OM System
The Adventurer's Companion
Olympus and the Micro Four Thirds Camera Tradition
Olympus Corporation traces its roots to 1919, when it was founded in Tokyo as Takachiho Seisakusho, a maker of microscopes and scientific optical instruments. The camera division emerged in the 1930s and grew steadily, eventually becoming one of the most influential forces in compact camera design across both film and digital eras. Olympus cameras became globally recognised for miniaturisation, durability, and a consistent willingness to challenge conventions held by larger-format rivals, prioritising portability without sacrificing image quality.
From Film SLRs to the Open MFT Standard
The OM-1 film SLR, introduced in 1972, established Olympus as a serious photographic brand by packaging professional-grade optics into a body significantly smaller and lighter than competing SLRs of the era. When the industry moved to digital, Olympus co-developed the Four Thirds standard in 2003 with Kodak. Olympus then co-founded the Micro Four Thirds standard in 2008 alongside Panasonic, creating an open mount that dozens of manufacturers would eventually join.
The 2021 Transition to OM System
In 2021, Olympus completed the sale of its imaging division to Japan Industrial Partners, a Tokyo-based investment firm, with the business formally transferring on January 1, 2021. The new company, OM Digital Solutions, was incorporated in October 2020 and began selling cameras under the OM System name from 2022 onward. The Micro Four Thirds mount itself is unchanged, so all Olympus MFT lenses function identically on current OM System bodies.
Micro Four Thirds: The Mount Ecosystem
The Micro Four Thirds (MFT) standard uses a 17.3 x 13 mm image sensor and a mount with a very short 19.25 mm flange distance. This geometry allows lens designers to create physically compact optics without the compromises that a larger-format mount imposes. The Micro Four Thirds System specification is maintained as an open industry standard, meaning glass designed by Olympus, Panasonic, Sigma, and Voigtlander shares the same mount and communicates electronically with all compliant bodies.
Sensor Size, Depth of Field, and the 2x Crop Factor
The MFT sensor produces a 2x crop factor relative to a full-frame 35 mm sensor, so a 25 mm MFT lens frames the same scene as a 50 mm lens on a full-frame body. Depth of field is also affected: an MFT lens set to f/1.4 produces blur roughly equivalent to f/2.8 on a full-frame camera. The smaller sensor does carry real advantages, since lenses can be shorter, lighter, and less expensive to manufacture at equivalent angles of view.
In-Body Image Stabilisation: A Signature Capability
Olympus established itself as a leader in sensor-shift in-body image stabilisation (IBIS), with multi-axis systems compensating for pitch, yaw, roll, vertical shift, and horizontal shift. The Camera and Imaging Products Association publishes standardised IBIS testing protocols, and Olympus bodies regularly demonstrated top performance under those measurements in independent laboratory evaluations. Reviewers consistently note that Olympus bodies make handheld shooting practical in low-light conditions at shutter speeds that would otherwise require a tripod.
Weather Sealing Across the Product Line
The Olympus OM-D E-M1 series and E-M5 series established a reputation for robust weather sealing at prices well below comparable sealed full-frame bodies. The E-M1 Mark III and E-M1X both carry IP53-class sealing ratings when paired with Pro-series lenses, allowing photographers to work in rain, dust, and freezing temperatures. This combination of a sealed body with a sealed lens represented a genuine differentiator for wildlife and outdoor photographers who needed portability alongside environmental protection.
The OM-D and PEN Naming Systems
Olympus organised its camera lineup under two primary families: the OM-D and the PEN. The OM-D name is an homage to the original OM-series film SLRs, with the E-M1 line targeting professionals, the E-M5 line at advanced enthusiasts, and the E-M10 as the entry point. The PEN cameras (E-P and E-PL series) omit the built-in viewfinder, favour a rangefinder-influenced body shape, and prioritise compactness for street and travel photography.
The Zuiko PRO Lens Lineup
Olympus branded its lenses Zuiko Digital, a name carried over from the film era, with the catalogue divided into PRO, Premium, and standard consumer tiers. The PRO tier covers professional weather-sealed optics with constant maximum aperture, including the M.Zuiko 12-40 mm f/2.8 PRO, the 40-150 mm f/2.8 PRO, and the 300 mm f/4 IS PRO (equivalent to 600 mm full-frame reach in a hand-portable size). The telephoto reach achievable with compact PRO glass is one of the strongest arguments for the MFT format among wildlife and sports photographers.
