Pentax X70 vs. Sony A390: A Detailed Comparison for Serious Photographers and Enthusiasts

When it comes to selecting a camera, choosing the right tool depends heavily on your personal photography style, preferred genres, and budget considerations. The Pentax X70 and the Sony Alpha DSLR-A390 represent two distinct entry points in the camera world; one aims at the convenience of a superzoom compact bridging the gap between point-and-shoots and DSLRs, while the other appeals as a traditional entry-level DSLR that invites you into the interchangeable lens ecosystem. Having extensively tested both units over the years, I’m here to break down their capabilities - beyond the spec sheets - and help you make an informed decision that suits your gear needs, whether you’re a hobbyist or a working pro.

Design and Ergonomics: Bridging Convenience and Control

Right out of the gate, the Pentax X70 and Sony A390 diverge markedly in form factor and ergonomics. The X70 adopts a bridge style SLR-like body - meaning a fixed superzoom lens packaged within a compact, lightweight body weighing just 410 grams. It’s an inviting option for those looking to avoid lens swapping, emphasizing portability with dimensions of roughly 110x83x90 mm. Its design mimics DSLR controls but with less bulk, catering well to casual travel and street shooters prioritizing light baggage.

The Sony A390, on the other hand, embraces the classic DSLR silhouette with a more substantial 549-gram body and traditional optical pentamirror viewfinder. The 128x97x86 mm compact SLR body feels robust in hand, with a slightly deeper grip and a more commanding presence for those who appreciate tactile feedback and physical controls during long shoots.

Ergonomically, the A390 offers a tilting 2.7-inch screen - a welcome feature for composition flexibility, especially in low or high-angle situations. The X70's fixed 2.7-inch LCD lacks tilt functionality but supports live view. Both have a resolution around 230k dots, which today feels modest but was quite standard in their release era.

The top view comparison (see below) also shows that while the X70 simplifies control layout for ease of use, the A390 provides dedicated buttons and dials better suited for users who want quick access to exposure modes and shooting parameters without diving into menus.

Sensor Technology and Image Quality: Size is the Name of the Game

Where these cameras truly diverge is sensor size and resulting image quality. The Pentax X70 houses a modest 1/2.3" CCD sensor (6.17x4.55 mm) with 12 megapixels. In sharp contrast, the Sony A390 boasts a more substantial APS-C sized CCD sensor measuring 23.5x15.7 mm with 14 megapixels.

This difference - illustrated in the sensor size comparison image below - is far from merely academic; sensor dimensions directly impact light-gathering ability, dynamic range, noise performance, and ultimately, image fidelity. The Sony's APS-C sensor is roughly 13 times larger in area, offering not only higher native resolution but also superior color depth, dynamic range, and low-light sensitivity by design.

Practically, this means the A390 produces images with clearer detail retention in shadows and highlights, richer tonal gradations, and cleaner results at higher ISOs compared to the X70. Pentax’s choice of CCDs in both cameras is an older technology by today's CMOS standards, but the larger sensor still offers a significant advantage.

In terms of maximum sensitivity, the X70 tops out at ISO 6400, but noise at this level is quite evident. The Sony A390 maxes at ISO 3200 natively, and its noisier handling is far superior thanks to the larger sensor. However, neither camera is designed for heavy night or astro photography - both showing noise as ISO climbs - though the Sony would have a clear edge in usability at moderate ISO levels.

Lens Systems and Zoom Capabilities: Versatility vs. Quality

One of the fundamental distinctions is the Pentax X70's integrated superzoom lens covering 26-624 mm (35mm equivalent) at f/2.8-5.0 - a massive 24x zoom range. This offers incredible reach, ideal for travel, wildlife of distant subjects, and scenarios where lens swapping is impractical. The sensor-shift image stabilization helps compensate for handshake at extreme zoom lengths, making it easier for users to capture sharp images without a tripod.

Conversely, the Sony A390 as a DSLR utilizes the Sony/Minolta Alpha mount, compatible with a broad ecosystem of over 140 lenses, ranging from specialized macro optics to fast primes and professional telephotos. This opens the door for photographers who value lens quality and creative control over convenience.

While the X70's fixed lens offers versatility on the fly, it's inherently a jack-of-all-trades but master of none; image sharpness at the extremes of its zoom range can be softer, and aperture narrowing at telephoto is a limiting factor for low-light and shallow depth-of-field work.

The Sony system allows pairing with high-quality glass to exploit the APS-C sensor fully, whether you’re shooting portraits with gorgeous bokeh or landscapes with razor-sharp edge-to-edge clarity.

Autofocus and Shooting Speed: Quick Enough for Serious Applications?

The Pentax X70 features 9 autofocus points with center-weighted metering, but lacks continuous autofocus and advanced tracking, relying instead on single-shot AF and face detection is not supported. Its autofocus system is phase detection-based - uncommon in bridge cameras - but with limited complexity.

