Sony RX100 III vs Sony A77: A Hands-On Camera Battle for the Ages

Choosing a camera that fits your unique style, needs, and workflow is a bit like crafting a personal recipe - the ingredients matter, but so do the method and subtle balancing act between flavor and function. Today, I’m unpacking two quite different Sony models: the pocket-friendly Sony Cyber-shot DSC-RX100 III and the more traditional but beastly Sony SLT-A77 DSLR. Though they share a brand and a heritage of quality, their DNA, design philosophy, and target audiences diverge sharply.

Having personally tested thousands of cameras over fifteen years - from lightweight compacts to pro-level beasts - I’m excited to break down this matchup on everything from sensor performance to real-world usability. Whether you’re a weekend snapper, a pro needing a secondary body, or a gear junkie craving detail, this article will offer a grounded perspective and - dare I say - some useful advice on which Sony suits what.

Before we dive into the nitty-gritty, here’s a quick physical size comparison to set the stage.

First Impressions: Size, Handling, and Controls

Let’s talk feel. The RX100 III is a large sensor compact, meaning it’s designed to slip smoothly into a coat pocket or purse, pocketable enough for travel, street photography, and casual day-to-day shooting without the bulk of interchangeable lenses. At just 102×58×41 mm and 290 grams, it’s a marvel of pocketability.

In contrast, the A77 is a proper mid-size DSLR body (143×104×81 mm, 732 grams) - substantial and reassuring in hand if you crave a traditional grip, extensive manual control dials, and that unmistakable heft signaling serious business. The A77 feels like it wants to be carried all day on rugged outdoor adventures or professional shoots.

Looking at the control layout from the top…

The RX100 III impresses with minimalist buttons and a tilting 3-inch screen that folds up for selfies or creative angles. The A77’s fully articulating screen is larger (also 3 inches) but with slightly lower resolution and more classic DSLR button real estate, including an illuminated top LCD panel handy in dim conditions.

The ergonomics speak volumes about target use: RX100 III for portability and casual fun, A77 for manual precision and professional workflows.

Sensor Technology: Pixel Battles and Image Quality

Let’s get to the heart - the sensor. These cameras boast very different beasts here, head to head:

• Sony RX100 III houses a 1-inch BSI-CMOS sensor, 20MP, measuring 13.2x8.8 mm (116 mm² sensor area). It sits between the typical compact and mirrorless sensor size, designed to eke out clean images from limited space.
• Sony A77 rocks an APS-C sized CMOS sensor, 24MP, at 23.5x15.6 mm (366 mm² sensor area). This is a mid-sized sensor classic, seen in many DSLRs.

Sensor size difference isn’t just a spec trivia contest - it directly impacts image quality, especially in dynamic range, noise control, and depth of field control. The larger A77 sensor naturally wins on overall detail, color fidelity, and flexibility in low-light shooting. The RX100 III makes clever use of backside illumination to improve sensitivity, but smaller sensors physically collect less light.

DxOMark scores (always a good technical reference, though not the whole story) support this:

• RX100 III: Overall 67; Color Depth 22.4 bits; Dynamic Range 12.3 EV; Low Light ISO 495
• A77: Overall 78; Color Depth 24 bits; Dynamic Range 13.2 EV; Low Light ISO 801

These numbers translate to a visible difference in shadow recovery, highlight preservation, and cleaner high-ISO images on the A77 - especially critical for landscape, portrait, and night photography.

LCD and Viewfinder: How You See the World

Bright, accurate previews and compositions are vital. Here’s a quick look at their displays.

The RX100 III’s 3” 1229k-dot tilting LCD is bright and clear, excellent in most lighting situations. The built-in electronic viewfinder (EVF) at 1440 dots is small but sharp for framing - a handy feature rarely found in compacts of the era.

The A77 ups the ante with a higher resolution EVF at 2359 dots, 100% coverage, and a larger magnification (0.73x vs 0.59x for RX100 III) - a noticeable step if you regularly shoot through the viewfinder. The fully articulating 3-inch screen on the A77 has a bit lower resolution (921 dots) but offers more versatile angles for video or awkward shooting positions.

Ergonomically, the A77’s viewfinder is more comfortable for prolonged use, making it pleasant for professional assignments - while the RX100 III’s tilting screen is a versatile tool for street and travel shooters who rely mostly on live view.

Autofocus and Shooting Performance

A good camera is nothing without reliable autofocus and shooting speed - especially for wildlife, sports, and fast-moving subjects.

