Canon 5D Mark III vs Sony A99: A Hands-On Expert Comparison for Serious Photographers

Choosing between two landmark cameras like the Canon EOS 5D Mark III and the Sony SLT-A99 can feel a bit like picking your favorite club for slaying photography giants. Both launched in 2012, these advanced DSLRs (or technically a translucent mirror SLT in Sony’s case) have loyal fan bases and offer robust performance. But like many long-lasting models, they each bring different strengths to the table depending on your creative ambitions and shooting style.

Having thoroughly tested thousands of cameras over the last decade and a half, including both these titans, I will walk you through the key differences, real-world performance, and practical advice to help you decide which might become your trusty workhorse. Whether you shoot landscapes, portraits, wildlife, or video, this detailed comparison caters to serious enthusiasts and professionals hunting for lasting value in this era of ever-evolving tech.

Feeling the Cameras in Hand: Ergonomics and Build Quality

Before you even hit the shutter, how a camera feels in your hands can make or break the shooting experience. Size, weight, grip comfort - these subtle things matter tremendously over long shoots.

Both cameras fall into a similar mid-size class, but the Canon 5D Mark III is notably heftier at 950g compared to the Sony A99’s lighter 812g. Those extra 140 grams can be a deal maker or breaker depending on your muscle reserves or travel style.

In terms of dimensions, Canon’s 152 x 116 x 76mm body is marginally larger, providing slightly more room for larger hands and a more substantial grip. The Canon’s build is rugged - extremely reassuring with its magnesium alloy shell and professional-level weather sealing, designed for assignment-ready durability.

Sony’s A99 is also weather sealed, but its smaller footprint (147 x 111 x 78mm) makes it a smidge more pocketable in your camera bag or for those street photographer roamings where discretion helps. Sony’s translucent mirror design lets them shave some weight despite packing similar sensor size and components.

Looking down at the controls, the Canon 5D Mark III offers a more classic DSLR interface, with numerous physical dials, a top LCD panel for quick info checks, and well-spaced buttons. While not backlit or touchscreen, the button layouts are big clubs for your thumbs if you like tactile feedback and rapid adjustments.

Contrast this with Sony, which opts for a fully articulating rear screen (more on that later), fewer focus points on physical buttons, and a higher resolution EVF that offers real-time exposure previews.

Bottom line on handling: If you like a bigger, solid grip and traditional DSLR feel - Canon wins. If you want lighter weight and an EVF-centered shooting experience, Sony’s A99 edges ahead.

Sensor Talk: Image Quality and Resolution Unpacked

The heart of every camera is its sensor, and here both the Canon and Sony deliver full-frame CMOS chips, but with some key differences.

Canon 5D Mark III packs a 22.3 MP sensor, while Sony marginally ups the ante with a 24.3 MP sensor - not a huge leap, but enough to notice for pixel peepers and those needing extra print size. Both sensors share similar optical low-pass filters (anti-aliasing), minimizing moiré but softening some fine detail.

From my lab testing and field experience, Sony's sensor has a DXO Mark overall score of 89 versus Canon’s 81, indicating superior raw dynamic range and color depth. Sony’s Bionz processor also contributes to cleaner outputs, with slightly better color fidelity - measured at 25 bits vs Canon’s 24 bits of color depth.

But don’t discount Canon’s 5D Mark III. Its sensor is legendary for pleasing skin tones and accurate color reproduction straight out of the box. This makes it a favorite among portrait and wedding photographers who need minimal post-processing.

Dynamic range: Sony’s 14 stops vs Canon’s 11.7 stops is a noticeable advantage for landscape shooters and anyone shooting scenes with harsh contrast between shadows and highlights.

Low-light ISO performance: Canon 5D Mark III’s low-light ISO score is around 2300, outperforming Sony's 1555 in tested conditions, meaning Canon handles noise better beyond ISO 6400. If you’re a night or astrophotographer, Canon’s cleaner high-ISO capability can be a big plus.

In practice: Both cameras produce stellar images; Sony offers more latitude in editing thanks to dynamic range, Canon is more forgiving for direct-to-client or event delivery due to cleaner noise control and beautiful colors.

The Viewfinder and Screen Experience: Optical vs Electronic

One area where these two go head-to-head is their viewfinder and rear screen technologies, which significantly affect the shooting workflow.

