The Sigma 18-50 2.8 DC DN Contemporary, released in summer 2024, is an RF mount version of a similar lens marketed for Sony and Fuji mounts in 2021 and 2022. It covers a 2.78X zoom range from wide to telephoto, similar to 29 to 80mm on full-frame, making it ideal for general use. If you’re seeking a compact lens for hiking and travel with a Canon APS-C R series camera, this lens may be for you. Here are my thoughts on this Sigma after two years of shooting.

Anole | EOS R7 and Sigma 18-50 2.8 DC DN at 50mm, F5.6, 1/320, ISO 100

This review consists of my opinions and observations as a hobbyist. No scientific measurements or MFT charts will be found here.

Compatibility

The Sigma 18-50 2.8 DC DN in RF mount lens works on Canon EOS R system cameras, but is optimized for cameras with APS-C (1.6X) sensors such as the EOS R7, R10, R50 and R100. Full-frame R cameras such as the EOS R and R5 scale sensor coverage to APS-C. It is not compatible with Canon SLR, DSLR and M series.

Sigma 18-50 2.8 DC DN | Photo courtesy Sigma Corp.

Construction

The exterior of the Sigma consists of a single nested barrel within a cylinder. There are no switches, distance scale, or decorative silkscreened rings. It is finished in matte black with white silkscreened labels set in a sans-serif typeface. The zoom and control rings are well ribbed and blend nicely into the barrel assembly. Although lens styling is different from Canon's Gothic travel mug look, this Sigma manages to complement the appearance of the Canon R7. 

R7 and Sigma 18-50 2.8 DC DN | Photo courtesy Sigma Corp.

The optical design of the 13-element lens in 10 groups is identical to the earlier renditions released for Sony and Fuji mounts. The size, weight, and shape are similar, although cosmetic differences exist due to mount specifications. For example, the Canon version has a larger plastic flange to accommodate the larger diameter of the RF mount, resulting in a barrel diameter that is considerably smaller than the mount diameter. 

The beefy plastic barrel and chromed brass mount feel more durable than Canon's RF 18-150 IS 3.5-6.3 STM. Component fit and finish are excellent. Basic weather sealing—a rubber casket on the mount—is provided. So far, no problems shooting in light rain around Honolulu. 

Zoom and Control Rings

The ribbed rubber zoom ring is large, grippy, and smooth turning. The clickless control ring—located near the flange—is smaller, but rotation is also very smooth. After two years of use, the zoom does not creep. 

At 18mm the single nested barrel is flush with the end. Racked out to 50mm, it extends, adding about 24mm in barrel length.

Taro Droplets | R7 and 18-50 2.8 DC DN | F5, 1/250, ISO 100

Focus

The 18-50mm 2.8 DC DN features a stepping motor, commonly called STM in Canon lingo. Autofocus is smooth and quiet. Indeed, focusing is silky smooth while tracking a subject with AI Servo or Movie Servo AF, or performing pulls in video mode. It fully supports native Canon autofocus protocols such as face and eye detection, vehicle tracking, etc.

The STM drives an internal lens group and the front element doesn't rotate or extend during focusing. STM coupled with internal focus is surprisingly fast—fast enough to track most swaying flowers, small critters, bikes and speeding vehicles.

Unlike Canon RF lenses, the active AF area of the Sigma 18-50 2.8 DC DN doesn't extend to the absolute edge of the frame. I estimate 80% coverage rather than the normal 100%. I don't normally need to lock AF in an extreme corner. However, the lack of 100% AF area coverage smells like a deliberate hobble by Canon...

Branches | R7 and 18-50 2.8 DC DN | 24mm, F5, 1/200 sec., ISO 100

Manual Focus

This lens lacks a dedicated manual focus (MF) ring. Instead, a narrow control ring is provided, programmable for camera functions such as exposure compensation, AF area patterns, etc. I assumed toggling the Focus Mode Switch on the R7 to MF would enable manual focus. I was wrong.

To enable the control ring for manual focus, it must be set up in the TAB menu. On the R7, open the TAB menu, tap the AF icon, tap menu 6, and enable “use as focus ring” under the “focus/control ring” category. Once enabled, manual focus works anytime the EVF or rear screen is active. When you half-press the shutter button while turning the control ring, a distance scale appears in the EVF. If you half-press the shutter button without turning the control ring, AF works normally. Nice!

