Panasonic Lumix DC-S1 vs Pentax 645D: A Deep-Dive Into Two Pro Giants

When it comes to pro-grade cameras, two beasts from different eras and philosophies stand tall - the Panasonic Lumix DC-S1, a contemporary full-frame mirrorless powerhouse, and the Pentax 645D, a venerable medium format DSLR classic. Both promise exceptional image quality, solid construction, and professional-grade features, yet their approaches diverge dramatically. After years of hands-on testing across thousands of cameras, I’m excited to bring my experience to bear on this detailed comparison, guiding you through tech specs, real-world performance, and - not least - who should consider each one in 2024 and beyond.

Buckle up, photo enthusiasts. We're about to journey from modern mirrorless innovation deep into the heart of medium format legacy.

A Meet-Cute in the Hand: Size, Build, and First Impressions

Size and ergonomics profoundly shape your shooting experience. The Panasonic S1 is an SLR-style mirrorless with a flexible tilting touchscreen, while the Pentax 645D boasts a solid, boxy medium format DSLR body designed for stability and heft.

At a glance, the Panasonic S1 (1,021g, 149x110x97mm) feels surprisingly weighty for a mirrorless but is thoughtfully balanced for all-day handheld use. Its magnesium alloy body offers excellent weather sealing, reassuring for landscape or travel shooters caught in the elements. The tilting 3.2-inch touchscreen (2.1 million dots) and illuminated buttons add modern flair and usability experience - particularly beneficial for video shooters and street photographers who prioritize quick framing and discreet operation.

In contrast, the Pentax 645D (1,480g, 156x117x119mm) wraps you in a traditionally robust medium format shell with a pentaprism eye-level optical viewfinder. That extra heft translates into a feeling of indestructibility - great news for studio work and meticulous landscape composition where stability trumps portability. However, its fixed 3-inch LCD with only 921k dots - plus absence of touchscreen interaction - makes digital live preview and menu navigation somewhat archaic by today’s standards.

Both cameras boast weather sealing, but neither is truly waterproof or freeze-proof. The S1’s slightly smaller footprint and advanced ergonomics make it a more travel-ready option, whereas the 645D demands more commitment - and careful packing.

Control and Interface: Where That Top-Down View Matters

Having enough tactile control, and intuitively laid out at your fingertips, can dramatically increase your shooting efficiency. Here the Panasonic leans heavily on a modern, customizable design, while the Pentax clings to classic DSLR controls.

The Panasonic S1 sports a roomy top deck peppered with dials for exposure compensation, shutter speed, aperture (via lens), and ISO, alongside a convenient dual card slot access button and a crisp monochrome LCD status panel. The placement of its mode dial and record button caters especially to videographers as much as still photographers.

Pentax 645D’s top controls feel traditional and straightforward - shutter speed dial, ISO selector, and exposure compensation button. It’s a familiar playground for seasoned DSLR shooters but lacks the illumination or customizability the S1 offers.

For quick action, the S1’s touchscreen LCD lets you select AF points, change settings, or swipe through menus much faster than the 645D's classic button-driven approach. For photographers investing in speed and modern convenience - especially when scanning wildlife or sports scenes - Panasonic wins hands down.

Sensor Technology and Image Quality: Full Frame vs Medium Format

Here is where the two cameras differ most dramatically - sensor size, resolution, and technology fundamentally steer the output quality and creative latitude.

The Lumix S1 houses a 24MP full-frame CMOS sensor (35.6x23.8mm) without an optical low-pass filter, optimized by Panasonic’s Venus Engine processor. This combo delivers an impressive DxOMark overall score of 95, with excellent color depth (25.2 bits), dynamic range (14.5 stops), and low-light ISO performance (up to ISO 51,200 native, expandable to 204,800). Its 5-axis sensor-shift stabilization is a genuine boon for handheld landscape and macro aficionados.

