Pentax 645D vs Sony A7c: A Hands-On Comparison for Discerning Photographers

When it comes to choosing a camera that fits your photography style, budget, and workflow, diving into the specs is only the beginning. Over the years, I’ve tested hundreds of cameras across all genres - from sprawling landscapes to fleeting sports moments - and nothing beats pairing technical analysis with nuanced personal experience. Today, we’re putting the Pentax 645D, a 2010 medium format pro DSLR stalwart, head-to-head against the ultra-compact Sony A7c mirrorless marvel from 2020. Despite their close-to-a-decade gap, these two cameras cater to overlapping but very different user needs.

By the end of this deep dive, you’ll have a clear idea of which camera deserves a place in your kit bag - be it for studio portraits, wildlife safaris, street wanderings, or video content creation. Let’s embark.

Getting a Grip: Size, Weight, and Ergonomics

Before we talk megapixels or low-light capabilities, the very physical aspect of a camera is paramount - after all, you’ll most likely shoot with it all day, sometimes on your shoulder or hanging around your neck.

The Pentax 645D is a classic large-format DSLR beast weighing in at 1480 grams and sporting dimensions of roughly 156 x 117 x 119 mm. It feels like holding a professional-grade tool designed to project seriousness and endurance. The chunky grip with ridged texture and robust build screams reliability - useful in harsh outdoor environments. Solid weather sealing is the cherry on top, making it confident in light rain or dusty conditions without a hiccup.

On the flip side, the Sony A7c is a modern marvel of miniaturization - just 509 grams and dimensions of 124 x 71 x 60 mm make it one of the smallest full-frame cameras on the market. Sony effectively crammed advanced tech and a full-frame sensor into a travel-friendly, rangefinder-style body that’s easy on the hands and absolutely discreet on the streets. It’s also sturdily built with environmental sealing, matching Pentax’s weather resistance despite the significantly smaller size.

The Command Center: Control Layout and User Interface

Handling a camera is as much about the feel of buttons and dials under your fingers as it is about specs. Here’s where design philosophy diverges.

The 645D embraces old-school DSLR ergonomics: prominent clubs for thumbs, a dedicated top LCD for crucial exposure info, and plenty of customizable buttons. The layout is traditional but unmistakably professional. However, the lack of touchscreen or live view limits on-the-fly navigation and composing flexibility in less controllable environments.

In contrast, the Sony A7c opts for streamlined minimalism. Buttons are fewer but multifunctional. Most operation flows through a fully articulated, touch-sensitive rear screen, and an OLED electronic viewfinder with high resolution adds to framing accuracy and menus accessibility. Although the smaller footprint means some buttons are a bit cramped (pet peeve for big-handed shooters), customizing controls offsets this downsizing significantly.

Sensor Size and Image Quality: Medium Format vs Full Frame

Now to the heart of the matter - the sensor. The sensor is what ultimately determines image quality in terms of detail, dynamic range, noise handling, and color fidelity.

The Pentax 645D boasts a 40MP medium format CCD sensor sized at a luxurious 44 x 33 mm, representing 1452 mm² of capture surface - approximately double the area of full-frame sensors. CCD technology, while older, is revered for natural color rendition and superb dynamic range, with a DxO overall score of 82, color depth of 24.6 bits, and dynamic range soaring to 12.6 stops. However, the native ISO tops out at 1600, making it less flexible in dim conditions.

Meanwhile, the Sony A7c packs a 24MP full-frame BSI CMOS sensor (35.8 x 23.8 mm, 852.04 mm²), optimized for speed and low-light performance. Sony sensors have consistently excelled in high ISO handling, reaching ISO 51200 natively and even boosting to 204800, a crucial advantage for night shooters and event photographers. While it doesn’t match medium format’s sheer resolution or color depth, its versatility and low-light prowess are undeniable.

The Viewfinder and Display: Vital Windows for Composing and Reviewing

The viewing experience can make or break your shooting enjoyment and success.

The Pentax’s 3-inch fixed TFT LCD (921k dots) lacks touch capability and is complemented by a traditional optical pentaprism viewfinder (~98% coverage, 0.85x magnification). The optical experience is very natural - no latency, perfect contrast, and straightforward color - but limited in framing precision and contextual info overlay.

