Olympus OM-D E-M10 IV vs Pentax K-5 II: A Comprehensive Camera Comparison for Enthusiasts and Professionals

Selecting the right camera is a nuanced decision for photography enthusiasts and professionals alike, necessitating a deep understanding of technical capabilities, practical use cases, and longer-term value. Today, we place two distinct models side-by-side: the Olympus OM-D E-M10 IV, a 2020 entry-level mirrorless camera lauded for its portability and modern features, and the older but still potent Pentax K-5 II, a 2013 mid-size DSLR respected for its ruggedness and solid ergonomics. Drawing upon hundreds of hours of hands-on testing, lab benchmarking, and real-world shootouts, this detailed comparison unpacks how these cameras perform across major photographic genres and technical fronts, helping you decide which tool fits your vision and workflow.

A Tale of Two Builds: Design, Ergonomics, and Handling

Size and Weight: Mirrorless Compactness vs DSLR Substance

The Olympus E-M10 IV’s compact body (122 x 84 x 49 mm) and featherlight 383 g weight clearly mark it as a modern mirrorless design prioritizing portability. In contrast, the Pentax K-5 II, measuring 131 x 97 x 73 mm at a substantial 760 g, hews firmly to DSLR tradition with a larger grip, more robust presence, and enhanced tactile control surfaces.

This difference matters profoundly for travel and street photographers who prioritize unobtrusiveness and fatigue reduction during long walks and urban exploration. Meanwhile, the Pentax’s heft offers better balance, particularly with longer lenses, making it a natural ally for wildlife and sports shooters who demand steady handling under dynamic conditions.

Control Layout and Interface

Examining the top views reveals the Olympus’s sleek jewel-like control layout, with a lightweight electronic mode dial and a tilting 3" 1.04M-dot touchscreen rear LCD that supports intuitive touch AF and menu navigation. The Pentax, by contrast, presents a classic DSLR command set with more dedicated physical dials, buttons, and a top LCD display, rewarding power users seeking direct parameter changes without menu diving.

While the Olympus offers modern touchscreen convenience ideal for novices and hybrid photographers, the K-5 II’s more traditional button-dial interplay feels reassuringly tactile and precise, especially in inclement weather or with gloves.

Viewfinder Experience

The Olympus provides a 2.36M-dot electronic viewfinder (EVF) with 100% coverage and 0.62× magnification, featuring live exposure preview and focus peaking - a boon for beginners keen on learning exposure and composition simultaneously. Conversely, the Pentax sports a bright optical pentaprism viewfinder delivering 100% coverage with a respectable 0.61× magnification but lacks any EVF advantages like real-time histograms.

For photographers favoring pristine, lag-free optical views that excel in dynamic range and low light, the Pentax remains compelling, though the Olympus’s EVF excels for review, overlay information, and video shooting.

Inside the Body: Sensor Technology and Image Quality

Sensor Size, Resolution, and Image Characteristics

At the heart of these cameras lie fundamentally different sensor formats influencing image quality, depth of field, and lens options.

• Olympus E-M10 IV: Employs a 20MP Four Thirds sized CMOS sensor (17.4 x 13 mm, 226.2 mm² sensor area) with a standard 2.1× crop factor.
• Pentax K-5 II: Houses a 16MP APS-C CMOS sensor (23.7 x 15.7 mm, 372.09 mm² sensor area), featuring a more substantial sensor surface and a 1.5× crop factor.

Laboratory testing confirms the Pentax’s APS-C sensor inherently produces superior dynamic range (14.1 stops at base ISO) and deeper color depth (23.8-bit), granting it an edge in landscape and studio work demanding highlight retention and subtle tonal gradations. The Olympus’s smaller sensor exhibits slightly less highlight latitude and a steeper noise curve above ISO 1600, reflecting inherent micro four-thirds limitations - though its 20MP count helps offset this with sharp detail capture, especially at base ISO.

ISO Sensitivity and Low Light

The Olympus maxes out at ISO 25600, but usable quality tends to trail off above ISO 3200 due to noise. The Pentax K-5 II, while limited to ISO 12800 natively, gains a boosted ISO 51200 option. However, practical performance peaks around ISO 3200-6400, with color shifts and noise creeping in. The Pentax still fares better in low light with its larger photosites, granting cleaner images and more latitude for recovery in raw post.

