Olympus E-M10 IV vs Sony A9 II: A Thorough Head-to-Head for Enthusiasts and Pros

Choosing between the Olympus OM-D E-M10 IV and the Sony Alpha A9 II is a classic case of juxtaposing compact, approachable entry-level design against the raw, professional-grade power of a flagship full-frame mirrorless. Over my 15+ years testing cameras, I've handled thousands of bodies, and this matchup is fascinating because it’s not just about specs, but whole philosophies and intended users.

In this detailed comparative review, I’ll draw on hands-on experience, technical evaluation, and real-world usage scenarios across photography genres - from portraits to wildlife, and video to travel - to help you find the camera that fits your style, needs, and budget. Buckle up as we dissect everything important - sensor tech, autofocus, ergonomics, image quality, and more.

Size, Handling, and Design: Compact Simplicity vs. Pro Ergonomics

Right off the bat, one of the starkest differences is in the physical build and handling. The Olympus E-M10 IV, sporting a Micro Four Thirds sensor, is delightfully compact and light - measuring 122 x 84 x 49 mm and just 383 grams. This makes it a breeze in your hand and an easy carry around town, perfect for street photography or casual shooting. The grip is modest but well-shaped, and the control layout is sufficiently comprehensive for this class of camera.

Contrast that to the Sony A9 II, a full-frame professional workhorse designed to be rugged and reliable in demanding conditions. It’s substantially larger and heavier at 129 x 96 x 76 mm and 678 grams. This bulk is intentional - the magnesium alloy body features extensive weather sealing (dust and moisture resistance) and a big, deep grip designed to comfortably support heavy telephoto lenses for extended wildlife or sports sessions.

While both cameras feature tilting 3-inch LCDs, the A9 II’s build quality screams “put me through the wringer” - a factor that greatly matters when you’re shooting outdoors in varying environments. Meanwhile, the E-M10 IV trades weather sealing for portability, appealing to travelers and street shooters who prioritize stealth.

Moving off size and feel, let’s look at their control interfaces next.

Controls and Interface: Intuitive Entry vs. Professional Customization

Olympus’ OM-D line is renowned for its classic DSLR-style layout, and the E-M10 IV continues this tradition with a clear emphasis on simplicity and ease of use. The top plate has straightforward dials for aperture, shutter speed, and exposure compensation, with dedicated buttons for quick access to key functions. The touchscreen is responsive, making menu navigation and focus selection fluid.

The Sony A9 II ups the ante with an array of customizable buttons, two SD card slots for redundancy, and a more complex top control layout designed to empower professionals who need to switch modes and settings in milliseconds. Also noteworthy is the illuminated button option on some pro models (though not present here), and a very bright electronic viewfinder (EVF) aiding shooting in bright conditions.

The A9 II’s EVF resolution of 3.686 million dots vastly surpasses the E-M10 IV’s 2.36 million, offering a stunningly detailed, lag-free preview vital for tracking fast moving subjects in wildlife or sports. Olympus doesn’t skimp here either - the E-M10 IV’s 2.36 million dots is respectable for an entry-level model but won’t satisfy pixel peepers or professionals.

Sensor and Image Quality: Micro Four Thirds Modesty vs. Full-Frame Power

Now to the heart of any camera: the sensor. The E-M10 IV sports a 20MP Four Thirds sensor measuring 17.4 x 13mm - significantly smaller than the Sony A9 II’s full-frame 24MP sensor at 35.6 x 23.8mm. The result of this size difference is profound when it comes to dynamic range, noise control, and depth of field.

The larger sensor area on the A9 II translates to cleaner images with less noise at higher ISOs (up to 204,800 boosted ISO), and richer tonal gradations. This is particularly advantageous in low-light or night/astro photography. Conversely, the Olympus with its smaller sensor maxes out at ISO 25,600 (native) and shows noticeable noise above ISO 3200 in real-world shooting.

However, the E-M10 IV’s 5-axis in-body stabilization helps compensate for the smaller sensor’s lower light capability by enabling slower shutter speeds without blur - great for macro or landscape handheld shooting.

The Olympus sensor's built-in anti-aliasing filter can slightly trade sharpness for moiré reduction, so in ultra-fine pattern detail shots (textile or architecture) you might notice less crispness than on the Sony.

Overall, if image quality and low-light performance top your list, the Sony clearly leads. But for casual, social, or travel shooters looking for great image quality with lighter gear, the Olympus sensor holds up well, especially with good technique and RAW editing.

Autofocus and Speed: Entry-Level Versus Blazing Performance

The Olympus E-M10 IV features a decent 121-point contrast-detection AF system relying on contrast peak detection. It supports face detection, touch focus on screen, and can do continuous AF at 8.7 fps burst shooting. It’s accurate and sufficient in good light, but contrast-detection means autofocus can hunt in dim conditions or fail on fast-moving subjects.

