Olympus E-M1 III vs Sony A7S II

Olympus E-M1 Mark III vs Sony A7S II: A Deep-Dive into Two Pro Mirrorless Titans

Comparing cameras at the professional mirrorless tier always demands a nuanced approach - it’s rarely about just specs on paper. Instead, it’s about how each performer adapts to real shooting situations, addresses unique photographic genres, and fits within larger workflows. Having spent countless hours in the field and studio with both Olympus and Sony gear, I’m excited to unfold this comprehensive head-to-head between the Olympus OM-D E-M1 Mark III and the Sony Alpha A7S II - two remarkable cameras crafted for pros, yet markedly different in philosophy and specialization.

Meeting the Contenders: Compact Power vs Full-Frame Sensitivity

Before plunging in, let’s set the stage. The Olympus E-M1 Mark III, released in early 2020, targets photographers craving rugged handling, lightning-fast shooting speeds, and a bushel of computational photography features - all wrapped up in the Micro Four Thirds (MFT) sensor system. In contrast, the Sony A7S II, launched in 2015 but still widely treasured, magnetizes low-light shooters with its full-frame 12MP sensor optimized for stellar high ISO performance and video.

This divergence - MFT versus full-frame - inherently colors everything else: resolution, depth of field, dynamic range, and even lens ecosystem options.

Size, Ergonomics & User Interface: Handling Individuality

One immediate impression when placing these cameras side by side is their physical demeanor. The Olympus E-M1 III sits smaller and lighter, weighing 580g compared to the Sony’s heftier 627g - not a monumental difference, but the E-M1 III’s chassis is distinctly more compact, thanks to the smaller sensor and streamlined design.

Olympus opts for a traditional SLR-style button layout, gravitating to seasoned photographers who prioritize direct access dials for shutter speed, ISO, and exposure compensation. The buttons are logically placed yet not overwhelmingly numerous - perfect for quick adjustments while shooting action or landscape scenes. Meanwhile, Sony’s A7S II features a clean top deck design with fewer dedicated dials, leaning more on menu navigation and programmable buttons. Its electronic viewfinder is slightly larger in magnification (0.78x vs 0.74x of Olympus), lending a marginal advantage for critical framing.

On the touchscreen front, Olympus’s fully articulating 3” screen with touch capabilities plays brilliantly for awkward angles, vlogging, and on-the-fly focusing tweaks. I personally appreciate the touch-to-focus and menu navigation shortcut options during handheld wildlife shots. Sony’s tilting 3” screen, while sharp and sizeable, lacks touch - adequate but less flexible for creative composition.

Sensor Technology & Image Quality: Different Paths to Excellence

Diving deeper, the core of any camera is its sensor - and here we have a classic trade-off.

The Olympus employs a 20MP Four Thirds sized CMOS sensor measuring 17.4 x 13 mm; by contrast, the Sony brandishes a full-frame 35.6 x 23.8 mm sensor at 12.2MP resolution. This size gulf (nearly four times the surface area) has profound implications.

Resolution & Detail Rendering: The Olympus’ 20MP pixel count delivers crisp and detailed images, especially in good light, making it appealing for landscape and macro shooters who want sharp, high-res files without massive storage demands. However, the smaller sensor size means deeper depth of field at equivalent apertures - advantageous for macro and street shooters craving more in-focus context, but less ideal for creamy bokeh.

Sony’s A7S II trades pixel count for larger photosites, enhancing low-light capabilities significantly. At 12MP, it won’t match Olympus for sheer resolution, but it produces impressively clean images at ISO 6400 and beyond, a sweet spot for astrophotography, events, and cinema-focused workflows.

Dynamic Range & Color Depth: DXOMark rankings give the Sony an overall score of 85, boasting a dynamic range of 13.3 EVs and color depth of 23.6 bits. Olympus sensors historically don’t top DXO’s charts, but the E-M1 III’s TruePic IX processor elevates RAW processing quality and noise reduction significantly, achieving commendable clarity and tonal transitions, especially beneficial in landscape shadow and highlight retention.

Autofocus Mastery: Speed, Accuracy, and Tracking

Autofocus can make or break a shoot, particularly in demanding genres like wildlife or sports.

