen Size
3.2" vs 3 0.2 inches larger display
Continuous Shooting
8.0fps vs 5.0fps 3 fps faster
Battery Life
560 shots vs 360 shots 200 more frames with a single charge
Timelapse Recording
Yes vs With optional app creative shooting
Dynamic Range
13.4 vs 13.2 higher dynamic range
Top LCD
Yes vs No Help viewing and changing settings easily
Anti Alias Filter Simulator
Yes vs No Turn on Anti Alias filter effect to minimise Moire
Storage Slot
2 vs 1 Extra storage slot

Common Strengths of Sony Alpha A7S and Pentax K-3
External Flash Shoe
Yes vs Yes Better for flash photography
Viewfinder
Yes (Electronic) vs Yes (Optical) Better framing and control
RAW Support
Yes vs Yes Better image quality
Face Detection Focus
Yes vs Yes very handy for portraits
LCD Screen Size
3 vs 3.2" Large display
Microphone Port
Yes vs Yes High quality audio recording option
Headphone Port
Yes vs Yes better video control
Environmental Sealing
Yes vs Yes shoot at tough conditions
AE Bracketing
Yes vs Yes Useful for tough lighting conditions and HDR
Dual-axis Electronic Level
Yes vs Yes Level the camera easily in two axis
Common Weaknesses of Sony Alpha A7S and Pentax K-3
Sony A7S vs Pentax K-3: Physical Specs and Body features Comparison

Size and weight is a big decision factor when you are trying to find the ideal camera for your needs. In this section, We are going to illustrate Sony A7S and Pentax K-3 side-by-side from the front, back and top in their relative dimensions. Sony A7S has external dimensions of 127 x 94 x 48 mm (5 x 3.7 x 1.89″) and weighs 489 g (1.08 lb / 17.25 oz) (including batteries). Pentax K-3 has external dimensions of 131 x 100 x 77 mm (5.16 x 3.94 x 3.03″) and weighs 800 g (1.76 lb / 28.22 oz) (including batteries).

Below you can see the front view size comparison of Sony A7S and Pentax K-3. Sony A7S is clearly the smaller of the two cameras. Its body is 4mm narrower, 6mm shorter and 29mm thinner than Pentax K-3.

Sony A7S vs Pentax K-3 Camera Size Comparison - Front View
Comparison image of Sony A7S and Pentax K-3 Size, Weight and External Dimensions - Front View

Here is the back view size comparison of Sony A7S and Pentax K-3.

Sony A7S vs Pentax K-3 Camera Size Comparison - Back View
Comparison image of Sony A7S and Pentax K-3 Size and Weight - Back View

Now lets look at the top view comparison of Sony A7S and Pentax K-3.
Sony A7S vs Pentax K-3 Camera Size Comparison - Top View
Top View Comparison image of Sony A7S and Pentax K-3 Size

Weight is another important factor especially when deciding on a camera that you want to carry with you all day. Sony A7S is significantly lighter (311g ) than the Pentax K-3 which may become a big advantage especially on long walking trips.

Also keep in mind that body weight is not the only deciding factor when comparing two interchangeable camera bodies, you have to also take into account the lenses that you will be using with these bodies. Since Sony A7S has a Full frame sensor and Pentax K-3 has a smaller APS-C sensor, Pentax K-3's lenses for a similar focal length and aperture will generally be lighter and smaller than the Sony A7S lenses.

Weight Comparison

DSLR Cameras

A7S
K-3
Min
Average
Max
Thickness Comparison

DSLR Cameras

A7S
K-3
Min
Average
Max

Weather Sealing

Both A7S and K-3 have weather sealings in their body, making them resistant to water and dust.

LCD Screen Size and Features

Pentax K-3's 3.2" LCD screen is slightly larger than Sony A7S's 3 screen.

On the other hand, Sony A7S LCD screen has a Tilting feature where you can change the angle of the screen to make it easier to shoot from waist or over the head levels. On the other hand, Pentax K-3 has a fixed type screen which provides less flexibility in shooting positions compared to A7S.
Sony A7S vs Pentax K-3: Sensor Comparison

Sony A7S has a 12.0MP Full frame (35.8 x 23.9 mm ) sized CMOS sensor and features Bionz X processor. On the other hand, Pentax K-3 has a 24.0MP APS-C (23.5 x 15.6 mm ) sized CMOS sensor and features Prime III processor.