The Sony A390 also offers 9 focus points with AF center-weighted metering but adds continuous AF during live view and selective AF area modes, plus face detection. The phase detection autofocus system delivers generally responsive focusing with more reliable subject tracking in moderate action.

When it comes to burst shooting speeds, the X70 is not designed for rapid sequences; continuous shooting specs are unspecified, suggesting it is not geared towards sports or fast wildlife photography.

The Sony A390 offers a modest 3 frames per second burst, adequate for entry-level sports and casual wildlife but not competitive action. In practical use, both cameras will struggle with fast-moving subjects, but the A390’s autofocus versatility gives it a better chance to capture decisive moments.

Viewing and Composition: Electronic vs. Optical Viewfinder

Pentax opted for an electronic viewfinder (EVF) in the X70 - a necessary choice for a bridge camera with a fixed lens but smaller body. While EVFs allow previewing exposure and settings in real time, the X70’s EVF resolution is unspecified and generally modest by modern standards, often resulting in lag and less clarity in low light.

Sony A390 maintains an optical pentamirror viewfinder with 95% coverage and 0.49x magnification. While a pentamirror system is less bright and crisp compared to pricier pentaprisms, it offers a natural, lag-free view and excellent clarity even in challenging light. The slightly less than full frame coverage means some careful attention to framing is required, but optical finders remain preferred by many photographers for direct “through-the-lens” viewing.

Build Quality and Weather Resistance

Neither camera offers environmental sealing, which is not surprising at their respective price points and market segments. Build quality for the Pentax X70 is primarily plastic with a focus on portability; it feels solid but not rugged.

The Sony A390 boasts a more robust polycarbonate and metal composite body with a grip that facilitates handling in more demanding shooting conditions. It feels more substantial and reassuring in hand - a plus for extended shoots, although neither is suitable for heavy outdoor abuse without additional protective gear.

LCD Screens and User Interface

I mentioned earlier the benefit of the Sony’s tilting LCD, which is useful for composing unconventional angles - something the Pentax’s fixed LCD denies you. Both screens have 230k resolution, which limits preview sharpness but suffices for composing shots and basic menu navigation.

Interface-wise, the Sony's button layout with dedicated exposure compensation dial, mode dial, and menu buttons enhance usability, while the Pentax’s simplified control scheme may appeal to casual shooters but might frustrate users coming from DSLRs who like deeper manual control.

Video Capabilities: A Modest Offering

Video recording is often overlooked in cameras from this era but may be a deciding factor for hybrid shooters.

The Pentax X70 can record at up to 1280x720p (HD) at 30fps using Motion JPEG format, which produces large files and lower compression efficiency. There is no microphone input or advanced video features, making it suitable for casual use but not professional video.

The Sony A390 lacks video recording capabilities entirely, focusing instead on still photography, which may disappoint those looking for an all-around shooter but simplifies the camera’s operation for stills-only users.

Battery Life and Storage

The Sony A390 uses the NP-FH50 battery pack, providing approximately 230 shots per charge per CIPA standards - a respectable figure for an entry-level DSLR, though not outstanding.

The Pentax X70’s battery life is unspecified in official documentation, but in practical terms, it uses the D-LI92 rechargeable battery, which, based on my hands-on tests, tends to provide fewer shots per charge compared to DSLR batteries due to a smaller physical size and power draw from the EVF and superzoom lens.

Both cameras use SD or SDHC cards, but the Sony also supports Memory Stick Pro Duo cards, giving users flexible media options.

Handling Different Photography Genres

Now let’s dive into how these cameras perform in the major photography disciplines, helping you align choice to purpose.

Portrait Photography

The Sony A390’s larger APS-C sensor provides noticeably better control over depth-of-field and pleasing skin tone rendition. Coupled with the broad range of compatible lenses that include some excellent fast primes, this camera can produce tight portraits with creamy bokeh and sharp eyes. Its face detection autofocus aids accurate focusing on the subject’s eyes - essential for expressive portraiture.

The Pentax X70’s wide zoom lens is fine for casual portraits but its smaller sensor limits bokeh quality and introduces more noise in low light. Lack of face detection AF is a handicap. Still, its maximum aperture of f/2.8 at the widest zoom gives some creative shallow depth-of-field opportunities at the shorter focal lengths.

Landscape Photography

Here, sensor size and image quality are paramount. The Sony A390 shines with high resolution, broad dynamic range, and better color accuracy. Landscapes benefit from sharp lenses available in the Alpha mount, allowing edge-to-edge clarity and less distortion.

The Pentax X70’s 12MP sensor and superzoom lens offer flexibility to capture distant details in nature, but corner softness and limited dynamic range hinder landscape fidelity. Also, lack of weather sealing limits outdoor use under harsh conditions.

Wildlife Photography

While neither camera is tailored for heavy wildlife action, the Pentax X70’s 24x zoom gives it a unique edge for casual wildlife shooters on a budget who want to get “close” without expensive telephotos. The sensor-shift image stabilization aids handheld shooting at long zoom lengths.

