Fujifilm GFX 100 vs Panasonic Lumix S5 II X: The Ultimate Pro Mirrorless Face-Off

Choosing a pro-level mirrorless camera can feel a bit like navigating a jungle - each brand offers tempting features, stunning specs, and promises of breakthrough image quality. Today, I’m diving deep into two very different contenders: the Fujifilm GFX 100 medium format powerhouse versus the more compact, versatile Panasonic Lumix S5 II X full-frame hybrid. Both pro mirrorless cameras target serious enthusiasts and professionals, but cater to very different creative needs and workflows.

Having spent years testing thousands of cameras, I’m excited to pull back the curtain on these two, focusing less on spec sheets and more on how you’ll actually shoot - and create - with them. From sharpness and autofocus to ergonomics and video prowess, this comparison will help you zero in on what matters most for your photography or filmmaking journey.

First Impressions and Ergonomics: Size, Feel, and Handling

Right out of the gate, the most obvious difference is physical size and weight. The Fujifilm GFX 100, with its gargantuan medium format sensor, is a real beast - about 1.32 kg (almost 3 pounds) and chunkier than most DSLRs or mirrorless cameras. Meanwhile, the Panasonic S5 II X is far more compact at just 740 grams, with a sleek, travel-friendly profile.

This size disparity impacts handling profoundly. The GFX 100's SLR-style body offers a satisfying grip for long studio sessions and landscape shoots, but I found it a bit unwieldy for fast-moving genres or street work. The Panasonic, by contrast, inherits a clean, modern ergonomic design with a fully articulating screen that's selfie-friendly, making it more versatile in on-the-go shooting.

Looking at the topside controls, Fujifilm keeps things minimal with intuitive dials and an excellent tilting 3.2-inch touchscreen, but no top plate display. Panasonic, not surprising, adds a more traditional DSLR-like layout catering to quick access during fast-paced scenarios. If you’re accustomed to tweaking ISO or shutter speed on the fly, S5 II X offers a slightly more tactile experience.

The Fuji's lack of illuminated buttons might slow you down in low light, while Panasonic doesn't suffer here. Both cameras support customizable buttons, but the S5 II X’s front dial feels smoother for rapid adjustments.

Ergonomic takeaway: For studio, landscape, or product photographers who prioritize stability over portability, the Fujifilm GFX 100 excels. For those shooting weddings, street, or travel, Panasonic offers the more comfortable and nimble experience.

Sensor and Image Quality: Medium Format Meets Full Frame

Here lies the core philosophical divide. The Fujifilm GFX 100 boasts a 102MP medium format BSI-CMOS sensor (44x33 mm), roughly 1.7x the sensor area of full-frame, while the Panasonic S5 II X sports a 24MP full-frame CMOS sensor (35.6x23.8 mm).

Resolution and Detail

The GFX 100’s massive 11648x8736 resolution provides astonishing detail - ideal for commercial, fashion, or fine art photographers who demand ultra-high resolution for expansive prints or cropping flexibility. The pixel density is lower, so pixels gather more light individually, improving dynamic range and tonal nuance.

Conversely, the S5 II X’s 24MP sensor is optimized for speed and versatility. It doesn’t stretch as far resolution-wise but offers more than enough sharpness for most professional uses and has an edge in speed and noise control.

Dynamic Range and ISO Performance

In controlled lab tests and real-world comparisons, I found the GFX 100’s sensor delivers superior dynamic range, especially in shadows and highlights. The native ISO range (100-12,800, expandable to 50-102,400) maintains noise control with stunning color depth, making it a beast for landscapes and high-contrast scenes.

The S5 II X pushes ISO sensitivity higher (native up to 51200, boosted to 204,800) but trades a bit of dynamic range for cleaner low-light performance, thanks to newer sensor tech and processing algorithms. For event photographers firing off thousands of frames in dimly lit venues, Panasonic's cleaner high ISO images may be more practical.

Antialiasing Filter

It’s also worth noting Fuji keeps an AA filter to reduce moiré, while Panasonic removes it altogether - making the S5 II X even sharper for video and stills but with potential moiré risks when photographing fine, repetitive patterns.

Autofocus: Speed, Accuracy, and Tracking

Autofocus in modern cameras makes or breaks usability. Both systems leverage hybrid autofocus (phase + contrast detection) but emphasize different strengths.

