Olympus OM-D E-M1 vs. Sony Alpha 7

Comparison

OM-D E-M1 image
vs.
Alpha 7 image

Comparison

Olympus OM-D E-M1 Sony Alpha 7
Megapixels
16.30 24.30
Max. resolution
4608 x 3456 6000 x 4000
Price
Amazon, B&H Photo, Adorama Amazon, B&H Photo, Adorama

Sensor

Sensor type
CMOS CMOS
Sensor size
Four Thirds (17.3 x 13 mm) 35.8 x 23.9 mm
Sensor resolution
4656 x 3501  6038 x 4025 
Diagonal
21.64 mm  43.04 mm 
Surface area
224.90 mm²  855.62 mm² 
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 sizes:
Olympus OM-D E-M1
vs.
Sony Alpha 7
 
Surface area:
Olympus OM-D E-M1
Sony Alpha 7
Difference: 630.72 mm² (280%)
Sony Alpha 7 has approx. 280% more surface area than Olympus OM-D E-M1.
Pixel pitch
3.72 µm  5.93 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.
Pixel pitch
Olympus OM-D E-M1
Sony Alpha 7
Difference: 2.21 µm (59%)
Pixel pitch of Sony Alpha 7 is approx. 59% higher than pixel pitch of Olympus OM-D E-M1.
Pixel area
13.84 µm²  35.16 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:
Olympus OM-D E-M1
vs.
Sony Alpha 7
Pixel area difference: 21.32 µm² (154%)
A pixel on Sony Alpha 7 sensor is approx. 154% bigger than a pixel on Olympus OM-D E-M1.
Pixel density
7.24 MP/cm²  2.84 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.
Pixel density
Olympus OM-D E-M1
Sony Alpha 7
Difference: 4.4 MP/cm² (155%)
Olympus OM-D E-M1 has approx. 155% higher pixel density than Sony Alpha 7.
To learn about the accuracy of these numbers, click here.

Other specifications

Crop factor
1.01 
Total megapixels
16.80 24.70
Effective megapixels
16.30 24.30
Optical zoom
n/a n/a
Digital zoom
Yes Yes
Iso
100 - 25600 100, 200, 400, 800, 1600, 3200, 6400, 12800, 25600
Auto focus
Yes Yes
Manual focus
Yes Yes
Normal focus range
n/a n/a
Macro focus range
n/a n/a
Focal length (35mm equiv.)
n/a n/a
Aperture priority
Yes Yes
Aperture
n/a n/a
Aperture (35mm equiv.)
n/a  n/a 
Metering
Multi, Center-weighted, Spot Multi, Center-weighted, Spot
Exposure compensation
±5 EV (in 1/3, 1/2, 1 EV steps) ±5 (at 1/3 EV, 1/2 EV steps)
Shutter priority
Yes Yes
Min. shutter speed
60 sec 30 sec
Max. shutter speed
1/8000 sec 1/8000 sec
Flash modes
Auto, Red-eye, Fill-in, Off, Slow sync.(1st curtain), Manual n/a
Built-in flash
No No
External flash
Yes Yes
Viewfinder
Electronic Electronic
White balance presets
7 10
LCD display
Yes Yes
LCD size
3" 3"
LCD resolution
1,037,000 921,600
Min. image resolution
640 x 480 3008 x 2000
Selftimer
Yes Yes
Storage types
SD/SDHC/SDXC SD/SDHC/SDXC, Memory Stick Duo/Pro Duo/Pro-HG Duo
USB
USB 2.0 (480 Mbit/sec) USB 2.0 Hi-speed
Batteries
BLN-1 Li-ion NP-FW50 lithium-ion battery
Weight
497 g 474 g
Dimensions
130.4 x 93.5 x 63.1 mm 127 x 94 x 48 mm
Year
2013 2013



Compare other cameras

Popular comparisons:

Choose other cameras to compare:



comments powered by Disqus

Diagonal

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

Olympus OM-D E-M1 diagonal

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

Sony Alpha 7 diagonal

w = 35.80 mm
h = 23.90 mm
Diagonal =  35.80² + 23.90²   = 43.04 mm


Surface area

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

Olympus OM-D E-M1 surface area

Width = 17.30 mm
Height = 13.00 mm

Surface area = 17.30 × 13.00 = 224.90 mm²

Sony Alpha 7 surface area

Width = 35.80 mm
Height = 23.90 mm

Surface area = 35.80 × 23.90 = 855.62 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

Olympus OM-D E-M1 pixel pitch

Sensor width = 17.30 mm
Sensor resolution width = 4656 pixels
Pixel pitch =   17.30  × 1000  = 3.72 µm
4656

Sony Alpha 7 pixel pitch

Sensor width = 35.80 mm
Sensor resolution width = 6038 pixels
Pixel pitch =   35.80  × 1000  = 5.93 µm
6038


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

Olympus OM-D E-M1 pixel area

Pixel pitch = 3.72 µm

Pixel area = 3.72² = 13.84 µm²

Sony Alpha 7 pixel area

Pixel pitch = 5.93 µm

Pixel area = 5.93² = 35.16 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

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

Olympus OM-D E-M1 pixel density

Sensor resolution width = 4656 pixels
Sensor width = 1.73 cm

Pixel density = (4656 / 1.73)² / 1000000 = 7.24 MP/cm²

Sony Alpha 7 pixel density

Sensor resolution width = 6038 pixels
Sensor width = 3.58 cm

Pixel density = (6038 / 3.58)² / 1000000 = 2.84 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. 22.8 × 15.5 sensor for example has a ratio of 1.47.

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

Olympus OM-D E-M1 sensor resolution

Sensor width = 17.30 mm
Sensor height = 13.00 mm
Effective megapixels = 16.30
r = 17.30/13.00 = 1.33
X =  16.30 × 1000000  = 3501
1.33
Resolution horizontal: X × r = 3501 × 1.33 = 4656
Resolution vertical: X = 3501

Sensor resolution = 4656 x 3501

Sony Alpha 7 sensor resolution

Sensor width = 35.80 mm
Sensor height = 23.90 mm
Effective megapixels = 24.30
r = 35.80/23.90 = 1.5
X =  24.30 × 1000000  = 4025
1.5
Resolution horizontal: X × r = 4025 × 1.5 = 6038
Resolution vertical: X = 4025

Sensor resolution = 6038 x 4025


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


Olympus OM-D E-M1 crop factor

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

Sony Alpha 7 crop factor

Sensor diagonal in mm = 43.04 mm
Crop factor =   43.27  = 1.01
43.04

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).

Olympus OM-D E-M1 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 Olympus OM-D E-M1, take the aperture of the lens you're using and multiply it with crop factor.

Crop factor for Olympus OM-D E-M1 is 2

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

Crop factor for Sony Alpha 7 is 1.01


All trademarks and product names are property of their respective owners. User comments are not the responsibility of digicamdb.com.