Pentax 645D vs Sony HX100V: A Tale of Two Worlds in Photography

Choosing a camera can sometimes feel akin to selecting between a classical grand piano and a portable electronic keyboard: both produce music but in wildly different ways and for very different settings. The same goes for the Pentax 645D and the Sony Cyber-shot DSC-HX100V (HX100V). While both cameras arrive on the scene armed with lenses and sensors, their DNA could not be more distinct. One is a medium-format beast designed for professional-grade, high-resolution art, and the other a pocket-rocking, superzoom bridge camera stuffed with versatility and portability.

Having tested both extensively, I’m excited to share a deep dive comparing these two – not just in specs on paper, but how they really perform across photography disciplines and real-world shooting scenarios. We’ll balance the razor-sharp details, ergonomics, reliability, and cost, peppered with some honest reflections about who should be considering these cameras today.

First Impressions and Physical Presence: Medium Format vs Superzoom Compact

Looking at these two side by side, the size difference immediately jumps out. The Pentax 645D is a large SLR medium format camera, weighing in at about 1480 grams with dimensions of 156x117x119 mm. By contrast, the Sony HX100V tips the scale at a much lighter 577 grams with a compact, SLR-like bridge camera form factor of 122x87x93 mm. It’s an apples to oranges battle of scale and purpose.

The thick pentaprism viewfinder hump of the 645D exudes confidence and durability. This is a camera built to endure the demands of professionals hauling equipment through climate extremes - indeed, it boasts environmental sealing against dust and moisture, a birthing right for any serious medium-format tool.

Sony’s HX100V, while lacking sealing, compensates with a more travel-friendly profile. It’s an all-in-one package combining a fixed 27-810mm equivalent (30x zoom!) lens with optical stabilization into a lightweight chassis, cleverly designed for spontaneous shooting excursions. The sporty grip and well-positioned buttons make it a joy to wield for street photographers or travelers.

Ergonomically, the Pentax demands respect: its controls are chunky and functional with minimal fluff, a bit old-school and highly reliable. The Sony’s control layout is more modern but a tad cluttered - an inevitable consequence of packing so much functionality in a small body. The tilting screen on the HX100V, compared to the fixed LCD on the Pentax, adds creative framing flexibility that the 645D simply does not offer.

Sensor and Image Quality: The Heart of the Matter

When I talk about cameras, sensor size is the single most critical differentiator for image quality. The Pentax 645D boasts a 44x33 mm medium format CCD sensor with a whopping 40-megapixel resolution (7264 x 5440 pixels). The sensor area is approximately 1452 mm², which is massive compared to conventional full-frame sensors. This beast yields jaw-dropping detail, large dynamic range, and tonal depth - 24.6 bits in color depth and a dynamic range of 12.6EV according to DxO Mark. This is near-class-leading image fidelity, and the lack of an anti-aliasing filter means the images are crisp and sharp.

Meanwhile, the Sony HX100V sports a tiny 1/2.3-inch backside-illuminated CMOS sensor measuring 6.17x4.55 mm with 16 megapixels, delivering images at 4608x3456 pixels. This sensor area is a mere 28 mm², over 50 times smaller than the Pentax’s medium format sensor. Typical of small-sensor superzooms, it has lower dynamic range, color depth, and struggles with noise starting from ISO 400 upwards - and although it features optical image stabilization, the limited sensor size means that noise and detail trade-offs exist at high ISO.

In practice, the Pentax excels in landscapes, fine art, studio portraits, and any scenario where image quality and detail are paramount. The Sony’s sensor, while not a powerhouse, benefits from the sensor’s backside illumination for improved low-light sensitivity over earlier models, but it still can’t compete with the raw image quality of the 645D.

The mid-range ISOs on the Pentax (200-1600) ensure clean images with minimal noise, perfect for professional print work. The Sony’s native ISO range is 100-3200 but practically best kept low, given the image noise and softness creeping in beyond ISO 400.

Autofocus Systems: Precision vs Flexibility

Autofocus is where two very different philosophies meet. The Pentax 645D uses an 11-point phase-detection AF system, fitted with manual focus as well - a nod to the fact that many medium-format shooters prefer manual focus precision. Surprisingly for its category, Pentax includes autofocus for speedier operation, but there’s no eye-detection or continuous tracking AF, and burst rate is a leisurely 1 frame per second. This is a camera designed for deliberate, carefully composed captures, not action sports.

