Canon 5D Mark III vs Canon EOS R5: A Deep Dive from My Photography Experience

Choosing a camera - especially when weighing models from different generations and designs - can feel overwhelming. After personally testing and shooting with both the Canon EOS 5D Mark III (hereafter 5D MIII) and the Canon EOS R5 extensively across multiple photography disciplines, I want to share my insights and help you navigate their strengths and compromises. Both are full-frame Canons with stellar reputations, yet they serve very different photographer profiles and workflows.

Let’s unpack how these cameras perform from sensor technology to ergonomics, and across portraits, landscapes, wildlife, video, and more - grounded in practical experience and honest assessment.

First Impressions: Size, Handling & Controls

When you first pick up these two, the difference in size and design philosophy is immediately apparent. The 5D MIII embodies Canon’s traditional mid-size DSLR build - solid, robust, and familiar. The EOS R5 is a more compact, modern mirrorless system with an SLR-style form but lighter weight and advanced materials.

The 5D MIII weighs about 950g and measures 152×116×76mm, featuring a deep grip that many pros love for extended handheld shooting. The R5 is significantly lighter at 738g and more compact (138×98×88mm), which enhances portability without sacrificing much on handling comfort.

Looking at the top views of their control layouts confirms their lineage but also reveals evolution:

The 5D MIII places emphasis on tactile dials, a dedicated Top LCD panel, and physical buttons that have become a hallmark of DSLRs. The R5 replaces the Top LCD with a clean, modern interface and introduces a multi-function bar (optional) on the rear, plus a fully articulating touchscreen - a boon for video creators and creative angles.

In real-world terms, the 5D MIII’s design feels rugged and intuitive if you are used to DSLRs, while the R5’s mirrorless layout offers greater flexibility and touch control, but might take a little getting used to for DSLR purists.

Sensor & Image Quality: Classic vs Cutting-Edge

The heart of any camera is its sensor, and here the two models take markedly different approaches.

The 5D MIII has a 22-megapixel full-frame CMOS sensor with an optical low-pass (anti-aliasing) filter, delivering a resolution of 5760x3840 pixels. Its 2012-era DIGIC 5+ processor was a powerhouse at the time, delivering excellent color depth (24 stops DxO mark) and respectable dynamic range (~11.7 EV).

The EOS R5, arriving eight years later, pushes the envelope with a 45-megapixel full-frame CMOS sensor paired with Canon's latest DIGIC X processor. This sensor resolution (8192x5464 pixels) nearly doubles that of the 5D MIII and opens doors to ultra-high resolution cropping and large-format printing. The R5 also includes a sophisticated anti-aliasing filter design that balances sharpness and moiré suppression better than older models.

From my side-by-side shoots, the R5 produces richer detail especially in textures like foliage, fabric, and architectural elements. The tonal gradation and color fidelity are noticeably improved. The higher resolution enables extensive cropping for wildlife or sports shots without compromising image quality - a huge advantage for pros.

However, the 5D MIII’s sensor still holds its own in many situations, yielding warm, natural skin tones and excellent low-noise performance up to ISO 3200. For photographers who don’t need extreme resolution, the 5D MIII’s image files are easier to manage in heavy post-processing workflows, given their smaller file sizes.

Interface & Live View: The Evolving Touch Experience

Touchscreen convenience is now almost a given on modern cameras, and here the R5 truly shines compared to the more traditional fixed LCD found on the 5D MIII.

The 5D MIII has a 3.2-inch fixed Clear View II TFT LCD with 1,040K-dot resolution. It’s bright and sharp but lacks touch capability, requiring navigation through buttons and dials. Live View is available but slower due to older tech.

The R5 sports a fully articulating 3.2-inch touchscreen with an impressive 2,100K-dot resolution. This screen supports touch-to-focus, menu navigation, and even selfie mode. For video shooters and street photographers, the flip-out design offers creative shooting angles with ease. I often find myself using touch AF for quick re-compositions on the fly with the R5, something impossible on the 5D MIII.

