Sigma 10-18mm F2.8 DN (Canon RF) Review

Dustin Abbott

October 21st, 2024

The Sigma 10-18mm F2.8 DC DN is the second of two Sigma zooms that we’ve seen rereleased on Canon’s RF mount, and they are very welcome. Earlier this year as I was doing my review of the Canon EOS R50 compact APS-C mirrorless camera I couldn’t help lament the state of the lens options for Canon’s RF-S mount. At the time of the review (two years since the release of the EOS R7, the first of Canon’s RF mount APS-C cameras), this was the sum total of the available lenses.

Yuck. I couldn’t imagine a less exciting lineup of lenses. The fastest maximum aperture in the bunch was F3.5, and that lens is F4 and smaller before you make it to 30mm. Canon clearly knew they had a problem, for between the time that I filmed my review and the time I released it, they announced that certain Sigma (and later Tamron) lenses would become available for RF-S (the APS-C version of Canon RF). Now, to be clear, this is only for APS-C lenses, but for now it seems like Canon is going to let third parties solve their APS-C lens problem. This is great news for consumers, however, because it means that Sigma’s lineup of DC DN lenses will be coming to Canon RF. The first release was the Sigma 18-50mm F2.8, a lens that I actually own and gave a positive RF mount review here. A few months later they have followed up with the second zoom release, this time the wide angle Sigma 10-18mm F2.8 DC DN. Is this also a lens worth considering for your Canon R-mount APS-C camera? You can find out my thoughts in the video review below…or read on.

Sigma 10-18mm F2.8 DC DN for Canon RF Review | Premium Wide Angle Goodness

__________________________________________________________________________________________________

Thanks to Gentec (Sigma’s Canadian Distributor), for sending me a review loaner of this lens. As always, this is a completely independent review. All opinions and conclusions are my own. *The tests and most of the photos that I share as a part of my review cycle have been done with the 45MP Canon EOS R5, which I reviewed here.

__________________________________________________________________________________________________

This becomes the first “fast” wide angle zoom for Canon RF-S (APS-C), giving a constant aperture of F2.8 over its zoom range. Now, to be fair, that’s not a big zoom range, but then again, Canon’s own RF-S 10-18mm not only has that same small zoom range but also has a variable aperture of F4.5-6.3! That means that the Sigma is over two stops faster at 18mm (F6.3 is 2 1/3rds stop slower than F2.8). And, while that zoom range is not large, it is enough to give you a variety of options for framing a scene, from this at 10mm:

…to this at 18mm:

This review of the 10-18mm RF is not a whole new review, but rather an update on how the 18-50mm RF translates to Canon RF. I’ve already tested the image quality at both a 26MP (Sony) and 40MP (Fuji) in 2023, so that covers the full gambit (and more) of what’s available on RF bodies. There are no optical surprises here, but I’m always curious to see how the lens changes in terms of its dimensions, but, most importantly, how well it autofocuses on a platform that it wasn’t originally designed for.

The 18-50mm RF is one of six lenses released by Sigma for Canon RF, and those six lenses represent all of the APS-C mirrorless lenses they’ve released over the past three years. You can see my review of the original releases on Sony here.

Sigma’s DC DN lenses have all fallen under the umbrella of their Contemporary lineup, and while Sigma has proven willing to experiment with new features and design elements within the ART and Sport lineups, the Contemporary lenses have all stuck to a fairly rigid design formula. That continues to be the case here, so this little zoom mostly looks and handles pretty similarly to other lenses in the lineup.

There’s nothing new here on the RF mount, but the lens is more of a standout on Canon due to having essentially zero quality competition. The 10-18mm RF is a genuine treat as an addition here. Why? Here’s a few reasons:

Has at least a weather sealing gasket
Better build quality than RF-S lenses
Includes a lens hood
Constant F2.8 aperture
Good up close performance
Great autofocus on RF

In essence, the poor competition makes this lens a star, though frankly I still found it one of the more compelling options on these other platforms as well.

The crop factor on Canon is different than Sony or Fuji, so the zoom range works a little different. Fuji/Sony have a crop factor of 1.5x, which means that the lens goes from a full frame equivalent of 15-27mm. Canon’s APS-C crop is 1.6x, and so that changes the effective focal range to 16-29mm. You’ll miss the extra bit of width at 10mm but get a little more reach. In this case, I think that most of us would prefer the extra millimeter of wide angle coverage, but that’s just not going to happen.