Computational Shooting Modes
Olympus introduced in-camera high-resolution shot modes that combine multiple sensor-shifted exposures into a single image, producing resolution that substantially exceeds the physical pixel count of the sensor. The E-M1 Mark II offered this mode for tripod shooting (up to 50 megapixels), while the E-M1 Mark III added a Handheld High Res Shot mode with motion correction for 50-megapixel output and up to 80 megapixels on a tripod. The Live ND mode, also introduced on the E-M1 Mark III, simulates long-exposure neutral-density filter effects entirely in-camera by averaging multiple sequential frames, removing the need for physical ND filters in many situations.
Who the Olympus System Suits Today
Photographers who prioritise weight and volume reduction while retaining serious optical quality are the natural audience for Olympus gear, and the second-hand market for Olympus OM-D bodies and Zuiko PRO lenses is mature, well-priced, and easy to enter. The telephoto reach-to-weight ratio in the MFT system is especially compelling for wildlife, bird, and travel photographers who cannot realistically carry full-frame telephoto systems on multi-day trips or aircraft carry-on luggage. Those who require the largest possible sensors for extreme low-light performance or ultra-shallow depth-of-field portraiture will find the MFT format less suited to those specific needs, but for outdoor, wildlife, and documentary work the system delivers genuine capability at a portable scale.
Frequently Asked Questions
- Is Olympus still making cameras?
Olympus completed the sale of its imaging division to Japan Industrial Partners in early 2021, with the business formally transferring on January 1, 2021. That division operates as OM Digital Solutions and now sells cameras under the OM System name from 2022 onward. The Micro Four Thirds mount, lens catalogue, and core engineering team continued under the new ownership. Cameras sold before 2022 carry the Olympus name, while cameras from 2022 onward are sold as OM System. Existing Olympus lenses and accessories remain fully compatible with current OM System bodies.
- What is the difference between Micro Four Thirds and full-frame sensors?
The Micro Four Thirds sensor measures 17.3 x 13 mm, compared to 36 x 24 mm for a full-frame sensor, producing a 2x crop factor. A 25 mm MFT lens captures the same field of view as a 50 mm full-frame lens. The smaller sensor allows more compact and lighter lenses at equivalent angles of view, and long telephoto focal lengths become especially portable. The trade-off is reduced light-gathering area, which affects noise at very high ISO settings and limits the shallowest achievable depth of field compared to full-frame at the same aperture number.
- Are Olympus lenses compatible with Panasonic cameras?
Yes. Both Olympus and Panasonic cameras use the Micro Four Thirds mount, which is an open standard. Olympus Zuiko lenses mount directly on Panasonic MFT bodies and vice versa. Some advanced autofocus modes may behave differently on a body from the other manufacturer, but fundamental autofocus, image stabilisation, and aperture control communicate correctly across brands. This cross-compatibility makes the MFT system one of the most interoperable camera ecosystems available.
- How good is the weather sealing on Olympus OM-D cameras?
The OM-D E-M1 and E-M5 series carry IP53-class sealing ratings when used with a matching sealed PRO-series lens. This rating indicates protection against dust ingress and resistance to water spray from any direction. Photographers routinely use these bodies in rain and dusty conditions without issues, and Olympus has long marketed the combination to wildlife and outdoor professionals. The sealing depends on the lens used: unsealed consumer lenses leave the mount junction unprotected, which reduces overall system weather resistance.
- What is Olympus in-body image stabilisation and how many stops does it provide?
Olympus in-body image stabilisation (IBIS) uses sensor-shift technology to compensate for camera movement along five axes: pitch, yaw, roll, and vertical and horizontal shift. The E-M1 Mark III claims up to 7.5 stops of compensation in body-only mode under CIPA standardised testing, and up to 7.5 stops in Sync IS mode when paired with a compatible stabilised lens. Independent reviewers have confirmed multi-stop real-world gains that make handheld shooting at very slow shutter speeds practical, particularly for static subjects in available light.
- What second-hand Olympus lenses are worth buying?
The used market for Olympus Zuiko PRO glass is deep and well-established. The M.Zuiko 12-40 mm f/2.8 PRO is widely regarded as an outstanding standard zoom with consistent sharpness and robust weather sealing. The 40-150 mm f/2.8 PRO is considered among the sharpest telephoto zooms in its size class, and the 300 mm f/4 IS PRO offers 600 mm equivalent reach in a hand-portable package. Earlier E-M5 Mark II and E-M1 original bodies are also available at accessible prices on the second-hand market.
- Is Micro Four Thirds good for video shooting?
Micro Four Thirds bodies from Olympus support 4K video recording, and the strong IBIS system is a significant asset for handheld video work, reducing the need for gimbals in many shooting situations. The E-M1 Mark III records 4K with Cinema 4K options included. Video has historically been a secondary priority in Olympus camera design compared to Panasonic GH-series bodies in the same MFT format. Panasonic MFT bodies accept the same Olympus lenses, making the lens investment transferable to a video-optimised body if dedicated video work is a priority.