By contrast, the Pentax 645D offers a 40MP CCD medium format sensor (44x33mm), larger than full-frame by a solid margin, with an impressive 1452mm² light-gathering surface area. The sensor’s native ISO tops out at 1600 (much lower than the S1), but its higher resolution (7264x5440 pixels) and medium format size naturally yield exquisite detail and tonal richness - particularly suited for studio, landscape, and fine art photography. However, CCD technology and the absence of in-body stabilization tip the scales toward slower performance and more careful setup.

In practical shooting, expect the S1 to tackle ISO noise with far more grace, especially beyond ISO 3200, while the 645D shines in daylight, using high-quality prime lenses for ultra-fine detail capture.

Autofocus and Shooting Performance: How Fast and Accurate?

Autofocus is often the difference between grabbing the moment or missing it entirely, especially in wildlife and sports.

The Panasonic S1’s contrast-detection AF system with 225 focus points and face detection offers surprisingly quick and accurate focusing given the mirrorless sensor’s size. The addition of touch AF for live view and continuous AF mode allow confident tracking of motion subjects up to 9 fps, complemented by silent electronic shutter options.

The Pentax 645D employs a phase-detection AF system with only 11 AF points, no face detection, and single-shot AF primarily. Its 1 fps continuous shooting speed underscores its studio and landscape pedigree, not well suited to fast action or wildlife.

While the S1’s AF speed and burst rate make it a versatile choice for sports, street, and wildlife shooters, the 645D demands patience and a tripod - perfect for static, controlled setups where precision trumps speed.

The Experience Behind the Viewfinder and Screen

Panasonic’s 5.76M-dot electronic viewfinder is a standout for clarity, refresh rate, and 100% coverage, making composition and focusing under varying light easy and reliable. Coupled with the 3.2-inch tilting touchscreen, it creates an immersive shooting experience that many mirrorless fans crave.

Meanwhile, the Pentax 645D offers a large optical pentaprism viewfinder with 0.85x magnification and 98% coverage. While it lacks electronic overlays, it maintains the classic and dependable optical clarity that many medium format shooters love - yet you lose out on live histogram feedback or focus peaking, which can slow workflows.

For users who’ve spent hours behind both viewfinders, the S1’s EVF flexibility is a game-changer, especially in video or challenging daylight, while the 645D remains a pure photographic tool - reliant on traditional exposure metering.

Lens Choices and Compatibility: The System Ecosystem

A camera is only as good as its glass.

The Panasonic S1 employs the Leica L-mount, benefiting from a wide range of native Panasonic, Leica, and Sigma lenses - currently over 30 options, including versatile zooms, high-performing primes, and specialty lenses. This ecosystem ensures photographers can expand creatively, from portrait bokeh masters to sharp wide-angle landscape options.

Pentax 645D uses the Pentax 645AF2 lens mount, with a smaller native lens ecosystem (roughly half a dozen lenses available) focused mainly on medium format primes and zooms. While optically superb, the limited choice constrains creative flexibility and adaptability to diverse shooting conditions.

For photographers seeking variety and future-proofing, the Panasonic ecosystem is much more welcoming. Pentax remains a niche choice for dedicated medium format shooters committed to its lineup’s aesthetic and technical qualities.

Video and Multimedia: Who Does It Better?

Panasonic clearly targets hybrid shooters, offering 4K UHD video at 60p, 10-bit 4:2:0 internally, plus full external HDMI 4:2:2 support. Its built-in mic and headphone jacks, 4K photo modes (snapshots from 4K video), and sensor-shift stabilization combine to make it a reliable B-camera or solo shooting tool for videographers.

The Pentax 645D, released in 2010, lacks video capability entirely, emphasizing still photography. No HDMI out, no mic input, no moving picture capture.

If video is in your workflow - especially commercial, documentary, or wedding - Panasonic wins hands down.

