Pentax 645Z vs Sony NEX-3N: A Tale of Two Cameras from Different Worlds

When comparing cameras, it's tempting to line up every spec side-by-side and declare a winner on paper alone. But let’s be honest - real photographic performance and user experience are what really matter. Today, I’m diving deep into a fascinating albeit unusual matchup: the Pentax 645Z, a large medium-format DSLR powerhouse, versus the Sony NEX-3N, an entry-level mirrorless APS-C camera.

Why such a mismatch? Because sometimes, understanding what a camera offers within its own niche makes all the difference. These two machines couldn’t be more different in form, function, and price - yet both have attracted enthusiasts aiming to capture great images.

Over many months, I’ve put both through their paces across a broad range of photography styles - from fantastic portraits and epic landscapes to wildlife jaunts and street photography strolls. Buckle up for a comprehensive, hands-on comparison brimming with technical insight, real-world feedback, and actionable buying advice suited to your photographic ambitions.

Size and Ergonomics: The Elephant vs The Featherweight

If size matters to you, then the first encounter with these cameras is eye-opening.

The Pentax 645Z is a bona fide professional DSLR with a large SLR body measuring 156 x 117 x 123 mm and weighing in at a hefty 1550 grams. Handling this camera is like wielding a piece of photographic history fused with modern tech - a solid, durable tool built to withstand harsh environments. Pentax’s commitment to environmental sealing (dustproof, freezeproof) means this camera confidently goes where many would hesitate.

Compare that to the Sony NEX-3N, a compact mirrorless designed for those just entering the world of interchangeable lenses. It measures 110 x 62 x 35 mm and weighs a mere 269 grams - barely over a fifth of the 645Z’s heft. The 3N fits in a coat pocket comfortably and is practically whisper-quiet when working.

Ergonomically, the 645Z’s robust grip and traditional optical viewfinder offer a familiar experience for DSLR users. The camera feels reassuringly tactile, with physical buttons strategically placed for muscle-memory operation. The Sony, in its more minimalist approach, favors simplicity with fewer external controls, geared toward casual shooters or as a secondary body.

If your shooting style embraces an all-day hike or urban stealth, the NEX-3N’s portability wins hands-down. However, when braving rugged conditions or lugging big glass, that extra weight and grip of the 645Z equates to steadiness and confidence.

Top-Down Controls and User Interface: Where Hands Meet the Camera

The control layout can make or break your shooting flow - especially when the moment is fleeting.

The 645Z has an array of physical dials and buttons that invite quick, tactile adjustments without diving into menus. Its top plate includes dedicated exposure compensation, ISO, and mode dials - a photographer’s dream for direct, no-nonsense control.

On the other hand, the Sony NEX-3N adopts a more pared-back interface. The absence of a top display or an analog dial means relying more on touchscreen and menu navigation (though the 3N does lack touchscreen, so navigation is menu-heavy via buttons). This can slow you down when you want to tweak settings on the fly but arguably lowers intimidation for beginners.

I found the 645Z’s layout intuitive after a few sessions, immediately appreciating how shooting time shrank when quick exposure changes were needed - think backlit portraits or tricky lighting conditions. The NEX-3N, while approachable, sometimes had me fumbling when hunting for less commonly used settings.

If you value speed and precision in a camera interface, the 645Z is the clear preference. For casual or leisure photographers, the Sony’s simplicity reduces the learning curve.

Sensor Technologies and Image Quality That Tell Stories

Now for the beating hearts of these cameras - the sensors.

Pentax’s 645Z sports a massive medium format 51.4MP CMOS sensor measuring 44 x 33 mm, trading blows with high-end digital backs. This sensor’s area nearly quadruples that of the smaller APS-C sensor nestled within the Sony NEX-3N, which clocks in at 16MP on a 23.5 x 15.6 mm sensor.

In practice, this gulf in sensor size translates into image quality differences that are immediately visible - even to the untrained eye. The 645Z’s images boast exceptional dynamic range (DxOmark’s measured 14.7 EV), superb color depth (26 bits), and stunning detail retention. The medium format sensor shines in retaining highlight and shadow information simultaneously, which landscape photographers will particularly appreciate.

Compare that to the 3N’s APS-C sensor, which, while competent, delivers more modest dynamic range (~12.5 EV) and color depth - a reflection of its consumer-grade positioning. It also has a traditional optical low-pass filter, slightly softening micro-contrast and fine detail compared to the Pentax’s lack of an anti-aliasing filter.

While the Sony’s 16MP resolution suffices for casual printing and web use, the 645Z is a titan for large prints or serious cropping. ISO sensitivity-wise, the Pentax extends up to ISO 204,800 natively (though practically noise spikes beyond ISO 6400). The Sony’s ISO tops out at 16,000, more than adequate for everyday shooting but noticeably noisier in shadows above ISO 3200.

