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Pentax K-3 Mark III vs Sony a7 III Comparison

Storage & Battery

Pentax K-3 Mark III

Pentax K-3 Mark III

Sony a7 III

Sony A7 III camera
Pentax K-3 Mark III
Sony a7 III
K-3 Mark III
a7 III
Refers to the year this camera was officially made available for sale.
Announcement Date
Refers to the date the manufacturer publicly announced the upcoming release and general specs of this camera.
March 30, 2021
February 27, 2018
Camera Type
Camera Size
Camera Weight

The Pentax K-3 Mark III outperforms the Sony a7 III with a score of 83 compared to 81. Both cameras were released at a similar price point, with the Pentax K-3 Mark III launching at $1999 in 2021 and the Sony a7 III at $2000 in 2018. They share the same depth of 74mm, but the Pentax K-3 Mark III is larger in size, measuring 135 x 104mm, and weighs more at 820g.

The Pentax K-3 Mark III’s higher score highlights its advantages as a DSLR, providing better image quality and performance. On the other hand, the Sony a7 III has its merits as a mirrorless camera, offering a lighter and more compact design at 650g and 127 x 96mm dimensions.

Taking the scores and specifications into consideration, the Pentax K-3 Mark III is the better option for photographers seeking superior performance and image quality. However, the Sony a7 III is a suitable alternative for those prioritizing portability and a more compact design.

Pentax K-3 Mark III vs Sony a7 III Overview and Optics

The Pentax K-3 Mark III narrowly wins in optics with a score of 82/100, compared to the Sony a7 III’s score of 81/100. Both cameras share several specifications, including a CMOS sensor, image stabilization, and a DXOMARK sensor score of 96.

The Pentax K-3 Mark III has a higher megapixel count at 26, compared to the Sony a7 III’s 24.2. This results in the Pentax capturing more detailed images. Additionally, the Pentax K-3 Mark III has a faster shooting speed of 12 frames per second, compared to the Sony a7 III’s 10 frames per second. This allows the Pentax to capture fast-moving subjects with greater ease. The Pentax also features a Prime IV processor and KAF2 lens mount, offering compatibility with a wide range of Pentax lenses.

On the other hand, the Sony a7 III has a full-frame sensor size, which provides better low-light performance and a shallower depth of field compared to the Pentax K-3 Mark III’s APS-C sensor. The Sony a7 III also features a Bionz X processor and an FE lens mount, making it compatible with a variety of Sony lenses.

Considering the optics of both cameras, the Pentax K-3 Mark III stands out with its higher megapixel count and faster shooting speed. However, the Sony a7 III offers a full-frame sensor, which may appeal to photographers who prioritize low-light performance and depth of field. Ultimately, the choice between these two cameras will depend on individual preferences and shooting requirements.