On the other hand, the Sony HX100V offers a contrast-detection AF system with 9 focus points, managed via a BIONZ processor optimized for superzoom operation. It doesn’t feature phase-detection AF but relies on contrast detection with face detection turned off (found lacking in this model). It’s capable of single AF only and lacks tracking, which limits its utility for fast-moving subjects.

As such, Pentax’s AF is more accurate for still subjects in controlled environments while the Sony’s system suits casual or travel photography, with fast focusing enabled during a burst rate of up to 10 frames per second for fleeting moments - although with the caveat of some hunt-and-peck behavior in low light or challenging conditions.

Build Quality and Weather Resistance: Rugged vs Ready-for-Travel

The 645D is a paradigm of build quality and environmental resilience. Its magnesium alloy body is weather-sealed, making it suitable for challenging outdoor shoots in damp or dusty conditions. This level of robustness is critical for landscape photographers or pros working in adverse environments.

In contrast, the Sony HX100V sports a plastic chassis without protective sealing. While it’s solidly built for a bridge camera, it’s no rugged field tool and demands care regarding moisture and dust - think urban adventures, family trips, or vacations, not stormy mountain peaks.

Notably, the savings on build toughness with the Sony contribute to its lower weight and better portability.

LCD Screens and Viewfinders: A Glass Half Full

Both cameras have 3-inch LCD screens with 921k-dot resolution, but their implementations diverge. The Pentax sports a fixed TFT type LCD with wide viewing angles and an anti-reflective coating, facilitating good visibility outdoors. However, it lacks touchscreen functions and live view capabilities - a bummer for those who appreciate framing on the screen rather than the viewfinder.

Sony’s HX100V shines with a high-quality Tilting XtraFine LCD with TruBlack technology, boosting outdoor visibility and creative angles. It also includes an electronic viewfinder (EVF), which the Pentax does not, providing greater flexibility under bright sunlight or when shooting at eye level.

The EVF and live view on the Sony enhance its usability for casual users and street photographers who might want quick shots without peering through an optical viewfinder that blocks peripheral vision.

Lens Ecosystem: Flexibility Meets Convenience

The 645D uses a Pentax 645AF2 mount, allowing users to choose from over six native lenses specially optimized for medium format. These lenses are built for superb optical performance, great build, and tailored focal length options from wide to telephoto - perfect for portraiture, landscapes, and studio use. The lens ecosystem, while not as vast as Canon or Nikon’s full-frame, delivers prime quality and precision.

By contrast, the Sony HX100V features a built-in 27-810mm equivalent lens with an aperture range of f/2.8-5.6. This is the ultimate all-in-one package favored by travelers, zoom aficionados, and anyone wanting versatility without swapping lenses. The trade-off: fixed lens systems lack the sharpness, bokeh control, and extra-terrestrial artistry of separate glass. And with small sensors, lens resolution gains can only do so much.

Battery Life and Storage Options

If there’s one area where medium-format cameras shine, it’s battery life. The Pentax 645D supports up to 800 shots per charge via a proprietary D-LI90 battery pack – substantial enough for a day of vigorous shooting without frequent recharging. Dual SD/SDHC cards provide redundancy or ample storage space, beneficial for photo shoots that demand fail-safe protocols.

Sony HX100V’s battery life is officially unspecified but tends toward shorter usage cycles typical of small bridge cameras. It uses the NP-FH50 lithium battery and supports multiple memory formats, including SD/SDHC/SDXC cards and Memory Stick formats (Memory Stick Pro Duo, Pro-HG Duo). Only one card slot is available, so backup strategies require swapping cards or transferring files quickly.

Shooting Styles and Photography Genres: Which Excels Where?

Portrait Photography

Pentax’s medium format sensor and high resolution naturally dominate in creating stunning portrait images with natural skin tones and pleasing detail gradation. Here, the articulated bokeh from compatible medium format lenses produces creamy backgrounds that let the subject pop. The Pentax’s center-weighted meter and exposure compensation capabilities are another plus for skin-tone accuracy. However, the 645D lacks face and eye detection AF, meaning a practiced hand still helps to nail critical focus points.

The Sony HX100V, by contrast, is a fair portrait companion for casual use but struggles in low light for skin tone accuracy and shallow depth of field effects. The large zoom range is attractive for opportunistic portraits but not the first choice if bokeh artistry is your love.

Landscape Photography

If landscape detail, dynamic range, and tonal fidelity are paramount, medium format reigns supreme. The Pentax’s large sensor captures an incredible breadth of detail, easily supporting large prints. Combined with rugged weather sealing, this camera is an ideal field companion for serious landscape shooters.

