{"id":10987,"date":"2022-02-03T16:35:00","date_gmt":"2022-02-03T21:35:00","guid":{"rendered":"https:\/\/admiringlight.com\/blog\/?p=10987"},"modified":"2022-02-04T10:58:42","modified_gmt":"2022-02-04T15:58:42","slug":"review-canon-rf-16mm-f-2-8-stm","status":"publish","type":"post","link":"https:\/\/admiringlight.com\/blog\/review-canon-rf-16mm-f-2-8-stm\/","title":{"rendered":"Review: Canon RF 16mm f\/2.8 STM"},"content":{"rendered":"\n

When the first details about the Canon RF 16mm f\/2.8 STM leaked in 2021, the lens sounded intriguing: the RF system could certainly use a mid-range ultra-wide prime. When later leaks suggested that the lens would cost only $299 and would be the same size as the nifty-fifty RF 50mm f\/1.8, I thought there was simply no way that could be true. The lens had to be for a new APS-C RF mount camera, or the leaked dimensions and price had to be wrong. You see, ultra-wide lenses for full-frame aren’t typically all that small, and they are almost never inexpensive. But the leaks were all 100% correct, and today I’m going to review Canon’s $299, ultra-compact ultra-wide prime lens for full-frame RF mount. Let’s dive in.<\/p>\n\n\n\n

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Canon EOS R5 with the RF 16mm f\/2.8 STM<\/figcaption><\/figure>\n\n\n\n

Construction and Handling<\/h3>\n\n\n\n

When you see the RF 16mm f\/2.8 STM for the first time, it looks instantly familiar. That’s because it shares the exact same lens body as the RF 50mm f\/1.8. The two lenses are identical in size, and nearly identical in weight. Only a closer look at the focal length number on the barrel, or the different looking front element gives you an indication that this is a different lens. The RF 16mm f\/2.8 is extremely compact and lightweight, but like all of Canon’s RF lenses, it’s nicely constructed, with a polycarbonate lens body and a metal lens mount. <\/p>\n\n\n\n

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The RF 16mm f\/2.8 STM and RF 50mm f\/1.8 STM share the same lens body<\/figcaption><\/figure>\n\n\n\n

Due to its extremely small size and light weight, the lens handles almost as if there’s nothing on the camera, and you’ll barely feel it if adding it to the bag. I’ve found it to be the perfect small lens to pop in the bag for day hikes where you don’t want to carry much gear but still may need an ultra-wide focal length. Now, when I want to travel light, I’ll bring the RF 16mm, the RF 24-105mm f\/4L and, if I feel like I need a little more reach, my tiny Minolta MD 135mm f\/3.5. <\/p>\n\n\n\n

The 16mm has a dual-purpose ring on the front of the lens, which can be switched between a focus ring and the RF-specific control ring. The ring turns smoothly and with a nice amount of damping. Unlike RF lenses with dedicated control rings, this ring does not click when turning. <\/p>\n\n\n\n

Like all of Canon’s non-L series lenses, the RF 16mm does not come with a lens hood, but Canon’s EW-65C is a nice locking, reversible and compact lens hood, and can be purchased for $30. When the lens was released, it sold for only $25, but has since seen a small price increase. This is fairly affordable by Canon’s standards, and due to the wider field of view, I didn’t hesitate to pick up the hood. With that said, Canon still should be including these hoods in the box, even on their affordable lenses. Almost all other lens makers include hoods with lenses at any price point. <\/p>\n\n\n\n

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The RF 16mm f\/2.8 STM with optional hood, on the EOS R6<\/figcaption><\/figure>\n\n\n\n

The RF 16mm f\/2.8 has a 43mm filter thread, and can take a polarizing filter without vignetting, though due to the way the lens focus barrel extends and retracts, I found it easier to attach and detach filters when the camera is powered on and the lens tube partially extended. When the camera is turned off, the focus group fully retracts and makes it difficult to get a grip on a polarizing filter to unscrew it. <\/p>\n\n\n\n

Autofocus<\/h3>\n\n\n\n

The 16mm f\/2.8, like many of Canon’s consumer grade lenses for the RF system, utilizes a stepping motor (STM) for autofocus. While Canon’s STM motors are typically slower and a little noisier than their USM motors, the one in the 16mm f\/2.8 is reasonably quick and relatively quiet as well. Much of this may be due to the shorter focus throw inherent in wide angle lenses. In use, the STM motor works very well for this lens, providing quick and quiet autofocus with good accuracy. <\/p>\n\n\n\n

