The Pentax K-S1 is 2 mm narrower, 23.4 mm taller, 35.2 mm deeper and 189 g heavier than the Olympus PEN E-P3.
| Olympus PEN E-P3 | Pentax K-S1 | |
|---|---|---|
| Size (W × H × D) | 122 × 69.1 × 34.3 mm | 120 × 92.5 × 69.5 mm |
| Weight | 369 g | 558 g |
| Lens | Micro Four Thirds | Pentax K |
| Sensor | Four Thirds | — |
| Announced | 2011 | 2014 |