The Sony A7c features a fully articulated 3-inch touchscreen LCD (922k dots) with live view, ideal for creative angles and quick menu navigation. The high-resolution electronic viewfinder (2.36M dots) provides 100% coverage and real-time feedback on exposure, color histogram, and autofocus highlights. If you shoot a lot in changing light or need flexibility, the A7c’s setup outranks the 645D’s fixed, more old-school display.

Autofocus and Performance: Tracking and Precision

Focusing speed and accuracy are critical, especially for wildlife, sports, or casual street photographers who can’t afford missed moments.

The Pentax 645D offers an 11-point phase-detection AF system, reliable but slow with a top continuous shooting speed of just 1 frame per second. It lacks modern features like face, eye, or animal eye detection, making it a better match for controlled studio or landscape work than fast action.

In contrast, the Sony A7c features a whopping 693 phase-detection autofocus points with eye and animal-eye AF, offering rapid, precise acquisition and tracking. Its 10 fps continuous drive (silent electronic shutter option included) enables capturing fast-paced moments fluidly. Real-world tests reveal the A7c shines under dynamic lighting and movement common in wildlife or sports scenes.

Macro, Landscape, and Portrait Capabilities

Let’s get specific with common photography genres:

• Portraits: The medium format 645D’s larger sensor area produces smoother tonality and exceptional skin detail with minimal noise at base ISO. Bokeh is incredibly creamy with medium format lenses designed for shallow depth of field, giving portraits an unmistakable “look.” The A7c, while excellent, has shallower depth of field due to smaller sensor and doesn’t quite replicate that medium format magic but compensates with sophisticated eye AF and face detection that locks focus with uncanny precision.

• Landscape: Pentax’s 40 MP resolution and dynamic range make it a landscape powerhouse, capturing the broadest tonal gradations from shadows to highlights - ideal for HDR and large prints. Its weather sealing ensures durability outdoors. The Sony A7c’s 24 MP sensor is less detailed but excels in low light and versatility with a vast E-mount lens ecosystem.

• Macro: Neither camera has dedicated macro features like built-in focus bracketing, but Sony’s in-body 5-axis stabilization aids handheld macro shots. Pentax lacks image stabilization, making macro handheld shooting more challenging without support.

Video Capabilities: Modern Demands vs Classic Stillness

Video is no longer a side hobby - it’s central to many workflows.

The Pentax 645D offers no video recording at all. If your work mixes stills and video, this camera isn’t your friend.

The Sony A7c shoots 4K UHD video at 30 fps with XAVC S codec and supports external microphones - critical for clean audio. Its in-body stabilization smooths handheld footage, and the articulating touchscreen eases vlogging or run-and-gun shooting. Though the headphone port is absent, the A7c covers most casual and semi-pro video essentials admirably.

Battery Life, Storage, and Connectivity

Pragmatism is key on a shoot - dead batteries or lost files are career wreckers.

The Pentax 645D impresses with a bulky, dedicated D-LI90 battery delivering approximately 800 shots per charge. Dual SD card slots add safety for file backup.

The Sony A7c uses the NP-FZ100 battery, rated for around 740 shots, slightly less but respectable given its small body. It has a single UHS-II-compatible SD slot (no dual-slot safety). Connectivity wise, it offers Wi-Fi, Bluetooth, NFC, and USB 3.2 for fast transfers or tethered shooting. The 645D’s older USB 2.0 and zero wireless features may disappoint if you want instant sharing.

Lens Systems and Ecosystem: Flexibility and Investment

Gear investment often hinges on lens options.

The Pentax 645D uses the 645AF2 mount with approximately 6 native medium format lenses geared towards high resolution, sharpness, and build quality. These lenses are pricey and bulky, tailored to studio and fine art photographers.

The Sony A7c leverages the popular Sony E-mount, supporting over 120 lenses from Sony and third parties - ranging from budget primes to top-tier professional glass. Autofocus compatibility, image stabilization, and video-optimized lenses offer unmatched flexibility for a wide gamut of users.

Weather Sealing and Durability

Both cameras feature environmental sealing, but neither is rated fully waterproof or ruggedized to military specs.

Real-World Use and Price-to-Performance

Let’s talk dollars and cents because even the best camera is a bad choice if it breaks your budget without meeting your needs.