Marked positions in the zoom range are 10, 12, 14, 16, and 18mm, and here’s what the same scene looks like at each of these marked positions.

Clearly this is a little lens that can make beautiful images, but is it worth twice as much as Canon’s own 10-18mm F4.5-6.3 IS STM lens?

Sigma 10-18mm RF-Mount Build and Handling

There’s really only one significant change to the 18-50mm on Canon, and that is that the lens mount portion of the lens has to be flared out to accommodate the much larger diameter of the RF mount.

Unlike the 18-50mm, however, this isn’t the widest part of the lens, so the exterior measurements don’t change despite this change. It is 72.2mm in diameter and 62mm in length (2.8 x 2.4″). That’s actually 2mm shorter than the Sony version, and this obvious reflects a slightly different flange difference between the two mounts. That extra bit of girth near the lens mount also adds a tiny bit of weight, with the RF version weighing 260g (9.17 oz). Other than these minor physical changes to the RF version, the build is otherwise identical to either the E-mount of X-mount versions.

This weighs about 110g more than the Canon, though the Canon is a very plasticky lens that also has a very slow aperture. The build quality between these two lenses can’t really be compared.

The 10-18mm RF is a mixture of metals and “thermal composites” (high grade engineered plastics) in construction, and the construction feels quality in the hand. It is built around a metal mount, unlike the Canon lens, which has a plastic mount.

The overall build quality just feels much higher than any of the Canon RF-S lenses that I’ve tested so far. This feels like a quality lens.

Up front we have the ability to use traditional filters in a very standard 67mm size.

There is a weather sealing gasket at the lens mount (thicker here on the RF mount than on previous versions), but, like other Contemporary lenses, there are no internal seal points.

The only thing on the barrel is the focus and zoom rings. The closest to the lens mount is is the focus ring, which is fairly narrow (10mm), ribbed, and moves smoothly. Like other lenses designed for mirrorless cameras, this is a focus-by-wire system in which input from the focus ring is routed through the focus motor. It is actually the focus motor that moves the elements, making manual focus more of an emulation than a direct movement of the elements. Some lenses pull this off better than others, and the Sigma 10-18mm DN is one of them. There is good weight/damping on the focus ring, and no visible steps during focus changes. I didn’t notice any focus lag either; the action on the ring and the movement of focus seemed directly linked. I will note that the lens will automatically alert the body to magnify the image when you are manually focusing, which is a big help in visually confirming focus. The focus weight is a little lighter than what I like, but not bad.

There is about 10mm between the focus ring and the beginning of the flared section that leads to the zoom ring. I appreciate some space there, as that was one of my complaints about the Sony 10-20mm; there was almost no room between the two rings on that lens, and it was easy to inadvertently move the wrong ring. There’s a very definite difference between two rings and position on the Sigma, though there is a different problem. At the fully retracted position (there is a slight external zoom action), the lens hood fits so tightly against the zoom ring that there isn’t a lot of space for your thumb to fit on the narrow ring. If you happen to have longer fingernails, you might actually find zooming a bit of a challenge.

The zoom action itself is very smooth. This is a “reverse zoom” in terms of the retraction; the inner barrel is fully retracted at 18mm and extends the furthest at 10mm, though the barrel extension is only about 10mm.

Sigma is experimenting with a new lens hood design for this lens. Rather than bayoneting into place, it is actually just a push on design. You still need to line up the markings on the hood and the barrel, but then you just push the lens hood into place rather than rotate it. A spring/lever mechanism holds the hood locked into place. You can release it by just doing a slight rotation to the left.

The primary “pro” of this design is it allows them to the make the lens hood a little thinner as there doesn’t need to be room in the hood design for the bayonet action. Sigma touts the fact that while the filter size of the 10-18mm is 12mm larger than the 18-50mm (67 vs 55mm), the diameter of the lens hood is only 3.8mm larger.

If you want to reverse the hood for storage, you now line up an arrow on the lens hood with the previous mark on the lens barrel and push it forward. Removing it simply requires a similar slight rotation to the left. As per usual, Sigma’s lens hoods are just a little bit nicer than the competition, including some soft-touch materials, texture variations, and lens information imprinted on them.

