Pentax K-x vs Sony Alpha A390: A Hands-On Expert’s Deep Dive into Two Entry-Level DSLRs

When it comes to entry-level DSLRs, the early 2010s were an intriguing era of rapid innovation and heated competition. The Pentax K-x and Sony Alpha A390 emerged as solid options for budding photographers looking for affordable ways to jump into the DSLR game. Having spent years testing cameras spanning from cheapskate shooters to flagships (and everything in between), I wanted to take an up-close, practical look at how these two 12- to 14-megapixel APS-C DSLRs stack up against each other in real-world scenarios and technical benchmarks.

This isn’t just about specs on paper - I’ve spent countless shooting hours across genres, dissecting image quality, handling nuances, autofocus quirks, and usability aspects that truly shape your everyday photography experiences. So if you’re weighing these cameras for portraits, landscapes, wildlife, or just travel snaps on a budget, buckle up for a thorough, no-nonsense comparison carefully tailored for enthusiasts and professionals alike.

First Impressions: Size, Build, and Ergonomics Battle

Right out of the gate, handling these cameras gives a snapshot into their makers’ design philosophies. The Pentax K-x is a compact SLR that screams portability without sacrificing too much control. The Sony A390, on the other hand, feels slightly chunkier but more solid in the grip department.

Pentax K-x

Weighing in at 580 grams and with dimensions of 123x92x68 mm, the K-x is impressively light and easy to carry all day, especially if your photography gigs involve hustle and bustle city shooting or travel. It’s built from lightweight plastics, so don’t expect tank-like durability, but it fits nicely even in smaller hands. The 4x AA battery approach is both a blessing and a curse - easy replacements worldwide but bulkier than modern battery packs.

Sony A390

The A390 is more of a minivan in feel - at 549 grams, it’s lighter yet bulkier (128x97x86 mm), hinting at more internal room and perhaps sturdier construction. The build is a bit more traditional Sony, with a grippy, chunky handhold designed for confident shooting. It uses the proprietary NP-FH50 battery, which while less universally replaceable than AAs, delivers respectable longevity in practice.

Glancing at the top plates, the Pentax layout is refreshingly minimal - but you lose some quick access controls compared to the Sony, which sports a dedicated mode dial, cooldown button clusters, and a tilting 2.7" screen (more on that next). For photographers who like to keep fingers on frequent settings without digging deep into menus, the A390 feels more plugged-in.

The Display and Interface Showdown

In the age of touchscreens (which neither camera offers), these LCDs are the windows into your framed moments and camera settings. Both offer a 2.7" screen size at 230K dots resolution, but Sony's tilting mechanism adds a versatile edge.

Pentax K-x’s Fixed TFT LCD

The fixed LCD is serviceable - adequate for framing after live view tap-on, but frustrating for awkward angles like ground-level macro or overhead street shots. The color representation and brightness are average; outdoors in strong sun, visibility drops considerably.

Sony A390’s Tilting LCD

Here the A390 scores with a versatile tilting screen that swings upward, handy for low-angle or above crowd shots. While the resolution and clarity are on par with the K-x, the tilting adds significant compositional freedom for shooting on the go. Menu navigation is intuitive but lacks touchscreen simplicity.

In usability tests, both cameras’ interfaces remain a step below modern DSLRs. Neither offers illuminated buttons or touchscreen shortcuts, forcing you to learn button combos and toggles, which newcomers may find daunting but is manageable with practice.

Sensor and Image Quality: APS-C Clash of CMOS vs CCD

Now to the core performance axis - the sensor. The Pentax K-x features a 12.4-megapixel APS-C CMOS sensor, while the Sony A390 relies on a 14.2-megapixel APS-C CCD sensor - both roughly the same size with focal length multipliers of 1.5x.

Pentax K-x CMOS Sensor

The K-x’s CMOS sensor benefits from improved noise control and higher native ISO support (up to 6400 natively, 12800 boosted). In my lab and field tests, the Pentax produced cleaner images in low light, retaining more detail and dynamic range - DxO Mark scores bear this out with an overall image quality score of 72 versus Sony’s 66.

Sony A390 CCD Sensor

The CCD sensor traditionally excels in color depth and texture rendition, which the A390 shows with slightly richer color separation (22.5 vs 22.8 bits in color depth, a negligible difference). However, the maximum ISO tops at 3200, leading to noisier images in dim environments. Dynamic range also sits lower (11.5 vs 12.5 EV), meaning highlights blown out quicker.

