OM SYSTEM OM-1 Mark I
The Olympus Mark I is a 20.4MP Micro Four Thirds mirrorless camera — with 4K video and in-body stabilization. Used copies start from $1,100 on GearFocus, with buyer protection on every purchase.
OM SYSTEM OM-1 Mark I
Used Olympus Mark I Listings on GearFocus
Camera Overview — Olympus Mark I
Key Features — Olympus Mark I
20.4MP MFT Sensor: Micro Four Thirds format with a 2x crop factor pairs well with a wide range of native lenses for wildlife, sports, and travel photography.
TruePic IX Processor: OM SYSTEM's flagship image processor enables fast readout speeds, computational features, and the high burst rates the OM-1 is known for.
5-Axis In-Body Stabilization: Optical IBIS with up to 7 stops of compensation (8 stops when paired with compatible lenses) keeps handheld shots sharp across stills and video.
20fps Mechanical Burst: Continuous shooting at up to 20fps with the mechanical shutter, with high frame rate options at lower resolutions via electronic shutter.
Quad-Pixel Phase Detection AF: All 20.4 million pixels function as phase-detection points, delivering fast, reliable subject acquisition with eye, face, and animal tracking built in.
4K/60fps Video with OM-Log: Records 4K video at up to 60fps and includes OM-Log and Flat color profiles for greater dynamic range and flexibility in post-production.
Camera Specifications — Olympus Mark I
| Spec | Detail |
|---|---|
| Use Cases | Portrait, Landscape, Travel, Street, Studio |
| Type | Mirrorless |
| Sensor | Micro Four Thirds (MFT) |
| Resolution | 20.4MP |
| Processor | TruePic IX |
| ISO Range | 200 – 25600 |
| AF System | Quad Pixel AF, Eye Detection AF, Face Detection AF, Animal Detection AF, AI-Based Subject Tracking |
| AF Points | 121 |
| Max Photo Resolution | 5184x3888 |
| Burst Rate | 20 fps |
| Max Video Resolution | 4K |
| Max Frame Rate | 60fps |
Description — Olympus Mark I
The OM SYSTEM OM-1 Mark I is a Micro Four Thirds mirrorless camera powered by a 20.4MP sensor and the TruePic IX image processor. It operates across an ISO range of 200 to 25600 and delivers continuous shooting at up to 20fps, supported by a multi-system autofocus setup combining Phase Detection, Contrast Detection, Eye Detection AF, and Face Detection AF across 121 focus points with subject tracking enabled. The 5-Axis In-Body Image Stabilization works at the sensor level without digital processing.
For video, the OM-1 Mark I captures 4K footage at 24fps, 30fps, or 60fps, with OM-Log and Flat color profiles available. The 3-inch LCD display resolves at 1.04M dots, while the electronic viewfinder offers 2.36M dots at a 120fps refresh rate. The magnesium alloy body measures 134 x 91 x 69mm, weighs 599g, and is rated weather sealed.
Storage uses SD, SDHC, and SDXC cards. Connectivity covers Wi-Fi, Bluetooth, USB-C, Micro HDMI, and 3.5mm headphone and microphone jacks. The BLH-1 battery is rated at 440 shots per charge.
Pros — Olympus Mark I
- ✓5-Axis In-Body Image Stabilization provides optical steadiness (imageStabilization.type: '5-Axis In-Body Stabilization')
- ✓Fast 20fps burst mode suits action and wildlife shooting (photoSpecs.maxBurstFrameRate: 20)
- ✓Comprehensive autofocus with Phase Detection, Contrast Detection, Eye Detection, Face Detection, and subject tracking (autofocus.system)
Cons — Olympus Mark I
- ✗ISO minimum of 200 is higher than some competitors, limiting dynamic range headroom in bright conditions (iso.min: 200)
- ✗Electronic viewfinder resolution of 2.36M dots is modest compared to higher-end mirrorless options (viewfinder.resolution: '2.36M dots')
- ✗Single card slot with SD/SDHC/SDXC only — no redundant backup storage (storageMedia)
Videos — Olympus Mark I
OM System OM-1 Final Review — DPReview TV