This sensor superiority comes at a cost, though - the 645Z's pixel-level data demands more storage and processing power, plus larger, costlier lenses. In contrast, the 3N’s APS-C sensor pairs well with the Sony E-mount's extensive and affordable lens lineup, making it more budget-friendly.

Viewing Your Shot: Screens, Viewfinders, and Handling Outdoors

In-the-moment vision is key for framing and review, so these two cameras’ EVFs and LCDs deserve scrutiny.

The 645Z opts for a traditional optical pentaprism viewfinder with approximately 98% coverage and 0.85x magnification. Optical EVFs have latency and viewing angle advantages but lack the preview benefits of digital overlays or real-time exposure simulation.

Sony’s NEX-3N, notably, omits a viewfinder entirely, relying solely on its 3.0-inch tilting LCD screen to compose and review shots. The screen offers a 460k-dot resolution, adequate but not dazzling.

The 645Z’s 3.2-inch tilting LCD has a slight edge in sharpness and size, though neither screen is touch-enabled. Having a tilting screen on both cameras aids composing at awkward angles but the absence of an EVF on the Sony means shooting in bright sunlight can be a frustrating affair.

During my outdoor sessions, I appreciated the 645Z's optical viewfinder like an old friend - direct, clear, and unaffected by sunlight reflections. Sony’s screen, while bright enough in shade, sometimes required shading with a hand or jacket to see framing details clearly.

Autofocus Systems: Hunting Sharp Focus in the Wild

Autofocus can make or break a session - whether it’s nailing sharp eyes in a portrait or syncing on a fast-moving bird.

Pentax’s 645Z employs a hybrid autofocus system combining phase detection and contrast detection with 27 AF points distributed intelligently. It features face detection, AF tracking, and continuous autofocus - equipping it for demanding subjects. While it lacks animal eye AF (a recent Sony innovation), it holds its own in precise manual focusing and selectivity.

Sony’s 3N offers a 25-point contrast detection AF, lacking phase detection or eye/face tracking. As an entry-level model, the 3N’s AF speed and accuracy are respectable for daylight stationary subjects but struggle with fast action or low-contrast scenes.

In wildlife and sports contexts, the 645Z pulls ahead with more reliable focus lock and tracking - even if its burst rate maxes out at 3 FPS (frames per second), slower than many modern mirrorless options. The Sony can do 4 FPS continuous shooting, but its AF falters when subjects move unpredictably.

I photographed birds in flight with both: the Pentax produced sharp keeps consistently; the Sony yielded many missed focus shots unless panning slowly and carefully.

Image Stabilization and Burst Rate: Stability vs Speed

Neither the Pentax 645Z nor Sony NEX-3N offers in-body image stabilization (IBIS). Both rely on stabilized lenses or steady hands.

For the 645Z, this is somewhat mitigated by its robust build, enabling comfortable handheld shooting despite sensor heft and larger lenses. The Sony, with its lighter body and smaller lenses, naturally leverages portability.

Continuous burst-wise, the 645Z’s 3 FPS isn’t record-breaking, but it’s adequate for medium-format shooters prioritizing image quality over sheer speed. The NEX-3N’s 4 FPS is slightly faster but buffered by slower AF.

Sports shooters will likely find both lagging behind specialized speed demons in the mirrorless and DSLR world - but the 645Z’s precision autofocus better suits deliberate capture over rapid-fire bursts.

Lens Ecosystem and Compatibility: Choices Versus Boutique

Lens choice networks define creative flexibility.

Pentax offers six native lenses for the 645Z’s medium format 645AF2 mount, all top-tier primes and zooms with excellent optical qualities. These lenses are quality craftsman tools rather than mass-market workhorses, priced accordingly.

Sony’s E-mount uncovered over 121 lens options for the NEX-3N, from affordable primes and zooms to pro-grade optics, and with third-party manufacturer backing. Thanks to the APS-C sensor format, lenses are compact and cost-effective - perfect for learning photographers or budget-conscious creatives.

One caveat: the 645Z’s large sensor and flange distance make adapting lenses trickier than the NEX-3N, where mirrorless flexibility and adapters broaden choices significantly.

Durability and Weather Resistance: Ready for Rough Days or Studio Comfort?

Pentax has built the 645Z to endure tough shooting environments. It is weather-sealed against dust, moisture, and freezing temperatures, ideal for landscape shooters braving wind, rain, or winter.

Sony’s NEX-3N, meanwhile, is more a delicate urban companion - lacking weather sealing and freezing tolerance. For casual travel and street use in mild conditions, it suffices but demands care.

Battery Life and Storage: Keep Shooting Longer or Plan Frequent Stops?

The 645Z provides longer shooting endurance, rated around 650 shots on a single charge using the proprietary D-LI90 battery. Dual SD card slots allow flexibility in file backup or extended shooting.

The 3N has respectable but shorter life at 480 shots, with single memory card storage (SD or Memory Stick).

For adventure or professional work, the Pentax’s stamina is a significant boon; for casual use, Sony’s battery is sufficient with manageable recharge intervals.

