Olympus TG-3 vs. Pentax 645D: A Tale of Two Cameras from Opposite Ends of the Spectrum

Choosing between the Olympus Tough TG-3 and the Pentax 645D is a bit like deciding whether to drive a rugged ATV through mud or cruise a luxury sedan along winding country lanes - they’re both vehicles, but designed for wildly different adventures. I’ve spent weeks side-by-side testing these two cameras, which couldn’t be more divergent in purpose yet each quite brilliant in their own realms.

In this candid, hands-on comparison, I’ll unspool the practical realities, technical chops, and real-world uses of both the compact Olympus TG-3 and the heavyweight medium-format Pentax 645D. Whether you’re a connoisseur of fine detail or an outdoorsy soul craving a camera that laughs in the face of mud, cold, and water, this article will serve you well.

Meet the Contenders: Small Wonder vs. Medium Format Giant

Olympus TG-3: A hardy, pocketable waterproof compact designed for those who want to shoot underwater worlds, snowy summits, or dusty festivals without worrying about weather or bumps. It boasts a fixed 25-100mm equivalent lens, a bright f/2.0 aperture at the wide end, and sensor-shift image stabilization in a splashproof, shockproof, freezeproof kit that fits comfortably in one hand.

Pentax 645D: A revolution in image quality for its 2010 vintage, the 645D is a robust pro-grade medium format DSLR with a massive 40MP CCD sensor. Weighing over 1.4 kg and armed with Pentax’s 645AF2 mount lenses, it’s built for studio, landscape, and high-end professional work where image detail and dynamic range trump portability.

Before we dive deeper, let’s lay out their physicality and controls because size and ergonomics are fundamental to how you’ll shoot.

Size, Weight, and Handling

The Olympus TG-3 is tiny - 112 x 66 x 31 mm and just 247g. It fits any jacket pocket and weighs less than a typical smartphone. Perfect if you’re packing light or tossing your camera in your daypack without fuss.

The Pentax 645D is a beast by comparison: 156 x 117 x 119 mm with a hefty 1480g weight. It feels like holding a professional tool crafted for precision work, complete with robust weather sealing, a classic pentaprism optical viewfinder, and tactile, chunky buttons for operation even with gloves.

Ergonomically, the TG-3’s fixed lens and minimal buttons mean it’s swift to kick off point-and-shoot shooting, but the control surfaces are a bit cramped - no clubs for your thumbs here. The Pentax, conversely, offers an arsenal of physical dials and buttons, an illuminated top panel, and a solid grip designed for serious shooting sessions.

Sensor Technology and Image Quality: Pixels and Beyond

At the heart of any camera, the sensor tells the tale of potential image fidelity.

Olympus TG-3’s Small 1/2.3” Sensor

The TG-3 sports a 16MP backside-illuminated (BSI) CMOS sensor measuring 6.17 x 4.55 mm (28.07mm²). While BSI technology boosts light-gathering on such a tiny sensor, it still cannot match larger sensors in dynamic range, noise handling, or color depth. This sensor is a common breed in compact cameras, favoring portability over image quality. It’s no surprise that the Olympus cannot shoot RAW, relying only on JPEG output.

What does this mean practically? Images are perfectly fine for casual shooting, web-sharing, social media, or even 8 x 10 prints, but they won’t rival larger sensor cameras in low light, fine detail, or color fidelity.

Pentax 645D’s Medium Format CCD Marvel

The Pentax 645D’s sensor steals the show if pure image quality is your obsession. Its medium format CCD measures a massive 44 x 33 mm (1452mm²) - over 50 times the area of the TG-3 sensor - with 40MP resolution (7264x5440 pixels).

This sensor’s sheer size plus the lack of an anti-aliasing filter (to boost resolution crispness, albeit at a moiré risk) delivers exceptional color depth (DxO color depth 24.6 bits), wide dynamic range (12.6 stops), and spectacular low-light performance (ISO up to 1600 native, with usable extended ranges).

Importantly, the 645D supports uncompressed, high-bit-depth RAW output - essential for professional retouching and tearing apart the image with all the tonal subtleties intact.

