Pentax I-10 vs Sony RX100 IV: A Deep Dive into Two Very Different Compact Cameras

Selecting the right compact camera hinges on what you prioritize most - portability? Image quality? Versatility? Both the Pentax I-10 and the Sony RX100 IV hold appeal for enthusiasts and professionals seeking compact tools, but they come from distinct corners of the market and cater to divergent needs. I’ve spent significant time testing and comparing these two models, and in this detailed review, I'll unpack how they stack up across every essential photography discipline, sharing insights from my hands-on experience. Whether you’re hunting for your first compact or looking to upgrade, I’ll help you sift through the specs to find your ideal match.

First Impressions: Design and Handling

When you pick up the Pentax I-10 and the Sony RX100 IV, you immediately notice their different design philosophies. The I-10 leans into a truly pocketable profile - it’s lightweight (just 153 g), slim, and has an uncomplicated control layout aimed at casual shooters or those valuing extreme portability. Its dimensions (101x65x28 mm) make it easy to slip into a jacket pocket or small bag.

By contrast, the Sony RX100 IV (298 g) is noticeably heavier and chunkier (102x58x41 mm) due to its larger 1” sensor and more complex mechanics - including a pop-up electronic viewfinder and a tilting 3” screen, features absent on the I-10. The extra heft is balanced by a solid grip and more tactile buttons, appealing to serious shooters looking for greater control.

Ergonomically, I found the RX100 IV’s interface far more intuitive for faster shooting. The Pentax’s minimal buttons feel limiting when switching settings rapidly. If you’re used to dials and customizable controls, the RX100 is the clear winner. However, if tiny size and simplicity top your priority list, the I-10’s minimalism might be just right.

Sensor Technology & Image Quality: The Heart of the Matter

At the core of any camera’s capability is its sensor. The Pentax I-10 sports a small 1/2.3" CCD sensor measuring 6.17x4.55 mm, delivering 12 megapixels. The Sony RX100 IV boasts a far larger 1” BSI-CMOS sensor at 13.2x8.8 mm with 20 megapixels. In practical terms, this sensor size difference (28.07 mm² vs. 116.16 mm² active area) translates into meaningful improvements in image quality.

The RX100 IV’s back-illuminated sensor excels at gathering light efficiently, offering a wider dynamic range (about 12.6 EV versus the I-10’s untested, but naturally limited range) and notably better high ISO performance (native ISO up to 12,800 with usable images beyond). The Pentax’s sensor, typical of compact cameras in its category and era, struggles beyond ISO 400, with noise and softness creeping in.

In daylight, both cameras produce respectable color and detail; however, the Sony captures finer textures, crisp shadows, and richer tones - a boon for landscape and portrait work demanding nuance. The I-10’s anti-aliasing filter and modest resolution mean slightly softer images with more artifacts in fine detail.

Bottom line: if image quality is non-negotiable, especially in challenging light, the RX100 IV earns the nod.

Focusing on Autofocus: Speed, Accuracy, and Tracking

Autofocus performance can make or break candid, wildlife, or sports photography. The Pentax I-10 employs contrast-detection autofocus with 9 points and no phase detection or face/eye detection. Its AF speed is leisurely, capable of single-shot AF only, with no continuous tracking - manageable for snapshots, but limiting for active subjects.

By comparison, the RX100 IV combines 25 AF points with advanced contrast detection and reliable face detection. It offers continuous AF tracking and selective AF, boosting accuracy for moving subjects, and supports eye-detection AF in live view, a significant advantage for portraits.

My field tests confirmed the RX100 IV’s superior ability to lock focus swiftly and maintain it on erratic subjects - ideal for wildlife or fast-paced street photography. The Pentax, while occasionally accurate in bright conditions, often hunted in lower light, frustrating any attempt at action capture.

Shooting Speed and Burst Modes

Burst shooting speeds reflect a camera’s readiness for fast action. The I-10 can manage only 1 fps continuous shooting– effectively limiting it to leisurely shooting conditions. The RX100 IV blows it away with a rapid 16 fps burst mode, a feature typically found in high-end interchangeable lens cameras.

This disparity is crucial for sports and wildlife photographers who need to capture decisive moments. Moreover, the Sony’s electronic shutter capability allows up to 1/32000s shutter speed, facilitating ultra-fast captures - an option missing from the Pentax.

Build Quality and Weather Resistance

Neither camera offers weather sealing, dustproofing, or freezeproofing - features that are increasingly essential for professionals in rugged environments or landscape photographers often out in unpredictable conditions. Both should be treated carefully in the field.