The main gotcha with configuring the control ring for MF is the loss of other control ring functions. Toggling the Focus Mode Switch from MF to AF changes nothing.

Waiʻanae Range | EOS R7 and Sigma 18-50 2.8 DC DN | 50mm, F2.8, 1/3200 and ISO 100 | I tested F2.8 on landscapes and was pleased how sharp it was.

Control Ring Mapping

If you don't need manual focus, you can program the control ring for other functions. I programmed the control ring for Exposure Compensation (EC). Two programming steps are required for setup on the R7 (probably R10 as well):

1. Press Menu button, select AF tab, tap menu 6 and set Focus/control ring to CONTROL (not FOCUS).
2. Select the Custom Functions tab, tap menu 3 and select Customize dials. Set the control ring to the desired function—, , , , etc.

I choose Exposure Compensation to align with similar settings I programmed on my other EOS cameras.

Image Quality

The Sigma 18-50 2.8 DC DN performs well with the extremely demanding 32.5MP sensor of the R7. Wide open at F2.8, I experienced sharp center-frame and mid-frame performance. This lens shows relatively little image quality degradation near the edges of the frame. However, the corners are a little soft wide open at 18mm. The mild softness in the periphery sharpens up as the lens is stopped down. Stopping down beyond F5.6 brought no improvement, but increased depth of field. Performance is similar across the zoom range with the exception of 50mm: it's so sharp across the frame that stopping down didn't make much difference. 

Hibiscus | EOS R7 and Sigma 18-50 2.8 DC DN | 50mm, F7.1, 1/500, ISO 100

Quasi Macro

Obviously, this is not a dedicated macro lens, although it focuses all the way down to .36x—good enough for flowers and small products. At macro distances, contrast and sharpness are surprisingly good for a compact zoom. The corners are a bit softer but such fine for typical centered subjects. Just realize that .36x happens at 12.1cm (4.8") and 18mm, so it may be tricky to get proper lighting on your subject. With that said, I had no problems shooting garden images in bright light.

Below is an example of a 20-image focus bracket, stacked in-camera. The Sigma handled the brutal 20 FPS electronic shutter of the R7 like a champ.

Chromatic aberration

Chromatic aberration (CA) is well-controlled and are usually not noticeable. For instance, a small amount of purple fringing is sometimes barely visible along the corners and edges of tree branches against a bright sky. CA reduces progressively as you stop down.

Trumpet Creeper | R7 and 18-50 2.8 DC DN at 8mm, F8, 1/80, ISO 250

Light Falloff

Light falloff or vignette may be observed, especially at F2.8, on the wide end of the zoom. Vignette is reduced as the aperture is stopped down. Initially, I didn’t notice any light falloff, but realized that Lightroom automatically removed it. In-camera JPEGs are automatically corrected, as are RAW files processed in Lightroom and Canon DPP4. I often prefer images with darker corners and edges and sometimes disable Profile Corrections for a natural vignette.

Flare

While shooting blazing Hawaiian sunsets, I found ghosting and flare minimal or nil. Typical high-contrast night scenes with street lights or interior lamps are usually immune to flare. Sigma's Super Multi-Layer Coating is performing well! Some of my Sigma lenses from decades ago were flare-prone, so I was delighted to observe such a big improvement.

Pier | EOS R7 and Sigma 18-50 2.8 DC DN | 50mm, F8, 1/640 sec., ISO 100

In flare prone lighting, remove unneeded filters and use a hood to help block stray light. I sometimes use my hand or hat to block stray sunlight.

Comparisons

Like most Canon R7 owners, my camera came with the RF-S 18-150 3.5-6.3 IS STM. How does it compare with Sigma beyond differing zoom ranges, apertures, and stabilization? First, they are in the same ballpark in terms of sharpness. Yes, the Sigma is a little sharper than the RF-S 18-150 3.5-6.3 IS STM, especially along the periphery, but the difference didn't jump out at me until I pixel peeped along the edges. 

AF speed and accuracy are close between the two lenses—a draw in my opinion. However, the Sigma is built better, weather-resistant, and has a smoother zoom ring. The Canon has better macro focus: .44x at 50mm. However, having F2.8 across the zoom range of the Sigma is a biggie and the main reason I bought it.