Real-World Image Quality Showdown: What’s the Difference?

Testing both cameras side by side in daylight, portrait, and macro scenarios reveals their signature strengths.

• Portraits: The 645D’s medium format sensor with carefully selected Pentax lenses renders skin tones with unparalleled smoothness and tonal nuance. Its shallow depth-of-field at wide apertures produces creamy bokeh that isolates subjects artistically. Meanwhile, the TG-3’s smaller sensor and fixed, slow-aperture telephoto end struggle with background separation, producing less creamy bokeh, but it can still manage decent portraits in good light using its face/eye detection autofocus.

• Macro: The TG-3 shines here with its ability to focus as close as 1 cm, aided by a bright f/2.0 lens opening and sensor-shift stabilization, allowing stunning close-ups without adapters. The 645D can do macro through specialized medium format lenses, but with less convenience and more setup, given its bulk and manual focus nature.

• Landscape: The 645D’s huge sensor captures landscape scenes with epic detail, wide dynamic range preserving highlight and shadow information, and withstanding subtle color gradations even in tricky conditions like sunsets. The TG-3 is a capable hiker’s compact with a decent dynamic range for a small sensor, but struggles with shadow recovery and noise above ISO 400.

• Low Light & Night: The TG-3’s max ISO of 6400 offers flexibility, but noise becomes quite apparent above ISO 800. It compensates with built-in stabilization and exposure flexibility (shutter speeds up to 4 seconds) for night shots. The 645D tops out at ISO 1600 native, but with much cleaner results, thanks to its sensor size. Unfortunately, the 645D lacks video and has no live view or night shooting advantages here.

Olympus TG 3 front Olympus TG 3 screen back Pentax 645D front Pentax 645D screen back

Autofocus Systems and Shooting Speed: Quick Draw vs. Precision Focus

Because autofocus systems can make or break your shooting experience, especially with moving subjects, let’s dissect each camera’s AF prowess.

• Olympus TG-3: Contrast-detection AF with face detection and continuous AF modes allows reliable focus in good light on still or moderately moving subjects. It offers 5 continuous frames per second, decent for casual action or wildlife snapshots. However, its limited focus point system and absence of phase-detection AF mean it can hunt slowly in low light or with fast subjects.

• Pentax 645D: A pro-grade 11-point phase-detection AF system anchors the 645D, designed for deliberate, precision-focused applications rather than sports or wildlife. It shoots single frame per second, leveraging the full sensor resolution without buffer bottlenecks. Its manual focus expertise is key - great for studio and landscape, less suited to fast-paced shooting.

Bottom line: The TG-3 wins in speed and convenience with its rapid AF confirmation for casual action; the 645D excels in deliberate, planned compositions demanding perfect focus accuracy.

Build Quality and Environmental Resistance: Toughness Matters

Here is where the TG-3 flexes its muscles: built to be abused.

• Olympus TG-3: Waterproof to 15m, shockproof from 2.1m drops, crushproof to 100kgf, and freezeproof to –10°C. This ruggedness makes it my go-to camera for hiking, snorkeling, skiing, or festival adventures where clumsy mishaps are expected. Its body is splashproof but not dustproof, so be mindful in sandy environments.

• Pentax 645D: Built like a tank with robust environmental sealing to resist dust and moisture, but not waterproof or freezeproof by design. It’s suited for harsh fieldwork but you’ll want a rain cover for assured protection. Its heavy weight calls for a sturdy tripod when shooting landscapes or studio portraits.

User Interface and Handling: Intuitive or Imposing?

With compact cameras, ease of use is key for quick snapping; for medium format models, control precision matters more.

• Olympus TG-3: A simple fixed 3-inch 460k-dot TFT LCD screen, no touchscreen, but a straightforward menu system and dedicated macro and underwater modes make it approachable. The lack of a viewfinder slows composition in bright sunlight, but its bright LCD and built-in GPS compensate. Limited exposure modes include aperture priority and manual exposure (rare in compacts), with no shutter priority.