Pentax K-3's sensor provides 12MP more than Sony A7S's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely. On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.

One other difference between these two cameras that is worth mentioning is that Pentax K-3's sensor doesn't have an anti-alias (Low-Pass) filter. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moire occurring in certain scenes.

Below you can see the A7S and K-3 sensor size comparison.

Sony A7S vs Pentax K-3 Sensor Size Comparison
Sensor Size and Resolution Comparison image of Sony A7S and Pentax K-3 Cameras


As seen above, Sony A7S has a 2.3x Larger sensor area than Pentax K-3. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.

DxOMark Sensor Scores

Both Sony A7S and Pentax K-3 sensors have been tested by DxoMark. DxoMark scores camera sensors for color depth (DXO Portrait), dynamic range (DXO Landscape) and low-light sensitivity (DXO Sports), and also gives them an overall score. Of the two cameras that we are comparing, A7S has scored 87, 7 points higher than K-3.

Model Overall Color Depth Dynamic Range Low-light ISO
Sony A7S 87 23.9 bits 13.2 Evs 3702 ISO
Pentax K-3 80 23.7 bits 13.4 Evs 1216 ISO
Sony A7S vs Pentax K-3 Comparison of Available Lenses
Which camera has more lenses?

Number of available lenses is a big decision factor while choosing your interchangeable lens camera. When we look at the available lenses for these two cameras, we see that Pentax K-3 has an advantage over Sony A7S There are 151 lenses for Pentax K-3's Pentax KAF2 mount, on the other hand there are only 128 lenses for Sony A7S's Sony E lens mount.

Another important factor is the availability of image stabilization. Pentax K-3 has a big advantage in this regard because it has a sensor based image stabilization which means that all the lenses mounted to this body will be stabilized. On the other hand, Sony A7S doesn't have this feature so you have to buy a lens with optical stabilization feature. Currently there are 31 lenses for Sony E mount with Optical Image Stabilization features.

Lens Type # of Sony A7S Lenses # of Pentax K-3 Lenses
Standard Zoom 12 (9 Full Frame) 22
Standard Prime 18 (9 Full Frame) 20
Wideangle Zoom 7 (6 Full Frame) 12
Wideangle Prime 42 (26 Full Frame) 24
Telephoto Zoom 9 (7 Full Frame) 21
Telephoto Prime 18 (14 Full Frame) 12
SuperZoom 8 (1 Full Frame) 15
Wideangle Fisheye Prime 2 (0 Full Frame) 3
Macro Prime 8 (7 Full Frame) 14
Perspective Control Prime 2 (2 Full Frame) 8
Telephoto Mirror Prime n/a n/a
TOTAL 128 (81 Full Frame) 151


Now let's compare some sample lenses from each mount with typical Focal ranges for Sony A7S and Pentax K-3 to see how these lenses compares:

Fast Standard Zoom Lenses
Model FF Equiv. Weight Weight w/ Cam Length Street Price
Sony FE 24-70mm F2.8 GM Lens Sony FE 24-70mm F2.8 GM
24 - 70mm 886gr 1375gr 136mm Amazon B&H Photo
Pentax DA 16-50mm F2.8 ED Lens Pentax DA 16-50mm F2.8 ED
24 - 75mm 565gr 1365gr 99mm Amazon B&H Photo
Fast Tele Zoom Equivalent Lenses
Model FF Equiv. Weight Weight w/ Cam Length Street Price
Sony FE 70-200mm F2.8 GM OSS Lens Sony FE 70-200mm F2.8 GM OSS
70 - 200mm 1480gr 1969gr 200mm Amazon B&H Photo
Pentax DA 50-135mm F2.8 ED Lens Pentax DA 50-135mm F2.8 ED
75 - 202.5mm 685gr 1485gr 136mm Amazon B&H Photo
Fast Normal Prime Equivalent Lenses
Model FF Equiv. Weight Weight w/ Cam Length Street Price
Sony FE 50mm F1.4 Lens Sony FE 50mm F1.4
50mm 778gr 1267gr 108mm Amazon B&H Photo
Pentax FA 31mm F1.8 L Lens Pentax FA 31mm F1.8 L
31mm 345gr 1145gr 69mm Amazon B&H Photo
Fast Wideangle Zoom Equivalent Lenses
Model FF Equiv. Weight Weight w/ Cam Length Street Price
Sony FE 16-35mm F2.8 GM Lens Sony FE 16-35mm F2.8 GM
16 - 35mm 680gr 1169gr 122mm Amazon B&H Photo
Pentax 12-24mm F4.0 ED AL Lens Pentax 12-24mm F4.0 ED AL
18 - 36mm 430gr 1230gr 84mm Amazon B&H Photo
24-105mm f4 Equivalent Lenses
Model FF Equiv. Weight Weight w/ Cam Length Street Price
Sony FE 24-105mm F4 G OSS Lens Sony FE 24-105mm F4 G OSS
24 - 105mm 663gr 1152gr 113mm Amazon B&H Photo
Pentax 17-70mm F4.0 AL SDM Lens Pentax 17-70mm F4.0 AL SDM
25.5 - 105mm 485gr 1285gr 94mm Amazon B&H Photo
Super-Tele Zoom Equivalent Lenses
Model FF Equiv. Weight Weight w/ Cam Length Street Price
Sony FE 100-400mm F4.5-5.6 GM OSS Lens Sony FE 100-400mm F4.5-5.6 GM OSS
100 - 400mm 1395gr 1884gr 205mm Amazon B&H Photo
Sigma 120-400mm F4.5-5.6 DG HSM Lens Sigma 120-400mm F4.5-5.6 DG HSM
120 - 400mm 1640gr 2440gr 203mm Amazon B&H Photo
What types of Photography are Sony A7S and Pentax K-3 Good for?
In this section, we rank and compare Sony A7S and Pentax K-3 for five different photography types in order to make your decision process easier in case you are specifically interested in one or more of these areas.

Sony A7S for Portrait Photography

GOOD

Pentax K-3 for Portrait Photography

GOOD
Large Full frame (35.8 x 23.9 mm) sensor
Electronic Built-in Viewfinder
Good Ergonomics&Handling
Average Resolution Sensor: 12.0MP
No Image Stabilization
Read the details
Large APS-C (23.5 x 15.6 mm) sensor
Very High Resolution Sensor: 24.0MP
Image Stabilization
Optical Built-in Viewfinder
Good Ergonomics&Handling
Read the details

Sony A7S for Street Photography

GOOD

Pentax K-3 for Street Photography

EXCELLENT
Large Full frame (35.8 x 23.9 mm) sensor
Electronic Built-in Viewfinder
Live-view
Face-Detection Focusing
Tilting LCD Screen
Medium sized Body
No Image Stabilization
Read the details
Large APS-C (23.5 x 15.6 mm) sensor
Image Stabilization
Optical Built-in Viewfinder
Live-view
Face-Detection Focusing
Large Body
Read the details

Sony A7S for Sports Photography

GOOD

Pentax K-3 for Sports Photography

EXCELLENT
Electronic Built-in Viewfinder
Good Ergonomics&Handling
Environmental Sealings
Fast Max shutter speed: 1/8000s
25 Focus Points
Good Low Light ISO
Wireless Connection
Average Continuous Shooting: 5.0fps
No Image Stabilization
Read the details
Image Stabilization
Optical Built-in Viewfinder
Good Ergonomics&Handling
Fast Continuous Shooting: 8.0fps
Environmental Sealings
Fast Max shutter speed: 1/8000s
25 Cross Type Focus sensors
27 Focus Points
Good Battery Life: 560 shots
Good Low Light ISO
Read the details

Sony A7S for Daily Photography

EXCELLENT

Pentax K-3 for Daily Photography

GOOD
Large Full frame (35.8 x 23.9 mm) sensor
Environmental Sealings
Medium size Body
489g
Body Thickness 48mm
Read the details
Large APS-C (23.5 x 15.6 mm) sensor
Environmental Sealings
Large Body
800g
Body Thickness 77mm
Read the details