Resolution and Sharpness

Sony’s bump to 14.2-megapixels means a bit more cropping and larger prints without loss, but the difference is subtle at standard print sizes. I found Pentax's 12-megapixel sensor produces impressively sharp files, aided by effective built-in sensor stabilization - which Sony lacks.

For those serious about image quality, the Pentax’s sensor architecture aligns better with versatility across genres, especially in challenging light.

Autofocus Systems and Burst Speeds for Action Lovers

Autofocus (AF) accuracy and speed can make or break your shots, especially for wildlife and sports photographers. Let’s see how these two cameras perform when speed and precision become non-negotiable.

Both cameras use phase-detection AF with 11 focus points (Pentax) and 9 focus points (Sony), but with some clear differences.

Pentax K-x AF

The K-x boasts 11 AF points with multi-area and face detection, though no eye or animal eye detection. It supports continuous AF during shooting, with a respectable 5 fps burst rate - quite speedy for an entry DSLR.

In real-world use, the K-x’s AF system locks focus quickly under good light, though it can hunt in low contrast or dim conditions. Tracking moving subjects works adequately but can struggle with erratic motion.

Sony A390 AF

The A390 has 9 AF points and includes face detection but not continuous tracking or advanced eye detection. More notably, its burst speed caps at 3 fps - a noticeable bottleneck for action.

While AF is reasonably accurate in daylight, it’s slower and prone to hesitation compared to the Pentax, especially in live view mode (which both cameras support). In low light, focus speed dropped markedly.

If you shoot wildlife, sports, or fast-moving street scenes often, the Pentax K-x better matches your needs with quicker continuous shooting and snappier AF.

Lens Ecosystems: Choosing Your Glass

No camera shines without glass, and thankfully both Pentax and Sony boast healthy lens collections - though with strategic differences.

Pentax K-x Lens Mount

The K-x uses the Pentax KAF2 mount, compatible with a robust lineup of 151 lenses spanning primes, zooms, macros, and specialty optics. Many affordable legacy lenses from Pentax also work great, often appealing to budget photographers seeking unique character.

Pentax lenses benefit from built-in stabilization complementing the K-x’s sensor-based shake reduction - resulting in steadier shots, a boon for macro and telephoto work without a tripod.

Sony A390 Lens Mount

The A390 uses the Sony/Minolta Alpha mount (A-mount), which supports around 143 lenses. Sony’s kit lenses are reliable performers, and Minolta glass brings classic sharpness and build, but there’s a smaller selection of ultra-affordable lenses compared to Pentax's ecosystem.

The A390 relies solely on in-lens stabilization if present, without sensor-shift (body) stabilization, which can limit handheld shooting capability at longer focal lengths or low shutter speeds.

If you prefer lens options ramping from budget-friendly to high-end primes, Pentax’s ecosystem slightly edges out Sony in diversity and value.

Battery Life and Storage: Powering Your Shoots

When you’re out shooting, nothing’s worse than the dreaded “low battery” warning cutting the creative flow short.

Pentax K-x

The K-x uses four AA batteries, which I actually found refreshingly practical. Need a recharge? Swap in a set of alkalines or NiMH rechargeables from a local store anytime - a lifesaver on remote trips. Battery life clocks around 1900 shots per charge (CIPA standard), very impressive for the category.

Sony A390

Sony’s NP-FH50 lithium-ion battery offers around 230 shots per charge - significantly lower endurance. This is a serious consideration for long days outdoors without opportunities to recharge.

On storage, both cameras accommodate SD/SDHC cards, but the Sony adds compatibility with Memory Stick Pro Duo - a slight plus for users invested in Sony proprietary media ecosystems.

Connectivity and Extras

Neither camera sports cutting-edge wireless features - no Wi-Fi, Bluetooth, NFC, or GPS. Pentax’s K-x is completely off the modern grid, while the Sony A390 offers HDMI output - useful for tethered display or playback on TVs - a small bonus for videographers or instant reviewing.

Neither camera supports external microphones or headphones, and video performance is basic at best.

Video Performance: Limited, But Present

If video is a serious part of your content creation, you’ll want to pay careful attention.

Pentax K-x Video Specs

The K-x shoots 720p HD video at 24 fps in Motion JPEG format - outdated by today’s standards but meaningful in 2009. Sound recording is built-in only with no external mic input, limiting audio quality.

Sony A390 Video

The A390 offers no video recording capabilities, focusing solely on stills.

For casual video, K-x is the obvious choice. Those wanting serious hybrid shooting should look elsewhere.

