The Olympus PEN E-PL9 is 2.9 mm narrower, 24.5 mm shorter, 30.5 mm thinner and 178 g lighter than the Pentax K-S1.
| Pentax K-S1 | Olympus PEN E-PL9 | |
|---|---|---|
| Size (W × H × D) | 120 × 92.5 × 69.5 mm | 117.1 × 68 × 39 mm |
| Weight | 558 g | 380 g |
| Lens | Pentax K | Micro Four Thirds |
| Sensor | — | Four Thirds |
| Announced | 2014 | 2018 |