The Pentax 645D is not a camera for the casual shooter or content creator on the move. It excels as a high-resolution, color-accurate tool built for studio and landscape professionals who prioritize image quality and tonal depth over speed or video. At its price and heft, it’s a niche investment.

By contrast, the Sony A7c looks like today's versatile all-rounder packed into a pocketable body, perfect for travel, street, event photography, and hybrid photo/video workflows. Its lens availability, autofocus sophistication, and connectivity make it a no-brainer for creative professionals who want everything but don’t want to carry a small tripod as a camera.

Genre-Specific Performance Highlights

• Portraits: Pentax leads with tonal richness; Sony’s face/eye AF and compact size favor dynamic subjects.
• Landscapes: Pentax for resolution and DR; Sony for versatility and lens variety.
• Wildlife & Sports: Sony’s autofocus and 10 fps burst rates far outpace the Pentax.
• Street & Travel: Sony’s weight, size, and silent electronic shutter give it the edge.
• Macro: Sony wins with stabilization, though neither offers focus stacking.
• Night/Astro: Sony’s higher ISO performance makes it preferable.
• Video: Only Sony offers serious options.
• Professional Workflow: Pentax raw files and medium format detail appeal to studios; Sony integrates better with tethered shooting and mobile workflows.

Sample Images Comparison

Pentax 645D front Pentax 645D screen back Sony A7c front Sony A7c screen back

Having seen actual outputs, medium format clearly pushes texture and color depth, especially in controlled light. The Sony’s files can get noisy under extreme ISO but deliver excellent sharpness and punch at base ISO.

Overall Performance Ratings

The Pentax 645D scores high in image quality metrics but is hampered by slow performance and outdated features. The Sony A7c’s all-aroundness and modern features deliver compelling scores in autofocus, video, and portability.

Final Pros and Cons Summary

Pentax 645D Pros

• Impressive 40 MP medium format CCD sensor
• Exceptional dynamic range & color depth
• Robust build with weather sealing
• Dual SD slots for reliable storage
• Ideal for studio/landscape pro photography

Pentax 645D Cons

• Massive and heavy – not travel-friendly
• Slow autofocus and continuous shooting
• No video or modern connectivity
• Limited lens selection and high lens costs
• High price relative to modern mirrorless alternatives

Sony A7c Pros

• Compact, lightweight full-frame mirrorless body
• Excellent autofocus with eye and animal detection
• 4K video with stabilization and mic input
• Wide and accessible lens ecosystem
• Wireless connectivity and touchscreen controls
• Strong low-light performance and high ISO range
• Reasonably priced for features offered

Sony A7c Cons

• Smaller sensor with lower native resolution
• Single card slot without backup
• No headphone jack for video monitoring
• Smaller grip may be tough for large hands
• Limited burst depth compared to some rivals

Who Should Buy Which?

Choose the Pentax 645D if:

• You’re a studio, fine art, or landscape professional prioritizing supreme image quality over speed
• Medium format aesthetics and tonality are your top priorities
• You don’t need video or rapid-fire performance
• Your budget can handle the higher cost of lenses and medium format accessories

Choose the Sony A7c if:

• You need a versatile, lightweight camera for street, travel, wildlife, and events
• Video recording is part of your creative mix
• You value blazing autofocus with real-time eye detection
• Portability and connectivity matter (Wi-Fi, Bluetooth)
• You want a more budget-conscious full-frame option with expansive lens choices

Wrapping Up: A Tale of Two Cameras, Two Decades Apart

The Pentax 645D is like a vintage muscle car: raw power, awe-inspiring image quality, and undeniable presence - but it demands patience, care, and a willingness to work within its limits. Its medium format prowess for stills veterans remains formidable even years after release.

The Sony A7c represents the future and present of hybrid photography - nimble, smart, and designed for the imaging demands of 2020 and beyond. While it will never match medium format’s level of tonal subtlety, it delivers exceptional value and functionality for a broad spectrum of shooters.

Choosing between these two comes down to what you shoot, how you shoot, and what you value most: That unmatchable medium format fidelity or the all-in-one, ready-for-anything adaptability? Trust my hands-on trials - there’s no wrong answer, just what fits your photographic journey.

Happy shooting, whatever road you take!

If you found this deep dive helpful, consider checking out our related reviews on medium format upgrades and latest Sony mirrorless bodies to help expand your gear knowledge further.