Real-World Photography Tests Across Genres

To better illustrate strengths and weaknesses, I evaluated both cameras across popular genres:

Pentax K x front Pentax K x screen back Sony A390 screen back

Portrait Photography

The Pentax produces pleasing skin tones with natural color rendering. Its built-in shake reduction helped retain sharp eye details even at slower shutter speeds, and background blur was smooth but not creamy compared to modern standards. Face detection improves focus acquisition moderately.

The Sony’s higher resolution sensor captures slightly more detail but skin tones sometimes skew cooler. Autofocus can lag and miss subtle blink cues in portrait sessions.

Landscape Photography

Both cameras deliver excellent resolution for printing poster-size prints. Pentax’s slightly superior dynamic range means better highlight and shadow retention, aiding complex scenes at sunrise or sunset. The Sony sensor’s high resolution shines on sunny days with good contrast.

Weather sealing is nonexistent on both - plan accordingly for rain or dusty hikes.

Wildlife and Sports Photography

Pentax’s higher burst frame rate and more responsive autofocus make it a better tool for capturing fleeting wildlife moments or fast-moving athletes. Sony’s 3 fps approach feels limiting here.

Street Photography

Pentax’s lightweight body and quiet operation lend itself well to candid street shooting. Sony’s tilting screen is handy for low-angle urban snaps but body size and slower AF reduce spontaneity.

Macro Photography

Pentax’s sensor-shift stabilization contributed to crisp macro shots handheld - a big plus. Sony’s stabilization doesn’t help here, requiring steadier technique or a tripod.

Night and Astro Photography

Pentax’s cleaner high ISO files and longer shutter speeds up to 1/6000 sec provide room for controlled exposure. The Sony misses out on extended ISO range and tends to show noise earlier under dim conditions.

Video Content Creation

K-x’s modest HD video lets beginners explore moving images; Sony offers no capture here, limiting versatility.

Travel Photography

Pentax’s lighter body, reliable battery life, and sensor stabilization make it excellent for on-the-go shoots.

Sony’s tilting screen and battery perks (if pack spares are available) offer some ease but lag behind on power.

Professional Use

Neither model is rugged or feature-packed enough for pro-level assignments - with no environmental sealing, limited connectivity, and standard dynamic range. That said, Pentax’s RAW support and compactness appeals as a solid backup camera.

Technical Summary and Performance Scores

Here’s a quick look at how Pentax and Sony measure up in key specs and standardized scores:

Which Camera Excels in Your Favorite Photography Types?

• Portrait: Tie, Pentax wins for stabilization, Sony for resolution.
• Landscape: Pentax, thanks to dynamic range.
• Wildlife/Sports: Pentax, better AF and burst.
• Street: Pentax for size, Sony for LCD versatility.
• Macro: Pentax, sensor stabilization.
• Night/Astro: Pentax, better ISO performance.
• Video: Pentax only.
• Travel: Pentax for endurance, Sony for LCD flexibility.
• Pro Work: Neither a top contender here.

Pros and Cons at a Glance

Final Verdict: Which Should You Buy?

Both cameras show their age, but for the budget-conscious enthusiast or beginner wanting a well-rounded package - especially if photography more than video is your bag - the Pentax K-x is the more versatile choice. Its sensor-based stabilization, better low-light performance, and generous burst speed give it an edge in most shooting scenarios, and the consumer-friendly AA battery system keeps you powered longer in the field.

The Sony A390 is an intriguing option for those valuing a tilting screen and a slightly higher resolution sensor for daylight shooting, but its lack of video and poor battery life are serious drawbacks if you intend to shoot extensively.

Who Should Pick Pentax K-x?

• Enthusiasts focused on stills with strong low-light and action needs.
• Portrait, macro, landscape, and wildlife photographers seeking value.
• Travelers who dislike carrying extra chargers.
• Anyone wanting HD video without buying a separate camcorder.

Who Should Consider Sony A390?

• Still photographers shooting mostly in well-lit conditions.
• Those who value flexible LCD angles for creative composition.
• Beginners transitioning from compact cameras with kit lenses.
• Users with existing Sony/Minolta lenses looking for budget DSLRs.

In the end, the Pentax K-x’s performance and flexibility win my recommendation as the more balanced entry-level DSLR, while the Sony A390 plays a niche role for style-conscious users who prize certain ergonomic quirks. Both cameras, now trading hands at very affordable prices on used marketplaces, remain viable stepping stones into the DSLR world when your budget counts and high-end features can wait.

Happy shooting, and may your next camera adventure bring sharp focus and vivid memories!