Olympus OM-D E-M1 III vs Sony Alpha A9 II: A Deep Dive Into Two Pro Mirrorless Titans

When it comes to professional mirrorless cameras, few models spark as much debate as the Olympus OM-D E-M1 Mark III and the Sony Alpha A9 Mark II. Both enthusiasts and seasoned pros are often caught between these two - one championing Micro Four Thirds technology’s remarkable compactness and versatility, the other wielding a full-frame powerhouse tailored for speed and clarity. Having tested thousands of cameras over 15 years, I bring you an in-depth, hands-on comparison to decode what makes each of these flagship cameras tick in the real world, and which one might be your best next investment.

Handling & Ergonomics: Size Matters - Or Does It?

First impressions matter, especially after long shoots when fatigue kicks in. The Olympus E-M1 III continues Olympus’s tradition of compact, lightweight bodies, weighing in at just 580 grams with dimensions measuring 134x91x69 mm. The Sony A9 II is a more substantial 678 grams and slightly larger at 129x96x76 mm - still very manageable but noticeably heftier.

In my experience, the Olympus’s smaller “SLR-style” mirrorless design is a delight for travel and street photographers - it slips unobtrusively into gear bags and rarely gets mistaken for heavy professional gear. The Sony, meanwhile, sports a robust full-frame grip that feels rock-solid in hand, particularly suited to those with larger mitts or who routinely use big glass.

Both cameras offer fully weather-sealed bodies, essential for demanding environments. Olympus’s build quality impressed me with its rugged magnesium alloy shell and excellent button sealing. Sony matches that with a tough build as well, supplemented by better dust resistance around card slots and battery doors.

Turning to control layouts, please, feast your eyes on the top-down views:

Sony’s top plate showcases a classic professional layout with dedicated dials for shutter speed, ISO, and exposure compensation - tactile and precise, perfect for quick adjustments under pressure. Olympus’s approach blends a similar functional design but takes advantage of a more compact interface that may appear cramped to large-handed shooters but no less efficient once you acclimate.

Both systems feature fully articulated screens (more on those soon), intuitive touch interfaces, and customizable buttons that make adapting to various shooting styles a cinch. My workflow tends to favor Sony’s larger, spaced-out controls for fast action work, but Olympus wins points for lightweight portability here.

Sensor & Image Quality: The Battle of Sizes and Sensitivities

At the heart of any camera is its sensor, and here lies the fundamental divide: The Olympus E-M1 III employs a 20MP Four Thirds sensor (17.4x13 mm), while the Sony A9 II uses a hefty 24MP full-frame sensor (35.6x23.8 mm).

What does this mean practically? The Olympus sensor area is about 226 mm², roughly a quarter of Sony’s 847 mm² chip. This size differential impacts depth of field control, noise performance, dynamic range, and overall image quality.

From extensive real-world testing - both in the studio and in challenging light - Olympus delivers sharp, contrasty images with commendable color fidelity. The lack of an anti-aliasing filter ensures crisp detail. However, when you push ISO beyond native 6400, noise creeps in noticeably, and shadow recovery is more limited than a full-frame sensor can handle.

Sony’s BSI-CMOS full-frame sensor excels in low-light performance, pushing native sensitivities up to 51200 ISO with usable results in harsh conditions, and an extended ISO up to 204800 when needed (albeit with some grain). Dynamic range is superior as well, grabbing more highlight and shadow detail without degradation. The increased resolution (6000x4000 pixels) gives more latitude for large prints or cropping - a boon for event and sports photography.

Color depth and tonal gradation on the Sony are exceptional for portraits and landscapes, producing rich skin tones and lush textures straight out of the camera. Olympus compensates with finely tuned color profiles and has gotten more natural skin rendition since firmware updates.

Both cameras shoot RAW (always a must for serious shooters) and offer excellent in-camera noise reduction and sharpening options, although I tend to recommend minimal in-camera processing to preserve detail flexibility during post-processing.

Autofocus Performance: Speed and Accuracy Under Pressure

For photographers capturing fleeting moments - be it wildlife, sports, or street action - autofocus is paramount. Here's where the Sony A9 II flexes its muscle with a staggering 693 focus points and advanced AI-driven Eye AF for both humans and animals. Olympus offers 121 focus points, respectable but not in the same league numerically.

Both cameras support phase-detection autofocus coupled with contrast-detection for precision. Olympus includes face detection but lacks animal eye AF, a feature Sony has mastered with relentless firmware improvements.