Peace Lily | R7 and 18-50 2.8 DC DN at 50mm, F6.3, 1/400 and ISO 100

Image Stabilization

Sadly, there is no stabilization (IS) in the Sigma 18-50 2.8 DC DN, whereas the RF-S 18-150 3.5-6.3 IS STM has stabilization. IS and IBIS combined on my R7 result in near gimbal-like smoothness for hand-held video. With only IBIS, hand-held Sigma clips are not as smooth. Worse yet, some cameras lack IBIS, leaving video and stills at the mercy of caffeine, heavy breathing, and trade winds. 

If you own an R7, its IBIS mechanism provides sensor-based stabilization for the Sigma. Canon claims up to 8 stops of IBIS stabilization. My experience is closer to 2 or 3 stops of IBIS stabilization with the 18-50 2.8 DC DN. While good enough for most people, I've gotten unstable as I drift into my golden years, and my hand-shake results in more blurry images with the Sigma than with the IS-blessed RF-S 18-150 3.5-6.3 IS STM.

Lens Hood

Hoods reduce flare by blocking stray light. They also provide front element protection from bumps, greasy fingers, and dust. Unlike Canon, Sigma provides hoods for all its lenses. In this case, a nice petal-type hood (LH582-02) is in the box. 

Sigma LH582-02 Hood | Photo courtesy Sigma Corp.

Fit and finish of the LH582-02 hood are great: quality plastic, fingerprint-resistant matte black exterior, flat black interior paint to nix reflections, and cosmetically matched to the lens. The hood may be reverse-mounted for compact storage.

Firmware

Lens firmware updates may be installed using a SD card, USB, or Wi-Fi. I stuck to the tried-and-true SD method: download the firmware from Sigma's website and place it on the root level of the SD card. Here are the firmware update steps I followed on the the R7:

• Insert the SD card and power on the camera.
• Open the TAB menu.
• Tap the icon, open menu 2, and select “firmware” from the menu list.
• Press SET and select “lens” from the list.
• Use the physical controls of the camera to start the firmware update (touchscreen disabled).

This method beats mailing the lens to Sigma for a ROM update or using Sigma's hockey puck USB dock! 

Friend | R7 and 18-50 2.8 DC DN at 50mm, F5.6, 1/320, ISO 100

Final Blurb

I was able to capture sharp images in almost any situation I threw at the Sigma 18-50 2.8 DC DN. I love the compact size, F2.8 aperture throughout the zoom range, smooth and peppy autofocus, weather resistance, and sharpness of this lens. It's a smart looker and, combined with my R7, it made for a wonderfully versatile and lightweight travel and wandering around town combo. However, if image stabilization (IS) is a crucial aspect of your shooting style, you may need to consider other options. 

Please support this site by purchasing this lens at Amazon.

Taro and Fence Shadows | R7 and 18-50 2.8 DC DN at 50mm, F5.6, 1/320 and ISO 100 | Converted to black and white in Photoshop Classic.

Features and Specs

• Focal Length: 18–50mm
• Maximum Aperture: f/2.8
• Aperture range: f/2.8 – f/22
• Angle of View: 73.4° – 30.0°
• Lens Construction: 13 elements in 10 groups (1 SLD and 3 aspherical)
• Super Multi-Layer Coating
• Brass bayonet mount with rubber dust and splash resistant seals
• Filter Size: 55mm
• Native algorithms for AF, communication and in-camera aberration correction (i.e., not reverse engineered).
• Compatible with lens aberration correction in Lightroom, DPP4, etc.
• 7-blade rounded diaphragm
• Autofocus: Inner focus system with stepping motor
• Stabilizer: no built-in stabilization
• Minimum Focusing Distance: 12.1cm (4.8") at 18mm and 30cm (11.9") at 50mm.
• Maximum Magnification: .36x or 1:2.8 (at 18mm)
• Mount: RF | APS-C coverage compatible with all R series cameras
• Accessories: lens hood LH582-02, front cap LCF-55mm III, rear cap LCR II

• Diameter x Length: 69.2mm x 74.5mm
• Weight: 300g (10.6 oz)

• Made in Japan

• $659 MAP (USA)

Source Materials

Sigma 18-50 2.8 DC DN Instructions (0120-9977-88). Sigma Corp.

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Created on October 30, 2026

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