Panasonic GH5S vs Pentax K100D: A Tale of Two Cameras Across Time and Technology

When you put the Panasonic GH5S and Pentax K100D side-by-side, it’s a bit like comparing a sleek modern electric sports car to a faithful old-school pickup truck - both get you somewhere, but how and why you drive matters. As someone who has wrangled both brand-new mirrorless marvels and vintage DSLRs through the trenches of every photography genre imaginable, this comparison is where history, technology, and practical artistry intersect.

Let me take you on a detailed journey through these two very different photographic beasts - not just specs on paper, but how they actually perform day to day, for both enthusiasts and pros.

First Impressions: Size, Ergonomics, and Handling

Handling comfort often defines how much joy you get from a camera. The GH5S boasts a robust, pro-level SLR-style mirrorless chassis, while the Pentax K100D is a more compact, entry-level DSLR.

Physically, the Panasonic GH5S (139x98x87 mm, 660g) feels as if it was carved out for marathon shooting sessions - deep grips, intuitive button placement, and balanced heft without being a burden. Its body is weather-sealed, giving peace of mind for outdoor shoots in rain or dust. The GH5S is almost an extension of your hand, which matters when focusing on pixel-perfect sharpness in portraiture or wildlife.

Conversely, the Pentax K100D is lighter and smaller (129x93x70 mm, 660g), but its compactness comes at a cost: ergonomically, it’s less refined, especially by modern standards. The smaller body coupled with fewer buttons and a fixed, low-res LCD screen may frustrate heavy shooters but will suit casual shooters or beginners looking for simplicity.

Between the two, the GH5S is the clear winner if handling and durability are non-negotiable for your photography workflow.

The Control Deck: Top View and Operating Layout

Controls can make or break productivity when chasing fleeting moments.

On top, the GH5S flaunts a sophisticated control panel with multiple dials for exposure compensation, ISO, and modes. The shooting mode dial alone covers everything from Program to fully manual, giving manual shooters real-time tactical control. No overwhelmed wrestle - just muscle memory in action.

The Pentax K100D’s top layout is straightforward but basic. The mode dial is limited to the essentials, and the slower shutter range (max 1/4000s) reflects its beginner target market. It lacks touchscreen and customizable buttons, which means fiddling through menus - slightly slower in the thick of action.

If you value immediate manual manipulation and speedy adaptability (say, during fast sports or wildlife shoots), the GH5S’s ergonomics will feel like home; the K100D is more about learning and slow, deliberate pace photography.

Sensor Showdown: Size, Resolution, and Image Quality

Here lies the heart of both cameras - the sensor. It’s where light becomes pixels.

The GH5S sports a Four Thirds CMOS sensor measuring 17.3x13 mm (approx. 225 mm²) with 10 megapixels, while the Pentax K100D offers a larger APS-C CCD sensor at 23.5x15.7 mm (approx. 369 mm²) with 6 megapixels.

You might scratch your head here - fewer megapixels on the GH5S in 2018 (an era of ever-bigger sensor resolutions) yet double the pixel count than the decade-older K100D. The key lies in design intent: Panasonic opted for larger photosites concentrating on higher sensitivity and better video performance rather than pushing megapixels higher. The GH5S’s sensor is optimized for low noise, especially at high ISO, vital for night, video, and low-light shooting.

On the flip side, the K100D’s CCD sensor produces pleasing color rendition and organic-looking images, albeit more limited dynamic range and low-light performance. The APS-C size gives a slight edge in shallow depth-of-field and overall image sharpness at similar apertures, but the older sensor tech means noisy images start creeping in beyond ISO 800.

In testing, GH5S files deliver clean highlights and shadows, boasting a remarkably wide usable ISO range up to 51,200 native ISO (boostable to 204,800). The K100D starts struggling above ISO 800 and maxes at ISO 3200. For landscapes and portraits where HDR and latitude matter, the GH5S pulls out ahead, but don’t discount the K100D’s charm in good light.

Interface and Viewing Experience: Backscreen and Viewfinder

I often joke that most photographers check the back screen more than the viewfinder - so screen quality and usability are big factors.

The Panasonic GH5S sports a 3.2-inch, fully-articulated touchscreen LCD with 1.62 million dots. It swivels, flips, and even turns selfie-friendly, which helps with video vlogging or shooting from awkward angles. The touch interface is responsive and enhances quick menu navigation or autofocus point selection.

The Pentax K100D by contrast offers a 2.5-inch fixed LCD with only 210,000 pixels - a relic by today’s standards. No touchscreen, no articulation. While the optical pentamirror viewfinder has decent 96% frame coverage, it can feel cramped and partially obstructed in low-light conditions.

The GH5S’s electronic viewfinder (EVF) perks the experience up further. With 3,680k dots resolution and 100% coverage plus 0.76x magnification, it shows a bright, detailed live preview, helpful for exposure preview and critical autofocus checks. The K100D’s optical viewfinder is timelessly natural and lag-free but limited in info overlay.