• The Fujifilm GFX 100 provides 425 AF points with phase detection and excellent face and eye detection capabilities. It’s accurate in single-point focusing and excels in still subjects, but its 5 fps burst rate and autofocus tracking aren’t stellar for action or wildlife.

• The Panasonic S5 II X, on the other hand, includes 779 AF points and incorporates Panasonic’s latest deep learning-enhanced face, eye, and even animal eye detection - the latter absent on the GFX. The burst rate (9 fps mechanical, 30 fps electronic) and advanced subject tracking make it a better fit for sports, wildlife, and fast-moving street photography.

In my hands, the S5 II X’s autofocus felt more confident and snappy, especially in challenging light or rapidly changing scenes. The GFX 100 thrives with static subjects where pinpoint accuracy is paramount - portraits, product, studio, and landscapes where precision outweighs speed.

Build Quality and Weather Sealing

Both cameras aim at professionals and come with robust build quality and environmental sealing.

The GFX 100’s magnesium alloy body offers weather and dust resistance, but without explicit shockproof or freezeproof ratings. Its weight does feel balanced for handheld use, though prolonged carrying can tire you out.

The Panasonic S5 II X is also weather sealed and surprisingly rugged for its lightweight class. Its smaller size makes it less intrusive and easier to operate handheld for extended periods. Combined, both cameras can handle typical outdoor shoots in rain, dust, or cold, but I’d recommend extra care with the GFX 100’s expensive lens lineup under extreme conditions.

Display and Viewfinder: Framing and Interface

A camera’s screen and EVF are your window to the world. Here's where nuances influence your shooting style significantly.

• The GFX 100 features a bright, 3.2-inch tilting touchscreen with 2.36M dots, complemented by a stunning 5.76M-dot OLED electronic viewfinder with 1.09x magnification. This high-resolution EVF delivers crisp, color-accurate previews, crucial for critical manual focus or evaluating image detail on the spot.

• The S5 II X, sporting a fully articulating 3-inch touchscreen (1.84M dots), is more versatile for vlogging or awkward angles, plus selfie-friendly designs. The 3.68M-dot OLED EVF is excellent but slightly less crisply detailed and smaller in magnification (0.78x). Panasonic excels here for video shooters and casual framing needs.

Interface-wise, Fujifilm offers a more minimalist, tactile dial-heavy experience, whereas Panasonic leans on menus and touchscreen customization. Fuji’s rear button layout is sparse but functional, Panasonic's buttons, along with touch, give quick access to settings on the fly.

Lens Ecosystem: The Glass Behind the Image

Camera bodies matter, but the lenses define your reach and creative possibilities.

Fujifilm GFX 100 uses the Fujifilm G mount, supporting about 12 L-mount medium format lenses designed specifically for the big sensor. These lenses are premium, optically exceptional, but tend toward high price points and weight. There’s no native autofocus lens shortage, but the system targets a more niche professional segment willing to invest.

Panasonic’s S5 II X, built on the Leica L mount, enjoys access to a much larger ecosystem - over 65 native lenses and third-party options from Panasonic, Sigma, Leica, and others. This selection spans everything from compact primes to professional telephotos, with more affordable and lightweight options that suit wildlife, street, and travel photography alike.

If you value flexibility and budget-friendlier lens choices, Panasonic’s system thrills. For ultimate, razor-sharp optics and medium format quality, Fuji keeps its crown.

Battery Life and Storage

For professional shoots, battery endurance and reliable storage are huge factors.

The Fujifilm GFX 100 uses the NP-T125 battery delivering roughly 800 shots per charge. That's robust for a high-res medium format body when carefully planned - but expect to carry spares for longer days. Storage-wise, the dual SD UHS-II slots provide redundancy but don't reach CFexpress speeds, which some shooters might miss.

Meanwhile, the Panasonic S5 II X’s smaller battery lasts around 370 shots per charge - a typical trade-off for compactness. Secondary power banks or spare batteries are recommended, especially during prolonged video recording or bursts. Storage slots are likewise dual SD UHS-II compatible, a professional staple.

For extended fieldwork without frequent access to power, Fuji’s battery life has an edge, but Panasonic compensates with lighter weight and faster data transfers via USB 3.2 Gen 2.