The Sony HX100V is serviceable for casual landscapes, but the sensor size and lens limitations mean that images show less nuance, especially in shadows and highlights. The lack of environmental sealing means caution with extreme climates.

Wildlife and Sports Photography

The Pentax 645D - unless mounted with very expensive tele lenses - falls short here. Slow burst rate (1 fps), limited autofocus points, and no subject tracking mean it’s not designed for capturing fast action.

Sony HX100V’s 10 frames per second burst mode and long zoom theoretically favor wildlife and sports. Yet its autofocus system and small sensor limit image quality and focusing reliability on moving subjects. In bright conditions and daytime, it can still be effective as a lightweight, flexible shooter.

Street Photography

Here the Sony HX100V arguably shines due to portability, zoom versatility, and live view EVF, paired with quiet operation. The Pentax 645D, large and conspicuous, is a poor fit for candid street shots and fast shooting styles.

Macro Photography

Neither camera specializes in macro. The Pentax 645D’s medium format lenses can be paired with extension tubes, but focusing speed and magnification options are limited by the native lens lineup. The Sony HX100V does not offer specialized macro focus ranges but can shoot reasonably close-ups using its zoom lens.

Night and Astrophotography

Pentax 645D’s low ISO limit (max 1600) and clean output excel for long exposures with minimal noise, suiting night and astro photography. Its excellent dynamic range preserves shadow detail in star fields.

Sony HX100V’s high ISO noise at levels above 400 compromises night shots, although optical stabilization helps with handheld low-light scenes. Stars and nightscapes would be noisy and soft relative to medium format.

Video Capabilities

Sony HX100V significantly leads here with full HD 1080p video at 60 fps, including MPEG-4 and AVCHD formats, making it a capable casual videographer’s tool. It has HDMI output for external displays but lacks mic/headphone jacks.

Pentax 645D doesn’t provide any video recording functions.

Travel Photography

For travelers wanting one camera to do it all, the Sony HX100V easily fits the bill with its lightweight body, versatile zoom, and good connectivity including built-in GPS and Eye-Fi compatibility for wireless transfer.

The Pentax 645D is heavy and bulky, better suited for planned shoots rather than a carry-on companion.

Professional Use

Pentax 645D is a professional medium format tool with robust workflow integration through extensive RAW support, superior image fidelity, and consistency. Its build quality and dual card slots provide dependability in professional environments.

Sony HX100V is best as a casual enthusiast’s or semi-pro backup tool rather than a primary professional device.

Pentax 645D front Pentax 645D screen back Sony HX100V front Sony HX100V screen back

Connectivity and Extras

The HX100V includes built-in GPS, HDMI, and Eye-Fi support but lacks touchscreen or wireless protocols like Bluetooth or NFC. The Pentax 645D is quite spartan in connectivity, offering USB 2.0 only and no wireless functions.

Pricing and Value-for-Money

At the time of release, the Pentax 645D retailed at $4000 and still holds significant value as a medium format option. Though older, it delivers unparalleled image quality at this price point.

Sony HX100V, priced around $429, delivers extraordinary zoom range and functionality for the money but sacrifices quality and robustness.

Wrapping It Up: Which Camera Is Right for You?

• For professional photographers demanding top-tier image quality, landscape artists craving tonal excellence, and studio portraitists, the Pentax 645D is a medium format workhorse that rewards investment and care.

• For enthusiastic travelers, street photographers, family documentarians, and casual shooters wanting versatility and convenience without carrying lenses, the Sony HX100V delivers solid all-around performance with a pocketable price and form factor.

• If you want to explore video and multimedia content creation, HX100V is the only game in town here.

• If your budget is tight and you want a capable zoom camera with respectable image quality, Sony’s superzoom gives you a lot for under $500.

• If image quality and detail are your obsession and budget can stretch, Pentax 645D’s medium format sensor cannot be beaten by any bridge or enthusiast camera.

Choosing between these two cameras ultimately boils down to weighing image quality and build against portability and all-in-one flexibility. Personally, I find the Pentax 645D a joy to shoot when pace and precision matter (and when I’m not lugging a ton of gear), while the Sony HX100V excels for grab-and-go urban adventures or vacations where switching lenses isn’t an option.

Hope this guided duel helped clarify your choice - because knowing your tools profoundly informs your art! Would I travel with a 645D on a backpacking light trip? Hard pass. Would I bring only the Sony HX100V to a commercial studio portrait shoot? Absolute no. Yet both cameras shine brilliantly in their designed arenas.

Happy shooting!