Sony SLT-A33 vs. Sony SLT-A77

Comparison

SLT-A33 image
vs.
SLT-A77 image

 

Sony SLT-A33 Sony SLT-A77
Megapixels
14.20 24.30
Max. resolution
4592 x 3056 6000 x 4000
Price
Amazon, B&H Photo, Adorama Amazon, B&H Photo, Adorama

Sensor

Sensor type
CMOS CMOS
Sensor size
23.5 x 15.6 mm 23.5 x 15.6 mm
Sensor resolution
4631 x 3067  6058 x 4012 
Diagonal
28.21 mm  28.21 mm 
Surface area
366.60 mm²  366.60 mm² 
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 sizes:
Sony SLT-A33
vs.
Sony SLT-A77
 
Surface area:
Sony SLT-A33
Sony SLT-A77
Difference: 0 mm² (0%)
Sony SLT-A33 and Sony SLT-A77 have the same surface area.
Pixel pitch
5.07 µm  3.88 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.
Pixel pitch
Sony SLT-A33
Sony SLT-A77
Difference: 1.19 µm (31%)
Pixel pitch of Sony SLT-A33 is approx. 31% higher than pixel pitch of Sony SLT-A77.
Pixel area
25.7 µm²  15.05 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:
Sony SLT-A33
vs.
Sony SLT-A77
Pixel area difference: 10.65 µm² (71%)
A pixel on Sony SLT-A33 sensor is approx. 71% bigger than a pixel on Sony SLT-A77.
Pixel density
3.88 MP/cm²  6.65 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.
Pixel density
Sony SLT-A33
Sony SLT-A77
Difference: 2.77 MP/cm² (71%)
Sony SLT-A77 has approx. 71% higher pixel density than Sony SLT-A33.
To learn about the accuracy of these numbers, click here.

Other specifications

Crop factor
1.53  1.53 
Total megapixels
14.60 24.70
Effective megapixels
14.20 24.30
Optical zoom
n/a n/a
Digital zoom
No No
Iso
Auto, 100, 200, 400, 800, 1600, 3200, 6400, 12800, 25600 with boost) Auto, 100, 200, 400, 800, 1600, 3200, 6400, 12800, 16000
Auto focus
Yes Yes
Manual focus
Yes Yes
Normal focus range
n/a n/a
Macro focus range
n/a n/a
Focal length (35mm equiv.)
n/a n/a
Aperture priority
Yes Yes
Aperture
n/a n/a
Aperture (35mm equiv.)
n/a  n/a 
Metering
Multi, Center-weighted, Spot Multi, Center-weighted, Spot
Exposure compensation
±2 EV (at 1/3 EV steps) ±5 EV (at 1/3 EV, 1/2 EV steps)
Shutter priority
Yes Yes
Min. shutter speed
30 sec 30 sec
Max. shutter speed
1/4000 sec 1/8000 sec
Flash modes
Auto, On, Off, Red-Eye, Slow Sync, High Speed Sync, Rear Curtain Auto, On, Off, Red-Eye, Slow Sync, High Speed Sync, Rear Curtain, Fill-in, Wireless
Built-in flash
Yes Yes
External flash
Yes Yes
Viewfinder
Electronic Electronic
White balance presets
6 8
LCD display
Yes Yes
LCD size
3" 3"
LCD resolution
921,000 921,000
Min. image resolution
2288 x 1280 3008 x 1688
Selftimer
Yes Yes
Storage types
SD/SDHC/SDXC/Memory Stick Pro Duo/ Pro-HG Duo SD/SDHC/SDXC/Memory Stick Pro Duo/ Pro-HG Duo
USB
USB 2.0 (480 Mbit/sec) USB 2.0 (480 Mbit/sec)
Batteries
Rechargeable NP-FW50 battery & charger Rechargeable NP-FM500H battery & charger
Weight
500g 732g
Dimensions
124x92x85 mm 143x104x81 mm
Year
2010 2011



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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 SLT-A33 diagonal

w = 23.50 mm
h = 15.60 mm
Diagonal =  23.50² + 15.60²   = 28.21 mm

Sony SLT-A77 diagonal

w = 23.50 mm
h = 15.60 mm
Diagonal =  23.50² + 15.60²   = 28.21 mm


Surface area

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

Sony SLT-A33 surface area

Width = 23.50 mm
Height = 15.60 mm

Surface area = 23.50 × 15.60 = 366.60 mm²

Sony SLT-A77 surface area

Width = 23.50 mm
Height = 15.60 mm

Surface area = 23.50 × 15.60 = 366.60 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 SLT-A33 pixel pitch

Sensor width = 23.50 mm
Sensor resolution width = 4631 pixels
Pixel pitch =   23.50  × 1000  = 5.07 µm
4631

Sony SLT-A77 pixel pitch

Sensor width = 23.50 mm
Sensor resolution width = 6058 pixels
Pixel pitch =   23.50  × 1000  = 3.88 µm
6058


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 SLT-A33 pixel area

Pixel pitch = 5.07 µm

Pixel area = 5.07² = 25.7 µm²

Sony SLT-A77 pixel area

Pixel pitch = 3.88 µm

Pixel area = 3.88² = 15.05 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 SLT-A33 pixel density

Sensor resolution width = 4631 pixels
Sensor width = 2.35 cm

Pixel density = (4631 / 2.35)² / 1000000 = 3.88 MP/cm²

Sony SLT-A77 pixel density

Sensor resolution width = 6058 pixels
Sensor width = 2.35 cm

Pixel density = (6058 / 2.35)² / 1000000 = 6.65 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. 22.8 × 15.5 sensor for example has a ratio of 1.47.

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

Sony SLT-A33 sensor resolution

Sensor width = 23.50 mm
Sensor height = 15.60 mm
Effective megapixels = 14.20
r = 23.50/15.60 = 1.51
X =  14.20 × 1000000  = 3067
1.51
Resolution horizontal: X × r = 3067 × 1.51 = 4631
Resolution vertical: X = 3067

Sensor resolution = 4631 x 3067

Sony SLT-A77 sensor resolution

Sensor width = 23.50 mm
Sensor height = 15.60 mm
Effective megapixels = 24.30
r = 23.50/15.60 = 1.51
X =  24.30 × 1000000  = 4012
1.51
Resolution horizontal: X × r = 4012 × 1.51 = 6058
Resolution vertical: X = 4012

Sensor resolution = 6058 x 4012


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 SLT-A33 crop factor

Sensor diagonal in mm = 28.21 mm
Crop factor =   43.27  = 1.53
28.21

Sony SLT-A77 crop factor

Sensor diagonal in mm = 28.21 mm
Crop factor =   43.27  = 1.53
28.21

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 SLT-A33 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 SLT-A33, take the aperture of the lens you're using and multiply it with crop factor.

Crop factor for Sony SLT-A33 is 1.53

Sony SLT-A77 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 SLT-A77, take the aperture of the lens you're using and multiply it with crop factor.

Crop factor for Sony SLT-A77 is 1.53


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