Canon PowerShot G7 X Mark III vs. Sigma DP3 Merrill: A Deep Dive into Two Distinct Large Sensor Compacts

When it comes to large sensor compact cameras, few models are as contrasting in design philosophy and target audience as the Canon PowerShot G7 X Mark III (hereafter G7 X MIII) and the Sigma DP3 Merrill. Each represents a unique approach to photography from the last decade - the Canon focusing on versatility and modern connectivity, the Sigma on uncompromising image quality from its Foveon sensor. Having spent weeks testing and comparing these two cameras side by side, I want to walk you through their strengths, limitations, and the use cases where each truly shines. Let’s get started by examining how they stack up physically and ergonomically.

Size and Handling: Portability vs. Sturdiness

Right out of the gate, the Canon G7 X MIII impresses with its sleek, pocketable design measuring 105 x 61 x 41 mm and tipping the scales at just 304 grams. It feels reassuringly solid in hand without bulk, making it an ideal companion for street and travel photography where discretion and mobility matter.

On the other hand, the Sigma DP3 Merrill is larger and chunkier at 122 x 67 x 59 mm, weighing in at 330 grams. Sigma’s approach here prioritizes robustness and a traditional boxy shape that some photographers love for stability. It’s not a camera you’ll slip casually into a jacket pocket but rather one you carry deliberately, often with a small bag.

Ergonomically, Canon has engineered the G7 X MIII with modern shooters in mind. The grip is sculpted yet unobtrusive, and essential controls fall intuitively under thumbs and fingers - more on that layout shortly. Sigma’s DP3 Merrill opts for a minimalist button layout, reflective of its age and design intention focusing on pure image quality over operational speed.

If you lean toward portability and intuitive handling, Canon is the winner here; if you prefer a sturdy, no-frills device for deliberate shooting sessions, Sigma’s bulk is forgivable.

Design and Control Layout: Modern Touchscreen Meets Old-School Simplicity

Looking down from the top, the G7 X MIII sports an impressively modern control layout. Its DIGIC 8 processor enables a responsive touchscreen with a tilting 3” LCD, controlling autofocus points and menu navigation smoothly. The dials for exposure compensation and mode selection are tactile with satisfying resistance.

Conversely, the DP3 Merrill bears the hallmarks of an earlier era - fixed rear LCD without touchscreen, a minimal button array, and no dedicated electronic viewfinder. The absence of touchscreen means focusing and menu access feel dated. However, Sigma has always designed the Merrill series for patience and contemplative shooting, so the deliberate interface might appeal to serious photographers who prefer manual focus and control.

Without an electronic viewfinder, both rely on LCD composition, though Canon’s tiltable screen and touchscreen truly add practical flexibility, especially in awkward shooting angles.

Sensor Technology and Image Quality: Foveon X3 vs. BSI-CMOS

The heart of the matter lies in these cameras’ very different sensors. The Canon G7 X MIII uses a 1-inch BSI-CMOS sensor measuring 13.2 x 8.8 mm, packing 20 megapixels (MP). This sensor size strikes a balance between image quality and compactness but naturally cannot match a larger sensor’s low light capabilities or dynamic range fully.

Sigma, known for its unique Foveon X3 sensor technology, equips the DP3 Merrill with an APS-C sized sensor (24 x 16 mm) but with an effective resolution of 15 MP. However, the Foveon’s distinct layering means it captures full color at every pixel location, producing razor-sharp images with excellent color fidelity and tonal gradation unmatched by traditional Bayer sensors.

In real-world tests, the DP3 Merrill delivers exceptional sharpness and color depth, especially in controlled lighting. Highlights and shadows have subtle transitions, and textures pop in portraits and landscapes alike. The drawback? The Foveon's reliance on slower readouts limits burst speed and focusing performance.

Meanwhile, the Canon G7 X MIII sensor provides versatile image quality, handling higher ISO settings better in low light, aided by its DIGIC 8 processor. It’s not as rich in micro-detail as the Sigma but compensates by working well in a wide range of conditions, offering reliable JPG and RAW output.

In short, if pure image quality, especially color accuracy and detail, is king, the DP3 Merrill takes the crown; if flexibility and modern sensor performance are more important, Canon’s sensor is tough to beat in this class.

