The OM System OM-1 Mark II and OM-3, line by line from OM System's spec pages: the same 20.4MP stacked sensor and AF, a different viewfinder, stabilization, burst speed, card slots and weight.
The OM System OM-1 Mark II (announced January 2024) and the OM-3 (announced February 2025) are built on the same 20.4MP stacked sensor and TruePic X processor. This post lists what OM System's spec pages give as the same on both, and every line where they differ.
This is a field note, not a rumor, so it has no OR rating. Every figure comes from OM System's own spec pages: the English product pages and the more detailed Japanese spec pages. Where those pages disagree with each other, the last section says so. Prices are left out, and so is any verdict.
The same on both
- Sensor: 4/3-type stacked back-illuminated Live MOS, 20.4MP effective
- Processor: TruePic X
- Autofocus: 1,053-point cross-type phase detection plus contrast AF. The same AI subject detection: people, cars and motorcycles, aircraft and helicopters, trains, birds, dogs and cats
- Rear screen: 3.0-inch vari-angle touch screen, 1.62M dots
- Shutter speeds: 1/8000 s mechanical, 1/32000 s electronic. Flash sync 1/250 s
- ISO: LOW (about 80) to 102400
- Electronic bursts: about 20 fps; about 50 fps with AF and AE tracking (SH2, listed lenses only); about 120 fps with focus and exposure fixed at the first frame (SH1). Pro Capture offers the same three speeds
- High Res Shot: tripod mode up to an 80MP-equivalent file, handheld up to 50MP-equivalent
- Live GND: ND2, ND4 and ND8, with soft, medium and hard filter types
- Video: C4K and 4K up to 60p, Full HD up to 60p, Full HD high-speed movies up to 240 fps, H.264 and H.265. 12-bit 4K and C4K RAW output over HDMI
- Weather sealing: IP53 with an IP53 lens (IPX1 with an IPX1 lens), freezeproof to -10°C
- Power: BLX-1 battery, charging in the camera over USB, USB PD power
- Ports: USB-C (USB 3.0), micro HDMI (Type D), 3.5 mm microphone and headphone jacks
- Color Creator: on both (listed on the Japanese spec pages)
Where they differ
OM-1 Mark II first, OM-3 second.
- Viewfinder: OLED, 5.76M dots, about 1.48x to 1.65x magnification, 21 mm eyepoint vs OLED, 2.36M dots, about 1.23x to 1.37x, 27 mm eyepoint
- Stabilization, body only: up to 8.5 stops (12-40mm F2.8 PRO II at 40mm) vs up to 6.5 stops in the center and 5.5 at the edges (12-45mm F4.0 PRO at 45mm)
- Stabilization, Sync IS: up to 8.5 stops (150-400mm F4.5 TC1.25x IS PRO at 150mm) vs up to 7.5 in the center and 6.5 at the edges (12-100mm F4.0 IS PRO at 100mm)
- Mechanical burst: about 10 fps vs about 6 fps
- Anti-shock burst: about 10 fps vs about 5.5 fps
- Live ND: up to ND128 vs up to ND64
- Card slots: two SD slots (UHS-II) vs one SD slot (UHS-II)
- Shutter rated for: 400,000 shots vs 100,000 shots (English spec pages; the Japanese pages do not list it)
- Color Profile Control and Monochrome Profile Control: not on the spec pages vs yes
- Video picture modes: Flat, OM-Log400, HLG vs the same plus OM-Cinema1 and OM-Cinema2
- Bluetooth: Low Energy 4.2 vs 5.2
- Wi-Fi: IEEE 802.11a/b/g/n/ac vs IEEE 802.11b/g/n
- Remote: 2.5 mm remote jack (RM-CB2 cable), works with the RM-WR1 remote vs no remote jack, RM-WR2 wireless remote only
- Battery life (CIPA): about 500 shots, 1,010 in quick sleep mode vs about 590, 1,040 in quick sleep mode (Japanese spec pages)
- Size (W × H × D): 134.8 × 91.6 × 72.7 mm vs 139.3 × 88.9 × 45.8 mm
- Weight with battery and card: 599 g vs 496 g
- Weight, body only: 511 g vs 413 g
- USB-AC adapter in the box: F-7AC (not in Europe and the Middle East) vs not included
A note on the stabilization figures: OM System rates the OM-3 under CIPA 2024 and gives separate center and edge numbers. The OM-1 Mark II pages give one number per case and use different test lenses, so the two sets were not measured the same way.
Where OM System's own pages disagree
- OM-1 Mark II width: 134.8 mm on the international spec summary and the Japanese spec page, 138.8 mm in the full spec lists on the US and UK pages. Height and depth match. The list above uses 134.8 mm.
- OM-1 Mark II battery life: about 500 shots (1,010 in quick sleep mode) on the Japanese spec page, 520 (1,100) on the US and UK pages.
- OM-1 Mark II stabilization: the summary at the top of the US page says up to 8 stops. Its full spec list, the UK and international pages and the Japanese page say 8.5.
- OM-3 flash sync socket: the US and UK spec lists include one. The Japanese spec page lists only the hot shoe as the flash terminal.
Sources
Both cameras take M.Zuiko lenses. The current lens line, copied from OM System's chart: M.Zuiko lens roadmap.
Source: OM System's spec pages for the OM-1 Mark II and OM-3 (US, international and Japan)
- OM-1 Mark II
- OM-3
- OM-1 vs OM-3
- Specs
Field note. Not a rumor, so it carries no rating.