The Sony A9 II radically improves this with a massive 693-point phase-detection AF system spread across almost the entire frame. This is the same system that vaulted Sony into the top tier for sports and wildlife photography. The A9 II boasts real-time Eye AF for humans and animals, intelligent subject tracking, and an incredible blackout-free 20 fps continuous shooting with full AF/AE tracking.

If you are shooting fast-paced subjects - be it soccer matches, birds in flight, or fast street photography - the A9 II provides a decisive advantage. Olympus is more beginner and hobbyist focused, and while capable for portraits or casual wildlife, it can’t compete in AF speed or tracking sophistication with the Sony.

Portrait Photography: Skin Tones, Bokeh, and Eye AF

Portrait photographers often prioritize skin tone rendering, natural bokeh, and accurate eye detection autofocus.

The Olympus OM-D E-M10 IV delivers pleasing skin tones with its TruePic VIII processor and color science that tends toward slightly punchy but realistic colors. The Micro Four Thirds lens ecosystem offers many excellent portrait primes - though the inherent crop factor (2.1x) changes perspective and bokeh character compared to full-frame. Background blur is less creamy, which some prefer for sharper subject separation, while others might find it less flattering.

The Sony A9 II, with its full-frame sensor, excels at creamy bokeh and shallow depth of field that isolates subjects beautifully. Paired with Sony’s rich array of fast prime lenses, portraits have a 3D pop and richly nuanced skin tones in JPEG and RAW. The inclusion of real-time Eye AF for humans and animals makes eyelash-sharp focus effortless, something that Olympus lacks.

Overall, for casual portraits or social media shooting, the E-M10 IV performs well, but for professional portrait shooters who need consistent razor-sharp eye focus and luxury bokeh, the Sony is the clear winner.

Landscape Photography: Resolution, Dynamic Range, and Portability

Landscape shooters demand high resolution, wide dynamic range, sharp lenses, and often weather sealing.

With its 24MP full-frame sensor, the Sony A9 II offers superior dynamic range and resolution - key for pulling detail from shadows and highlights in challenging natural light. High-quality Sony G Master lenses add crystalline sharpness across the frame. The weather-sealed body enables confidence in misty, windy, and dusty conditions.

The Olympus E-M10 IV offers respectable 20MP resolution and good in-body stabilization to aid slow-shutter handheld shots. Its lens ecosystem is mature with many sharp primes and versatile zooms but generally smaller and slower compared to pro full-frame lenses. The lack of weather sealing is a downside for serious landscapes out in inclement weather.

Thanks to its smaller size and lighter weight, the Olympus scores high for portability - meaning you’ll likely bring it more often on casual hikes or day trips. The Sony, while bulkier, excels when technical image quality is paramount, such as for gallery prints or detailed post-processing.

Wildlife and Sports Photography: Speed, Tracking, and Burst Rate

Here the Sony A9 II was purpose-built with photographers like photojournalists, sports pros, and wildlife shooters in mind.

Its 20 fps blackout-free shooting, ultra-fast hybrid AF system, and large buffer are game-changers. The 693 phase-detection points cover nearly the entire sensor area, combined with animal eye AF, provide nearly flawless tracking of erratic subjects. The dual SD card slots with UHS-II create reliability during long, fast shooting bursts.

By contrast, Olympus’s 8.7 fps burst and contrast-detection AF struggles with consistently nailing focus on rapidly moving subjects, especially in low light. The exclusion of animal eye AF limits wildlife photography effectiveness.

Professional sports or bird photographers will find the Sony A9 II indispensable, while enthusiasts shooting occasional wildlife or amateur sports can get by with Olympus - provided conditions are favorable.

Street and Travel Photography: Stealth, Weight, and Versatility

Street shooters prize discretion and quick handling, while travelers emphasize size, battery life, and flexibility.

The Olympus E-M10 IV shines here by virtue of its pocketable size, light weight, and respectable battery life (360 shots per charge). Its 5-axis IS aids in low light handheld shooting on the go. The touchscreen makes tap-to-focus intuitive for candid moments. While image quality is less stellar than full-frame, it is more than adequate for social sharing and blog publishing.

The Sony A9 II, despite being heavier (678g) and bigger, remains reasonably portable for a professional-grade camera and offers double the battery life. The higher build quality and robust lens options bring tradeoffs in bulk but unmatched versatility on long trips or when “leaving nothing to chance.”

Street photographers who prize invisibility may find the Olympus more comfortable; however, professionals traveling for assignments will appreciate the A9 II’s endurance and reliability.

Macro and Close-Up: Stabilization and Precision

Macro photography demands precise focusing and excellent stabilization to resolve minuscule details.

The Olympus E-M10 IV benefits from in-body 5-axis stabilization, which works harmoniously with its Micro Four Thirds lenses designed with close focusing distances. The crop factor effectively extends focal lengths, also helping with subject magnification.

