Sigma SD1 vs. Canon EOS 7D

Comparison

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SD1 image
vs
EOS 7D image
Sigma SD1 Canon EOS 7D
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Megapixels
15.40
18.00
Max. image resolution
4800 x 3200 x 3
5184 x 3456
Note: Sigma SD1 uses Foveon X3 image sensor, which is a new type of sensor that has 3 layers of photoelements stacked together in 1 pixel location. Traditional CCD/CMOS sensors have 1 pixel for 1 color, whereas Foveon sensor captures all 3 colors (blue, green, and red) at every pixel.

Sensor

Sensor type
Foveon
CMOS
Sensor size
24 x 16 mm
22.3 x 14.9 mm
Sensor resolution
4806 x 3204
5196 x 3464
Diagonal
28.84 mm
26.82 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
1.16 : 1
(ratio)
Sigma SD1 Canon EOS 7D
Surface area:
384.00 mm² vs 332.27 mm²
Difference: 51.73 mm² (16%)
SD1 sensor is approx. 1.16x bigger than 7D sensor.
Pixel pitch
4.99 µm
4.29 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: 0.7 µm (16%)
Pixel pitch of SD1 is approx. 16% higher than pixel pitch of 7D.
Pixel area
24.9 µm²
18.4 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: 6.5 µm² (35%)
A pixel on Sigma SD1 sensor is approx. 35% bigger than a pixel on Canon 7D.
Pixel density
4.01 MP/cm²
5.43 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: 1.42 µm (35%)
Canon 7D has approx. 35% higher pixel density than Sigma SD1.
To learn about the accuracy of these numbers, click here.

Specs

Sigma SD1
Canon 7D
Crop factor
1.5
1.61
Total megapixels
15.40
19.00
Effective megapixels
15.40
18.00
Optical zoom
Digital zoom
No
ISO sensitivity
Auto
Auto, 100, 200, 400, 800, 1600, 3200, 6400, (12800 with boost)
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, Average
Centre weighted, Evaluative, Spot, Spot-AF
Exposure compensation
±3 EV (in 1/3 EV steps)
±5 EV (in 1/3 EV, 1/2 EV steps)
Shutter priority
Yes
Yes
Min. shutter speed
15 sec
30 sec
Max. shutter speed
1/2000 sec
1/8000 sec
Built-in flash
External flash
Viewfinder
Optical (pentaprism)
Optical (pentaprism)
White balance presets
6
6
Screen size
3"
3"
Screen resolution
460,000 dots
920,000 dots
Video capture
Max. video resolution
1920x1080 (30p/25p/24p)
Storage types
Compact Flash (Type I, UDMA compatible)
CompactFlash type I, CompactFlash type II, Microdrive
USB
USB 2.0 (480 Mbit/sec)
USB 2.0 (480 Mbit/sec)
HDMI
Wireless
GPS
Battery
Lithium-Ion rechargeable battery
Lithium-Ion LP-E6 rechargeable battery
Weight
280 g
860 g
Dimensions
145.5 x 112.5 x 80.0 mm
148.2 x 110 x 73.5 mm
Year
2010
2009



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vs

Diagonal

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

Sigma SD1 diagonal

w = 24.00 mm
h = 16.00 mm
Diagonal =  24.00² + 16.00²   = 28.84 mm

Canon 7D diagonal

w = 22.30 mm
h = 14.90 mm
Diagonal =  22.30² + 14.90²   = 26.82 mm


Surface area

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

SD1 sensor area

Width = 24.00 mm
Height = 16.00 mm

Surface area = 24.00 × 16.00 = 384.00 mm²

7D sensor area

Width = 22.30 mm
Height = 14.90 mm

Surface area = 22.30 × 14.90 = 332.27 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

SD1 pixel pitch

Sensor width = 24.00 mm
Sensor resolution width = 4806 pixels
Pixel pitch =   24.00  × 1000  = 4.99 µm
4806

7D pixel pitch

Sensor width = 22.30 mm
Sensor resolution width = 5196 pixels
Pixel pitch =   22.30  × 1000  = 4.29 µm
5196


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

SD1 pixel area

Pixel pitch = 4.99 µm

Pixel area = 4.99² = 24.9 µm²

7D pixel area

Pixel pitch = 4.29 µm

Pixel area = 4.29² = 18.4 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

SD1 pixel density

Sensor resolution width = 4806 pixels
Sensor width = 2.4 cm

Pixel density = (4806 / 2.4)² / 1000000 = 4.01 MP/cm²

7D pixel density

Sensor resolution width = 5196 pixels
Sensor width = 2.23 cm

Pixel density = (5196 / 2.23)² / 1000000 = 5.43 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

SD1 sensor resolution

Sensor width = 24.00 mm
Sensor height = 16.00 mm
Effective megapixels = 15.40
r = 24.00/16.00 = 1.5
X =  15.40 × 1000000  = 3204
1.5
Resolution horizontal: X × r = 3204 × 1.5 = 4806
Resolution vertical: X = 3204

Sensor resolution = 4806 x 3204

7D sensor resolution

Sensor width = 22.30 mm
Sensor height = 14.90 mm
Effective megapixels = 18.00
r = 22.30/14.90 = 1.5
X =  18.00 × 1000000  = 3464
1.5
Resolution horizontal: X × r = 3464 × 1.5 = 5196
Resolution vertical: X = 3464

Sensor resolution = 5196 x 3464


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


SD1 crop factor

Sensor diagonal in mm = 28.84 mm
Crop factor =   43.27  = 1.5
28.84

7D crop factor

Sensor diagonal in mm = 26.82 mm
Crop factor =   43.27  = 1.61
26.82

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).

SD1 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 Sigma SD1, take the aperture of the lens you're using and multiply it with crop factor.

Crop factor for Sigma SD1 is 1.5

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

Crop factor for Canon 7D is 1.61

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