Olympus TG-320 vs Sony A7 III: A Comprehensive Comparison for Every Photographer

Choosing the right camera is a crucial decision for photographers, whether you're a casual shooter, an enthusiast venturing into more serious work, or a seasoned professional seeking gear upgrades. Today, we're diving deep into a comparison of two vastly different cameras - the rugged Olympus TG-320, a compact waterproof point-and-shoot, and the powerhouse Sony Alpha A7 III, a professional-grade full-frame mirrorless camera. This comparison aims to help you understand their respective strengths, weaknesses, and ideal use cases based on over 15 years of hands-on camera testing.

Why these two? While they cater to very different audiences and price points, their contrast makes for an enlightening study of how camera technology serves distinct photographic goals. This comparison is shaped by real-world testing, technical analysis, and practical insights - here’s everything I’ve learned to help you make the best choice.

First Impressions: Size and Design Differences

At a glance, the Olympus TG-320 and the Sony A7 III couldn't be more different in size and style.

The TG-320 is incredibly compact and lightweight, measuring just 96x63x23mm and weighing 155 grams. This makes it ideal for adventurous shooters who want to travel light or capture images underwater and in extreme conditions without bulky gear.

In contrast, the Sony A7 III is a much larger, heavier camera (127x96x74mm, 650 grams) with a classic SLR-style mirrorless design. Its robust magnesium alloy body incorporates extensive weather sealing, giving it professional durability but at the cost of portability.

Ergonomics and Handling

The TG-320’s compactness comes at the expense of control and customization. Its small handgrip and button layout feel cramped for larger hands. Additionally, it lacks advanced manual controls or dials, which limits creative flexibility.

The Sony A7 III offers an ergonomic grip, well-placed buttons, customizable dials, and a top LCD display for key settings at a glance.

From my hands-on experience, the A7 III’s controls support quick adjustments in dynamic shooting scenarios - something you’ll miss on the TG-320.

Sensor and Image Quality: A World Apart

Sensor technology profoundly affects image quality, affecting resolution, low light performance, dynamic range, and more. Let’s break down how these two compare.

Olympus TG-320

• Sensor: 1/2.3" CCD sensor, 14MP
• Max resolution: 4288 x 3216
• ISO range: 80 - 1600 (native)
• Image processing: TruePic III+

The TG-320’s small, older CCD sensor limits its image quality. While it delivers decent daylight images, noise becomes apparent quickly past ISO 400, and dynamic range is tight, causing highlight clipping and blocked shadows in challenging light.

Sony A7 III

• Sensor: Full-frame 35.8x23.8 mm BSI-CMOS sensor, 24MP
• Max resolution: 6000 x 4000
• ISO range: 100 - 51200 (expandable to 50-204800)
• Image processing: Bionz X

The A7 III’s large full-frame sensor offers exceptional image quality, with superior color depth, incredible low-light capabilities (noise is well controlled even at ISO 6400+), and a wide dynamic range that preserves highlight and shadow detail.

In practical terms, this means the A7 III produces cleaner, sharper images with more depth and nuance. I tested both cameras in multiple environments - indoor low light, outdoor bright sunlight, and high-contrast scenes - and the A7 III’s performance was clearly superior across the board.

Display and Viewfinder Experience

An often overlooked usability aspect is the camera's display and viewfinder system, critical for composing and reviewing shots comfortably.

Olympus TG-320

• 2.7" fixed TFT color LCD
• Resolution: 230k dots
• No viewfinder

The TG-320's screen is basic - small, low resolution, and fixed in place. This is adequate for casual framing but becomes challenging in bright sunlight. The lack of any viewfinder means you rely solely on the backscreen.

Sony A7 III

• 3" tilting LCD with touchscreen functionality
• Resolution: 922k dots
• High-resolution OLED electronic viewfinder (EVF) with 2,359k dots coverage

The A7 III offers a bright tilting touchscreen for flexible shooting angles, plus a highly detailed EVF that simulates an optical viewfinder experience with 100% frame coverage and real-time exposure previews.

From extensive field use, the EVF is invaluable for clear composition in all lighting conditions and rapid action shooting, where quick eye-to-viewfinder switching saves precious moments.

Autofocus Performance and Speed

Accurate and fast autofocus profoundly impacts success rates across photography genres - from static portraits to rapid sports action.

Olympus TG-320

• Contrast-detection AF with face detection
• Single AF mode only, no manual focus
• Continuous shooting at 1 fps

The TG-320 uses basic contrast detection AF with face detection. Autofocus is slow and often hunts in low light or low contrast scenes. There is no manual focus or advanced AF area selection, limiting control. Its continuous shooting speed of about 1 frame per second is slow by today’s standards.

Sony A7 III

• Hybrid autofocus system with 693 phase-day focus points + 425 contrast-detection points
• Eye AF for humans and animals (very precise)
• Continuous shooting at up to 10 fps with AF/AE tracking

The A7 III’s autofocus system is sophisticated and versatile, combining phase detection pixels embedded across the sensor with contrast detection for precise and fast tracking. Eye AF works impressively well even at wide apertures and moving subjects, a game-changer for portrait and wildlife photographers.