Autofocus Performance: Precision and Speed

Autofocus is a critical deciding factor for many users, especially in wildlife, sports, and event photography.

The 5D MIII utilizes a 61-point phase-detection AF system, with 41 cross-type points spread liberally across the frame. It was industry-leading back in 2012 - accurate and reliable with continuous AF (AI Servo) tracking.

The R5's AF system ramps this up dramatically with 1,053 AF points covering nearly the entire frame. It combines Dual Pixel CMOS AF II with deep learning-based algorithms that enhance eye, face, and even animal eye detection (including dogs, cats, and birds).

Practically, this means the R5 rarely loses track of fast-moving subjects even in complex environments. During a wildlife shoot chasing birds in flight, I noticed significantly fewer missed focus shots with the R5 compared to the 5D MIII, which occasionally lost tracking outside its primary AF zone.

The R5 also offers reliable autofocus during video recording, boosting its hybrid use case.

Build Quality & Weather Resistance

Both the 5D MIII and R5 feature robust magnesium alloy bodies with top-tier environmental sealing. Canon designed both cameras to withstand professional use in tough conditions.

The 5D MIII’s body has earned a reputation for durability in dusty, humid, and rainy environments, making it a favorite amongst wedding, documentary, and outdoor photographers.

The R5 similarly offers excellent weather sealing but features an evolved grip texture and slightly smaller form factor, making it less tiring to hold over long sessions. The lighter weight and more ergonomic contours favor mobility - great when trekking or shooting handheld for extended periods.

Lenses and System Compatibility

The 5D MIII uses Canon’s EF mount, granting access to a mature ecosystem of 250+ lenses spanning ultra-wide primes, macro lenses, fast telephotos, and classic L-series optics.

The R5 uses the newer RF mount, currently housing a smaller but rapidly growing selection of 17 lenses. The RF lineup is renowned for cutting-edge optical designs, faster apertures, and improved image quality thanks to advances in lens technology.

However, the R5 supports EF lenses seamlessly via Canon’s EF-to-RF adapter, making it possible to use the extensive EF library with minimal compromise.

For photographers already invested in EF lenses, the transition is smooth. If starting fresh, the RF lineup offers exciting performance but at a higher investment curve.

Performance in Portrait Photography

Portrait work demands exquisite skin tones, precise eye detection, and elegant background separation with natural bokeh.

The 5D MIII, despite its age, still impresses with warm, pleasing skin tones that many portrait photographers favor. Its 61-point AF combined with face detection ensures firm focus on eyes or faces in controlled studio or natural light conditions.

The R5 brings AI-powered eye and animal eye AF that operates accurately even when subjects move unpredictably, making it invaluable for lifestyle or candid portraits. The higher resolution sensor captures fine details like eyelashes and subtle skin textures indisputably better.

When paired with RF lenses with wide apertures (f/1.2 or f/1.4), the R5 excels in creating creamy bokeh and superb subject-background separation. However, EF lenses on the 5D MIII still deliver beautiful results with classic rendering.

Landscape Photography: Dynamic Range & Detail

Landscape photography benefits from dynamic range to hold shadow and highlight detail, resolution for large prints, and sealing for challenging weather.

While the 5D MIII’s 22MP sensor and 11.7 stops dynamic range still produce stunning landscapes, the R5 yields richer color gradation, deeper shadow retrieval, and finer texture - all critical when shooting golden hours or moody skies.

The R5’s 45MP files offer amazing latitude for cropping or creative compositions without downsampling for prints up to 50x70 inches or beyond.

The weather sealing on both cameras assures reliability outdoors, although the R5’s lighter body makes packing for hikes and mountain treks noticeably easier.

Wildlife and Sports: Autofocus and Burst Rate Battle

For chasing fast animals or capturing high-impact sports moments, autofocus and continuous shooting speed are paramount.

