Pentax KF vs. Pentax K-3 Mark III

Comparison

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KF image
vs
K-3 Mark III image
Pentax KF Pentax K-3 Mark III
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Megapixels
24.24
25.73
Max. image resolution
6000 x 4000
6192 x 4128

Sensor

Sensor type
CMOS
CMOS
Sensor size
23.5 x 15.6 mm
23.3 x 15.5 mm
Sensor resolution
6051 x 4007
6213 x 4142
Diagonal
28.21 mm
27.98 mm
Sensor size comparison
Sensor size is generally a good indicator of the quality of the camera. Sensors can vary greatly in size. As a general rule, the bigger the sensor, the better the image quality.

Bigger sensors are more effective because they have more surface area to capture light. An important factor when comparing digital cameras is also camera generation. Generally, newer sensors will outperform the older.

Learn more about sensor sizes »

Actual sensor size

Note: Actual size is set to screen → change »
vs
1.02 : 1
(ratio)
Pentax KF Pentax K-3 Mark III
Surface area:
366.60 mm² vs 361.15 mm²
Difference: 5.45 mm² (2%)
KF sensor is slightly bigger than K-3 Mark III sensor (only 2% difference).
Pixel pitch
3.88 µm
3.75 µm
Pixel pitch tells you the distance from the center of one pixel (photosite) to the center of the next. It tells you how close the pixels are to each other.

The bigger the pixel pitch, the further apart they are and the bigger each pixel is. Bigger pixels tend to have better signal to noise ratio and greater dynamic range.
Difference: 0.13 µm (3%)
Pixel pitch of KF is approx. 3% higher than pixel pitch of K-3 Mark III.
Pixel area
15.05 µm²
14.06 µm²
Pixel or photosite area affects how much light per pixel can be gathered. The larger it is the more light can be collected by a single pixel.

Larger pixels have the potential to collect more photons, resulting in greater dynamic range, while smaller pixels provide higher resolutions (more detail) for a given sensor size.
Relative pixel sizes:
vs
Pixel area difference: 0.99 µm² (7%)
A pixel on Pentax KF sensor is approx. 7% bigger than a pixel on Pentax K-3 Mark III.
Pixel density
6.63 MP/cm²
7.11 MP/cm²
Pixel density tells you how many million pixels fit or would fit in one square cm of the sensor.

Higher pixel density means smaller pixels and lower pixel density means larger pixels.
Difference: 0.48 µm (7%)
Pentax K-3 Mark III has approx. 7% higher pixel density than Pentax KF.
To learn about the accuracy of these numbers, click here.



Specs

Pentax KF
Pentax K-3 Mark III
Crop factor
1.53
1.55
Total megapixels
24.78
26.78
Effective megapixels
24.24
25.73
Optical zoom
 
Digital zoom
Yes
ISO sensitivity
Auto, 100-102400
Auto (100-1600000)
RAW
Manual focus
Normal focus range
Macro focus range
Focal length (35mm equiv.)
Aperture priority
Yes
Yes
Max. aperture
Max. aperture (35mm equiv.)
n/a
n/a
Metering
Multi, Center-weighted, Spot
Multi, Center-weighted, Highlight-weighted, Spot
Exposure compensation
±5 EV (in 1/3 EV, 1/2 EV steps)
±5 EV (in 1/3 EV, 1/2 EV steps)
Shutter priority
Yes
Yes
Min. shutter speed
30 sec
30 sec
Max. shutter speed
1/6000 sec
1/8000 sec
Built-in flash
External flash
Viewfinder
Optical (pentaprism)
Optical (pentaprism)
White balance presets
8
8
Screen size
3"
3.2"
Screen resolution
1,037,000 dots
1,620,000 dots
Video capture
Max. video resolution
1920x1080 (60i/50i/30p/25p/24p)
3840x2160 (30p/​24p)
Storage types
SD/SDHC/SDXC (UHS-I)
SD/SDHC/SDXC
USB
USB 2.0 (480 Mbit/sec)
USB 3.0 (5 GBit/sec)
HDMI
Wireless
GPS
Battery
D-LI109 lithium-ion battery
D-LI90 Lithium-ion battery
Weight
684 g
820 g
Dimensions
125.5 x 93 x 74 mm
134.5 x 103.5 x 73.5 mm
Year
2022
2021




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Diagonal

Diagonal is calculated by the use of Pythagorean theorem:
Diagonal =  w² + h²
where w = sensor width and h = sensor height

Pentax KF diagonal

w = 23.50 mm
h = 15.60 mm
Diagonal =  23.50² + 15.60²   = 28.21 mm

Pentax K-3 Mark III diagonal

w = 23.30 mm
h = 15.50 mm
Diagonal =  23.30² + 15.50²   = 27.98 mm


Surface area

Surface area is calculated by multiplying the width and the height of a sensor.