Canon 5D Mark III uses a traditional optical pentaprism viewfinder, 100% coverage, 0.71x magnification. This means no lag, bright, direct optical viewing crucial under fast conditions or bright sunlight. Canon’s rear screen is a fixed 3.2" Clear View II TFT LCD with 1040k dots, great for framing and playback but no touchscreen or articulation.

Sony’s A99, by contrast, sports a 2.36 million dot electronic viewfinder (EVF) - one of the highest-res EVFs at its release. This gives an exposure preview in real time, focus peaking highlights, and better compositional aid for tricky scenes. The tradeoff? Minimal latency and electronic artifacts, but overall a bright, versatile experience.

The Sony’s rear screen is a 3" fully articulated TFT LCD with 1229k dots - ideal for low-angle shooting, video, or selfies (yes, Sony’s “selfie-friendly” feature, which Canon lacks). No touch functionality on either, though my preference for quick menu navigation often leans to Canon’s button clusters.

In live previews, Canon’s contrast-detection autofocus in live view is slower than Sony’s phase-detection AF, which benefits from the SLT design allowing continuous AF during video/live view use.

Autofocus and Burst Shooting: Chasing the Action

If you shoot fast-moving subjects - think wildlife, sports, or energetic kids - autofocus and burst rate can influence your choice like nothing else.

Canon 5D Mark III boasts a 61-point autofocus system, with 41 cross-type points covering a broad central area and excellent tracking capabilities. Its autofocus is phase-detection based, notably precise in low light and works very well with Canon’s extensive EF lens lineup.

Sony A99’s AF system is built around a 19-point phase-detection array, with 11 cross-type sensors. The catch? Fewer AF points compared to Canon, meaning less coverage for erratic subjects or off-center compositions. But Sony benefits from real-time focal plane phase detection both in EVF and live view.

Regarding burst rates, the Canon 5D Mark III shoots continuously at 6 fps, reliable and fast enough for many sports and wildlife scenarios, though not blazing. Sony A99 pushes ahead with a high 10 fps burst rate, double Canon’s speed, thanks to its electronic front shutter and SLT mirror design.

From hands-on experience, Sony’s faster frame rate and continuous AF make it more appealing for sports shooters and wildlife photographers chasing quick action. However, Canon’s AF accuracy and broader AF point spread remain strong for tracking complex movement at the center and nearby.

Lens Ecosystem: Opening Up Your Creative Toolbox

Buying a camera isn’t just about the body - it’s the lenses that will unlock your creative potential.

Canon’s EF lens mount is a mature platform with over 250 lenses available, ranging from affordable third-party primes to ultra-sharp L-series professional zooms and specialty glass like tilt-shift and macro lenses. This is an incredible advantage for any pro or enthusiast wanting flexibility.

Sony A99 uses the Sony/Minolta Alpha mount, reasonably well supported but with about 143 lenses available, fewer than Canon. You can use some third-party options and adapters, but the selection and native lens investment opportunities are smaller. For specialized lenses or vintage glass users, Canon’s ecosystem is simply richer.

Sony also advantages those who want in-body image stabilization, beneficial for shaky hands or macro, helping harness sharpness without relying solely on stabilized lenses - something Canon’s 5D Mark III lacks natively.

Video Capabilities: Which is the Better Hybrid Shooter?

Though these cameras are primarily stills-focused, video features can’t be ignored.

Canon 5D Mark III records Full HD 1080p at 30fps, using an H.264 codec, with manual controls, headphone and mic inputs, but no 4K video (understandably for 2012 vintage tech). The video is solid and has become a workhorse in many documentary or hybrid shooters’ setups - favored for its skin tone rendering.

Sony A99 also offers Full HD 1080p, but available at 60fps for smoother motion, uses AVCHD, MPEG-4, and H.264 codecs, plus the same mic and headphone jacks. Sony’s fully articulating screen gives a tight advantage for vlogging, dramatic low angles, and monitoring, plus sensor-based image stabilization aids video smoothness.

If video hybrid work is on your radar, Sony A99 nudges ahead with more frame rate options, articulating screen, and stabilization, even if 4K was still years away at release.

Battery Life, Storage, and Connectivity: Practical Day Features

If you’re out shooting all day (or multi-day trips), battery life and storage flexibility are key.

Canon 5D Mark III shines here with a CIPA-rated 950-shot battery life, very impressive. The LP-E6 battery is reliable and widely supported.

Sony A99, by contrast, manages about 500 shots per charge, significantly less, a known limitation from its EVF power drain.

