Sony Alpha a9 II vs. Canon EOS 40D

Comparison

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Alpha a9 II image
vs
EOS 40D image
Sony Alpha a9 II Canon EOS 40D
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Megapixels
24.20
10.10
Max. image resolution
6000 x 4000
3888 x 2592

Sensor

Sensor type
CMOS
CMOS
Sensor size
35.6 x 23.8 mm
22.2 x 14.8 mm
Sensor resolution
6026 x 4017
3893 x 2595
Diagonal
42.82 mm
26.68 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
2.58 : 1
(ratio)
Sony Alpha a9 II Canon EOS 40D
Surface area:
847.28 mm² vs 328.56 mm²
Difference: 518.72 mm² (158%)
Alpha a9 II sensor is approx. 2.58x bigger than 40D sensor.
Note: You are comparing sensors of vastly different generations. There is a gap of 12 years between Sony Alpha a9 II (2019) and Canon 40D (2007). Twelve years is a huge amount of time, technology wise, resulting in newer sensor being much more efficient than the older one.
Pixel pitch
5.91 µm
5.7 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: 0.21 µm (4%)
Pixel pitch of Alpha a9 II is approx. 4% higher than pixel pitch of 40D.
Pixel area
34.93 µm²
32.49 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: 2.44 µm² (8%)
A pixel on Sony Alpha a9 II sensor is approx. 8% bigger than a pixel on Canon 40D.
Pixel density
2.87 MP/cm²
3.08 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: 0.21 µm (7%)
Canon 40D has approx. 7% higher pixel density than Sony Alpha a9 II.
To learn about the accuracy of these numbers, click here.



Specs

Sony Alpha a9 II
Canon 40D
Crop factor
1.01
1.62
Total megapixels
28.30
10.50
Effective megapixels
24.20
10.10
Optical zoom
 
Digital zoom
Yes
No
ISO sensitivity
Auto, 100-51200 (expandable to 50-204800)
Auto, 100, 200, 400, 800, 1600, 3200 (H)
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, Highlight-weighted, Average, Spot
Multi, Center-weighted, Spot
Exposure compensation
±5 EV (in 1/3 EV, 1/2 EV steps)
±2 EV (in 1/3 EV, 1/2 EV steps)
Shutter priority
Yes
Yes
Min. shutter speed
30 sec
30 sec
Max. shutter speed
1/32000 sec
1/8000 sec
Built-in flash
External flash
Viewfinder
Electronic
Optical (pentaprism)
White balance presets
9
6
Screen size
3"
3"
Screen resolution
1,440,000 dots
230,000 dots
Video capture
Max. video resolution
3840x2160 (30p/​25p/​24p)
Storage types
SD/SDHC/SDXC
Compact Flash (Type I or II)
USB
USB 3.0 (5 GBit/sec)
USB 2.0 (480 Mbit/sec)
HDMI
Wireless
GPS
Battery
NP-FZ100 lithium-ion battery
Canon Lithium-Ion
Weight
678 g
822 g
Dimensions
128.9 x 96.4 x 77.5 mm
146 x 108 x 74 mm
Year
2019
2007




Choose cameras to compare

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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 a9 II diagonal

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

Canon 40D diagonal

w = 22.20 mm
h = 14.80 mm
Diagonal =  22.20² + 14.80²   = 26.68 mm


Surface area

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

Alpha a9 II sensor area

Width = 35.60 mm
Height = 23.80 mm

Surface area = 35.60 × 23.80 = 847.28 mm²

40D sensor area

Width = 22.20 mm
Height = 14.80 mm

Surface area = 22.20 × 14.80 = 328.56 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 a9 II pixel pitch

Sensor width = 35.60 mm
Sensor resolution width = 6026 pixels
Pixel pitch =   35.60  × 1000  = 5.91 µm
6026

40D pixel pitch

Sensor width = 22.20 mm
Sensor resolution width = 3893 pixels
Pixel pitch =   22.20  × 1000  = 5.7 µm
3893


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 a9 II pixel area

Pixel pitch = 5.91 µm

Pixel area = 5.91² = 34.93 µm²

40D pixel area

Pixel pitch = 5.7 µm

Pixel area = 5.7² = 32.49 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 a9 II pixel density

Sensor resolution width = 6026 pixels
Sensor width = 3.56 cm

Pixel density = (6026 / 3.56)² / 1000000 = 2.87 MP/cm²

40D pixel density

Sensor resolution width = 3893 pixels
Sensor width = 2.22 cm

Pixel density = (3893 / 2.22)² / 1000000 = 3.08 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 a9 II sensor resolution

Sensor width = 35.60 mm
Sensor height = 23.80 mm
Effective megapixels = 24.20
r = 35.60/23.80 = 1.5
X =  24.20 × 1000000  = 4017
1.5
Resolution horizontal: X × r = 4017 × 1.5 = 6026
Resolution vertical: X = 4017

Sensor resolution = 6026 x 4017

40D sensor resolution

Sensor width = 22.20 mm
Sensor height = 14.80 mm
Effective megapixels = 10.10
r = 22.20/14.80 = 1.5
X =  10.10 × 1000000  = 2595
1.5
Resolution horizontal: X × r = 2595 × 1.5 = 3893
Resolution vertical: X = 2595

Sensor resolution = 3893 x 2595


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 a9 II crop factor

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

40D crop factor

Sensor diagonal in mm = 26.68 mm
Crop factor =   43.27  = 1.62
26.68

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 a9 II 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 a9 II, take the aperture of the lens you're using and multiply it with crop factor.

Crop factor for Sony Alpha a9 II is 1.01

40D 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 40D, take the aperture of the lens you're using and multiply it with crop factor.

Crop factor for Canon 40D is 1.62

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