KF sensor area

Width = 23.50 mm
Height = 15.60 mm

Surface area = 23.50 × 15.60 = 366.60 mm²

K-3 Mark III sensor area

Width = 23.30 mm
Height = 15.50 mm

Surface area = 23.30 × 15.50 = 361.15 mm²


Pixel pitch

Pixel pitch is the distance from the center of one pixel to the center of the next measured in micrometers (µm). It can be calculated with the following formula:
Pixel pitch =   sensor width in mm  × 1000
sensor resolution width in pixels

KF pixel pitch

Sensor width = 23.50 mm
Sensor resolution width = 6051 pixels
Pixel pitch =   23.50  × 1000  = 3.88 µm
6051

K-3 Mark III pixel pitch

Sensor width = 23.30 mm
Sensor resolution width = 6213 pixels
Pixel pitch =   23.30  × 1000  = 3.75 µm
6213


Pixel area

The area of one pixel can be calculated by simply squaring the pixel pitch:
Pixel area = pixel pitch²

You could also divide sensor surface area with effective megapixels:
Pixel area =   sensor surface area in mm²
effective megapixels

KF pixel area

Pixel pitch = 3.88 µm

Pixel area = 3.88² = 15.05 µm²

K-3 Mark III pixel area

Pixel pitch = 3.75 µm

Pixel area = 3.75² = 14.06 µm²


Pixel density

Pixel density can be calculated with the following formula:
Pixel density =  ( sensor resolution width in pixels )² / 1000000
sensor width in cm

One could also use this formula:
Pixel density =   effective megapixels × 1000000  / 10000
sensor surface area in mm²

KF pixel density

Sensor resolution width = 6051 pixels
Sensor width = 2.35 cm

Pixel density = (6051 / 2.35)² / 1000000 = 6.63 MP/cm²

K-3 Mark III pixel density

Sensor resolution width = 6213 pixels
Sensor width = 2.33 cm

Pixel density = (6213 / 2.33)² / 1000000 = 7.11 MP/cm²


Sensor resolution

Sensor resolution is calculated from sensor size and effective megapixels. It's slightly higher than maximum (not interpolated) image resolution which is usually stated on camera specifications. Sensor resolution is used in pixel pitch, pixel area, and pixel density formula. For sake of simplicity, we're going to calculate it in 3 stages.

1. First we need to find the ratio between horizontal and vertical length by dividing the former with the latter (aspect ratio). It's usually 1.33 (4:3) or 1.5 (3:2), but not always.

2. With the ratio (r) known we can calculate the X from the formula below, where X is a vertical number of pixels:
(X × r) × X = effective megapixels × 1000000    →   
X =  effective megapixels × 1000000
r
3. To get sensor resolution we then multiply X with the corresponding ratio:

Resolution horizontal: X × r
Resolution vertical: X

KF sensor resolution

Sensor width = 23.50 mm
Sensor height = 15.60 mm
Effective megapixels = 24.24
r = 23.50/15.60 = 1.51
X =  24.24 × 1000000  = 4007
1.51
Resolution horizontal: X × r = 4007 × 1.51 = 6051
Resolution vertical: X = 4007

Sensor resolution = 6051 x 4007

K-3 Mark III sensor resolution

Sensor width = 23.30 mm
Sensor height = 15.50 mm
Effective megapixels = 25.73
r = 23.30/15.50 = 1.5
X =  25.73 × 1000000  = 4142
1.5
Resolution horizontal: X × r = 4142 × 1.5 = 6213
Resolution vertical: X = 4142

Sensor resolution = 6213 x 4142


Crop factor

Crop factor or focal length multiplier is calculated by dividing the diagonal of 35 mm film (43.27 mm) with the diagonal of the sensor.
Crop factor =   43.27 mm
sensor diagonal in mm


KF crop factor

Sensor diagonal in mm = 28.21 mm
Crop factor =   43.27  = 1.53
28.21

K-3 Mark III crop factor

Sensor diagonal in mm = 27.98 mm
Crop factor =   43.27  = 1.55
27.98

35 mm equivalent aperture

Equivalent aperture (in 135 film terms) is calculated by multiplying lens aperture with crop factor (a.k.a. focal length multiplier).

KF equivalent aperture

Aperture is a lens characteristic, so it's calculated only for fixed lens cameras. If you want to know the equivalent aperture for Pentax KF, take the aperture of the lens you're using and multiply it with crop factor.

Crop factor for Pentax KF is 1.53

K-3 Mark III equivalent aperture

Aperture is a lens characteristic, so it's calculated only for fixed lens cameras. If you want to know the equivalent aperture for Pentax K-3 Mark III, take the aperture of the lens you're using and multiply it with crop factor.

Crop factor for Pentax K-3 Mark III is 1.55

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