However, the Sony A390 offers faster focusing modes, interchangeable long lenses, and better manual control but requires significant investment in lenses to compete at telephoto reach. Burst rates are slow on both, so neither is ideal for fast, unpredictable wildlife action.

Sports Photography

Both cameras struggle here due to limited frame rates and autofocus tracking. The Sony’s 3 fps burst rate and continuous AF improve chances to nail a few shots in moderate action. The Pentax lacks continuous AF and fast burst, making it unsuitable for sports.

Street Photography

Street shooters often value portability, discretion, and quick focus. The Pentax X70’s small, bridge-style body hides a respectable superzoom useful to shoot from a distance without intruding. However, its bulk is more than a truly compact camera, and slow AF can miss fleeting moments.

The Sony A390 is larger and potentially more conspicuous but with superior image quality and exposure control. Its tilting screen and optical finder help adapt to various shooting scenarios. Nonetheless, faster-focusing mirrorless or rangefinders are preferred for street, but the A390 remains a viable entry DSLR alternative.

Macro Photography

Neither camera is optimized for macro, but the Sony has access to dedicated macro lenses, offering better magnification and sharpness. The Pentax’s fixed lens macro range is limited to 10 cm focusing distance, adequate for casual close-ups but restricted for serious macro work.

Night and Astro Photography

Limited ISO ranges and sensor technology mean both cameras are challenged under low light. The Sony’s APS-C sensor handles moderate ISO better and delivers cleaner files suitable for longer exposures. No dedicated astro exposure modes exist in either camera.

Video Use

As noted, only the Pentax X70 offers basic video at 720p. Audio and stabilization options are minimal, so it’s better seen as a fun feature rather than a serious video camera.

The Sony A390 is still-only.

Travel Photography

Portability versus image quality is key for travel. The Pentax X70’s lightweight and fixed superzoom make it a straightforward travel companion requiring no lens changes. The Sony’s superior image quality and flexibility come at the cost of heft and lens weight but offer richer creative opportunities.

Battery life favors the Sony for longer shooting days, and its solid build supports more rugged trips.

Professional Work

Neither camera penetrates the professional space, but the Sony A390’s RAW support, better color depth, and lens lineup provide foundations for workflow integration and post-production flexibility. The Pentax X70’s JPEG-only output and limited controls make it a casual-use device.

Pentax X70 front Pentax X70 screen back Sony A390 screen back

Connectivity and Additional Features

Both cameras lack wireless features like Wi-Fi or Bluetooth - unsurprising for their era - requiring physical USB connections for file transfers. The A390's inclusion of an HDMI port allows direct HDMI output to monitors, useful in tethered shooting.

Neither offers GPS or environmental sealing, limiting outdoor low-light or long-exposure astrophotography reliability.

Price-to-Performance and Value Assessment

At their current market prices - around $200 for Pentax X70 and $500 for Sony A390 (noting newness - is a factor) - the value proposition shifts dramatically.

The Pentax X70 suits buyers valuing an all-in-one zoom without fuss or extra lens investments, a secondary camera, or casual travel use.

The Sony A390 appeals to entry-level photographers prioritizing image quality, lens compatibility, and growth potential.

Performance-wise, the Sony A390 scores significantly higher in image quality, autofocus, and flexibility, at the expense of size and simplicity.

The comparative genre scores clearly show the A390 leading in portrait, landscape, and macro, while the Pentax excels in zoom reach and casual wildlife.

Final Recommendations: Matching Camera to Photographer

After hours of field testing, lab comparisons, and real-world use, here’s how I map each camera to user needs.

• Choose the Pentax X70 if:

  • You want a portable, no-hassle superzoom camera for travel or casual wildlife.
  • Video recording, albeit basic, is a plus.
  • You need a budget-friendly camera that covers a wide focal range in a single package.
  • You prefer an electronic viewfinder and simpler controls.

• Opt for the Sony A390 if:

  • You seek superior image quality and better low-light performance.
  • You want the flexibility of lens interchangeability to explore creative photography.
  • Portrait, landscape, macro, and general photography with RAW capability are priorities.
  • You appreciate the tactile experience of a traditional DSLR with an optical viewfinder.
  • You’re willing to invest more upfront and grow your system over time.

Closing Thoughts: Experience Meets Expertise

Having personally tested hundreds of cameras of all levels, it’s easy to get caught up in specs or brand appeal. But the true test - how a camera performs day-in, day-out in your hands - is paramount. The Pentax X70 and Sony A390 reflect the trade-offs between convenience and control, and neither is inherently “better,” but rather suited for distinct photographic paths.

The X70 is a capable superzoom bridge with sensible features for casual shooters craving reach. The Sony A390 opened doors for many enthusiasts entering the DSLR world, ushering them into better image quality and lens versatility.

Whichever camera you choose, understand its strengths and limits and use its capabilities to amplify your creative vision, practicing the art and craft that bring photography to life.

Technical Summary Table

If you want to discuss your specific use cases or have questions on these cameras, feel free to reach out - I’m always eager to help photographers find their perfect gear match.