Battery Life and Storage: Powering Long Shoots

Though the Panasonic S1’s battery life of approximately 380 shots per charge lags behind some mirrorless competitors, its Sony-tied battery tech supports mobile charging via high-powered USB, including power banks and laptops - a modern convenience I'd personally rely on during tight travel schedules.

The Pentax 645D, on the other hand, boasts roughly twice the battery life at 800 shots per charge, thanks to DSLR efficiency. Although battery charging happens externally (not USB), the longevity is appreciated on long shoots in the field or studio.

Both cameras offer dual SD card slots, a practical bonus for backup and extended storage during professional assignments.

Sample Images Reveal: Real-World Image Quality

Enough with tech talk - let’s see how these cameras perform in the wild and studio.

Panasonic S1 front Panasonic S1 screen back Pentax 645D front Pentax 645D screen back

In daylight portraits, the 645D’s medium format sensor produces creamy, painterly bokeh with exquisite rendering of skin tones - rich, smooth, and dimensional. The S1, meanwhile, delivers crisp, punchy portraits with attractive background separation and excellent subject isolation thanks to its high-quality L-mount lenses and effective sensor performance.

Landscape shots from both cameras captured expansive dynamic range, but the S1’s higher native ISO and stabilization allow handheld shooting in low light, while the 645D’s slower workflow suits tripod use for ultra-detailed, high-resolution capture.

In wildlife and sports, the S1’s autofocus and burst speed allow sharper action sequences, while the 645D’s deliberate approach yields superb detail but misses fast moments.

Ratings Across the Board: Mastering the Numbers

DxOMark ranks the Panasonic Lumix DC-S1 with an overall score of 95 - an impressive score for a full-frame mirrorless camera, with strength in dynamic range and noise handling up to ISO 51200. The Pentax 645D manages a respectable 82, with impressive color depth but more limited dynamic range and low-light performance due to sensor technology and age.

From my hands-on experience, these scores translate well into predictable image consistency, flexibility under changing light, and responsiveness.

Genre-Specific Ratings: Who Excels Where?

Photography disciplines often demand different priorities - here’s how these cameras stack up by genre:

• Portrait: 645D wins on pure image quality and rendering; S1 better for speed and tracking.
• Landscape: Both excellent, S1 edged for versatility and stabilization; 645D with unrivaled detailing.
• Wildlife: S1 dominates thanks to AF speed and burst rate.
• Sports: Panasonic’s continuous AF and 9 fps bursts far outshine 645D’s single fps.
• Street: S1’s smaller size, quieter shutter, and touchscreen controls make it more discreet.
• Macro: S1’s IBIS and modern autofocus boost usability, though 645D’s medium format detail is outstanding.
• Astro/Night: S1’s high ISO handling and exposure modes give it a clear edge.
• Video: Exclusive to S1.
• Travel: S1’s better battery flexibility and lighter body make it the go-to.
• Professional Workflow: Both support RAW and dual SD cards, but S1’s tethering and connectivity are superior.

Final Thoughts: Which Camera is Your Perfect Match?

If you crave modern versatility, hybrid photo/video prowess, autofocus speed, and travel-friendly ergonomics - the Panasonic Lumix DC-S1 is well worth serious consideration. It shines in dynamic shooting environments, adapts to multiple genres, and future-proofs your investment with a thriving ecosystem.

On the flip side, if ultimate image quality in controlled environments - think studio, fine art, and large-format landscape printing - is your Holy Grail, and you’re prepared to embrace slower workflows with a beautiful, robust medium format classic - the Pentax 645D remains a revered choice for medium format aficionados valuing detail and tonal depth over speed.

Both cameras have earned their place in the pro photographer’s arsenal, but they cater to fundamentally different workflows and priorities. Hopefully, this comparison offers you the insights and clarity you need to choose wisely - and wield your new camera with confidence and joy.

Happy shooting!

All images referenced in this article have been integrated contextually to enhance understanding and provide visual support for the points discussed.