Sony A77 has a
24.0MP APS-C (23.5 x 15.6 mm ) sized CMOS sensor and features Bionz processor. On the other hand, Nikon D90 has a
12.0MP APS-C (23.6 x 15.8 mm ) sized CMOS sensor .
Sony A77's sensor provides 12MP more than Nikon D90'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 A77 and D90 sensor size comparison.
Sony A77 and Nikon D90 have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the same focal length and aperture.
DxOMark Sensor Scores
Both Sony A77 and Nikon D90 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, A77 has scored 78, 5 points higher than D90.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Sony A77 |
78 |
24.0 bits |
13.2 Evs |
801 ISO |
Nikon D90 |
73 |
22.7 bits |
12.5 Evs |
977 ISO |