Sony Alpha 7 vs. Sony Alpha SLT-A99
Comparison
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| Sony Alpha 7 | Sony Alpha SLT-A99 | ||||
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Megapixels
24.30
24.30
Max. image resolution
6000 x 4000
6000 x 4000
Sensor
Sensor type
CMOS
CMOS
Sensor size
35.8 x 23.9 mm
35.8 x 23.8 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 »
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 »
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| Sony Alpha 7 | Sony Alpha SLT-A99 | |
Surface area:
| 855.62 mm² | vs | 852.04 mm² |
Difference: 3.58 mm² (0.4%)
Alpha 7 sensor is slightly bigger than Alpha SLT-A99 sensor (only 0.4% difference).
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.
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.
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.
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: 0 µm² (0%)
Sony Alpha 7 and Sony Alpha SLT-A99 have the same pixel area.
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.
Higher pixel density means smaller pixels and lower pixel density means larger pixels.
To learn about the accuracy of these numbers,
click here.
Specs
Sony Alpha 7
Sony Alpha SLT-A99
Total megapixels
24.70
24.70
Effective megapixels
24.30
24.30
Optical zoom
Digital zoom
Yes
No
ISO sensitivity
100, 200, 400, 800, 1600, 3200, 6400, 12800, 25600
Auto, 100, 200, 400, 800, 1600, 3200, 6400, 12800, 25600
RAW
Manual focus
Normal focus range
Macro focus range
Focal length (35mm equiv.)
Aperture priority
Yes
Yes
Max. aperture
Metering
Multi, Center-weighted, Spot
Multi, Center-weighted, Spot
Exposure compensation
±5 EV (in 1/3 EV, 1/2 EV steps)
±5 EV (in 1/3 EV, 1/2 EV steps)
Shutter priority
Yes
Yes
Min. shutter speed
30 sec
30 sec
Max. shutter speed
1/8000 sec
1/8000 sec
Built-in flash
External flash
Viewfinder
Electronic
Electronic
White balance presets
10
8
Screen size
3"
3"
Screen resolution
921,600 dots
1,229,000 dots
Video capture
Max. video resolution
Storage types
SD/SDHC/SDXC, Memory Stick Duo/Pro Duo/Pro-HG Duo
Memory Stick PRO Duo/Pro-HG Duo; SD, SDHC and SDXC
USB
USB 2.0 (480 Mbit/sec)
USB 2.0 (480 Mbit/sec)
HDMI
Wireless
GPS
Battery
NP-FW50 lithium-ion battery
Lithium-Ion NP-FM500H rechargeable battery
Weight
474 g
812 g
Dimensions
127 x 94 x 48 mm
147 x 111 x 78 mm
Year
2013
2012
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Diagonal
Diagonal is calculated by the use of Pythagorean theorem:
where w = sensor width and h = sensor height
| Diagonal = √ | w² + h² |
Sony Alpha 7 diagonal
w = 35.80 mm
h = 23.90 mm
h = 23.90 mm
| Diagonal = √ | 35.80² + 23.90² | = 43.04 mm |
Sony Alpha SLT-A99 diagonal
w = 35.80 mm
h = 23.80 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.
Alpha 7 sensor area
Width = 35.80 mm
Height = 23.90 mm
Surface area = 35.80 × 23.90 = 855.62 mm²
Height = 23.90 mm
Surface area = 35.80 × 23.90 = 855.62 mm²
Alpha SLT-A99 sensor area
Width = 35.80 mm
Height = 23.80 mm
Surface area = 35.80 × 23.80 = 852.04 mm²
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 |
Alpha 7 pixel pitch
Sensor width = 35.80 mm
Sensor resolution width = 6038 pixels
Sensor resolution width = 6038 pixels
| Pixel pitch = | 35.80 | × 1000 | = 5.93 µm |
| 6038 |
Alpha SLT-A99 pixel pitch
Sensor width = 35.80 mm
Sensor resolution width = 6038 pixels
Sensor resolution width = 6038 pixels
| Pixel pitch = | 35.80 | × 1000 | = 5.93 µm |
| 6038 |
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 |
Alpha 7 pixel area
Pixel pitch = 5.93 µm
Pixel area = 5.93² = 35.16 µm²
Pixel area = 5.93² = 35.16 µm²
Alpha SLT-A99 pixel area
Pixel pitch = 5.93 µm
Pixel area = 5.93² = 35.16 µm²
Pixel area = 5.93² = 35.16 µm²
Pixel density
Pixel density can be calculated with the following formula:
One could also use this 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 7 pixel density
Sensor resolution width = 6038 pixels
Sensor width = 3.58 cm
Pixel density = (6038 / 3.58)² / 1000000 = 2.84 MP/cm²
Sensor width = 3.58 cm
Pixel density = (6038 / 3.58)² / 1000000 = 2.84 MP/cm²
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 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:
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
Alpha 7 sensor resolution
Sensor width = 35.80 mm
Sensor height = 23.90 mm
Effective megapixels = 24.30
Resolution horizontal: X × r = 4025 × 1.5 = 6038
Resolution vertical: X = 4025
Sensor resolution = 6038 x 4025
Sensor height = 23.90 mm
Effective megapixels = 24.30
| r = 35.80/23.90 = 1.5 |
|
Resolution vertical: X = 4025
Sensor resolution = 6038 x 4025
Alpha SLT-A99 sensor resolution
Sensor width = 35.80 mm
Sensor height = 23.80 mm
Effective megapixels = 24.30
Resolution horizontal: X × r = 4025 × 1.5 = 6038
Resolution vertical: X = 4025
Sensor resolution = 6038 x 4025
Sensor height = 23.80 mm
Effective megapixels = 24.30
| r = 35.80/23.80 = 1.5 |
|
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 |
Alpha 7 crop factor
Sensor diagonal in mm = 43.04 mm
| Crop factor = | 43.27 | = 1.01 |
| 43.04 |
Alpha SLT-A99 crop factor
Sensor diagonal in mm = 42.99 mm
| Crop factor = | 43.27 | = 1.01 |
| 42.99 |
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 7 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 7, take the aperture of the lens
you're using and multiply it with crop factor.
Crop factor for Sony Alpha 7 is 1.01
Crop factor for Sony Alpha 7 is 1.01
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
Crop factor for Sony Alpha SLT-A99 is 1.01
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.