In my hands-on tests on moving subjects, the Sony A9 II tracked subjects with uncanny precision and speed - locked onto erratic birds mid-flight with ease, maintained sharpness on runners sprinting toward the lens, and rarely lost focus in challenging lighting. Burst shooting at 20 fps with continuous AF further secures critical frames during fast sequences.

Olympus’s E-M1 III, however, is no slouch. It offered smooth subject tracking once focused, with good low-light AF thanks to its phase-detect points spread broadly across the frame. The camera can shoot bursts at an astonishing 60 fps, but this is with electronic shutter, which sometimes produced minor rolling shutter artifacts not present in Sony’s mechanical shutter sequences.

For portrait work, both deliver excellent eye detection - Olympus’s AF performs admirably in moderately lit studios, but the Sony’s superior AF even extends into tricky lighting and backlit conditions.

Display & Viewfinder: Composing Your Shot

Detailing viewfinder and screen capabilities rounds out your shooting experience. Both cameras feature 3-inch articulating screens with touch functionality (Olympus’s is fully articulated, ideal for low and high angles; Sony’s tilts - less flexible but still functional).

The Sony’s higher resolution 1440k-dot screen offers a more vibrant, sharper preview, while the Olympus’s 1037k-dot panel feels serviceable but less crisp when scrutinizing fine details on the fly.

EVFs, however, show a clear Sony advantage. The A9 II’s 3.686 million-dot EVF provides a crystal clear, responsive viewfinder experience with excellent magnification (0.78x) and 100% coverage. Olympus offers a respectable 2.36 million-dot EVF with 0.74x magnification and also 100% coverage, but perceptibly less detailed than Sony’s.

In bright outdoor shooting, Sony’s EVF gives you more confidence framing critical compositions and avoiding missed focus, especially when working at wide apertures or tracking fast-moving subjects.

Burst Rates & Buffer Capacity: How Fast Is Fast Enough?

Burst shooting is often the deciding factor for dynamic photography genres like sports and wildlife. Olympus boldly offers up to 60 fps continuous shooting in silent electronic shutter mode, yet this comes with some compromises - slight rolling shutter distortion and buffer limitations depending on RAW or JPEG modes.

Sony provides a rock-solid 20 fps continuous burst with full AF/AE tracking and a sizeable buffer that holds hundreds of RAW files without slowing, invaluable when timing is everything.

While Olympus’s numbers look impressive on paper, in practice, Sony’s mechanical shutter burst is more reliable and consistent, especially in extended shooting sessions.

Weather Sealing and Durability: Ready for Anything?

Both cameras boast magnesium alloy bodies with dust and splash-proof seals, making them excellent choices for tough environments - think snow-covered mountains or desert landscapes.

Neither is officially waterproof or shockproof, so rugged care is still advised, but I’ve tested both under light rain and dust storms with no issues. The Sony’s slightly larger weather-sealed compartments for cards and ports give it a slight edge in aggressive weather conditions.

Lenses and Ecosystem: Glass Matters

Olympus champions the Micro Four Thirds mount with roughly 107 lenses available, ranging from ultra-wide to super-telephoto primes and macros. The lens ecosystem is mature, compact, and often significantly more affordable than full-frame counterparts. Olympus’s system particularly shines for macro and compact travel setups.

Sony’s E-mount system boasts an ever-growing lineup of over 120 lenses, including some stellar professional optics from Sony, Zeiss, and other respected manufacturers. The downside? These lenses tend to be bigger, heavier, and pricier, reflecting their full-frame design and quality.

If portability and budget-friendly glass are priorities, Olympus pulls ahead. For those demanding the ultimate optical performance and widest selection of ultra-high-end lenses, Sony dominates.

Battery Life, Storage, and Connectivity: Staying Power Matters

Sony delivers a noteworthy battery performance on the A9 II thanks to the NP-FZ100 battery, rated at roughly 690 shots per charge, a comfortable margin for full-day shoots. Olympus’s E-M1 III uses the BLH-1 battery, with about 420 shots per charge - respectable but requiring spare batteries for longer sessions.

Both cameras feature dual SD card slots with fast UHS-II support, crucial for professional redundancy. USB 3.1 Gen 1 ports for tethering or charging are present, along with full-size HDMI outputs.

Wireless connectivity includes built-in Wi-Fi and Bluetooth on both - Sony edges ahead with NFC support as well for seamless pairing.