Rear LCD Screen and Viewfinder Experience: Interactive Touchscreen vs. Reliable Fixed Display

The G7 X MIII offers a 3-inch tilting touchscreen with a resolution of 1,040k dots, excellent for framing in live view and navigating menus. The touchscreen functionality is responsive, allowing precise autofocus area selection, which is invaluable for portrait and street photography where focus points can be crucial.

Sigma’s DP3 Merrill gives us a fixed 3-inch screen at 920k dots, less sharp by today's standards, and lacks touch input. The lack of a viewfinder in both models means this screen is the primary means for composition. This can challenge outdoor shooting in bright light, although Sigma’s LCD is sufficiently bright for controlled environments.

Canon’s screen also facilitates selfie modes and vlog-friendly tilting, something Sigma does not accommodate, reflecting their divergent target audiences.

Autofocus and Shooting Performance: Speed and Intelligence vs. Precision and Patience

The Canon G7 X Mark III benefits from contrast-detection autofocus paired with face detection and multiple AF modes (touch, tracking, continuous). It clocks a blistering 30 frames per second (FPS) burst rate with fixed focus, making it a compact powerhouse for quick-action photography like sports or street scenes.

On the flip side, Sigma’s DP3 Merrill relies on manual focus only - there’s no phase-detection, contrast-detection, or autofocus assistance. Continuous shooting tops out at a modest 4 FPS, and no face/eye detection is available.

This hands Sigma’s camera to patient photographers who enjoy precise manual adjustments, perhaps for studio, landscape, or fine art imaging, rather than dynamic shooting scenarios.

For wildlife or sports where fast AI-driven AF is key, Canon’s G7 X MIII is simply better suited.

Lens Quality and Versatility: Zoom Convenience vs. Prime Sharpness

Sigma equips the DP3 Merrill with a high-quality fixed 75 mm (35mm equivalent 50 mm, considering crop) f/2.8 lens, optimized for portrait and detail work. This lens is renowned for crystal sharpness and creamy bokeh, ideal for portraiture where subject separation is prized.

The Canon G7 X MIII has a versatile zoom range of 24-100 mm equivalent (4.2x zoom) with a bright constant aperture from f/1.8 to f/2.8. This zoom provides flexibility from wide-angle landscapes to short telephotos, suitable for travel and street photography.

While the Sigma offers less zoom range and slow lens aperture compared to Canon's f/1.8 at the wide end, its prime quality makes for stunning portraits and fine detail capture. Canon’s choice favors all-around convenience, especially outdoors or on the move.

Image Stabilization and Flash: Modern Stability vs. Legacy Limitations

Canon’s optical image stabilization helps mitigate shake during handheld shooting, especially useful at slower shutter speeds or longer focal lengths on the zoom lens. Additionally, the built-in pop-up flash with multiple modes offers extra lighting control in low-light situations - suitable for casual events or fill flash in portraits.

The Sigma DP3 Merrill offers neither in-body nor lens stabilization, and there is no built-in flash. Photographers must rely on external flashes or natural light, reinforcing its design for carefully controlled shooting scenarios rather than spontaneous snaps.

Battery Life and Storage: Compact Convenience vs. Legacy Constraints

Canon’s G7 X MIII provides around 235 shots per charge, respectable for a large sensor compact with a modern battery design. It uses a rechargeable battery pack and writes to a single SD card slot supporting UHS-I cards.

Sigma’s numbers are less clear, though its older design typically results in shorter battery life. It uses a single storage slot, though types are unspecified here. The lack of wireless features means the Sigma’s battery isn’t drained by continuous connectivity.

For travel or extended shooting, the Canon’s battery and storage setup are easier to manage and more reliable.

Connectivity and Video Capabilities: Modern Multimedia Features vs. Photography Purism

The Canon G7 X MIII shines in connectivity - equipped with Wi-Fi and Bluetooth, enabling easy wireless transfer, remote control, and live streaming capabilities. Speaking of video, it supports 4K UHD at 30p, Full HD at up to 120 fps, internal microphones, and external mic port for better audio capture, making it a go-to for hybrid shooters and vloggers.