The Olympus E-M1 III features a hybrid autofocus system with 121 phase-detection points, covering a broad sensor area with fast, accurate acquisitions. Its advanced AI-driven algorithms enable impressive subject tracking, including effective face and eye detection - though, notably, it lacks animal eye AF. When I tested it on bird flight sequences, the 60 fps continuous shooting combined with reliable AF tracking provided sharp keepers even in challenging lighting.

Sony’s A7S II leans on 169 contrast-detection points without phase AF on the sensor (a rarity for modern full frame). The trade-off is slightly slower AF performance, particularly in continuous tracking scenarios. However, the eye detection AF for humans works reliably in well-lit conditions. The camera’s low-light sensitivity also means the AF performs consistently in dim environments where Olympus might struggle more.

Build Quality & Environmental Sealing

Both cameras cater professionally built and weather-sealed magnesium-alloy bodies, suitable for demanding outdoor use. Olympus has a slight edge with freezeproof claims and robust dust and splash resistance, which is reassuring during mountain or macro expeditions. Sony also seals well against dust and moisture, safeguarding field reliability - although the older design lacks Olympus’s freezeproof rating.

In terms of grip, Olympus’s deeper, more pronounced grip delivers snug holding comfort on long treks, especially when paired with heavier lenses. Sony’s thinner grip and minimalistic design favor portability but at the cost of extended handling comfort.

Exploring Lens Ecosystems: MFT Versus Sony E Mount

Lens availability dramatically influences long-term system investment.

Olympus taps into the extensive Micro Four Thirds lens ecosystem with over 100 native lenses, including affordable primes and professional-grade zooms like the 12-40mm f/2.8 PRO, known for its razor-sharp imagery and weather sealing. The MFT lens lineup is mature, diverse, and also benefits from third-party options offering excellent value.

Sony’s E mount system offers over 120 lenses. While zoom-heavy compared to primes, Sony’s stable includes some highly specialized optics (e.g., ultra-fast primes for portraits and cine lenses). The A7S II’s full-frame sensor maximizes these lens’s optical potential, especially for shallow depth of field effects and low-light scenarios.

Battery Life & Storage Flexibility

Battery life matters especially for travel or event shooting.

Olympus uses the BLH-1 battery, rated for about 420 shots per charge under CIPA standards - a step up from many mirrorless competitors. The provision for dual UHS-II SD card slots adds redundancy and high-speed recording options, highly prized by pros.

Sony’s A7S II uses the smaller NP-FW50 battery, delivering around 370 shots per charge, slightly less enduring for long days on location. Storage options are single slot only (SD or Memory Stick formats), which limits instant backup opportunities compared to Olympus.

Video Capabilities: Beyond Stills

Both mirrorless cameras cater extensively to video shooters but diverge in target applications.

Olympus offers 4K UHD recording at 30/25 fps with decent bitrate, complementing with full HD up to 60 fps. Notable is its inclusion of microphone and headphone ports, 5-axis sensor stabilization smoothing handheld footage, and clean HDMI output - essentials for hybrid shooters or videographers on the go.

Sony’s A7S II is a video workhorse with more advanced 4K internal recording at 30p/24p, and high frame rate Full HD at 120 fps for slow-motion capture. The sensor’s native ISO range excels in dark conditions, making it a mainstay for cinematic shooting in challenging environments. It also features robust audio connectivity.

Photo Genres in Focus: Matching Strengths to Needs

With these technical bases set, let’s evaluate them across popular photographic disciplines.

Portrait Photography

The Olympus E-M1 III delivers sharp images with pleasant skin tones. Its lack of a full-frame sensor means depth of field is generally deeper, limiting extremely creamy bokeh unless using specialized lenses. Eye autofocus is solid but can struggle in ultra-low light.

Sony’s A7S II, with its full-frame sensor and fast lens support, produces gorgeous subject separation critical for flattering portraits. The 12MP resolution may be lower than some competitors but produces files excellent for web and print. Its color rendering is warm and natural.

Landscape Photography

Olympus’s 20MP sensor combined with excellent weather sealing and in-body stabilization makes it an excellent travel and landscape companion - especially when paired with the MFT system’s compact wide-angle lenses.

The Sony offers outstanding dynamic range, low noise at base and mid ISO, and larger sensor area for nuanced tonal gradations. The lower resolution is often not a hindrance for fine print sizes.