Both models feel solid but noticeably different in heft and endurance. The RX100 IV’s metal body lends a reassuring robustness, while the Pentax’s plastic construction is lighter but less resistant to abuse.

Screen and Viewfinder: Composition Tools Explored

Screen size and quality strongly influence usability. The Pentax I-10 has a fixed 2.7” screen with just 230k dots resolution - acceptable but uninspiring for reviewing images or navigating menus. The Sony’s 3” tiltable LCD with 1,229k dots resolution is significantly sharper and more versatile for composing high and low-angle shots.

Furthermore, the RX100 IV incorporates a pop-up electronic viewfinder with an impressive 2.36 million-dot resolution, 100% coverage, and 0.59x magnification. For bright outdoor shooting or precise manual focus, this is invaluable.

The Pentax’s lack of any viewfinder restricts composition options to the LCD, which can be difficult in sunshine or fast-moving situations. For photographers who rely heavily on a viewfinder, the RX100 IV is clearly preferable.

Lens and Zoom Range: Flexibility in Framing

Lens focal range affects how versatile a compact camera can be. The Pentax I-10 offers a 28-140mm equivalent zoom (5x) with a slow aperture range of f/3.5-5.9, limiting low-light or depth of field control. The Sony RX100 IV covers 24-70mm (2.9x) with brighter optics (f/1.8-2.8), allowing more creative control, especially in portraits and low-light street scenarios.

The RX100’s sharper optics and bright aperture excel at shallow depth of field effects, delivering creamier bokeh and better background separation. The Pentax, with its smaller aperture and sensor size, struggles to deliver comparable subject isolation.

Image Stabilization: Steady Shots in Your Hands

Pentax includes sensor-shift stabilization in the I-10, helping reduce blur in handheld shots, which is commendable for such a small sensor camera. Sony implements optical image stabilization (OIS) in the RX100 IV’s lens, proven more effective at smoothing motion blur.

In real-world tests, I found the RX100 IV’s stabilization more reliable, delivering sharper handheld images and smoother video footage. This advantage extends shooting possibilities in low light and at slower shutter speeds.

Video Capabilities: From Casual Clips to 4K Quality

Video recording is where the Sony RX100 IV truly shows its technological superiority. It records 4K UHD (3840x2160) at 30, 25, and 24 fps - a professional-grade feature uncommon in compact cameras from its era. It also supports high frame rate Full HD slow motion (up to 120 fps), and multiple codecs (MPEG-4, AVCHD, XAVC S) for flexible workflows.

The Pentax I-10 is limited to 1280x720 HD video at 30 fps with Motion JPEG compression, resulting in significantly lower quality files with larger sizes. No external microphone inputs exist on either camera, constraining audio control.

If video is part of your creative mix, the RX100 IV is clearly the more capable choice. Its superior stabilization, sensor, and recording options provide sharp, detailed footage suited to professional use.

Battery Life and Storage Options

The Pentax I-10 uses a proprietary D-LI92 battery with unspecified rated endurance but realistically short battery life due to compact form and electronics. The Sony RX100 IV’s NP-BX1 battery is rated for approximately 280 shots per charge, typical for advanced compacts but modest compared to DSLRs.

Both cameras offer a single slot for SD/SDHC/SDXC cards. The Sony also supports Memory Stick formats, giving users more storage flexibility.

Connectivity and Wireless Features

The Pentax I-10 includes Eye-Fi compatibility, allowing wireless image transfers with specific SD cards but lacks Bluetooth or NFC. The Sony RX100 IV features built-in Wi-Fi with NFC for quick smartphone pairing, facilitating remote control and instant sharing. No Bluetooth is available on either, but Sony’s integrated wireless is more seamless.

Examining the Cameras Across Photography Genres

To understand how these cameras perform in different contexts, I tested both across multiple photography disciplines. Here’s a quick breakdown:

Portrait Photography

Portraits require accurate skin tones, pleasing bokeh, and reliable eye autofocus.

• Sony RX100 IV: Bright f/1.8 aperture creates lovely background blur; face and eye detection improve sharp focus on subjects; larger sensor captures smooth skin gradations.
• Pentax I-10: Smaller sensor and slow f/3.5 aperture limit bokeh quality; no face detection means less reliable focus on eyes; prone to flatter skin rendering.

Landscape Photography

The key here is dynamic range and resolution.