Sony A7S for Landscape Photography

AVERAGE

Pentax K-3 for Landscape Photography

AVERAGE
Large Full frame (35.8 x 23.9 mm) sensor
Environmental Sealings
Live-view
Average Resolution Sensor: 12.0MP
Read the details
Large APS-C (23.5 x 15.6 mm) sensor
Very High Resolution Sensor: 24.0MP
Environmental Sealings
Live-view
Read the details

Sony A7S vs Pentax K-3: OUR DECISION

You may have already made your decision about which camera suits better for your needs and your budget so far but in case you wonder how we rated Sony A7S and Pentax K-3, below you can find their scores in five different aspects. Our Decision Algorithm dynamically scores cameras using 63 different specs, current price and DxO Mark scores (where possible) in order to make a more objective and consistent comparison.

Here is a summary of how Sony A7S and Pentax K-3 scores compare:

Sony A7S
Imaging
Features
Value
Portability
Overall
Ranked #39 out of 86 in SLR-style mirrorless cameras
Ranked #71 out of 1220 in all Cameras
Pentax K-3
Imaging
Features
Value
Portability
Overall
Ranked #18 out of 94 in Mid-size SLR cameras
Ranked #70 out of 1220 in all Cameras

Sony A7S
Sony A7S
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Pentax K-3
Pentax K-3
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Pentax K-3 vs Sony A7S Specs Table
Detailed comparison of specifications
General Sony Alpha A7S Pentax K-3
Brand Sony Pentax
Announced 2014-04-06 2014-04-10
Body Type SLR-style mirrorless Mid-size SLR
Sensor
Type CMOS CMOS
Size Full frame APS-C
Dimensions 35.8 x 23.9 mm 23.5 x 15.6 mm
Area 855.62mm2 366.60mm2
Megapixels 12 megapixels 24 megapixels
Max Resolution 4240 x 2832 6016 x 4000
Max Native Light sensitivity 409,600 ISO 51,200 ISO
Min Native Light sensitivity 100 ISO 100 ISO
RAW Support
Autofocus
AF Touch
AF Continuous
AF Single
AF Tracking
AF Selective
AF Center
AF Multi Area
AF Live View
AF Face Detection
AF Contrast Detection
AF Phase Detection
Number of Focus Points 25 27
Lens
Manual Focus
Lens Mount Sony E Pentax KAF2
Number of Available Lenses 128 151
Screen
Type Tilting Fixed type
Size 3 3.2"
Resolution 1,230k dots 1,037k dots
Touch Screen
Viewfinder
Viewfinder Electronic Optical (pentaprism)
Viewfinder Resolution 2,359k dots no electronic viewfinder
Viewfinder Coverage 100% 100%
Viewfinder Magnification 0.71x 0.64x
Photography Features
Max Mechanical Shutter 1/8000s 1/8000s
Shutter Priority
Aperture Priority
Manual Exposure Mode
Custom White Balance
Image Stabilization No Sensor-shift
Built-in Flash
Flash Range no built-in flash 13.00 m (at ISO 100)
Max Flash Sync n/a 1/180s
External Flash
Continuous Shooting 5.0 fps 8.0 fps
Multi-Segment
Average
Spot
Partial
AF-Area
Center Weighted
AE Bracketing
WB Bracketing
Video Features
Max Video Resolution 3840 x 2160 1920 x 1080
Video Formats MPEG-4, AVCHD, XAVC MPEG-4, H.264
Microphone Port
Headphone Port
Connectivity
Wireless Connectivity Built-In None
HDMI
Physical
Environmental Sealing
Weight 489g 800g
Dimensions 127 x 94 x 48mm 131 x 100 x 77mm
Battery Life 360 shots 560 shots
Other Features
Timelapse Recording With Downloadable App
GPS None Optional
DxO Sensor Scores
DxO Overall Score 87 80
DxO Color Depth 23.9 23.7
DxO Dynamic Range 13.2 13.4
DxO Low Light ISO 3702 1216
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