Video Capabilities: More Than Just Stills

For hybrid shooters, video specs matter. Olympus supports 4K UHD video up to 30p with a high bitrate of 102 Mbps and offers headphone and microphone jacks (essential for monitoring audio). The E-M1 III lacks 4K at 60p and logs profiles, which limits color grading flexibility.

Sony supports 4K UHD up to 30p in XAVC S format, with slightly lower bitrate (~100 Mbps) but solid quality. It also includes headphone/mic ports and more advanced features, such as S-Log3 profiles, that better cater to professional videographers looking to color-grade footage.

Neither camera has 4K60p video, which may disappoint some video-centric users. In-camera 4K photo modes are absent in both.

Putting It All Together: Which Camera Excels in Which Genre?

Olympus E M1 III front Olympus E M1 III screen back Sony A9 II front Sony A9 II screen back

Photography genres strain cameras in unique ways, so let’s allocate some camera scorecards by specialty.

Portraiture

Sony’s full-frame sensor yields creamy bokeh and rich skin tones, with its Eye AF providing superb catchlight sharpness. Olympus’s smaller sensor limits bokeh smoothness but offers excellent detail and color accuracy. Both cameras deliver reliable AF and skin tone rendition, but Sony leads here for studio and event portraits.

Landscape

The dynamic range advantage and higher resolution of the Sony make it ideal for landscapes under varied lighting. Olympus’s compactness and weather sealing attract hikers and outdoor warriors, but images will have less latitude in post compared to Sony.

Wildlife

Sony’s autofocus coverage, animal eye AF, and burst shooting at 20 fps give it the upper hand for wildlife photography. Olympus’s 60 fps burst seems tempting but suffers from electronic shutter artifacts, and lack of animal eye AF is noticeable.

Sports

Here again, Sony’s tracking AF and large buffer make it the go-to choice for professional sports shooters. Olympus can keep up in less demanding scenarios but is outclassed by Sony’s speed and precision.

Street Photography

Olympus’s lightweight, compact design, silent shooting modes, and fully articulated screen empower street photographers seeking discretion and agility. Sony’s size is less portable, and its louder shutter can draw attention.

Macro

Olympus shines in macro photography, with a mature Micro Four Thirds lens lineup offering superb macro lenses, combined with in-body 5-axis stabilization aiding critical focusing precision. Sony has excellent macro lenses too, but bulkier and less specialized options.

Night/Astro

Sony’s higher ISO capabilities and lower noise performance equip it better for astrophotography and night scenes. Olympus can manage but requires lighting conditions closer to optimal.

Video

Both cameras support high-quality 4K video, but Sony leads with professional video features like advanced picture profiles and superior EVF, making it more video-friendly overall.

Travel

Portability, weather sealing, and battery life factor heavily here. Olympus is lighter and smaller but Sony’s longer battery life allows fewer battery swaps, though at 678 grams the Sony isn’t exactly a burden.

Professional Use

Sony offers more comprehensive professional features - excellent file handling, superior AF systems, and robust build - justifying its nearly $4500 price. Olympus delivers impressive performance priced under $2000, great for pro-level enthusiasts or as a secondary camera.

Final Thoughts: Who Should Pick What?

The Olympus OM-D E-M1 III and Sony Alpha A9 II are both brilliant workhorses but answer different needs elegantly.

Choose the Olympus E-M1 III if you:

• Prioritize portability and travel convenience without sacrificing build quality
• Shoot macro, landscapes, and street photography where light burst speed isn’t critical
• Want excellent stabilization, good stills quality, and weather resistance at a friendly price point
• Prefer a comprehensive Micro Four Thirds lens ecosystem that’s compact and affordable

Choose the Sony A9 II if you:

• Need blistering autofocus speed, tracking, and buffer for sports or wildlife pro workflows
• Demand the best low-light performance and wider dynamic range for portraits and landscapes
• Shoot hybrid with advanced video features and a preference for top-tier EVF and controls
• Are willing to invest in a larger system with extensive high-end lens options and longer battery life

Both cameras maintain cutting-edge technologies but cater to distinct users. The Olympus delivers spectacular value and agility for enthusiasts and semi-pros, whereas Sony represents a superlative full-frame flagship that remains a workhorses’ favorite.

If budget allows and you chase commercial-quality performance for action and professional video, Sony’s A9 II is worth every penny. If you lean toward compactness, versatility, and excellent image quality for diverse photography - Olympus’s E-M1 III is a smart choice.

Hopefully, this deep dive gave you a clear lens on the strengths and compromises of both systems. Choosing your next camera isn’t just about specs; it’s about which tool aligns with your creative vision and shooting style. Happy snapping!