During tests, I found the A7 III could reliably track fast-moving subjects in sports and wildlife settings, with minimal focus hunting - even in lower light situations thanks to sensitivity down to -3 EV.

Build Quality and Environmental Resilience

How well a camera endures real-world conditions matters, especially for travel, wildlife, or adventure photography.

Olympus TG-320

• Waterproof to 10 meters
• Freezeproof to -10°C
• Shockproof from 1.5m drops
• Dustproof

The TG-320 is designed as a tough, go-anywhere compact. Its ruggedized, sealed body assures peace of mind while underwater, in snowy conditions, or rough terrain. I tested it on beach vacations and mild hikes - its resilience is a key selling point here.

Sony A7 III

• Magnesium alloy body with dust and moisture resistance
• Not waterproof or freezeproof rated
• Weightier and less shock resistant than TG-320

The A7 III’s weather sealing suffices for most outdoor use, but it is not designed for underwater or extreme shock protection. Handling with care or weatherproof housing is advised for harsher environments.

Lens Ecosystem and Flexibility

No camera is better than its glass, and lens choice is deeply linked to creative and technical potential.

Olympus TG-320

• Fixed zoom lens (28-102mm equivalent, 3.6x optical zoom)
• Max aperture f/3.5 - f/5.1
• Macro focusing down to 3cm

No interchangeable lenses here. The built-in zoom is versatile for casual shooting but limited flexibility for artistic or specialized work.

Sony A7 III

• Sony E-mount system with over 120 compatible lenses (native and third party)
• Supports a wide range: primes, zooms, macro, super telephoto, specialty lenses
• Full compatibility with professional-grade optics featuring wide apertures and optical stabilization

The A7 III’s lens ecosystem is one of the most extensive on the market, enabling photographers to tailor their setup to any genre or challenge. Whether you need a fast 85mm f/1.4 portrait prime, a rugged 100-400mm wildlife zoom, or ultra-wide landscapes, options abound.

Battery Life and Storage Considerations

Battery longevity and storage solutions affect day-long shoots and travel usability.

Olympus TG-320

• Proprietary LI-42B battery
• Approx. 150 shots per charge
• Single SD/SDHC/SDXC card slot

With moderate battery life, extended outings require spare batteries. Capacity and speed suffice for the casual user. Storage via single card is straightforward.

Sony A7 III

• Larger NP-FZ100 battery
• Excellent battery life: about 610 shots per charge (CIPA rating)
• Dual card slots (UHS-II SD + SD, Memory Stick compatible)
• Faster USB 3.1 charging and data transfer

After extensive shooting sessions, I found the A7 III’s battery life reliable for professional workflows without daily battery swaps. Dual slots give peace of mind through backup or overflow.

Video Capabilities

While both cameras can shoot video, their specifications and suitability differ greatly.

Olympus TG-320

• HD video max 1280x720 @ 30fps
• MPEG-4, H.264 compression
• No external mic input, basic sound control
• No image stabilization enhancements for video

Basic HD video is sufficient for casual footage but lacks professional features or 4K resolution.

Sony A7 III

• 4K UHD video at 30/24p, Full HD up to 120fps for slow motion
• XAVC S codec for high bitrates, better color depth
• 5-axis in-body stabilization optimized for video
• External microphone and headphone jacks for professional audio monitoring
• Time-lapse recording support

For serious videographers, the A7 III is a versatile tool, capable of top-tier 4K capture, slow motion, and advanced audio management. It stands out for hybrid shooters doing both stills and movies.

Genre-Specific Photography Performance

Understanding how these cameras fare in different photographic disciplines helps clarify the best use scenarios.

Portrait Photography

• Olympus TG-320: Decent face detection autofocus and macro ability; image quality is soft at wide apertures; limited bokeh capability due to small sensor and slow lens.
• Sony A7 III: Excellent eye and animal eye AF, rich color depth, creamy bokeh achievable with fast prime lenses. Ideal for professional portraits.

Landscape Photography

• TG-320 struggles with dynamic range and resolution; fixed lens limits framing.
• A7 III excels, with vast sensor area capturing detailed, wide dynamic range images. Weather sealing adds reliability in fieldwork.

Wildlife and Sports Photography

• TG-320’s slow AF and 1 fps continuous shooting render it unsuitable.
• A7 III’s 10 fps burst and sophisticated AF tracking lock onto fast subjects precisely.

Street Photography

• TG-320’s compact, rugged design offers discrete shooting.
• A7 III is bulkier but with silent shutter options; its superior AF helps in dynamic scenes.

Macro Photography

• TG-320 features close macro focusing down to 3cm, good for casual macro work.
• A7 III partnerships with dedicated macro lenses enable high magnification and precision focusing.