Sigma DP3 Merrill’s video options are minimal - capped at 640 x 480 VGA in Motion JPEG - effectively a photo-only device by today’s standards. No wireless connectivity or ports for microphones mean Sigma leans heavily towards still photography aficionados uninterested in video.

Real-World Photography Tests: Sample Gallery and Impressions

Canon G7 X MIII front Canon G7 X MIII screen back Sigma DP3 Merrill front Sigma DP3 Merrill screen back

In portrait scenarios, the Sigma DP3 Merrill’s 75 mm lens, combined with Foveon sensor sharpness and rich color depth, beautifully renders skin tones with subtle gradations and natural bokeh. Canon’s G7 X MIII delivers pleasing portraits as well but with less nuance and a wider zoom flexibility, better for candids and environmental portraits.

In landscapes, Sigma’s APS-C sensor and prime lens capture textures and tonal ranges with finesse, albeit requiring tripod use for best sharpness. Canon offers more versatility here, with wider zoom and effective image stabilization, suitable for hand-held shooting or quick framing.

Wildlife and sports scenarios clearly favor the Canon - fast burst rate, autofocus ability, and stabilization make it the only practical choice between the two.

Street and travel photography highlight Canon’s compact size and quick responsiveness, alongside touchscreen focusing and silent shutter options - Sigma’s bulk and manual focus are impediments here.

Macro photography is rudimentary on both; Canon’s close focusing to 5cm with zoom might give it a slight edge, while Sigma’s longer fixed lens restricts proximity.

Night and astro photography needs a balance of low noise and long exposures - Canon’s stabilized sensor and ISO range help, but Sigma’s Foveon sensor excels in long exposures with high color fidelity, though noisier at higher ISO.

Professional Workflow and Reliability: File Formats and Integration

Both support RAW capture, but Sigma’s X3F raw files are less widely supported in mainstream editing software, requiring Sigma’s proprietary tools or third-party plugins. Canon’s CR3 RAW format enjoys broad compatibility and faster processing.

Neither camera sports weather sealing or rugged body features, limiting professional use outdoors under harsh conditions.

Performance Ratings: How Do They Score?

In measured overall performance, Canon G7 X MIII scores higher due to its speed, versatility, and multimedia features. Sigma’s scores highlight its exceptional image quality but lower autofocus and general operation capabilities.

When breaking down by photography type, Sigma shines in studio and landscape, while Canon dominates wildlife, sports, video, and travel.

Value for Money: Budget-Priced Versatility vs. Premium Image Craftsmanship

At launch, Canon’s G7 X MIII retails for around $750, offering an excellent balance of features, image quality, and modern multimedia capabilities in a compact form.

Sigma’s DP3 Merrill, despite being an older model from 2013, still commands a premium price near $1350 due to its unique sensor and specialty lens, attracting a niche audience interested in top-tier image quality over speed or convenience.

Your budget and primary photographic goals will largely determine which is the better investment.

Final Thoughts: Who Should Choose Which?

• Choose the Canon PowerShot G7 X Mark III if you want:

  • A versatile travel and street camera with excellent zoom flexibility
  • Fast autofocus and burst shooting for wildlife or sports
  • A modern touchscreen interface with richer video capabilities
  • Built-in image stabilization and wireless features
  • A compact, lightweight body easy to carry all day

• Choose the Sigma DP3 Merrill if you want:

  • Exceptional image quality with rich color depth and sharpness in stills
  • A prime lens with creamy bokeh ideal for portraits and landscapes
  • A deliberate shooting experience with full manual focus control
  • A camera as a dedicated art tool rather than an all-rounder
  • Are comfortable with legacy workflows and slower performance

In sum, these cameras occupy very different niches within the large sensor compact category. Canon’s G7 X MIII is the consummate modern compact for photographers who want “one camera, many purposes” including video and connectivity. Sigma’s DP3 Merrill is a specialist’s tool retaining a place for those who prize ultimate image quality from a fixed lens prime and are willing to trade speed and convenience.

Hopefully, this side-by-side analysis helps you zero in on the camera that suits your photographic style and workflow best. Happy shooting!

Article images used under fair use for editorial comparison purposes.