Sony Alpha 7S vs. Panasonic Lumix DMC-GH4

Comparison

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Alpha 7S image
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Lumix DMC-GH4 image
Sony Alpha 7S Panasonic Lumix DMC-GH4
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Megapixels
12.20
16.05
Max. image resolution
4240 x 2832
4608 x 3456

Sensor

Sensor type
CMOS
CMOS
Sensor size
35.6 x 23.8 mm
Four Thirds (17.3 x 13 mm)
Sensor resolution
4278 x 2852
4620 x 3474
Diagonal
42.82 mm
21.64 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
3.77 : 1
(ratio)
Sony Alpha 7S Panasonic Lumix DMC-GH4
Surface area:
847.28 mm² vs 224.90 mm²
Difference: 622.38 mm² (277%)
Alpha 7S sensor is approx. 3.77x bigger than GH4 sensor.
Pixel pitch
8.32 µm
3.74 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: 4.58 µm (122%)
Pixel pitch of Alpha 7S is approx. 122% higher than pixel pitch of GH4.
Pixel area
69.22 µm²
13.99 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: 55.23 µm² (395%)
A pixel on Sony Alpha 7S sensor is approx. 395% bigger than a pixel on Panasonic GH4.
Pixel density
1.44 MP/cm²
7.13 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: 5.69 µm (395%)
Panasonic GH4 has approx. 395% higher pixel density than Sony Alpha 7S.
To learn about the accuracy of these numbers, click here.



Specs

Sony Alpha 7S
Panasonic GH4
Crop factor
1.01
2
Total megapixels
12.40
17.20
Effective megapixels
12.20
16.05
Optical zoom
Digital zoom
Yes
Yes
ISO sensitivity
Auto, 100 - 102,400 (expandable to 50 - 409,600)
Auto, 200-25600
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 steps)
Shutter priority
Yes
Yes
Min. shutter speed
30 sec
60 sec
Max. shutter speed
1/8000 sec
1/8000 sec
Built-in flash
External flash
Viewfinder
Electronic
Electronic
White balance presets
10
5
Screen size
3"
3"
Screen resolution
921,600 dots
1,036,000 dots
Video capture
Max. video resolution
1920x1080 (60p/60i/50p/50i/30p/25p/24p)
4096x2160 (24p)
Storage types
SD/SDHC/SDXC, Memory Stick Duo/Pro Duo/Pro-HG Duo
SD/SDHC/SDXC
USB
USB 2.0 (480 Mbit/sec)
USB 2.0 (480 Mbit/sec)
HDMI
Wireless
GPS
Battery
Rechargeable battery pack NP-FW50
Li-ion Battery Pack
Weight
489 g
560 g
Dimensions
126.9 x 94.4 x 48.2 mm
132.9 x 93.4 x 83.9 mm
Year
2014
2014




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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

Sony Alpha 7S diagonal

w = 35.60 mm
h = 23.80 mm
Diagonal =  35.60² + 23.80²   = 42.82 mm

Panasonic GH4 diagonal

w = 17.30 mm
h = 13.00 mm
Diagonal =  17.30² + 13.00²   = 21.64 mm


Surface area

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

Alpha 7S sensor area

Width = 35.60 mm
Height = 23.80 mm

Surface area = 35.60 × 23.80 = 847.28 mm²

GH4 sensor area

Width = 17.30 mm
Height = 13.00 mm

Surface area = 17.30 × 13.00 = 224.90 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

Alpha 7S pixel pitch

Sensor width = 35.60 mm
Sensor resolution width = 4278 pixels
Pixel pitch =   35.60  × 1000  = 8.32 µm
4278

GH4 pixel pitch

Sensor width = 17.30 mm
Sensor resolution width = 4620 pixels
Pixel pitch =   17.30  × 1000  = 3.74 µm
4620


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

Alpha 7S pixel area

Pixel pitch = 8.32 µm

Pixel area = 8.32² = 69.22 µm²

GH4 pixel area

Pixel pitch = 3.74 µm

Pixel area = 3.74² = 13.99 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

Alpha 7S pixel density

Sensor resolution width = 4278 pixels
Sensor width = 3.56 cm

Pixel density = (4278 / 3.56)² / 1000000 = 1.44 MP/cm²

GH4 pixel density

Sensor resolution width = 4620 pixels
Sensor width = 1.73 cm

Pixel density = (4620 / 1.73)² / 1000000 = 7.13 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

Alpha 7S sensor resolution

Sensor width = 35.60 mm
Sensor height = 23.80 mm
Effective megapixels = 12.20
r = 35.60/23.80 = 1.5
X =  12.20 × 1000000  = 2852
1.5
Resolution horizontal: X × r = 2852 × 1.5 = 4278
Resolution vertical: X = 2852

Sensor resolution = 4278 x 2852

GH4 sensor resolution

Sensor width = 17.30 mm
Sensor height = 13.00 mm
Effective megapixels = 16.05
r = 17.30/13.00 = 1.33
X =  16.05 × 1000000  = 3474
1.33
Resolution horizontal: X × r = 3474 × 1.33 = 4620
Resolution vertical: X = 3474

Sensor resolution = 4620 x 3474


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


Alpha 7S crop factor

Sensor diagonal in mm = 42.82 mm
Crop factor =   43.27  = 1.01
42.82

GH4 crop factor

Sensor diagonal in mm = 21.64 mm
Crop factor =   43.27  = 2
21.64

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).

Alpha 7S 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 Sony Alpha 7S, take the aperture of the lens you're using and multiply it with crop factor.

Crop factor for Sony Alpha 7S is 1.01

GH4 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 Panasonic GH4, take the aperture of the lens you're using and multiply it with crop factor.

Crop factor for Panasonic GH4 is 2

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