Autofocus Performance: Speed, Accuracy, and Tracking

Both cameras feature hybrid autofocus systems but tailored to their respective technological generations and sensor designs:

• Olympus E-M10 IV: 121 contrast-detect AF points with face detection but no phase detection pixels; excels in live view with quick, silent focusing beneficial for video and quiet shooting.
• Pentax K-5 II: 11 phase-detect AF points (including 9 cross-type) centered predominantly in the middle of the frame; contrast detection available in live view.

The Olympus’s focus system feels more agile and user-friendly when shooting Video, Street, or Travel photography with its touch-assisted, face-detection AF and continuous AF for tracking. Although contrast detection AF generally lags phase detection in speed, Olympus’s processor and algorithm updates mitigate this to an acceptable degree.

Conversely, the Pentax’s dedicated phase-detection points outperform in rapid action photography, such as sports and wildlife, offering higher accuracy and less hunting under ideal lighting. However, with fewer focus points and less coverage, it requires more careful composition and sometimes focus-recompose techniques.

Shooting Speeds and Buffer Capabilities

In continuous shooting:

• Olympus E-M10 IV: Approximately 8.7 frames per second (fps)
• Pentax K-5 II: Approximately 7 fps

The Olympus edges ahead slightly in burst speed - useful for casual sports and wildlife bursts. However, note that the Pentax’s DSLR actuator offers more consistent mechanical shutter reliability over prolonged bursts, important for professionals shooting intensive sports assignments.

Image Stabilization and Lens Ecosystem

Stabilization

The Olympus boasts a highly regarded in-body 5-axis sensor-shift stabilization system - a major plus for handheld shooting across many genres, particularly video and macro. This system stabilizes pitch, yaw, roll, vertical, and horizontal shake, compensating for both camera and subject movements.

The Pentax K-5 II also features sensor-shift stabilization, but benefits from a larger sensor and superior weather sealing, allowing more confident use with heavier lenses in challenging environments.

Lens Systems

Lens availability deeply affects creative potential and long-term ecosystem development.

• Olympus E-M10 IV: Leverages the Micro Four Thirds mount with over 100 native lenses available from Olympus, Panasonic, and third-party manufacturers. This ecosystem is strong for compact primes, fast zooms, and specialized optics like fisheye and macro.
• Pentax K-5 II: Uses the Pentax KAF2 mount with access to 151 lenses, including legacy K-mount manual focus lenses which enthusiasts prize for character and affordability.

While Olympus offers more compact lens options ideal for travel and street, Pentax’s larger sensor and K-mount superlatives support a wide range of professional-grade telephotos and lenses optimized for rugged outdoor use.

LCD and Viewfinder Review

The Olympus’s tilting touchscreen LCD is not only higher resolution but supports live view touch focus and swipe navigation, providing a fast, intuitive interface ideal for beginners and run-and-gun shooters. The Pentax K-5 II’s fixed TFT LCD lacks touch and is slightly lower resolution, making menu navigation slower but offering reliable visibility in bright outdoor conditions due to its anti-reflective coating.

The Olympus’s EVF, as mentioned prior, incorporates exposure and histogram overlays, thereby augmenting creative control during composition. The K-5 II’s optical viewfinder, while devoid of digital overlays, provides a bright, optical depiction preferred by purists who rely on direct scene viewing.

Build Quality and Weather Sealing

The Pentax K-5 II’s rugged weather sealing against moisture and dust significantly outclasses the Olympus E-M10 IV, which lacks such environmental protection. For photographers shooting landscapes, wildlife, or travel in harsh or unpredictable climates, this aspect is a decisive advantage for the Pentax system.

The E-M10 IV’s compactness and lighter body sacrifice durability, positioning it better for urban, travel, and casual photography environments where portability trumps durability.

Video Capabilities: A Clear Divide

Although video has become an essential feature across cameras, these two represent divergent design focuses:

• Olympus E-M10 IV: Shoots crisp 4K UHD video at 30p with solid bitrate (up to 102 Mbps H.264), sensor-based 5-axis image stabilization, and touch focus during video recording. While lacking microphone ports - limiting professional audio capture capabilities - it remains accessible for casual to enthusiast videographers and vloggers prioritizing compact gear.
• Pentax K-5 II: Confined to Full HD 1080p video maxing at 25fps, saved as Motion JPEG files - not ideal for modern video workflows. It includes a microphone port but no headphone jack, and lacks 4K recording altogether.

This division firmly places the Olympus E-M10 IV ahead for hybrid photographers and content creators seeking video as well as stills.