• Pentax 645D: A rock-solid 3-inch LCD with high 921k resolution, wide viewing angles, and anti-reflective coating gives clear previews. Its optical pentaprism offers 98% framing coverage with 0.85x magnification for confident composition. The interface is bulky but intuitive, with manual focus override and extensive exposure controls. No touch or live view, keeping everything direct and mechanical. The illuminated top screen is a neat pro feature for shooting low-light events.

Lens Ecosystem and Compatibility: One Fixed Lens vs. Medium Format Versatility

A vital consideration for future-proofing your investment.

• The Olympus TG-3 has a fixed 25-100mm equivalent f/2.0-4.9 zoom lens - good optical quality for a compact but no option to swap lenses. This limits creative flexibility but reduces complexity.

• The Pentax 645D accepts the robust Pentax 645AF2 mount lenses. There are six native lenses available from ultra-wide to super-telephoto with fantastic optical designs. Plus, adapters exist for legacy lenses. This medium format lens lineup is among the best for landscape, portrait, and studio work - not to mention macro photography, thanks to longer focal lengths and superior optics.

Battery, Storage, and Connectivity: Staying Powered and Connected

• Olympus TG-3: Powered by an Olympus LI-92B battery rated for 330 shots; built-in GPS, Wi-Fi connectivity for instant sharing, HDMI out for playback. Storage via a single SD card slot or internal memory (limited). USB 2.0 for file transfer. Decent endurance but might need spare batteries for multi-day trips.

• Pentax 645D: Uses Pentax D-LI90 battery with roughly 800 shots per charge - a huge advantage for extended shoots where battery swaps are difficult. Two SD/SDHC card slots allow robust storage and backup. No wireless or HDMI ports, reflecting its vintage and studio-oriented design, but USB 2.0 is present for tethered file transfers.

Specialized Performance by Photography Discipline

Let’s break down how each fares in key genres:

Value and Price-to-Performance: What Will You Get for Your Money?

The Olympus TG-3 retails around $350, making it accessible to hobbyists, travel photographers on a budget, or outdoor adventurers needing a tough, waterproof shooter. Its compact size, bundled rugged features, and Wi-Fi sharing add substantial value for the price. It’s a specialized compact for casual use or scenarios rough for typical cameras.

The Pentax 645D’s steep $4000 price positions it firmly in the professional stratosphere. For that sum, you get a medium format powerhouse with industry-leading image quality, a proven sensor, and a fully weather-sealed pro body. However, it lacks modern niceties like live view, video, or wireless connectivity and is hugely impractical for casual use.

Pros and Cons Summary

Final Verdict: Who Should Pick Which?

If you’re an outdoor enthusiast, adventurous traveler, or cheapskate wanting a rugged companion to carry on your explorations, the Olympus TG-3 delivers unbeatable ruggedness, ease of use, and convenience at a modest price. Its waterproof and shockproof design means you worry less and shoot more even in harsh conditions. Yes, image quality is limited by a tiny sensor, but that’s the tradeoff for extraordinary durability and portability. It makes a brilliant secondary or “fun” camera alongside a smartphone or larger system.

If you’re a professional or serious enthusiast seeking the ultimate in image quality for studio, landscape, and detailed portraits, the Pentax 645D remains a formidable contender. Despite being a decade old, its medium format sensor still blows many modern DSLRs out of the water in color depth and tonality. Its rugged build and lens array make it a reliable workhorse, but you’ll be paying for image quality above all else, while sacrificing portability and speed on-the-go.

Closing Thoughts

I’ve got to admit, I love both cameras - but for vastly different reasons. The Olympus TG-3 keeps on ticking through mud, waves, and snow with cheerful ruggedness; the Pentax 645D captures scenes with a majestic level of detail you can quite literally lose yourself in during post-processing. If you understand each camera’s niche and respect the trade-offs, you’ll find joy with either.

Think about where your photography adventures take you. For everyday toughness and easy carry, go with the TG-3. For the highest possible fidelity in controlled environments, invest in the 645D.

Hope this deep dive helps you find the perfect fit for your photographic journey!

Happy shooting!

• Your seasoned camera tester and fellow seriously curious photographer