The Sony A9 II provides similar 5-axis stabilization in a larger sensor format. Its native full-frame lenses generally have longer minimum focus distances. However, Sony’s vast array of macro lenses and adapters allows for professional-level close-up work, with superior image quality and background blur.

For casual macro enthusiasts, Olympus offers a neat, accessible package. Professionals seeking the finest detail and quality will gravitate towards the Sony ecosystem.

Night and Astro Photography: ISO Capability and Exposure Modes

Low light shooting is where sensor size and noise characteristics truly come into focus.

The Sony A9 II’s full-frame sensor and boosted ISO ceiling to 204,800 (expandable) makes it a powerhouse for night or astrophotography. Its low noise at high ISOs enables capturing stars and landscapes under moonlight without excessive long exposure or noise reduction. The camera also provides flexible exposure modes and a silent electronic shutter for undisturbed shooting.

The Olympus E-M10 IV maxes out at ISO 25,600 natively and is noisier in dim conditions. However, its image stabilization and compact form factor make it easier for handheld night shots, trading ultimate image purity for portability.

If astro or long-exposure night photography is a priority, Sony’s A9 II is your friend. For casual night shooting or cityscapes, Olympus holds its own.

Video Features: 4K, Stabilization, and Audio Support

Both cameras offer 4K video at 30p, but there a few critical differences.

Olympus captures UHD 4K internally at 102 Mbps with H.264 encoding. However, it lacks microphone and headphone jacks, limiting external audio control - a big consideration for serious videographers. It also does not include advanced video-centric features like log profiles or 10-bit color.

The Sony A9 II shoots 4K UHD at 100 Mbps (XAVC S), but with added pro features including mic and headphone ports for real-time audio monitoring. The superior sensor and image processor enable richer video quality and smoother autofocus while filming. In-body 5-axis stabilization assists handheld shooting for both.

For casual video shooters or vloggers, the Olympus is a capable, compact option. Filmmakers or hybrid shooters will prefer the greater control and video integration of the Sony.

Battery Life and Storage: Practical Considerations for Field Use

Battery life can’t be ignored, especially for all-day shoots or extended trips.

The Olympus OM-D E-M10 IV offers around 360 shots per charge - enough for a day of casual shooting but with limited buffer for burst-heavy work. Its single SD card slot supports UHS-II speeds but offers no redundancy.

Sony’s A9 II doubles the battery life with the NP-FZ100 battery, delivering about 690 shots per charge under typical conditions. Dual SD card slots supporting UHS-II also allow simultaneous backup or overflow storage, enhancing reliability immensely for pros.

If you’re a casual shooter, the Olympus battery life and single card slot are fine; for professionals shooting weddings, sports, or wildlife, Sony’s dual slots and longer endurance are vital.

Price and Value: Entry-Level Affordability vs Pro Investment

The Olympus OM-D E-M10 IV is priced around $699, making it one of the most accessible Micro Four Thirds cameras with robust features. It’s an excellent value for hobbyists, beginners upgrading from smartphones, or travelers wanting quality without bulk.

The Sony A9 II, at roughly $4498, is a substantial investment aligned with its flagship status. This price reflects cutting-edge AF tech, full-frame image quality, advanced build, and pro-level video and connectivity.

While Olympus excels in affordability and beginner usability, Sony is an elite tool designed for careers and serious passion projects.

Final Scores by Category

How They Fare Across Photography Genres

Sample Images: Comparing Real-World Output

Olympus E M10 IV front Olympus E M10 IV screen back Sony A9 II front Sony A9 II screen back

Conclusion: Which Camera Fits You?

After extensive hands-on testing and benchmarking, the choice between these cameras hinges on your shooting priorities and budget.

• Choose the Olympus E-M10 IV if:

  • You desire a lightweight, compact camera for travel, everyday snapshots, or street photography.
  • You’re an enthusiast wanting solid image quality without overwhelming complexity.
  • Portability and affordability are more important than absolute image quality.
  • You shoot mainly portraits, landscapes, or casual macro where lower burst rates and AF speed are tolerable.
  • You want competent 4K video for occasional use without professional audio needs.

• Choose the Sony A9 II if:

  • You are a professional or semi-pro needing unparalleled autofocus speed, accuracy, and tracking for sports or wildlife.
  • Image quality and high ISO performance are mission-critical.
  • You require robust build quality, weather sealing, and extended battery life.
  • You shoot fast-action subjects regularly and rely on large buffer depths.
  • You want professional video features including mic/headphone jacks and pro codecs.
  • You are ready to invest significantly in lenses and accessories aligned with pro workflows.

Both cameras bring their own strengths to the table. The E-M10 IV is a reliable, capable camera for many types of photography, especially for those who prioritize comfort and cost. The A9 II is a professional tool where performance, durability, and image quality justify its higher investment.

Whatever your path, understanding these key differences will help you make a considered purchase that supports your photographic journey.

If you have specific use cases or additional questions, I’m happy to provide tailored recommendations or lens pairing advice to maximize your chosen system. As always, happy shooting!