The 10-80mm DN has two different minimum focusing distances for the wide and telephoto ends of the zoom range. At 10mm you can focus as closely as 11.6cm (4.6″) and can get as high as a 0.25x magnification…though you have to be pretty much right on top of your subject to get it.

At 18mm that disance extends to 19.1cm (4.6″) and the magnification drops to just 0.14x…though shots at 18mm are a whole lot easier to get!

Get close enough and you can produce some creative shots like this.

The aperture iris is electromagnetic and controlled from within the camera (no aperture ring). It has seven rounded aperture blades that do a fairly good job of retaining a circular shape even with the lens stopped down, though frankly you won’t have a lot of opportunity to shoot shallow depth of field shots with a wide angle lens like this.

Stopping down will produce a decent (but not exceptional) 14 bladed sunstar effect.

There is no optical stabilization on the lens, unfortunately, which is the one advantage I can point to for the Canon RF-S 10-18mm. I happened to test on a camera that had in body image stabilization, so I didn’t miss it, but many of Canon’s smaller APS-C cameras don’t have IBIS.

On other platforms the Sigma is a rather plain lens in terms of features and build. Because of so little competition on Canon, however, it feels next level in terms of build and handling. It’s a nicely made little lens that follows a familiar, well-executed Sigma formula.

Autofocus and Video

Sigma continues to utilize a stepping focus motor (STM) in these smaller lenses as the elements are smaller and lighter than lenses and don’t require the higher torque that some of their large aperture full frame or sports oriented lenses. Autofocus is something that Canon does very, very well, and it is clear to me that Sigma has received access to the focus protocols and algorithms, as the 10-18mm RF definitely handles like a first party lens.

The STM motor provides fast, quiet, and accurate autofocus. Eye detection works fine, and I was able to grab some action photos without difficulty.

AF had no problem with a group photo of some friends and I on the golf course, though, to be fair, it isn’t difficult to have a LOT in focus with a wide angle lens like this.

Autofocus speed was excellent, near instantaneous both indoors and outdoors, and utterly reliable and accurate. My focus tests showed extremely rapid transitions from close to distant subjects. Focus breathing is extremely low, so this helps the transitions feel very smooth and rapid.

This is also a huge factor in video recording, as focus pulls are not only quick and confident, but the extremely low focus breathing helps them to feel very seamless and cinematic. No steps, no pulses, but just clean, smooth transitions that are nicely cinematic.

My “hand test” (where I block the view of my face with my hand and then move the hand to allow focus to pop back to the eye) also went well. Focus transitioned confidently from my hand to my test and vice versa.

The lens is not parfocal, however, and I did notice that there were moments of defocus before the lens refocused while zooming and do video recording. I also noticed a bit of warping as I began to move the from the wide end towards the telephoto end.

But overall this is a really solid autofocus system that delivers a fantastic performance on Canon.

Sigma 10-18mm RF Optical Performance

The Sigma 10-18mm RF sports a relatively complex optical formula for such a small lens. There are 13 elements in 10 groups, and that includes number of exotic elements like 4 aspherical elements (including a large GM aspherical concave lens as the front element), 3 FLD elements, and one SLD element. The MTF chart and comparison shows a significant improvement over the older Sigma 10-20mm F3.5 that the was equivalent lens for DSLRs. The MTF chart shows a very strong center and midframe at both ends of the zoom range with minimal falloff in the corners at 10mm. There’s a stronger falloff at 18mm in the corners.

In this section I will be reusing some of my results from the 40MP Fuji X-Trans sensor. It is higher resolution than anything Canon currently makes (current resolution points are between 24 – 33MP. Fuji’s images are also harder to sharpen than Canon, so you will have no problem getting beautiful results on Canon bodies. You can expect sharpness results to look better on Canon. I don’t currently own a Canon RF APS-C camera, so I’m doing this test on my the APS-C mode of my EOS R5, which is only 17MP. That’s fine for showing real world images as I’ve done in this review, but not really for evaluating the limits of the performance.

It has no problem producing beautiful images.