The RF 16mm f\/2.8 does not have an optical image stabilizer built in, but it works well with the in-body stabilization of the R5 and R6, and I was typically able to achieve sharp hand-held exposures of around half a second to one second in duration. <\/p>\n\n\n\n

Continue: Image Quality<\/a><\/h4>\n\n\n\n\n\n\n\n

Image Quality<\/h3>\n\n\n\n

With an ultra-wide field of view, a supremely compact size, and a bargain price of just $299, I was expecting the RF 16mm to be a pretty poor lens optically. However, while there are certainly some significant compromises made to hit the size and price goals, I was pleasantly surprised by the quality of the images the lens produced. The biggest concession made in design was with native distortion, which then cascades to affect sharpness when corrected. As such, let’s begin our discussion with distortion.<\/p>\n\n\n\n

Distortion<\/h4>\n\n\n\n

If you were wondering how Canon made a full-frame 16mm f\/2.8 lens the size of a nifty-fifty, you need only look at the native distortion to get your answer. The lens produces images with a simply huge amount of barrel distortion, which is then corrected with software to provide the final image. The distortion of the native optics is high enough to almost give a slight fisheye look when uncorrected, which can be seen in the shot below:<\/p>\n\n\n\n

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Ohio Statehouse – Canon EOS R5 with Canon RF 16mm f\/2.8 STM @ f\/8, 1\/60s, ISO 100, Distortion Uncorrected<\/figcaption><\/figure>\n\n\n\n

It’s worth noting that the field of view of the lens when uncorrected for distortion is significantly wider than what a typical 16mm rectilinear lens would produce, and when corrected, the final 16mm FOV is realized. This can work in your favor in some circumstances. Distortion matters far less for something like landscape photography, and in these cases, leaving the distortion uncorrected when processing the RAW files can allow you to use the effectively 14mm FOV of the uncorrected lens, while also showing increased sharpness in the corners (as I’ll discuss further below). However, for most uses, you will want to correct the distortion using a lens profile in your preferred RAW converter. Adobe Lightroom\/Camera RAW and DxO PhotoLab already have profiles, while Capture One does not as of this writing. Below is the same image as above, but with the profile from DxO PhotoLab 5 applied. <\/p>\n\n\n\n

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Ohio Statehouse – Canon EOS R5 with Canon RF 16mm f\/2.8 STM @ f\/8, 1\/60s, ISO 100, DxO PhotoLab Profile Applied, 3:2 crop for 16mm FOV<\/figcaption><\/figure>\n\n\n\n

In evaluating the profiles from Adobe and DxO, it’s interesting to see Adobe’s profile only corrects for the image inside the ‘standard’ 3:2 crop after correction. If you expand the cropped area, the distortion of the leftover image is terrible and essentially unusable. DxO, however, fully corrects the area outside the crop too – and in fact by default creates images using a near 16:10 aspect ratio that takes advantage of the natively wider field of view. As such, when using DxO, you can almost use the lens as a 14-15mm lens, and even select which area of the crop to use if you want to maintain a 3:2 aspect ratio. This can be very useful when cropping after leveling the camera to minimize perspective distortion, such as in the shot below. Click to Enlarge<\/em><\/p>\n\n\n\n

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Distortion Profiles, Lightroom vs. DxO, RF 16mm f\/2.8 (Click to Enlarge)<\/figcaption><\/figure>\n\n\n\n

Sharpness<\/h4>\n\n\n\n

Despite the small size and low cost, the 16mm f\/2.8 is predominantly quite a sharp lens, at least away from the image edges. Central sharpness is very good starting right at f\/2.8, and that sharpness extends over about 75% of the frame. Wide open, edges and corners are soft. Stopping down a few stops brings the central region up to excellent sharpness, and improves edge and corner performance to good levels. That is, good levels if the image is not corrected for distortion. As mentioned above, you will need to correct for distortion when shooting anything with lots of straight lines, but landscape work often does not require it. The shot below is uncorrected for distortion, and then slightly cropped to the normal 16mm field of view, to avoid the dark corners that appear with the uncorrected image. If you click on the image to enlarge, then zoom in to the full resolution image, you can see that good sharpness is maintained even towards the edges and corners. <\/p>\n\n\n\n

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Cedar Falls – Hocking Hills State Park, Ohio – Canon EOS R5 with Canon RF 16mm f\/2.8 STM @ f\/11, 30s, ISO 100<\/figcaption><\/figure>\n\n\n\n