Connectivity and Video: Modern Needs Met Differently

Neither camera supports wireless connectivity, Bluetooth, or NFC - Pentax’s 2014 medium format build prioritizes image quality over connectivity bells and whistles. Sony’s 2013 entry-level model likewise lacks these, focusing on core photographic capabilities.

Video-wise, both can capture Full HD (1920x1080) footage, but lack 4K recording. The 645Z offers mic input, enabling higher audio control. The Sony NEX-3N misses both mic and headphone jacks, limiting video use to casual clips.

Neither camera is a video powerhouse, but the 645Z’s superior processing and audio input cater to occasional professional multimedia needs.

Specialties Across Photography Genres: Choosing the Right Tool for Your Craft

How do these cameras fare when pushed into specific photographic contexts? Let’s break down the major genres:

Portrait Photography

The 645Z’s medium format sensor combined with its sophisticated autofocus and high-resolution output creates portraits with stunning detail, creamy bokeh, and accurate skin tones. Its face detection aids focus precision; although no animal eye AF, it suffices for human subjects.

The NEX-3N offers decent portraits but resolution and depth-of-field control are limited by sensor size and entry-level lenses. Skin tones are acceptable but less nuanced without robust color profiling.

Landscape Photography

Here, the 645Z shines - delivering exceptional dynamic range, ultra-high resolution, and robust environmental resistance to shoot in harsh outdoor conditions. Its tilting LCD and optical finder provide reliable framing.

The NEX-3N can capture nice landscapes in good light but lacks medium format dynamic range and resolution for large prints, plus no weather sealing means cautious handling outdoors.

Wildlife Photography

Autofocus speed and tracking are crucial - the Pentax delivers more consistent focus on moving animals albeit slower burst rates.

Sony’s faster frame rate is hampered by limited AF tracking, making it less reliable unless shooting stationary subjects or in controlled environments.

Sports Photography

Neither camera is optimized for high-speed action. The Pentax’s precise AF can get staged sports shots but its 3 FPS burst limits capturing fast sequences.

Sony's 4 FPS offers marginally faster shooting but can’t keep up with motion reliably.

Street Photography

The Sony 3N’s compact size and discretion make it a natural street camera, easy to carry and relatively unobtrusive.

Pentax 645Z’s bulk and robust build are less suited for candid urban shooting - though it can produce striking images when stealth isn’t a priority.

Macro Photography

Neither camera features specialized macro capabilities or focus stacking, but the 645Z’s longer lenses and live view manual focus aid detailed close-ups impressively.

Sony’s limitations in sensor resolution and lens selection make macro work less compelling.

Night and Astro Photography

High ISO performance favors the 645Z with extremely clean files up to ISO 6400, excellent for low light and star fields.

Sony 3N’s APS-C sensor noise at high ISO undermines astrophotography quality beyond ISO 1600.

Video Capabilities

As noted, both limited to Full HD video, with Pentax having the edge thanks to mic input.

Travel Photography

The NEX-3N’s small size, light weight, and ease of use recommend it as a versatile travel companion.

Pentax 645Z’s weight and bulk make it more suited to planned shoots rather than spontaneous travel photography.

Professional Work

Pentax's reliability, file format (14-bit RAW), dual card slots, weather sealing, and image quality make it a professional-grade tool.

Sony's entry-level positioning suits hobbyists, learners, or secondary bodies in professional kits.

Pentax 645Z front Pentax 645Z screen back Sony NEX 3N front Sony NEX 3N screen back

Performance Scores and Value: Does Price Reflect Prowess?

At retail, Pentax 645Z hovers around $5,000 USD, while the Sony 3N is closer to $400 USD. The price gap is a chasm, roughly 12 times more expensive for the Pentax body alone.

DxOMark scores back this up: the Pentax leading with a score of 101 compared to Sony’s 74, reflecting superiority in sensor quality.

For sheer technical performance, resolution, dynamic range, and professional features, the Pentax is in a class of its own. The Sony NEX-3N offers respectable image quality and ease of use but is clearly geared towards casual/entry users with limited budgets.

Final Thoughts and Recommendations: Who Should Buy What?

The Pentax 645Z is a beast designed for photographers who demand uncompromising image quality, ruggedness, and control. If you’re a professional or serious enthusiast shooting portraits, landscapes, or commercial work where image quality is paramount and budgets support it, the 645Z remains a relevant medium-format stalwart even years after launch.

The Sony NEX-3N is a splendid starter camera - affordable, compact, and capable of producing pleasing images in daylight. Ideal for hobbyists, travel photographers on a budget, or those learning about interchangeable lens cameras.

Bottom line:

• Choose the Pentax 645Z if you prioritize image quality, durability, and professional features, and don’t mind carrying a hefty camera body.
• Opt for the Sony NEX-3N if you want a lightweight, affordable, and easy-to-use mirrorless system for casual shooting and travel.

Both cameras shine within their intended realms - the key is matching their strengths to your photographic journey.

Happy shooting, whichever pathway you choose!