For those that are interested, Canon is not going to allow you to even experiment with this lens for full frame. Only the 1.6x crop option is available; all other options are greyed out.

I will redo the vignette and distortion tests, however, as the vignette amount does change from one mount to another. Here’s a look at the before and after of manual corrections of both at 10mm:

I didn’t expect to see any real difference in distortion (it’s the same optical formula), but I’ve noticed a trend with lenses first developed for Sony that then move other mounts that the vignette tends to be heavier.

At 10mm there is a significant amount of barrel distortion. I settled on a +23 to correct it, though there is definitely some “mustache” shape to the distortion pattern where correcting the barrel distortion across the majority of the frame tends to create some pincushion distortion in the corners. The standard profile does a cleaner job of correcting the distortion. On Sony I needed a +53 to correct the vignette, but on Fuji and on Canon I had to max out the slider (+100). That’s close to two stops higher.

So how about the “telephoto” end of the zoom range?

The distortion flips to pincushion style at 18mm but it was very linear and easy to cleanly correct for (I used a -4 on Canon). Vignette was a little lighter but still required a +74 to correct (+36 more than on Sony). Sigma gets profile support on Canon in camera for everything but distortion for some reason. There is already a correction profile available for Lightroom/ACR that will also clean things up nicely for RAW files. So, not a flawless performance, but nothing critical here, either.

How about chromatic aberrations?

I saw very little longitudinal chromatic aberrations before and after the plane of focus. You can see very little fringing in all of the shiny metal and crystal bits on this decorative reindeer.

Lateral Chromatic Aberrations usually show up along the edges of the frame as fringing on either side of high contrast areas, but that doesn’t seem to be an issue here. Winter is the most obvious time to see issues with LaCA due to all the bare branches, but I don’t see any issues here even with corrections turned off.

That’s good news, as you are far more likely to see lateral CA on a wide angle zoom in real world images than you are to see longitudinal CA.

So how about resolution and contrast? All chart tests done with a the X-H2 (40MP) using a tripod and a two second delay. Here’s a look at my test chart:

And here are the crops (at roughly 200% magnification) from the center, mid-frame, and extreme corner shot at 10mm and at F2.8:

In the center of the frame we can see that the Sigma 10-18X has no problem. It still looks fantastic. Mid-frame is a little murkier, though the corner look relatively good. Stop down to F4 and the mid-frame and the corners take a nice leap forwards:

There’s a bit more on tap at F5.6, so that means that real world landscape images at 10mm will look very nice all across the frame.

Diffraction comes early on pixel dense cameras like the X-H2, so I actually found F8 to have very slightly less contrast compared with F5.6. After F8 things go downhill fast as diffraction robs away contrast and acuity. By F22 (minimum aperture) the image looks very soft.

$19-Diffraction$

I would recommend sticking with F5.8-F8 for landscape work on a high resolution camera to get your best results.

I slightly preferred the overall image quality at 12mm. The center is about the same as 10mm, but the results in the midframe and corners are clearly better.

Real world 12mm images look great, though the absolute edges aren’t pin sharp on 40MP.

14mm is very similar to 12mm in contrast, though I didn’t feel like it resolved some of the fine lines quite as well. Take a look at the number 2 and the area around it on the right as compared to the left (12mm).

There’s a clear improvement at F4, however, and landscape apertures look pretty great in real world images.

16mm is mostly similar to 14mm with perhaps a little better detail and contrast…particularly along the edges of the frame.

I did note a mild regression at 18mm in my Sony E-mount review, but I’m seeing it less here on Fuji. As I compare 16mm and 18mm across the frame I see some give and take. Some areas favor 16mm, others favor 18mm. The performance is mostly similar between the two focal lengths, making the overall sharpness and contrast very consistent across this zoom range.

I chose this crop because it illustrates the challenge well – there is very little to distinguish between the two focal lengths…even side by side and magnified to 200%!

As before, you can see some improved contrast a bit more detail by stopping the lens down. I found a more significant different at F5.6 than at F4. By F5.6 the improved contrast is very noticeable.

The two ends of the zoom range are the most important, as you’ll often be in situations where you want to go as wide as possible, while the 18mm end will give both the maximum reach but also will be the go to for up close work…like in the shot of these mushrooms.