Once the distortion profile is applied, the rather extreme level of image stretching at the edges reduces edge and corner resolution substantially, resulting in some edge softness and smudged corners. When shooting architecture or other distortion-sensitive subjects, you will just have to deal with that small reduction in resolution at the edges. Here, too, I also find DxO Photolab’s profile to be better than Adobe’s, and better resolution is maintained at the image edges after correction. Below is an image, distortion corrected in DxO Photolab. Click here for a 100% crop<\/a> of the lower right corner to see the type of corner and edge smearing that is visible after distortion correction. <\/p>\n\n\n\n

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Franklin County Common Pleas Courthouse – Canon EOS R5 with Canon RF 16mm f\/2.8 STM @ f\/10, 1\/50s, ISO 100<\/figcaption><\/figure>\n\n\n\n

Despite these compromises, I find the lens very useful for most general purpose wide-angle photography. Serious architectural photographers will likely want to use a more well-corrected optic for critical work, but the lens works well considering its price point and other design considerations. <\/p>\n\n\n\n

Bokeh<\/h4>\n\n\n\n

Being an ultra-wide angle lens, the RF 16mm f\/2.8 won’t allow for huge amounts of blur, but with the f\/2.8 maximum aperture and reasonably close minimum focus distance, the lens is definitely capable of providing some level of subject separation. The bokeh from the RF 16mm isn’t anything special, but it is nicer than I expected in such an inexpensive optic. The bokeh is not super creamy, and can have a slight bright ring at the edges of specular highlights, however, it is also not really objectionable either. Specular highlights take on a slight gumdrop shape near the edges, but the overall rendering is relatively neutral. In all, it’s a slightly above average performance here for such a lens.<\/p>\n\n\n\n

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Sundial – Canon EOS R5 with Canon RF 16mm f\/2.8 STM @ f\/2.8, 1\/125s, ISO 100<\/figcaption><\/figure>\n\n\n\n

Color, Contrast, and Chromatic Aberration<\/h4>\n\n\n\n

The RF 16mm f\/2.8 does not lack when it comes to color and contrast. The lens produces images with rich color and excellent contrast, right from f\/2.8. This is one area where inexpensive lenses often fail to impress, but Canon has done an excellent job in this department. Images really show a lot of punch and this can be far more important for most day to day shooting than fine detail in the corners. <\/p>\n\n\n\n

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Columbus Grove – Canon EOS R5 with Canon RF 16mm f\/2.8 @ f\/9, 1\/40s, ISO 100<\/figcaption><\/figure>\n\n\n\n

The inexpensive nature of the lens does show itself in chromatic aberration performance, however. The lens can show a fairly high amount of lateral chromatic aberration, which worsens at the edges, though this is mostly correctable in post-processing. It also will display purple fringing with high contrast areas, such as tree branches against a bright sky. These flaws are to be expected at this price point. <\/p>\n\n\n\n

Flare and Vignetting<\/h4>\n\n\n\n

The RF 16mm f\/2.8 STM shows a mixed performance against bright light. With the sun located close to the center of the frame, flare is relatively well controlled, with minimal loss of contrast and only a few ghosts visible. As the light source moves closer to the edge of the frame, flare becomes more prominent, with more significant ghosting. Sensor reflections can also be visible when shooting into the sun. I would recommend picking up the lens hood for this lens, as it can help with maintaining good contrast with the sun just out of frame. <\/p>\n\n\n\n

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Franklin County Common Pleas Court – Canon EOS R5 with Canon RF 16mm f\/2.8 STM @ f\/14, 1\/125s, ISO 100<\/figcaption><\/figure><\/div>\n\n\n\n

The RF 16mm shows very prominent vignetting at f\/2.8. The vignetting slightly intrudes on the image frame before distortion correction, resulting in completely dark extreme corners in the native RAW file, though these are cropped out after distortion correction. Vignetting eases upon stopping down, but never fully goes away. <\/p>\n\n\n\n

As you can see, the RF 16mm f\/2.8 STM is far from a perfect optic. It combines generally strong resolution with excellent color and contrast, but compromises in the optical design to hit the size and price desired show up in very strong barrel distortion, some chromatic aberration and average performance against flare and vignetting. Still, when you consider the minuscule size and the bargain basement price for an ultra-wide lens, the 16mm f\/2.8 shows itself to be a very competent performer. <\/p>\n\n\n\n

Continue: Conclusion and Image Samples<\/a><\/h4>\n\n\n\n\n\n\n\n

Conclusion<\/h3>\n\n\n\n

Pros:<\/h4>\n\n\n\n