Sony A580 has a
16.0MP APS-C (23.5 x 15.6 mm ) sized CMOS sensor and features Bionz processor. On the other hand, Sony A77 has a
24.0MP APS-C (23.5 x 15.6 mm ) sized CMOS sensor and features Bionz processor.
Sony A77's sensor provides 8MP more than Sony A580's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Below you can see the A580 and A77 sensor size comparison.
Sensor Size and Resolution Comparison image of Sony A580 and Sony A77 Cameras
Sony A580 and Sony A77 have the same sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture. On the other hand, since Sony A580 has 49% larger pixel area compared to Sony A77, it has potential to collect more light on pixel level hence have less noise in low light / High ISO images.
DxOMark Sensor Scores
Both Sony A580 and Sony A77 sensors have been tested by DxoMark. DxoMark scores camera sensors for color depth (DXO Portrait), dynamic range (DXO Landscape) and low-light sensitivity (DXO Sports), and also gives them an overall score. Of the two cameras that we are comparing, A580 has scored 80, 2 points higher than A77.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Sony A580
80
23.8 bits
13.3 Evs
1121 ISO
Sony A77
78
24.0 bits
13.2 Evs
801 ISO
Sensor size sets the circle of confusion, so it drives how much depth of field each
of these bodies gives you at a given aperture. You can calculate it exactly for the
Sony A580
or the
Sony A77 ,
including hyperfocal distance.