You can see from the crop that while the amount of detail at F2.8 on a high resolution sensor isn’t pin-sharp, it is sharp enough to work in most situations.

You are also most likely to get visible bokeh at 18mm. This image allows us to look at both the sharpness of the subject and the bokeh beyond.

At a pixel level I can see that contrast doesn’t “wow” me, but at every other viewing magnification the image looks great. There’s no “bleeding” around the edges of the leaves due to low contrast, and the quality of the bokeh is pretty nice. Wide angle lenses are almost never going to give you amazing bokeh (that’s just not their strength), but I would be happy in getting images like the one above.

Here’s another bokeh shot of a field of frost covered sweet fern. You can see a bit of busyness in the transition zone as things move out of focus (some outlining), but beyond that the bokeh gets fairly soft and creamy.

Flare resistance was fairly good in most situations, with good contrast and only minor issues with ghosting. That performance was pretty similar to what I saw on Sony. Here’s a fresh shot that shows good flare resistance.

I did see some “flashing” with the sun right out of the frame when shooting video, though I did find it fairly artistic and not distracting. Again, that’s a subjective evaluation, and I would recommend watching the video review to draw more conclusions for yourself. Here’s a few screenshots to show the effect.

Overall my feelings were very positive about the flare resistance.

Canon has nice color science, and that means that it isn’t difficult to get images with beautiful color when using the 10-18mm RF on a Canon body.

Here’s another shot that shows nice, rich levels of color saturation.

The Sigma 10-18X is able to navigate the bump to 40MP on Fuji better than most zoom lenses I have tested on the sensor, and that means that Canon RF shooters at lower resolution levels (and easier sensors to sharpen) should be pretty satisfied with the amount of detail you can achieve with this lens.

That Fuji sensor is a monster for making lenses look softer at a pixel level, but that’s not on Sigma. Compared to other lenses, it actually holds up well. Here’s the Tamron 11-20mm F2.8 RXD (another lens that looked very good on Sony but softer on Fuji), and you can see that the Sigma definitely better.

All things considered, I feel like there is a lot of optical performance here for such a small package. You can see many more beautiful images by visiting the image gallery here.

Conclusion

I’ve been recommending the Sigma 10-18mm F2.8 DC DN to a lot of people looking for a good APS-C wide angle zoom on multiple platforms, so I’m not surprised that it performs well on Canon RF mount. Autofocus was fantastic, image quality looks great, and the lens remains very impressive despite its small size. It’s a great match for smaller APS-C bodies in size, and the performance is strong enough to delight owners.

There really isn’t much in terms of competition, so it’s an easy lens to recommend on RF. It is actually the premium option, and while it is isn’t cheap at $659 USD, neither is it ridiculously expensive.

It’s great to see Canon’s RF mount starting to open to these third party offerings, and very quickly we will see the amount of lenses available for RF-S (APS-C) tripled due to Canon’s move to open the protocols. This gives Canon shooters a seriously good little option, and the Sigma 10-18mm 2.8 DN is what I would be buying if I were in the market right now.

Pros:

Fantastic job porting to Canon
Extremely compact and lightweight
Nicely made with a weather sealing gasket
Useful focal range with constant F2.8 aperture
Great autofocus performance
Good video AF performance
Almost non-existent focus breathing
Good sharpness across zoom range
Nice colors
Good flare resistance
Nicer build and handling than RF lenses

Cons:

No optical stabilizer
Fairly strong and complex barrel distortion at 10mm
Twice as expensive as Canon’s own offering

__________________________________________________________________________

GEAR USED:

Purchase the Sigma 10-18mm RF @ B&H Photo | Adorama | Amazon | Camera Canada | Amazon Canada | Amazon UK | Amazon Germany

Purchase the Sigma 18-50mm RF @ B&H Photo | Adorama | Amazon | Camera Canada | Amazon Canada | Amazon UK | Amazon Germany

_______________________________________________________________

Purchase the Canon EOS R50 @ Camera Canada | B&H Photo | Adorama | Amazon | Amazon Canada | Amazon UK | Amazon Germany

___________________________________________________________________

Purchase a Canon EOS R7 @ B&H Photo | Amazon | Camera Canada | Amazon Canada | Amazon UK | Amazon Germany | Ebay