For live view shooting, video, and fast adjustments on the fly, the GH5S delivers a modern user interface that professionals will appreciate - while the K100D stays faithful to DSLRs of yesteryear with its essentials-only approach.

Autofocus: Hunting or Snapping?

Autofocus capabilities were a significant leap between these cameras, representing a decade-plus technological chasm.

The Panasonic GH5S harnesses a contrast-detection AF system with 225 focus points and touch-selectable areas, plus advanced face detection and autofocus tracking. While it lacks phase-detect AF on the sensor, the GH5S's algorithm and processing power compensate with increased accuracy in video and stills. Its continuous AF tracking at 12 fps burst rates is solid for wildlife and sports.

The K100D, surfacing in the era of DSLRs’ infancy, uses an 11-point phase-detection AF with three cross-type points. Although phase-detection AF traditionally has an edge in speed, the K100D’s system is comparatively slow and prone to hunting in low contrast or dim light. No liveview AF is available, and face detection didn’t exist here.

For wildlife and sports, the GH5S's autofocus strikes a balance of speed and precision - while the K100D fits best in static or slow-moving subjects, like portraits or still life.

Burst Rate and Shutter Mechanisms

Continuous shooting performance can determine if you freeze that winning moment or watch it vanish.

With 12 fps, the GH5S is well suited to action, catching every fraction of decisive movement. For its time, this is a very respectable number, with an electronic shutter speeding things up to 1/16,000s for freezing motion in bright daylight. Mechanical shutter maxes out at 1/8000s.

The K100D’s 3 fps is modest but consistent for its class. Its max shutter speed is 1/4000s, which is adequate except when pushing widest apertures in strong light. No silent electronic shutter exists, so shutter noise and vibrations are notable during prolonged shooting.

For professionals focusing on fast-paced sports or wildlife photography, GH5S’s shutter system wins hands down.

Lens Ecosystem and Mount Compatibility

A camera’s potential ties closely to its glass.

The GH5S uses the Micro Four Thirds mount - an ecosystem with over 100 native lenses from Panasonic and Olympus, plus many third-party options, including fast primes and versatile zooms. Its 2.1x crop factor is higher than APS-C, meaning you need to adjust your lens choices for field of view. However, it allows smaller, lighter lenses often preferred for travel or video.

The Pentax K100D, on the other hand, uses the KAF mount - which boasts around 150 lenses, including some classic, affordable primes and modern options from Pentax and third parties. With a 1.5x crop, it offers a balance between wide-angle and telephoto reach, favored by enthusiasts transitioning from kit lenses.

While both ecosystems are mature, Panasonic’s MFT lenses shine in video stabilization (though the GH5S itself lacks in-body stabilization) and compact size, whereas Pentax offers rugged, weather-sealed (on some models), optically excellent lenses with retro character.

Depending on your photography leanings - lightweight flexibility versus classic DSLR glass - either system has merits.

Build Quality and Weather Sealing

The GH5S was designed with pros in mind, featuring extensive weather sealing against moisture and dust ingress. Though not fully waterproof or shockproof, it can handle tough conditions in the field without worry.

The Pentax K100D lacks environmental sealing, making it vulnerable in harsh environments, limiting its ruggedness mainly to casual or studio use.

For landscape, wildlife, or travel photographers often outdoors, the GH5S’s durability is a significant advantage.

Video Capabilities: Pacific Gigabit Power vs. Analog Flashbacks

Here’s where the GH5S leaps meters ahead.

It offers 4K video recording at 60p (4096x2160), with professional codecs (MOV, H.264, H.265) and 150 Mbps bitrate, plus excellent audio inputs (mic and headphone jacks). The fully articulating screen aids framing, and advanced video-centric features like 4K photo mode, focus stacking, and high ISO performance make it a hybrid video-still powerhouse.

The K100D, a vintage DSLR, has no video functionality - zip. If cinema-quality footage is on your radar, that’s an instant deal-breaker.

For vloggers, filmmakers, or hybrid shooters, the GH5S is in a league of its own compared to the archaic K100D.

Battery Life and Storage

Both cameras use reasonably comparable batteries, though the GH5S uses a proprietary Lithium-ion battery rated around 440 shots per charge, typical for mirrorless bodies.

The K100D runs on 4 x AA batteries - a mixed blessing. While AA cells are easy to find globally and swap quickly, their lifespan per charge is limited, and performance may vary.

Storage-wise, the GH5S offers dual SD card slots supporting UHS-II V60 cards for faster data handling essential in 4K video and burst shooting. The K100D has a single SD/MMC slot.

Practicality favors GH5S for heavy shooters and video users, while K100D offers simplicity and AA battery flexibility.

Connectivity and Modern Conveniences

A stark contrast here.

The GH5S features built-in Wi-Fi and Bluetooth for fast image transfer and remote control - a modern necessity for workflows, instant sharing, and tethering.

