Panasonic Lumix DMC-G1 vs. Sony Alpha DSLR-A390

Comparison

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Lumix DMC-G1 image
vs
Alpha DSLR-A390 image
Panasonic Lumix DMC-G1 Sony Alpha DSLR-A390
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Megapixels
12.10
14.20
Max. image resolution
4000 x 3000
4592 x 3056

Sensor

Sensor type
CMOS
CCD
Sensor size
Four Thirds (17.3 x 13 mm)
23.5 x 15.7 mm
Sensor resolution
4011 x 3016
4616 x 3077
Diagonal
21.64 mm
28.26 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

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vs
1 : 1.64
(ratio)
Panasonic Lumix DMC-G1 Sony Alpha DSLR-A390
Surface area:
224.90 mm² vs 368.95 mm²
Difference: 144.05 mm² (64%)
Alpha DSLR-A390 sensor is approx. 1.64x bigger than G1 sensor.
Note: You are comparing cameras of different generations. There is a 2 year gap between Panasonic G1 (2008) and Sony Alpha DSLR-A390 (2010). All things being equal, newer sensor generations generally outperform the older.
Pixel pitch
4.31 µm
5.09 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: 0.78 µm (18%)
Pixel pitch of Alpha DSLR-A390 is approx. 18% higher than pixel pitch of G1.
Pixel area
18.58 µm²
25.91 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: 7.33 µm² (39%)
A pixel on Sony Alpha DSLR-A390 sensor is approx. 39% bigger than a pixel on Panasonic G1.
Pixel density
5.38 MP/cm²
3.86 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: 1.52 µm (39%)
Panasonic G1 has approx. 39% higher pixel density than Sony Alpha DSLR-A390.
To learn about the accuracy of these numbers, click here.

Specs

Panasonic G1
Sony Alpha DSLR-A390
Crop factor
2
1.53
Total megapixels
13.10
14.90
Effective megapixels
12.10
14.20
Optical zoom
Digital zoom
Yes
No
ISO sensitivity
Auto, 100, 200, 400, 800, 1600, 3200
Auto, 100, 200, 400, 800, 1600, 3200
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
Centre weighted, Intelligent Multiple, Spot
Multi, Center-weighted, Spot
Exposure compensation
±3 EV (in 1/3 EV steps)
±2 EV (in 1/3 EV steps)
Shutter priority
Yes
Yes
Min. shutter speed
Bulb+60 sec
30 sec
Max. shutter speed
1/4000 sec
1/4000 sec
Built-in flash
External flash
Viewfinder
Electronic
Optical (pentamirror)
White balance presets
7
6
Screen size
3"
2.7"
Screen resolution
460,000 dots
230,400 dots
Video capture
Max. video resolution
Storage types
MultiMedia, SDHC, Secure Digital
SD/ SDHC, Memory Stick Pro Duo
USB
USB 2.0 (480 Mbit/sec)
USB 2.0 (480 Mbit/sec)
HDMI
Wireless
GPS
Battery
Lithium-Ion rechargeable battery
Lithium-Ion NP-FH50 rechargeable battery
Weight
385 g
549 g
Dimensions
124 x 83.6 x 45.2 mm
128 x 97 x 86 mm
Year
2008
2010



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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

Panasonic G1 diagonal

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

Sony Alpha DSLR-A390 diagonal

w = 23.50 mm
h = 15.70 mm
Diagonal =  23.50² + 15.70²   = 28.26 mm


Surface area

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

G1 sensor area

Width = 17.30 mm
Height = 13.00 mm

Surface area = 17.30 × 13.00 = 224.90 mm²

Alpha DSLR-A390 sensor area

Width = 23.50 mm
Height = 15.70 mm

Surface area = 23.50 × 15.70 = 368.95 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

G1 pixel pitch

Sensor width = 17.30 mm
Sensor resolution width = 4011 pixels
Pixel pitch =   17.30  × 1000  = 4.31 µm
4011

Alpha DSLR-A390 pixel pitch

Sensor width = 23.50 mm
Sensor resolution width = 4616 pixels
Pixel pitch =   23.50  × 1000  = 5.09 µm
4616


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

G1 pixel area

Pixel pitch = 4.31 µm

Pixel area = 4.31² = 18.58 µm²

Alpha DSLR-A390 pixel area

Pixel pitch = 5.09 µm

Pixel area = 5.09² = 25.91 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

G1 pixel density

Sensor resolution width = 4011 pixels
Sensor width = 1.73 cm

Pixel density = (4011 / 1.73)² / 1000000 = 5.38 MP/cm²

Alpha DSLR-A390 pixel density

Sensor resolution width = 4616 pixels
Sensor width = 2.35 cm

Pixel density = (4616 / 2.35)² / 1000000 = 3.86 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

G1 sensor resolution

Sensor width = 17.30 mm
Sensor height = 13.00 mm
Effective megapixels = 12.10
r = 17.30/13.00 = 1.33
X =  12.10 × 1000000  = 3016
1.33
Resolution horizontal: X × r = 3016 × 1.33 = 4011
Resolution vertical: X = 3016

Sensor resolution = 4011 x 3016

Alpha DSLR-A390 sensor resolution

Sensor width = 23.50 mm
Sensor height = 15.70 mm
Effective megapixels = 14.20
r = 23.50/15.70 = 1.5
X =  14.20 × 1000000  = 3077
1.5
Resolution horizontal: X × r = 3077 × 1.5 = 4616
Resolution vertical: X = 3077

Sensor resolution = 4616 x 3077


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


G1 crop factor

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

Alpha DSLR-A390 crop factor

Sensor diagonal in mm = 28.26 mm
Crop factor =   43.27  = 1.53
28.26

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).

G1 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 G1, take the aperture of the lens you're using and multiply it with crop factor.

Crop factor for Panasonic G1 is 2

Alpha DSLR-A390 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 DSLR-A390, take the aperture of the lens you're using and multiply it with crop factor.

Crop factor for Sony Alpha DSLR-A390 is 1.53

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