The higher the number of megapixels, the more detail the cameras sensor can capture.
26 MP
24.2 MP
Image Resolution
Image resolution is measured in pixels and megapixels, width by height. The higher the number, the higher its resolution.
6192 x 4128 px
6000 x 4000 px
Sensor Type
The camera sensor captures light and records the image. Sensors vary in physical size, the number of pixels, and quality.
Sensor Size
The sensor size contributes to the overall quality as well as the dynamic and tonal range a camera can capture. As a rule of thumb, the more surface there is to read the light, the more information it will capture.
23 x 15.5 mm
23.8 x 35.6 mm
Sensor Format
Refers to the most commonly used sensor sizes.
Full Frame
Frame Rate
The number of sequential frames per second the camera can write to the memory card when shooting in burst or continuous mode.
12 fps
10 fps
Lens Mount
The lens mount will tell you what type of lens range you can fit onto the camera body. Often the same camera company will have different lens ranges for different cameras.
Pentax KAF2
Sony FE
Image Processor
The image processor in the camera converts the information collected on the sensor for digital storage on the memory card.
Prime IV
Bionz X
Aspect Ratio
The aspect ratio refers to the proportional difference between width and height. The most popular aspect ratios are 3:2 and 4:3.
Minimum ISO (Native)
Refers to the lowest native (or 'base') ISO setting. Lower ISO are less sensitive to light but make a cleaner image.
Maximum ISO (Native)
Refers to the highest native (or 'base') ISO setting. Higher ISO is necessary for low-light situations or night photography, but higher ISOs often introduce grain or noise.
Minimum ISO (Expanded)
Expanded (or extended) ISO is a digitally enhanced feature available on some cameras. It allows you to push beyond the native ISO range if necessary.
Maximum ISO (Expanded)
Expanded (or extended) ISO is a digitally enhanced feature available on some cameras. It allows you to push beyond the native ISO range if necessary.
Minimum Shutter Speed
The minimum shutter speed will tell you the longest exposure your camera can take without using an external accessory.
30 s
30 s
Maximum Shutter Speed
The maximum shutter speed tells you the length inside 1 second the camera will capture. These can sometimes be extended with accessories such as extra external batteries.
1/ 8000 s
1/ 8000 s
Autofocus Points
Autofocus points show where the camera is focusing graphically as squares or brackets in Live View or on an electronic viewfinder. These points are also used for light meter readings.
In-body Stabilization
In-body Stabilization means the camera has a certain technology embedded that counteracts camera shake.
Viewfinder Type
The viewfinder type is either electronic or optical. Electronic viewfinders will have a small screen in the viewfinder. Optical viewfinders will use prisms and mirrors to look through the lens.
Optical (pentaprism)
Viewfinder Resolution
2,359,296 dots

Pentax K-3 Mark III vs Sony a7 III Video Performance

The Pentax K-3 Mark III outperforms the Sony a7 III in video capabilities, scoring 83/100 compared to the Sony a7 III’s 70. Both cameras share some common specifications, including a maximum video resolution of 4K and video dimensions of 3840 x 2160. However, the Pentax K-3 Mark III excels in certain areas, while the Sony a7 III has its own advantages.

The Pentax K-3 Mark III boasts a higher maximum video frame rate of 60fps, double that of the Sony a7 III’s 30fps. This allows for smoother and more fluid motion capture in video recordings.

On the other hand, the Sony a7 III does not have any significant advantages in video capabilities over the Pentax K-3 Mark III. It shares the same 4K resolution and video dimensions but falls short in frame rate and time-lapse features.

Considering the differences in video capabilities, the Pentax K-3 Mark III stands out as the superior choice for videographers and enthusiasts seeking higher frame rates and built-in time-lapse functionality. The Sony a7 III, while still a capable camera, may not be the ideal choice for those prioritizing video performance.

Indicates if this camera is capable of recording video.
Max Video Resolution
The best resolution this camera can capture video in. Modern cameras can capture up to 8K video.
Max Video Dimensions
Video resolution measured by the greatest number of pixels possible in each frame, width by height. A higher resolution means more detail or clarity in your video.
3840 x 2160 px
3840 x 2160 px
Max Video Frame Rate
How many frames per second your video will capture. Most cameras have options for multiple frame rates, depending on the resolution you shoot in. For a general video, 24p or 30p is the standard, but more serious filmmakers may need a higher frame rate for creative effect.
60 p
30 p
Time-Lapse Built In
A built in time-lapse mode will allow continuous shooting throughout a prolonged period of time to be compressed into a sped up video.
Video File Format
Different cameras can record in various video file formats. The File format you record in can impact how you edit and use the files.

Pentax K-3 Mark III vs Sony a7 III Features and Benefits

The Pentax K-3 Mark III wins the feature comparison with a score of 87/100, while the Sony a7 III scores 81/100. Both cameras share some common specifications, such as touchscreen capabilities, Wi-Fi, and Bluetooth connectivity. Neither camera has GPS functionality.

The Pentax K-3 Mark III outperforms the Sony a7 III in terms of screen size and resolution. With a 3.2-inch screen and a resolution of 1,620,000 dots, the Pentax K-3 Mark III provides a larger and sharper display for users. This contributes to a better user experience when reviewing images and navigating the camera’s menus.