• RX100 III offers contrast-detection AF with 25 points and face detection, plus eye detection. No phase-detection AF, which tends to be faster and better for tracking.
• A77 features a hybrid AF system, combining 19 phase-detection points (11 cross-type) and contrast detection, resulting in snappy and precise focusing performance.

Continuous shooting capabilities:

• RX100 III: 10 fps - impressive for a compact, can catch fleeting moments in action photography within reason.
• A77: 12 fps - even faster, thanks to the advanced SLT mirror technology and dedicated AF sensors.

I’ve tested both systems extensively, and while the RX100 III AF is commendably quick in good-light static subjects, it sometimes hunts in low contrast or dim lighting. The A77’s hybrid AF system locks and tracks moving subjects more consistently and with noticeably less “hunting,” an advantage when shooting sports or wildlife.

Face detection worked reliably on both, but A77’s larger sensor depth and AF range improved results in portrait scenarios with tricky lighting.

Real-World Use Across Photography Genres

Let’s dig into how these cameras perform where it counts - in your hands, through your lens, and across various photography styles.

Portrait Photography: Skin Tones and Bokeh

Both cameras have strengths here but approach portraiture differently.

• RX100 III’s lens (24-70mm f/1.8-2.8) is sharp and fast, with a bright aperture for a compact - great for controlling depth of field. However, the 1-inch sensor’s physical size limits background blur (bokeh). It still produces pleasant backgrounds but won’t match the creamy separation from the A77’s APS-C sensor.

• A77 thrives in portraits, especially with fast primes or telephoto lenses. Larger sensor + putative shallower depth of field = creamy, artful bokeh. Skin tones render with rich, natural hues, benefiting from the greater color depth and dynamic range. Eye detection, while manual in this model, is aided by precise AF points.

Bottom line: for portraits with dreamy bokeh or professional headshots, the A77 is clearly preferable. The RX100 III is great for snapshots and environmental portraits but can’t quite imitate that DSLR creaminess.

Landscape Photography: Detail, Dynamic Range, and Durability

The A77’s larger sensor and higher dynamic range shine in landscape photography - especially when shooting RAW and post-processing exposures to recover shadows and highlights. The higher maximum ISO flexibility helps in low light or sunrise situations without excessive noise.

The RX100 III, while capable, sometimes shows limitations in shadow noise if pushing exposures extensively.

Another point: the A77 offers environmental sealing, providing modest protection against dust and moisture - an advantage when trekking through unpredictable terrain, though not fully rugged.

RX100 III lacks weatherproofing, so careful handling and protective cases are essential outdoors.

Wildlife and Sports: AF Speed, Burst, and Lens Reach

Here, the A77 flexes hard.

• More advanced AF and faster burst shooting increase successful action shots.
• Compatibility with a broad ecosystem of Sony/Minolta Alpha lenses (over 140 lenses available) means you can mount long telephotos for wildlife and sports - essential for reach and detail.

The RX100 III’s fixed 24-70mm equivalent zoom and lesser AF system limit its capacity in these fast and distant-focused genres - great for casual wildlife scenes but less so for long-distance subjects.

Street and Travel Photography: Discretion, Portability, and Battery Life

If you prize stealth and convenience, the RX100 III strikes gold. Lightweight, pocketable, and subtle, it doesn’t scream “professional photographer,” letting you blend into urban scenes or grab spontaneous shots without lugging a backpack. Optical image stabilization and fast lens ensure sharp shots even at slower shutter speeds.

Battery life, however, is moderate for both - RX100 III rated around 320 shots vs A77’s more enduring 470 shots per charge - typical DSLR advantage.

For longer trips, bringing extra batteries for either camera is smart, but in terms of hand-carrying ease and spontaneous use, RX100 III wins.

Macro and Night Photography: Focus and ISO Performance

• Macro: The RX100 III shines with a minimum focus range of 5cm, allowing close-ups without additional accessories - ideal for casual macro work. The A77 can achieve close focus distances but often requires dedicated macro lenses for optimal results.

• Night and Astro: The A77’s larger sensor and higher ISO tolerance produce cleaner night skies and star shots, particularly with the addition of manual focus primes and longer exposures aided by its tripod-ready build. The RX100 III's smaller sensor adds noise quicker at high ISOs, limiting astrophotography potential.