Wildlife & Sports Photography

Olympus’s blazing 60 fps burst rate with effective AF tracking and its inherent telephoto reach from the 2.1x crop factor (e.g., a 300mm MFT lens behaves like a 600mm full-frame equivalent) make it ideal for birding and wildlife enthusiasts on a budget.

Sony’s slower 5 fps burst and contrast-detection AF make it less suited for fast action, though outstanding for low-light sports indoors or nighttime events.

Street Photography & Travel

Compactness and silence are vital here. Olympus’s electronic shutter up to 1/32000s combined with small lenses offers stealth and quickness.

Sony’s bigger sensor produces shallower depth of field for discreet portraits and creative backgrounds, albeit in a slightly more conspicuous body.

Macro Photography

Olympus shines here with its meticulous focus bracketing, focus stacking capabilities, and deep depth of field allowing exceptionally sharp close-ups without sacrificing field coverage.

Sony’s macro performance relies on lens capability; the lack of focus stacking weights against it.

Night & Astro Photography

Sony dominates in night scenarios with a sensor designed for extreme high ISO performance (ISO 102400 native, expandable to 409600). Its less dense pixel arrangement reduces noise without sacrificing star detail.

Olympus does well to ISO 25600 but with somewhat more noise, making it second-best for astrophotographers.

Professional Workflows

Both cameras shoot RAW with robust color management and comprehensive manual controls. Olympus’ dual card slots and faster USB 3.1 connectivity aid professional reliability. Sony’s older USB 2.0 and single slot constrain some modern multi-backup workflows.

Real-World Performance & Image Samples

Handling and shooting nuances truly reveal themselves over time. The Olympus E-M1 III’s quick start-up, responsive touch interface, and intuitive menus make it a delight for fast-paced shooting. Its 5-axis stabilization combined with stabilized lenses often turns handheld shots into tack-sharp masterpieces. In contrast, the A7S II’s quieter, more deliberate response suits thoughtful, slower-paced workflows, with an emphasis on low-light excellence.

Olympus E M1 III front Olympus E M1 III screen back Sony A7S II front Sony A7S II screen back

Image samples from both cameras displayed side-by-side highlight Olympus’s crisp detail and punchy colors in daylight scenarios, while Sony’s files excel with cleaner shadows and brighter night scenes with minimal noise.

Scoring & Value Assessment

Our expert team calibrated overall performance and genre-specific scores - taking into consideration build, sensor, autofocus, video, and price.

Olympus holds a remarkable overall balance, excelling particularly in burst shooting and versatility at a commanding price of ~$1800. Sony, priced higher (~$2766), remains unbeatable in high ISO and video quality, rewarding specialized users.

Final Thoughts: Who Should Choose What?

Choose the Olympus OM-D E-M1 Mark III if:

• You need a compact, highly weather-resistant pro camera for fast action, wildlife, and macro photography.
• You prioritize resolution and detail in a smaller, lightweight system.
• You want cutting-edge autofocus with excellent tracking and in-body stabilization.
• You value dual card slots and articulate touchscreens for versatile shooting angles.
• Your budget is around $1800 and you want a broad native lens ecosystem.

Opt for the Sony A7S II if:

• Ultra-high ISO, low noise performance in near-darkness is your top priority (night, astro, indoor sports).
• You require advanced 4K video with high frame rates and professional audio connectivity.
• You favor full-frame imagery with smooth bokeh and tonal subtlety for portraits and cinematic work.
• You’re comfortable in a single card slot setup and an older but still very capable interface.
• Your budget accommodates a $2700 investment for specialized, high-end video/still hybrid capabilities.

Closing: A Matchup of Different Philosophies, Both Resilient Champions

The Olympus E-M1 Mark III and Sony A7S II represent two sides of the same pro mirrorless coin - one favoring speed, versatility, and compact precision with a smaller sensor, the other emphasizing sensitivity and cinematic imaging via full-frame prowess. Neither is universally “better”; instead, each thrives in distinct photographic universes. Understanding your priorities regarding genre, budget, and system growth will steer you to the right choice with confidence.

Having tested thousands of cameras over my career, I can affirm that both the Olympus and Sony remain benchmarks - trusted digital workhorses that continue to inspire creativity years after their launch.

Whether you seek the nimble champion in Olympus or the low-light sorcerer in Sony, you’re investing in tools that will expand your photographic vision and deliver stunning results in the field and beyond.

Happy shooting and may your next camera perfectly match your artistic journey.