The Sony a7 III, on the other hand, offers a flip screen, which the Pentax K-3 Mark III lacks. This feature makes it easier for photographers to capture images from various angles and positions. The flip screen also comes in handy for vlogging and self-portraits. However, the Sony a7 III’s screen is smaller at 3 inches and has a lower resolution of 921,600 dots, compared to the Pentax K-3 Mark III.

Considering these points, the Pentax K-3 Mark III is the superior camera when it comes to screen size and resolution, providing a better overall user experience. The Sony a7 III’s flip screen is a useful feature for certain shooting situations, but its smaller size and lower resolution make it less appealing compared to the Pentax K-3 Mark III. Ultimately, the choice between the two cameras depends on the individual needs and preferences of the photographer.

Built-in Flash
A built-in flash will often be positioned right above the lens. This will automatically pop up when you activate it.
External Flash
External flashes are often connected through a hot shoe at the top of a camera, or a cable at the side of the camera.
GPS features in a camera will include location metadata to each of your photographs.
Weather Sealing
Weather sealing capabilities will give you more confidence when shooting in unfavourable conditions.
Screen Type
Touch Screen
Touchscreen allows you to change camera settings and access menus with a swipe of your finger, instead of using buttons.
Screen Size
Screen Resolution
Screen dots indicate the resolution of the LCD screen by including each sub pixel.
1,620,000 dots
921,600 dots
Flip Screen
A flip screen (or articulating screen) is a second screen which can flip out from the side or top of the camera. This rotating screen allows you more freedom to take photos at different angles.
Live View
Live View feature allows you to see a continuous live video of what is being seen through your lens.
Bluetooth capabilities allow you wireless control of your camera with other external devices.

Pentax K-3 Mark III vs Sony a7 III Storage and Battery

The Pentax K-3 Mark III and the Sony a7 III perform highly in storage and battery. Both cameras possess two memory card slots and accept SD/SDHC/SDXC cards. However, the Sony a7 III also accepts Memory Stick Duo/Pro Duo/Pro-HG Duo cards.

The Pentax K-3 Mark III offers superior battery life, providing 800 shots per charge with its D-LI90 battery type. The Sony a7 III falls slightly behind with 750 shots per charge using the NP-FZ100 battery. Both models support USB charging.

Storage and Battery
Storage and Battery
Memory Card
SD / SDHC / SDXC (1 slot is UHS-II compatible)
SD / SDHC / SDXC, Memory Stick Duo / Pro Duo / Pro-HG Duo
Dual Memory Card Slots
Battery Type
Battery Life
Approximately how long this cameras battery will last measured by how many photographs you will be able to take.
800 shots
750 shots
USB Charging
Sensor scores tested by DXOMARK
Overall Score
DXOMARK overall sensor score.
Portrait (Color Depth)
As described by DXOMARK 'The Portrait score in our camera sensor reviews defines color depth performance and its unit is a number of bits. A color depth of 22 bits is excellent; differences below 1 bit are barely noticeable.'
25.1 bits
Landscape (Dynamic Range)
As described by DXOMARK 'The Landscape score in our camera sensor tests defines the maximum dynamic range of the camera sensor and its unit is an exposure value (EV). A value of 12 EV is excellent with differences below 0.5 EV usually not noticeable.'
14.7 EVs
Sports (Low-Light ISO)
Described by DXOMARK as 'The maximal value of ISO sensitivity needed to reach a given value of Signal-to-Noise Ratio (SNR). The greater the value, the better'
Main Features
Extra Features
Construction and Durability
Handling and Ergonomics
Value for Money
Total Score

Alternatives to the Pentax K-3 Mark III and Sony a7 III

Pentax K-3 Mark III vs Sony a7 III Comparison image.

Are you still undecided about which camera is right for you? Have a look at these popular comparisons that feature the Pentax K-3 Mark III or the Sony a7 III:

User Scores
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