Video and Multimedia

Both cameras shoot Full HD video at respectable frame rates:

• RX100 III maxes out at 1080p60, offering AVCHD, MPEG-4, and XAVC S formats.
• A77 also shoots 1080p60, with formats including MPEG-4, AVCHD, and H.264, plus a microphone port for external audio - a major plus for video creators.

Neither offers 4K recording, which is more expected in later models, but the A77’s mic port and articulating screen give it the edge for amateur to semi-professional video.

Build Quality, Weather Sealing, and Durability

The A77’s environmental sealing (dust and moisture resistant) adds confidence during serious shoots outdoors and adverse weather. The body’s robust polycarbonate chassis and metal mounts withstand heavy usage.

The RX100 III, designed for portability, lacks these features and should be treated more like a delicate tool - perfect in stable conditions, carried carefully on travels.

Lens Ecosystem and Compatibility

Here, there’s a stark contrast:

• The RX100 III’s fixed 24–70mm f/1.8-2.8 lens is versatile for everyday shooting but fixed - no swapping lenses.
• The A77’s Sony/Minolta Alpha mount offers access to 143 lenses, from ultra-wide to super-telephoto, plus third-party options - a tremendous advantage for professionals or serious enthusiasts.

This fact alone tilts the choice heavily toward the A77 for anyone wanting system flexibility.

Battery Life and Storage

As a compact, the RX100 III uses the NP-BX1 battery, rated around 320 images per charge under standard testing conditions. In my hands, continuous shooting or frequent viewfinder use can reduce this, so spares are wise for a day out.

The A77’s larger NP-FM500H battery boosts longevity to 470 shots per charge - more generous for long days or professional assignments.

Both cameras support SD/SDHC/SDXC memory cards and Sony’s proprietary Memory Stick, giving plenty of storage flexibility.

Connectivity and Extras

• RX100 III boasts built-in Wi-Fi and NFC for easy image sharing and remote control from smartphones - very handy for casual shooters or social media enthusiasts.
• The A77 has Eye-Fi card support for wireless transfer but lacks Bluetooth or NFC. It does feature built-in GPS, excellent for geotagging outdoor images.

Neither has USB 3.0 or HDMI 2.0 but both have standard HDMI out (micro or mini) for external monitors.

Price and Value Considerations

Let’s talk dollars: as of now, the RX100 III hovers around $748, while the A77 is roughly $900 - not vastly different, considering the A77 offers larger sensor and system flexibility.

If your budget is tight and you want an all-in-one travel companion with great image quality that fits in a pocket, the RX100 III remains compelling.

On the other hand, investing in the A77 sets you up with a real system camera that, while larger, grows with your ambitions through lenses and accessories.

Overall Scores and Genre-Specific Performance

Let’s get quantitative. Based on testing software and my hands-on impressions, here’s a summarized scorecard:

And to see where each camera excels in various photography types…

Sample Images: Seeing Is Believing

Nothing beats seeing sample images side-by-side. Here are gallery shots capturing portraits, landscapes, and action sequences, all straight from the respective cameras with minimal processing.

Sony RX100 III front Sony RX100 III screen back Sony A77 front Sony A77 screen back

Look for the RX100 III’s crisp details but note the A77’s richer tonality and better shadow nuance.

The Verdict: Who Should Buy Which Camera?

For the Enthusiast and Traveler

If you want pocket-sized versatility and solid image quality for everyday shooting, vacations, street photography, and casual video, go with the RX100 III. It’s lightweight, discreet, and smartly engineered to punch above its weight in a compact package.

For the Serious Hobbyist or Professional

If you need a system camera with room to grow, an extensive lens lineup, superior image quality, and demanding shooting modes - the Sony A77 is a more future-proof choice, particularly for portraits, wildlife, landscapes, and video projects requiring external mics.

Final Thoughts: Balancing Convenience with Capability

I’ve always found camera choice to come down to the eternal trade-off: portability vs. performance. The RX100 III embodies the growing power of compacts without the bulk; the A77 reminds us of the enduring appeal of a proper DSLR system with its optical viewfinder, rugged body, and interchangeable glass.

Personally, I’ve carried the RX100 III for trips when I wanted minimal fuss but decent creative control - perfect for quick candid shots and light landscapes. The A77, meanwhile, is my go-to when I have the time, energy, and intention to craft images carefully, especially for print or client work.

Whichever Sony you pick, both represent strong choices within their classes - it comes down to how and where you want to shoot.

Happy snapping!