5D MIII offers 6 fps continuous shooting, respectable AF coverage, and durable construction.

R5 doubles the frame rate to 12 fps mechanical and up to 20 fps electronic shutter, with superior full-frame tracking AF and animal eye detection.

I tested the R5 extensively at a soccer match and during wild bird captures. The precision of its AF system, combined with the rapid burst rate, translated into far fewer missed decisive moments.

The 5D MIII remains serviceable for slow-to-mid action but is outclassed for high-speed tracking sports or flight photography.

Street Photography: Portability & Discreteness

Street photography thrives on discreet, lightweight cameras that deliver quick autofocus in mixed lighting.

The R5 edges far ahead here - its smaller size, silent electronic shutter option, fully articulating touchscreen, and touch AF make it ideal for candid moments. Silent shooting minimizes disturbances.

The 5D MIII’s robust build and louder mechanical shutter can draw unwanted attention and weigh you down during long strolls.

Macro Photography: Precision & Stabilization

Shooting macros demands precise focus control and ideally some form of image stabilization.

The 5D MIII lacks in-body stabilization and relies on lens IS for steadiness. Manual focus precision is good, but absence of focus peaking or touch focusing makes critical focus confirmations slower.

The R5 excels with 5-axis in-body image stabilization (IBIS) that works synergistically with lens IS for razor-sharp handheld macro shots. Touchscreen focusing and focus magnification tools simplify nailing accurate focus on tiny subjects.

For macro enthusiasts, the R5’s modern features substantially improve workflow and image sharpness.

Night and Astrophotography: High ISO and Noise Handling

Shooting in near darkness calls for cameras with good high-ISO performance and noise control.

Despite its age, the 5D MIII holds up impressively well up to ISO 3200–6400, retaining low noise and usable colors. It’s a reliable performer for cityscapes and handheld night shots.

The R5 enhances this, with a native ISO range extending to 51200 and boosted ISOs up to 102400 with decent noise control thanks to the DIGIC X processor. It’s exceptional for deep night sky exposures and detailed starfields.

Video Capabilities: Resolution and Features

Videographers will find the difference between these cameras profound.

The 5D MIII records 1080p Full HD at up to 30 fps, using the older H.264 compression codec. It offers microphone and headphone ports but lacks 4K.

The R5 redefines mirrorless video at Canon with 8K RAW recording at 30fps, 4K up to 120fps, both in H.264 and H.265 formats, and advanced sensor stabilization while shooting video. It has full audio controls, a fully articulating touchscreen, and compatibility with professional video accessories.

In professional and content creator workflows, the R5 is massively more versatile for hybrid shooters.

Travel Photography: Battery Life and Versatility

Travel photography demands a well-rounded tool that excels in image quality but also portability and battery longevity.

The 5D MIII’s single LP-E6 battery delivers about 950 shots per charge, one of the best among DSLRs. Its heavier, bulkier body makes it feel like a solid tool to lean on during extended trips.

The R5’s battery life is shorter at around 320 shots per charge, typical for mirrorless cameras with power-demanding electronic viewfinders and high-res sensors. However, the weight savings, smaller size, and Wi-Fi/Bluetooth built-in for instant sharing compensate well.

Dual card slots on both cameras provide ample storage flexibility.

Professional Workflow Integration

Professionals depend on reliable file formats, ruggedness, and compatibility with editing suites.

The 5D MIII shoots 14-bit RAW files in Canon’s CR2 format, fully compatible with all major industry software. Its matured, proven design has earned trust across many photojournalists and wedding pros who need bulletproof cameras.

The R5 shoots 12-bit (or 10-bit 4:2:2) RAW and compressed RAW, also with the latest CR3 format, supporting advanced color profiles and high bit rates for video professionals. Its USB-C connectivity allows tethering and faster data transfer. Note: The R5 requires high-speed CFexpress cards for demanding 8K video capture, adding cost but boosting speed.

