Sony Alpha SLT-A99


Brand: Sony
Model: Alpha SLT-A99
Megapixels: 24.30
Sensor: 35.8 x 23.8 mm
Price: check here »

Sensor info

Sony Alpha SLT-A99 comes with a 35.8 x 23.8 mm CMOS sensor, which has a diagonal of 42.99 mm (1.69") and a surface area of 852.04 mm².
42.99 mm
Surface area
852 mm²
Pixel pitch
5.93 µm
Pixel area
35.16 µm²
Pixel density
2.84 MP/cm²
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 Alpha SLT-A99 sensor: 35.8 x 23.8 mm
The sensor has a surface area of 852 mm². There are approx. 24,300,000 photosites (pixels) on this area. Pixel pitch, which is a measure of the distance between pixels, is 5.93 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 35.16 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. Sony Alpha SLT-A99 has a pixel density of 2.84 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 Alpha SLT-A99 compares to other cameras, click here.


Brand: Sony
Model: Alpha SLT-A99
Effective megapixels: 24.30
Total megapixels: 24.70
Sensor size: 35.8 x 23.8 mm
Sensor type: CMOS
Sensor resolution: 6038 x 4025
Max. image resolution: 6000 x 4000
Crop factor: 1.01
Optical zoom:
Digital zoom: No
ISO: Auto, 100, 200, 400, 800, 1600, 3200, 6400, 12800, 25600
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: Multi, Center-weighted, Spot
Exposure Compensation: ±5 EV (in 1/3 EV, 1/2 EV steps)
Shutter priority: Yes
Min. shutter speed: 30 sec
Max. shutter speed: 1/8000 sec
Built-in flash:
External flash:
Viewfinder: Electronic
White balance presets: 8
Screen size: 3"
Screen resolution: 1,229,000 dots
Video capture:
Storage types: Memory Stick PRO Duo/Pro-HG Duo; SD, SDHC and SDXC
USB: USB 2.0 (480 Mbit/sec)
Battery: Lithium-Ion NP-FM500H rechargeable battery
Weight: 812 g
Dimensions: 147 x 111 x 78 mm
Year: 2012

Compare Alpha SLT-A99 with another camera



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

Sony Alpha SLT-A99 diagonal:

w = 35.80 mm
h = 23.80 mm
Diagonal =  35.80² + 23.80²   = 42.99 mm

Surface area

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

Width = 35.80 mm
Height = 23.80 mm

Surface area = 35.80 × 23.80 = 852.04 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

Sony Alpha SLT-A99 pixel pitch:

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

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

Sony Alpha SLT-A99 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

Sony Alpha SLT-A99 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.

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
3. To get sensor resolution we then multiply X with the corresponding ratio:

Resolution horizontal: X × r
Resolution vertical: X

Sony Alpha SLT-A99 sensor resolution:

Sensor width = 35.80 mm
Sensor height = 23.80 mm
Effective megapixels = 24.30
r = 35.80/23.80 = 1.5
X =  24.30 × 1000000  = 4025
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

Sony Alpha SLT-A99 crop factor:

Sensor diagonal = 42.99 mm
Crop factor =   43.27  = 1.01

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).

Sony Alpha SLT-A99 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 SLT-A99, take the aperture of the lens you're using and multiply it with crop factor.

Crop factor for Sony Alpha SLT-A99 is 1.01

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