The K100D offers no wireless options, relying on USB 2.0 (sluggish) for wired transfers and no tethering support.

For studio pros or event shooters needing speed and networking, modern protocols on the GH5S are invaluable.

Pricing and Value: Bang for Your Buck?

If we zoom out to a price perspective - the GH5S retails around $2,498 brand new. The K100D is discontinued and often found secondhand for under $200. There’s no direct competition in cost, but value is relative.

Is paying a premium for modern tech with video beats worth it? Absolutely, if your workflow or ambitions require cutting-edge flexibility, performance, and image quality.

If budget is tight or you want to learn fundamentals without distraction, the K100D remains a solid entry-level DSLR that can produce impressive images with thoughtful use.

The Verdict: Who Should Choose Which?

To wrap up this decade-spanning duel:

• Choose the Panasonic GH5S if you:

  • Need professional video and high-speed photo performance
  • Shoot low-light, wildlife, sports, or demanding landscape scenarios
  • Want a weather-sealed, rugged, and feature-rich mirrorless system
  • Value excellent autofocus tracking and versatile lens options
  • Require strong connectivity and dual card slots for reliability

• Choose the Pentax K100D if you:

  • Are budget-conscious and enjoy learning photography fundamentals
  • Prefer optical viewfinder simplicity without digital distractions
  • Shoot mostly in good lighting and static subjects like portraits or casual landscapes
  • Want rugged, manual control without investing heavily
  • Collect vintage DSLRs or value the classic K-mount lens ecosystem

Photography Genre Performance: A Closer Look Across Styles

Let’s assess how each fares by genre:

Panasonic GH5S front Panasonic GH5S screen back Pentax K100D front Pentax K100D screen back

Portraits

• GH5S: Excellent skin tone reproduction, smooth 10MP bokeh-friendly sensor, reliable eye detection AF. Larger aperture lenses complement its fast, precise manual focusing.
• K100D: Warm tones and organic rendering, but limited shallow depth of field (smaller aperture lenses) and slower AF. Great introduction to portrait lighting.

Landscapes

• GH5S: Superior dynamic range, crisp details, ability to bracket exposures easily, weather sealing protects on location.
• K100D: Respectable resolution with APS-C; struggles with shadows in high contrast. No weather sealing limits outdoor shooting risks.

Wildlife

• GH5S: Burst rate (12fps), accurate AF tracking, compact tele lenses with stabilization available.
• K100D: 3 fps is limiting; AF can struggle on moving subjects; fewer telephoto lens speed options.

Sports

• GH5S: Fast shutter, continuous AF, helps freeze motion in low light.
• K100D: Good for slow sports; shutter speed and burst limitations apparent.

Street Photography

• GH5S: Slightly bulky but quiet electronic shutter available; tilt screen aids composition.
• K100D: Compact, discreet, optical viewfinder preferred by some enthusiasts; slower AF limits spontaneous capture.

Macro

• GH5S: Focus bracketing and stacking support for extreme precision.
• K100D: Manual focus required; fewer assistive features.

Night / Astro

• GH5S: High ISO freedom, long exposure modes, clean files.
• K100D: ISO noise at 3200, limited exposure control.

Video

• GH5S: Ultra HD 4K, pro audio, versatile codecs.
• K100D: No video.

Travel

• GH5S: Relatively compact system, good battery, ruggedness welcomed.
• K100D: Light, easy to carry; limited features.

Professional Workflows

• GH5S: Raw + Log video, tethering, dual cards, color profiles.
• K100D: Raw support; basic tethering; less suited to workflows dependent on modern file formats.

Performance in Numbers: Authoritative Scoring Analysis

While DxOMark data isn't available for both, real-world tests and expert reviews consistently rank the GH5S higher for ISO noise handling, dynamic range, and autofocus speed.

Notice the GH5S’s dominance in video, low-light, and speed-dependent photography. The K100D holds steady in controlled portrait and daylight genres.

Conclusions from a Seasoned Tester’s Perspective

Having logged thousands of shutter clicks on both mirrorless and DSLR systems, here’s my nutshell: The Panasonic GH5S is a killer hybrid pro camera - designed for those who demand serious video alongside excellent stills, requiring durability and advanced tech. It’s robust, versatile, and just fun to use once you master its extensive features.

The Pentax K100D is a trusty workhorse for those stepping into DSLR ownership with a modest budget or nostalgia for optical simplicity. It teaches fundamentals well and still makes pleasing images when pushed thoughtfully.

If budget permits and you want a tool suited for the future of photography (and yes, filmmaking), the GH5S almost writes itself onto your gear list.

But if you’re just starting, on a tight budget, or enjoy the charm of classic photographic experiences, the K100D deserves a long look and can be a rewarding partner on your creative journey.

Ultimately, both cameras tell their own stories. Whichever you pick, remember - good photography is still about the eye, the moment, and a bit of magic behind the lens.

Happy shooting!

End of Comparison Article