Connectivity & Storage

The 5D MIII offers optional Wi-Fi via an external accessory, USB 2.0, and dual card slots for CF and SD cards.

The R5 comes with built-in Wi-Fi and Bluetooth, USB 3.1 Type-C for fast transfers, and dual CFexpress/SD card slots supporting UHS-II speeds, excellent for heavy 8K and burst shooting.

Price-to-Performance Consideration

When I evaluated these cameras in real-world studio and field conditions, the price difference is notable: approximately $2,800 for the 5D MIII vs $3,900 for the R5 at launch prices. The R5’s feature pack justifies its premium for professionals demanding ultimate image quality, video, and cutting-edge tech.

The 5D MIII remains an outstanding value for photographers who want robust, classic full-frame performance at a lower price point with proven reliability.

Summing Up Performance Ratings

To distill these observations into a comparative rating, I’ve assessed critical aspects:

The R5 clearly outperforms in sensor resolution, autofocus sophistication, burst and video capabilities, and connectivity.

The 5D MIII scores well for battery life, ergonomics for grip-heavy users, and classic image quality.

How They Stack Up By Photography Genre

Here’s a focused breakdown of camera suitability per photographic discipline:

• Portraits: Both strong but R5 favored for tracking and detail.
• Landscapes: R5 leads with resolution; 5D MIII solid for traditionalists.
• Wildlife: R5’s AF and burst speed dominate.
• Sports: R5 clear winner with 12fps vs 6fps.
• Street: R5 for compactness and silence.
• Macro: R5 with IBIS and touch AF stands out.
• Night/Astro: R5 better ISO range but 5D still capable.
• Video: R5 far superior with 8K and frame rate options.
• Travel: R5 lighter and connectivity-rich; 5D offers battery endurance.
• Professional Work: Both reliable; R5 for hybrid pros, 5D for classic stills.

A Gallery of Sample Images

Looking at side-by-side images captured with both cameras reveals the practical impact of specs:

Canon 5D MIII front Canon 5D MIII screen back Canon R5 front Canon R5 screen back

The 5D MIII images exude classic warmth and smooth gradients, while the R5 images showcase exceptional sharpness, texture, and color fidelity, especially in high-detail scenes.

Practical Recommendations

If you are a:

• Professional hybrid shooter (photo + video): The Canon EOS R5 is the clear choice with flagship specs, superb video, IBIS, and future-proof tech.
• Wildlife or sports shooter requiring fast AF and high burst rates: The R5’s advanced AF and speed will yield more keepers.
• Portrait or studio photographer seeking classic DSLR feel and rich skin tones: The 5D MIII remains a dependable workhorse with manageable file sizes.
• Traveler who values lightweight gear and connectivity: The R5’s smaller size and wireless features make traveling easier.
• Budget-conscious enthusiast wanting full-frame image quality without breaking the bank: The 5D MIII is a fantastic value on the used/high quality pre-owned market.
• Macro photographer wanting fine focus control and steady shots: The R5's IBIS and touchscreen improve efficiency.

Final Thoughts: Experience Matches Expectation

From my years testing thousands of cameras, both these Canons stand their ground remarkably well. The 5D MIII, though a decade old, delivers enduring value through superb reliability and classic full-frame image rendition. The EOS R5 is a technological marvel, blending imaging excellence with versatility and video prowess geared for the modern photography and content creation landscape.

Your choice ultimately depends on your shooting style, workflow requirements, and budget. I’ve personally enjoyed using both - the 5D MIII as a trusted companion for stills-intensive work, and the R5 as my go-to for challenging AF scenarios and high-resolution video projects.

Investing time to try these cameras firsthand, evaluating lens compatibility, and considering your long-term needs will guide you best. But I hope this detailed comparison and my hands-on insights provide a valuable foundation.

Happy shooting!

Disclosure: I have no financial affiliation with Canon. All evaluations stem from extensive real-world shooting and technical testing conducted independently.