Sigma SD15
Specs
Sensor info
Sigma SD15 comes with a
20.7 x 13.8 mm Foveon sensor, which has a diagonal of
24.88 mm (0.98") and a surface area of
285.66 mm².
Note: Sigma SD15 uses Foveon X3 sensor, which 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.
If you want to know about the accuracy of these numbers,
click here.
Actual sensor size
Note: Actual size is set to screen → change »
This is the actual size of the SD15 sensor: 20.7 x 13.8 mm
The sensor has a surface area of 285.7 mm².
There are approx. 4,700,000 photosites (pixels) on this area.
Pixel pitch, which is a measure of the distance between pixels, is 7.8 µm.
Pixel pitch tells you the distance from the center of one pixel (photosite) to the center of the next.
Pixel or photosite area is 60.84 µm². The larger the photosite, the more light it can capture and the more information can be recorded.
Pixel density tells you how many million pixels fit or would fit in one square cm of the sensor. Sigma SD15 has a pixel density of 1.65 MP/cm².
These numbers are important in terms of assessing the overall quality of a digital camera. Generally, the bigger (and newer) the sensor, pixel pitch and photosite area, and the smaller the pixel density, the better the camera. If you want to see how SD15 compares to other cameras, click here.
Pixel or photosite area is 60.84 µm². The larger the photosite, the more light it can capture and the more information can be recorded.
Pixel density tells you how many million pixels fit or would fit in one square cm of the sensor. Sigma SD15 has a pixel density of 1.65 MP/cm².
These numbers are important in terms of assessing the overall quality of a digital camera. Generally, the bigger (and newer) the sensor, pixel pitch and photosite area, and the smaller the pixel density, the better the camera. If you want to see how SD15 compares to other cameras, click here.
Specifications
Brand:  Sigma 
Model:  SD15 
Effective megapixels:  4.70 
Total megapixels:  4.70 
Sensor size:  20.7 x 13.8 mm 
Sensor type:  Foveon 
Sensor resolution:  2655 x 1770 
Max. image resolution:  2640 x 1760 x 3 
Crop factor:  1.74 
Optical zoom:  
Digital zoom:  No 
ISO:  Auto, 100, 200, 400, 800, 1600, 3200 
RAW support:  
Manual focus:  
Normal focus range:  
Macro focus range:  
Focal length (35mm equiv.):  
Aperture priority:  Yes 
Max aperture:  
Max. aperture (35mm equiv.):  n/a 
Depth of field:  simulate → 
Metering:  Centerweighted average, Centre weighted, Evaluative, Spot 
Exposure Compensation:  ±3 EV (in 1/3 EV steps) 
Shutter priority:  Yes 
Min. shutter speed:  B+30 sec 
Max. shutter speed:  1/4000 sec 
Builtin flash:  
External flash:  
Viewfinder:  Optical (pentaprism) 
White balance presets:  8 
Screen size:  3" 
Screen resolution:  460,000 dots 
Video capture:  
Storage types:  SDHC, Secure Digital 
USB:  USB 2.0 (480 Mbit/sec) 
HDMI:  
Wireless:  
GPS:  
Battery:  LithiumIon rechargeable battery 
Weight:  750 g 
Dimensions:  144 x 107.3 x 80.5 mm 
Year:  2010 
Compare SD15 with another camera
Popular comparisons:
 Sigma SD15 vs. Sigma SD1 Merrill
 Sigma SD15 vs. Sigma SD1
 Sigma SD15 vs. Nikon D800
 Sigma SD15 vs. Nikon D7000
 Sigma SD15 vs. Sigma SD14
 Sigma SD15 vs. Nikon D7100
 Sigma SD15 vs. Sigma DP3 Merrill
 Sigma SD15 vs. Nikon D5100
 Sigma SD15 vs. Canon EOS Rebel T3i
 Sigma SD15 vs. Canon EOS 30D
 Sigma SD15 vs. Nikon D3200
Diagonal
Diagonal is calculated by the use of Pythagorean theorem:
where w = sensor width and h = sensor height
Diagonal = √  w² + h² 
Sigma SD15 diagonal:
w = 20.70 mm
h = 13.80 mm
h = 13.80 mm
Diagonal = √  20.70² + 13.80²  = 24.88 mm 
Surface area
Surface area is calculated by multiplying the width and the height of a sensor.
Width = 20.70 mm
Height = 13.80 mm
Surface area = 20.70 × 13.80 = 285.66 mm²
Width = 20.70 mm
Height = 13.80 mm
Surface area = 20.70 × 13.80 = 285.66 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 
Sigma SD15 pixel pitch:
Sensor width = 20.70 mm
Sensor resolution width = 2655 pixels
Sensor resolution width = 2655 pixels
Pixel pitch =  20.70  × 1000  = 7.8 µm 
2655 
Pixel area
The area of one pixel can be calculated by simply squaring the pixel pitch:
You could also divide sensor surface area with effective megapixels:
Pixel area = pixel pitch²
You could also divide sensor surface area with effective megapixels:
Pixel area =  sensor surface area in mm² 
effective megapixels 
Sigma SD15 pixel area:
Pixel pitch = 7.8 µm
Pixel area = 7.8² = 60.84 µm²
Pixel area = 7.8² = 60.84 µm²
Pixel density
Pixel density can be calculated with the following formula:
You could also use this 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 
Sigma SD15 pixel density:
Sensor resolution width = 2655 pixels
Sensor width = 2.07 cm
Pixel density = (2655 / 2.07)² / 1000000 = 1.65 MP/cm²
Sensor width = 2.07 cm
Pixel density = (2655 / 2.07)² / 1000000 = 1.65 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:
3. To get sensor resolution we then multiply X with the corresponding ratio:
Resolution horizontal: X × r
Resolution vertical: X
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 → 

Resolution horizontal: X × r
Resolution vertical: X
Sigma SD15 sensor resolution:
Sensor width = 20.70 mm
Sensor height = 13.80 mm
Effective megapixels = 4.70
Resolution horizontal: X × r = 1770 × 1.5 = 2655
Resolution vertical: X = 1770
Sensor resolution = 2655 x 1770
Sensor height = 13.80 mm
Effective megapixels = 4.70
r = 20.70/13.80 = 1.5 

Resolution vertical: X = 1770
Sensor resolution = 2655 x 1770
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 
Sigma SD15 crop factor:
Sensor diagonal = 24.88 mm
Crop factor =  43.27  = 1.74 
24.88 
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).
Sigma SD15 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 SD15, take the aperture of the lens
you're using and multiply it with crop factor.
Crop factor for Sigma SD15 is 1.74
Crop factor for Sigma SD15 is 1.74
Enter your screen size (diagonal)
My screen size is
inches
Actual size is currently adjusted to screen.
If your screen (phone, tablet, or monitor) is not in diagonal, then the actual size of a sensor won't be shown correctly.
If your screen (phone, tablet, or monitor) is not in diagonal, then the actual size of a sensor won't be shown correctly.