Both use dual card slots - but Canon sticks to Compact Flash plus SD cards, whereas Sony supports Memory Stick PRO Duo and SD cards, a slightly more versatile combo.

Connectivity-wise, Canon requires optional wireless adapters, whereas Sony offers built-in GPS for geotagging - a nice touch for travel photographers.

Shooting by Genre: An Expert’s Summary Breakdown

Let’s boil all this down into how the Canon 5D Mark III and Sony A99 perform across photography disciplines.

Portrait Photography

• Canon 5D Mark III: Better skin tone rendering, superb color accuracy, 61-point AF with face detection, strong bokeh from EF lenses.
• Sony A99: Slightly higher resolution, EVF aids critical focusing but fewer AF points may mean slower focus on off-center eyes.

Winner: Canon edges slightly ahead for classic portrait shooters valuing color and customization.

Landscape Photography

• Sony A99: Superior dynamic range (14 stops), slightly higher megapixels, articulating screen to compose tricky angles, in-body stabilization.
• Canon 5D Mark III: Reliable dynamic range but lower compared to Sony, excellent file integrity, rugged weather sealing.

Winner: Sony for dynamic range and versatility, Canon solid for rugged outdoor use.

Wildlife & Sports Photography

• Sony A99: Higher burst rate (10fps), sensor-based stabilization, strong video options; fewer AF points but fast.
• Canon 5D Mark III: Larger AF point count (61), better low-light focusing, slower 6fps.

Winner: Sony for action-packed shooting requiring speed; Canon for precision AF in dim conditions.

Street Photography

• Sony A99: Smaller, lighter, EVF preview helps in tricky light, articulating screen provides discreet angles.
• Canon 5D Mark III: Larger and heavier; optical viewfinder great in bright sunlight.

Winner: Sony’s smaller size and EVF make it more discreet and portable.

Macro Photography

• Sony A99: In-body stabilization helps handheld macro shots.
• Canon 5D Mark III: Broad lens ecosystem with superb close-focus lenses.

Winner: Slight edge to Sony for stabilization; Canon for toy box of macro glass.

Night & Astro Photography

• Canon 5D Mark III: Better high-ISO noise control and long exposures.
• Sony A99: Higher dynamic range but slightly more noise at high ISO.

Winner: Canon for clean night images.

Video

• Sony A99: 1080p60, stabilization, articulated screen.
• Canon 5D Mark III: 1080p30, solid codec, superior skin tones.

Winner: Sony for video versatility.

Travel & Everyday

• Sony A99: Lighter, GPS built-in, articulation.
• Canon 5D Mark III: Longer battery, reliable performance but bulkier.

Winner: Sony for portability; Canon for battery endurance.

Professional Work

• Both robust with dual card slots, ruggedness, and comprehensive manual controls.
• Canon’s mature color science and lens options make it the choice for clients.

Real-World Sample Shots: Seeing Is Believing

It’s one thing to read specs, another to see output side by side.

Canon 5D MIII front Canon 5D MIII screen back Sony A99 front Sony A99 screen back

From my personal shoots, Canon’s JPGs deliver pleasing color straight out of camera, needing less editing. Sony RAWs offer more flexibility for editing but require more work in post. Both excel at fine detail and large print sizes.

Performance Ratings Overview

DXO Mark and independent reviews consistently rate Sony A99 higher overall (89 vs 81 for Canon), mostly due to dynamic range and speed. But subjective factors like color preference and lens value swing personal choices.

Final Thoughts and Recommendations

So, which should you buy?

Wrapping It Up

Both the Canon 5D Mark III and Sony A99 remain formidable cameras well past their release dates. Choosing between them hinges less on pure specs and more on your personal workflow needs, shooting preferences, and budget constraints.

Canon is the classic, reliable workhorse with gorgeous color, a richer lens ecosystem, longer battery life, and excellent low-light capabilities. Meanwhile, Sony offers innovative EVF tech, faster shooting speeds, and features attractive to hybrid shooters and those valuing agility and more modern conveniences.

If you want my personal take - having lugged both through demanding assignments and studio sessions - the Canon 5D Mark III feels like a trusted old friend with a proven track record and solid performance. The Sony A99 is for those willing to embrace a bit more modern styling, speed, and versatility but who can live with a smaller lens pool and shorter battery life.

Whatever you choose, both cameras can deliver outstanding image quality and longevity when paired with good lenses and thoughtful technique. And that, dear reader, is where your journey in photography truly begins.

I hope this comparison helps you wield your next photo weapon wisely - happy shooting!