Pentax K-1 vs. Pentax 645Z

Comparison

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K-1 image
vs
645Z image
Pentax K-1 Pentax 645Z
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Megapixels
36.40
51.40
Max. image resolution
7360 x 4912
8256 x 6192

Sensor

Sensor type
CMOS
CMOS
Sensor size
35.9 x 24 mm
44 x 33 mm
Sensor resolution
7389 x 4926
8269 x 6217
Diagonal
43.18 mm
55.00 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 : 1.69
(ratio)
Pentax K-1 Pentax 645Z
Surface area:
861.60 mm² vs 1452.00 mm²
Difference: 590.4 mm² (69%)
645Z sensor is approx. 1.69x bigger than K-1 sensor.
Note: You are comparing cameras of different generations. There is a 2 year gap between Pentax K-1 (2016) and Pentax 645Z (2014). All things being equal, newer sensor generations generally outperform the older.
Pixel pitch
4.86 µm
5.32 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: 0.46 µm (9%)
Pixel pitch of 645Z is approx. 9% higher than pixel pitch of K-1.
Pixel area
23.62 µm²
28.3 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: 4.68 µm² (20%)
A pixel on Pentax 645Z sensor is approx. 20% bigger than a pixel on Pentax K-1.
Pixel density
4.24 MP/cm²
3.53 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: 0.71 µm (20%)
Pentax K-1 has approx. 20% higher pixel density than Pentax 645Z.
To learn about the accuracy of these numbers, click here.



Specs

Pentax K-1
Pentax 645Z
Crop factor
1
0.79
Total megapixels
36.77
52.99
Effective megapixels
36.40
51.40
Optical zoom
 
Digital zoom
ISO sensitivity
Auto, 100-204800
Auto, 100-204800
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, 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
1/8000 sec
1/4000 sec
Built-in flash
External flash
Viewfinder
Optical (pentaprism)
Optical (pentaprism)
White balance presets
8
10
Screen size
3.2"
3.2"
Screen resolution
1,036,800 dots
1,037,000 dots
Video capture
Max. video resolution
1920x1080 (60i/50i/30p/25p/24p)
1920x1080 (60i/50i/30p/25p/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-LI90 lithium-ion battery
Rechargeable Lithium-ion Battery D-LI90
Weight
1010 g
1550 g
Dimensions
136.5 x 110 x 85.5 mm
156 x 117 x 123 mm
Year
2016
2014




Choose cameras to compare

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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 K-1 diagonal

w = 35.90 mm
h = 24.00 mm
Diagonal =  35.90² + 24.00²   = 43.18 mm

Pentax 645Z diagonal

w = 44.00 mm
h = 33.00 mm
Diagonal =  44.00² + 33.00²   = 55.00 mm


Surface area

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

K-1 sensor area

Width = 35.90 mm
Height = 24.00 mm

Surface area = 35.90 × 24.00 = 861.60 mm²

645Z sensor area

Width = 44.00 mm
Height = 33.00 mm

Surface area = 44.00 × 33.00 = 1452.00 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

K-1 pixel pitch

Sensor width = 35.90 mm
Sensor resolution width = 7389 pixels
Pixel pitch =   35.90  × 1000  = 4.86 µm
7389

645Z pixel pitch

Sensor width = 44.00 mm
Sensor resolution width = 8269 pixels
Pixel pitch =   44.00  × 1000  = 5.32 µm
8269


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

K-1 pixel area

Pixel pitch = 4.86 µm

Pixel area = 4.86² = 23.62 µm²

645Z pixel area

Pixel pitch = 5.32 µm

Pixel area = 5.32² = 28.3 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

K-1 pixel density

Sensor resolution width = 7389 pixels
Sensor width = 3.59 cm

Pixel density = (7389 / 3.59)² / 1000000 = 4.24 MP/cm²

645Z pixel density

Sensor resolution width = 8269 pixels
Sensor width = 4.4 cm

Pixel density = (8269 / 4.4)² / 1000000 = 3.53 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

K-1 sensor resolution

Sensor width = 35.90 mm
Sensor height = 24.00 mm
Effective megapixels = 36.40
r = 35.90/24.00 = 1.5
X =  36.40 × 1000000  = 4926
1.5
Resolution horizontal: X × r = 4926 × 1.5 = 7389
Resolution vertical: X = 4926

Sensor resolution = 7389 x 4926

645Z sensor resolution

Sensor width = 44.00 mm
Sensor height = 33.00 mm
Effective megapixels = 51.40
r = 44.00/33.00 = 1.33
X =  51.40 × 1000000  = 6217
1.33
Resolution horizontal: X × r = 6217 × 1.33 = 8269
Resolution vertical: X = 6217

Sensor resolution = 8269 x 6217


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


K-1 crop factor

Sensor diagonal in mm = 43.18 mm
Crop factor =   43.27  = 1
43.18

645Z crop factor

Sensor diagonal in mm = 55.00 mm
Crop factor =   43.27  = 0.79
55.00

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).

K-1 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-1, take the aperture of the lens you're using and multiply it with crop factor.

Since crop factor for Pentax K-1 is 1, the equivalent aperture is aperture.

645Z 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 645Z, take the aperture of the lens you're using and multiply it with crop factor.

Crop factor for Pentax 645Z is 0.79

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