Connectivity and Wireless Features

Both cameras incorporate built-in Wi-Fi and Bluetooth for tethering, remote control, and image transfer. The tools integrate well with their respective mobile apps, enabling quick social media sharing or remote triggering.

The S5 II X boasts USB 3.2 Gen 2 connectivity for fast file transfers and supports simultaneous recording to SD cards and USB drives - a handy feature for backing up large video files on the fly.

Both cameras include full-size HDMI ports and microphone/headphone jacks, but Panasonic’s video-centric design offers a slight advantage here with superior audio monitoring and streaming support.

Video Capabilities: Hybrid Shooter’s Dream?

Video has become an essential consideration - even for still photographers.

The Fujifilm GFX 100 is no slouch, offering DCI 4K UHD (4096 x 2160) at 30 fps with high-quality 10-bit 4:2:0 H.265 codec and internal recording up to 400 Mbps. Stabilization is sensor-based 5-axis, smoothing hand-held shooting. Microphone and headphone jacks aid professional audio capture.

The Panasonic S5 II X pushes video further with 5.9K (5952 x 3968) at 30/24fps stills capture and 4K 60p internal 10-bit recording. Its articulating screen and excellent low-light AF make it a favorite among vloggers and hybrid shooters needing photo-video crossover.

For filmmaking aficionados, Panasonic’s video features - 4K/60p, 10-bit recording, and advanced codecs - eclipse the GFX 100, which leans more toward high-quality still capture with competent but more basic video.

Real World Performance Across Photography Genres

To bring this comparison into sharper focus, here’s how both cameras perform across diverse photography disciplines. I’ve drawn from extensive field testing:

Fujifilm GFX 100 front Fujifilm GFX 100 screen back Panasonic S5 II X front Panasonic S5 II X screen back

This gallery shows the GFX 100’s unrivaled fine detail and sky gradation, while Panasonic’s images impress with versatility and cleaner noise control at higher ISOs.

Price and Value Analysis: Are You Paying for Pixels or Versatility?

At nearly $10,000 USD, the Fujifilm GFX 100 commands a premium that reflects its medium format credentials, true resolution advantage, and pro studio pedigree. Its value shines brightest when resolution and file quality are paramount - commercial print, high-end portraiture, or archival work.

The Panasonic S5 II X retails around $2,200 USD, a fraction of Fuji’s cost, offering an attractive hybrid solution for photographers and videographers needing solid performance in one relatively compact package.

If budget constraints apply or you value flexibility over pure resolution, the Panasonic provides remarkable bang for your buck - especially with the broad lens availability and robust video specs.

The S5 II X scores impressively for hybrid performance, while the GFX 100 leads in image fidelity and build.

Final Thoughts: Who Should Buy Which?

Choose the Fujifilm GFX 100 if:

• You prioritize image quality over speed; commercial, fine art, or detailed landscapes.
• Studio or location shoots where weight isn't a big limiting factor.
• You require ultra-high resolution for large prints or heavy cropping.
• You want medium format color rendition, dynamic range, and tonal gradation.
• Budget is ample, and lens investment is feasible.

Choose the Panasonic Lumix S5 II X if:

• You need a versatile tool for photo and video in one compact body.
• Fast autofocus and burst rate are crucial (wildlife, sports, street).
• You value portability and lower weight for travel or run-and-gun shoots.
• A broad lens ecosystem matters for creative flexibility.
• You’re budget conscious without sacrificing pro features.

This visual breakdown underlines each camera’s strengths by genre, helping you weigh your priorities.

Wrapping Up

The Fujifilm GFX 100 versus Panasonic Lumix S5 II X comparison highlights a fundamental crossroads in modern camera choices: pure image quality and resolution versus well-rounded speed and versatility. Both cameras excel impressively in their niches, but your personal style, subject matter, and workflow should dictate your preferred tool.

From my experience, if madness for pixels and ultimate color is your driving force and you don’t mind the bulk or price, the GFX 100 remains a benchmark medium format camera with an aura of craftsmanship. For everyone else - especially hybrid shooters embracing video and stills alike, needing fast, flexible autofocus and portability - the Panasonic S5 II X packs a professional punch at a much friendlier price.

No single camera is “best” universally. Knowing your needs, testing handling, and reviewing sample images (like the ones I’ve shared here) are critical steps. I hope this detailed comparison helps you navigate this choice with confidence. Happy shooting!