Night and Astrophotography

• TG-320 limited to ISO 1600, struggles with noise; lacks manual controls.
• A7 III supports high ISO, long exposure modes, and captures cleaner low-light images.

Travel Photography

• TG-320’s waterproof, shockproof rugged design is a top travel companion for riskier environments.
• A7 III offers versatility and image quality but requires extra care and weight considerations.

Professional Work

• TG-320 not suited due to fixed lens, lack of RAW support, and limited controls.
• A7 III shines with RAW capture, tethering options, robust build, and versatile lens systems.

Connectivity and Workflow Integration

Smooth image transfer and camera integration can improve workflow efficiency.

Olympus TG-320

• No wireless or Bluetooth connectivity.
• USB 2.0 for data transfer.
• No GPS or NFC support.

Sony A7 III

• Built-in WiFi, Bluetooth, and NFC for seamless file sharing and remote control.
• USB 3.1 connection supports fast tethering and direct charging.
• Compatible with Sony’s Imaging Edge and other professional workflow software.

Price-to-Performance Assessment

• Olympus TG-320: Originally positioned as an affordable, rugged point-and-shoot for outdoor enthusiasts, it remains available at budget prices. Its performance fits casual needs, especially underwater or adventure uses.

• Sony A7 III: At around $2000 body-only (as of its announcement), it represents a mid-range professional investment. The price reflects extensive features, robust build, and top-tier image quality, with significant scope for lens upgrades.

Summary: Pros and Cons at a Glance

Feature	Olympus TG-320	Sony A7 III
Image Quality	Adequate for casual daylight shots; limited dynamic range and high ISO	Exceptional full-frame quality; outstanding low-light and dynamic range
Autofocus	Basic, face detection; no manual focus; slow	Advanced hybrid AF with Eye AF and fast continuous tracking
Build & Durability	Waterproof, shockproof, freezeproof	Weather-sealed, robust but not ruggedized for underwater or shocks
Portability	Ultra-compact and lightweight	Larger and heavier but still manageable for travel
Lens Options	Fixed zoom lens only	Extensive E-mount ecosystem with professional optics
Video	Basic 720p HD	High-quality 4K and slow-motion Full HD with pro audio support
Battery Life	~150 shots per charge	Excellent; ~610 shots with dual card slots
Connectivity	None	Built-in WiFi, Bluetooth, NFC, and USB 3.1
Price	Budget-friendly	Mid-range professional price

Who Should Consider the Olympus TG-320?

• You want a durable, waterproof camera for underwater, beach, hiking, or travel use.
• Your focus is casual photography with automatic modes - no need for manual settings.
• Small size, rugged build, and shockproof design are high priorities.
• You’re seeking an affordable camera primarily for snapshots, quick memories, or as a secondary travel device.

Who Should Invest in the Sony A7 III?

• You demand professional-level image quality across a wide range of photographic styles.
• You need fast, reliable autofocus for portraits, wildlife, sports, or events.
• Investing in a flexible camera system with a vast lens and accessory ecosystem is important.
• You create high-end video content requiring 4K capture and professional audio controls.
• Weather sealing and durable body are necessary for diverse conditions, excluding extreme waterproof environments.
• Your budget allows for a robust full-frame mirrorless system.

Final Thoughts: Choosing What Matters Most

If you're looking for an affordable, rugged waterproof compact for casual and adventurous use, the Olympus TG-320 remains a trustworthy companion - though its aging sensor and limited feature set mean it's best as a second, supplemental camera rather than a primary photographic tool.

Conversely, the Sony A7 III is a remarkably versatile professional mirrorless camera that outperforms the TG-320 in nearly all technical aspects. With top-tier autofocus, stellar low-light capabilities, and a broad lens selection, it is a true workhorse for semi-pros and pros alike. Its slightly larger form factor is the price you pay for unmatched performance and creative freedom.

Above are examples highlighting the dramatic image quality difference: the A7 III’s photographs showcase rich detail and color fidelity, while the TG-320 provides serviceable images for casual use but with softness and reduced tonal range.

Overall Ratings & Recommendations

The A7 III rates highly for image quality, autofocus, and versatility. The TG-320 scores well for durability and portability but falls short in critical performance areas.

If your photographic journey is just beginning or you need a versatile all-rounder with professional aspirations, the Sony A7 III is a worthy investment. For casual adventure enthusiasts who prioritize a durable, no-fuss camera, the Olympus TG-320 still impresses with ruggedness and simplicity.

Remember, the best camera is one you’ll enjoy using and that fits your individual needs and style. I hope this detailed guide helps you confidently find the camera that matches your photographic ambitions.

Feel free to reach out with questions or share your experiences!

About the Author

With over 15 years testing thousands of cameras across every genre - from macro to wildlife, landscape to fast-paced sports - I bring practical, evidence-based insights grounded in hands-on experience. My aim is to empower photographers of all levels to make informed, confident choices based on real-world performance and tech know-how.

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