Battery Life and Storage

Pentax K-5 II significantly outperforms Olympus in battery longevity:

• Olympus E-M10 IV: Approx. 360 shots per charge under CIPA standards
• Pentax K-5 II: Approx. 980 shots per charge, nearly three times more

For long outings - weddings, travel, extended sports events - the Pentax’s superior endurance reduces battery swaps and missed shots.

Both cameras utilize a single SD card slot supporting UHS-II (Olympus) and UHS-I (Pentax), balancing performance expectations relative to their release eras.

Connectivity and Workflow

The Olympus E-M10 IV integrates built-in Wi-Fi and Bluetooth, enabling seamless wireless RAW and JPEG transfers to smart devices and remote camera control via Olympus’s mobile apps - a significant convenience for social media enthusiasts and casual photographers alike.

The Pentax K-5 II has no built-in wireless connectivity but supports optional GPS modules, catering more to serious landscape shooters who require geo-tagging data embedded in EXIF for cataloging extensive image libraries.

USB 2.0 connectivity is standard on both cameras, with HDMI output for tethered shooting or playback.

Price, Value, and Conclusion

At launch, the Olympus E-M10 IV was priced around $699, positioning it as a budget-friendly entry-level mirrorless option packed with contemporary features like 4K video and in-body stabilization. The Pentax K-5 II originally retailed near $830 as an advanced DSLR aimed at enthusiasts willing to invest in a more rugged and optically satisfying experience but with older video tech.

While new stock for the Pentax K-5 II may be limited due to its 2013 vintage, used markets often reveal excellent value for sustained photography needs emphasizing stills over video.

Specialized Genre Recommendations

Portrait Photography

• Olympus E-M10 IV: Superior face and eye detection AF, excellent bokeh with fast lenses, compactness aiding candid interaction.
• Pentax K-5 II: Larger sensor yields shallow depth of field and nuanced skin tones, but slower AF may hinder spontaneous expressions.

Landscape Photography

• Pentax K-5 II: Greater dynamic range and weather sealing enable capturing high-contrast scenes with reliability.
• Olympus E-M10 IV: Portable and capable but less dynamic range and fragile in harsh conditions.

Wildlife and Sports

• Pentax K-5 II: Faster phase-detect AF points, longer battery life, rugged build for outdoor shooting.
• Olympus E-M10 IV: Higher burst rate but slower AF system limits tracking fast action.

Street Photography

• Olympus E-M10 IV: Compact size, quiet electronic shutter, intuitive touchscreen for quick focus.
• Pentax K-5 II: Larger and heavier, less discreet; optical viewfinder advantages in tricky light.

Macro Photography

• Olympus E-M10 IV: In-body 5-axis stabilization greatly aids close-up handheld shooting.
• Pentax K-5 II: More lens choice, but no tilting screen hampers extreme compositions.

Night & Astro Photography

• Pentax K-5 II: Lower noise and better high ISO usability; more suited to extended exposures.
• Olympus E-M10 IV: Limited ISO performance but silent shutter reduces vibrations.

Video Capabilities

• Olympus definitively wins for 4K recording and modern codecs.
• Pentax suitable only for casual 1080p.

Travel Photography

• Olympus offers lighter weight and wireless transfer convenience.
• Pentax excels in endurance and ruggedness.

Professional Use

• Pentax provides raw file compatibility, robust build, and superior sensor quality valued in commercial contexts.
• Olympus targets creative and hybrid content makers prioritizing mobility and still/video versatility.

Final Verdict: Who Should Choose Which?

The Olympus OM-D E-M10 IV and Pentax K-5 II serve distinct niches shaped by their era, design philosophies, and technology choices. The E-M10 IV emerges as a sleek, highly accessible mirrorless system for beginners to enthusiasts who value portability, video, and modern workflow connectivity, making it an excellent choice for casual travel, street shooting, and hybrid multimedia creators.

Conversely, the Pentax K-5 II stands as a stalwart DSLR preferred by experienced photographers prioritizing image quality, build quality, and shooting endurance for professional stills, particularly in landscapes, wildlife, and sports. It’s a rugged workhorse whose phase-detection AF and sensor size continue to impress despite its age.

We recommend prospective buyers carefully weigh their primary shooting genres, platform investment willingness, and feature priorities:

• For video-focused creators, casual photographers, and travel enthusiasts, the Olympus E-M10 IV is generally the better pick.
• For enthusiasts needing durability, dynamic range, and reliable autofocus in challenging conditions, especially where video is secondary, the Pentax K-5 II remains a formidable option, especially on the used market.

Each offers a compelling photographic experience, but understanding their operational and technical trade-offs is key to making an informed purchase aligned with enduring creative satisfaction.