• Sony RX100 IV: Larger sensor offers wider dynamic range, sharper details (20 MP vs. 12), ideal for landscapes with bright skies and shadow detail.
• Pentax I-10: Limited dynamic range and resolution reduce image depth; lacks weather sealing - limiting outdoor endurance.

Wildlife Photography

Speed and tracking matter most.

• Sony RX100 IV: Fast 16 fps burst, effective tracking AF, and brighter zoom (up to 70mm) help capture transient wildlife moments.
• Pentax I-10: Single-frame shooting and slower AF hamper wildlife action; longer zoom of 140mm helps subject framing but soft image quality limits resulting shots.

Sports Photography

High frame rate and quick focus are vital.

• Sony RX100 IV: Clearly superior with high fps and tracking.
• Pentax I-10: Not suitable for fast action due to slow AF and single fps.

Street Photography

Portability and low light prowess come into play.

• Pentax I-10: Smaller and lighter - very pocketable for street; however, slower AF and dimmer lens impact shooting in low light.
• Sony RX100 IV: Bulkier but retains some discretion; excels in low light and quick AF locking.

Macro Photography

Focus precision and minimum focus distance are key.

• Sony RX100 IV: 5 cm macro close focusing and sharp optics deliver crisp close-ups.
• Pentax I-10: 10 cm minimum focus distance limits true macro effect; optical softness noticeable.

Night / Astro Photography

High ISO performance and long exposures matter.

• Sony RX100 IV: Low noise at high ISO and electronic shutter up to 1/32000s offer versatility; better choice for astro.
• Pentax I-10: Poor high ISO performance constrains low-light usability.

Video Use

Already covered above - Sony leads by a substantial margin.

Travel Photography

Combination of image quality, size, battery life.

• Pentax I-10: Ultra-portable and lightweight; decent for snapshots and casual travel.
• Sony RX100 IV: Heavier but offers higher image quality, better video, and more controls - great for a versatile travel companion.

Professional Work

RAW file support, reliable controls, and quality output essential.

• Sony RX100 IV: RAW support, advanced controls, higher fidelity files position it as a professional “pocket DSLR” alternative.
• Pentax I-10: No RAW, limited controls - better suited to casual use.

Summary of Camera Performance Scores

For a quick glance at overall and genre-specific performance, these score charts paint the picture clearly:

Price-to-Performance: What Does Your Budget Gain You?

The Pentax I-10 retails around $310 - an affordable, truly pocket-friendly option for those prioritizing ultra-compactness and simple operation. Its limitations in sensor size, image quality, autofocus, and video reflect that price point.

The Sony RX100 IV, priced closer to $900, demands a serious investment but rewards it with a powerful sensor, pocket DSLR-level features, exceptional autofocus, 4K video, and a premium lens. This makes it a compelling choice for enthusiasts who want the best ultra-compact without compromises.

Final Thoughts: Which Camera Fits You?

If your style is casual shooting, always on the move, and you want something that fits in your palm with minimal settings fuss - the Pentax I-10 is a neat, wallet-friendly companion. It produces decent daylight snaps and has basic stabilization and video function. Perfect for beginners or as a carry-all convenience camera.

But if image quality, speed, versatility, and creative control rank high, the Sony RX100 IV is a powerhouse that packs advanced sensor tech and pro-level features into a compact body. I’ve used this camera extensively for portraits, street, and travel photography - it delivers consistently sharp images with brisk autofocus and great video. It feels like a serious imaging tool that won’t slow you down.

Both are niche devices serving different photographer types, but in my view, the leap in image quality, speed, and versatility you get with the Sony justifies the higher price for most enthusiasts and professionals. The Pentax is best for those whose absolute priority is smallest size and simplicity.

In-Depth Image Gallery

To give you real-life visual evidence of these conclusions, here are side-by-side sample images from both cameras captured under varying conditions. Pay close attention to sharpness, noise, color rendition, and depth of field.

Pentax I 10 front Pentax I 10 screen back Sony RX100 IV front Sony RX100 IV screen back

In essence, choosing between the Pentax I-10 and Sony RX100 IV comes down to your balance of size, image quality, and shooting flexibility. I hope this hands-on, comprehensive evaluation helps you make that call with confidence. Should you want a highly capable all-rounder in a compact size, Sony’s RX100 IV is tough to beat; but if true pocket ease and simplicity matter above all - the Pentax I-10 holds its own.

Happy shooting wherever your journey takes you!