So, how is it compared to others? Of course, you can measurbate endlessly with their "Compare Cameras" Tool. But for quick reference for all readers here, I tabulate the results of some of the current popular models of APS-C DSLRs, of different brands in the market, as below, ranked by the overall DxOMark (Highest Mark First):-
| Make & Model | DxOMark (Overall Mark for Measuring Image Quality of the RAW file) | Dynamic Range (in EV Steps) | Highest Low Light ISO Speed (Maximum Tolerance Limit for the Same DxO Reference Standard) |
| Nikon D90 | 72.6 | 12.5 | 977 |
| Nikon D5000 | 72 | 12.5 | 868 |
| Nikon D300s | 69.8 | 12.2 | 787 |
| Sony A380 | 67.4 | 11.8 | 614 |
| Sony A550 | 65.8 | 11.8 | 807 |
| Sony A350 | 65.4 | 11.5 | 595 |
| Canon 7D | 64.9 | 11.7 | 809 |
| Pentax K-m | 63.5 | 11.4 | 513 |
| Canon 500D | 62.5 | 11.5 | 663 |
| Nikon D3000 | 62.4 | 11.1 | 563 |
| Pentax K-7 | 61 | 10.6 | 536 |
Of course, if you are to compare Full Frame models, they will give much better results and hence higher marks. The same logic applies to 4/3 and m4/3 half-frame models, which have lower marks. So, the sensor size is just the determinative factor here. And, it proves once again that packing more pixels a smaller APS-C sensor makes no sense!
Furthermore, it can be noted that newer camera models usually should produce better results than the olders, especially when they have the same pixel count or using the same (series of) sensor, but there are some exceptions occasionally, the K-7 is unfortunately the case, of which all the test scores and IQ performances are all worst and inferior than its Predecessor, the K20D! :-( (But that exactly what I have been talking about since the first K-7 samples appeared on the net and after I measurbated it myself, also.)
Read Also:-
Why the IQ of the K-7 (Sensor) could be Worse than That of the K20D?