————————————————————————–

Want to support this channel? Use these affiliate links to shop at: B&H Photo | Amazon | Adorama | Camera Canada | Amazon Canada | Amazon UK | Ebay | Make a donation via Paypal

Buy DA Merchandise https://bit.ly/TWIMerch

Keywords: Sigma 10-18 DN Review, Sigma 10-18mm Review, Sigma 10-18mm F2.8, Sigma 10-18mm F2.8 DN, Sigma 18-50mm F2.8 DN Review, DC, DN, F2.8, Canon R50, R100, Canon R7, RF-Mount, 33MP, Review, Hands On, Dustin Abbott, Real World, Comparison, Sharpness, Bokeh, Flare Resistance, Autofocus, Image Quality, Sample Images, Video, Portrait, Photography, let the light in, #letthelightin, DA, Weather Sealing, #SIGMA, #SIGMA1018mmContemporary, #SIGMAContemporary, #sigmadcdn

DISCLAIMER: This article and description contains affiliate links, which means that if you click on one of the product links, I’ll receive a small commission. As an Amazon Associate I earn from qualifying purchases.

Sigma 18-50mm F2.8 DN RF Review

Dustin Abbott

August 5th, 2024

Earlier this year I was doing my review of the Canon EOS R50 compact APS-C mirrorless camera. While I liked many things about the camera itself, I couldn’t help lament the state of the lens options for Canon’s RF-S mount. At the time of the review (two years since the release of the EOS R7, the first of Canon’s RF mount APS-C cameras), this was the sum total of the available lenses.

Yuck. I couldn’t imagine a less exciting lineup of lenses. The fastest maximum aperture in the bunch was F3.5, and that lens is F4 and smaller before you make it to 30mm. Canon clearly knew they had a problem, for between the time that I filmed my review and the time I released it, they announced that certain Sigma (and later Tamron) lenses would become available for RF-S (the APS-C version of Canon RF). Now, to be clear, this is only for APS-C lenses, but for now it seems like Canon is going to let third parties solve their APS-C lens problem. This is great news for consumers, however, because it means that lenses like the Sigma 18-50mm F2.8 DC DN are now available for Canon RF. I love the Sigma 18-50mm, having first reviewed it when it released on Sony back in 2021 and then last year when it became available on Fuji X-mount. I found it useful enough on Fuji that I purchased one myself, and have happily used it since. So how well has the 18-50mm survived the transition to Canon. You can find out my thoughts in the video review below…or read on.

Sigma RF 18-50mm F2.8 DN RF Review: The Best APS-C Option on Canon?

__________________________________________________________________________________________________

Thanks to Gentec (Sigma’s Canadian Distributor), for sending me a review loaner of this lens. As always, this is a completely independent review. All opinions and conclusions are my own. *The tests and most of the photos that I share as a part of my review cycle have been done with the 45MP Canon EOS R5, which I reviewed here.

__________________________________________________________________________________________________

The good news is that this is a great porting of the lens. It’s pretty clear here that this is no “reverse engineering” but rather a direct license of focus algorithms, as this is not only the best focus experience of the now three platforms that I’ve tested the lens on, but also one of the better focus experiences I’ve had on Canon in general amongst lenses priced under $1000.

This review of the 18-50mm RF is not a whole new review, but rather an update on how the 18-50mm RF translates to Canon RF. I’ve already tested the image quality at both a 24MP (Sony in 2021) and 40MP (Fuji in 2023)) level, so that covers the full gambit (and more) of what’s available on RF bodies. There are no optical surprises here, but I’m always curious to see how the lens changes in terms of its dimensions, but, most importantly, how well it autofocuses on a platform that it wasn’t originally designed for.

The 18-50mm RF is one of six lenses released by Sigma for Canon RF, and those six lenses represent all of the APS-C mirrorless lenses they’ve released over the past three years. You can see my review of the original releases on Sony here.

Sigma’s DC DN lenses have all fallen under the umbrella of their Contemporary lineup, and while Sigma has proven willing to experiment with new features and design elements within the ART and Sport lineups, the Contemporary lenses have all stuck to a fairly rigid design formula. That continues to be the case here, so this little zoom mostly looks and handles pretty similarly to other lenses in the lineup.

There’s nothing new here on the RF mount, but the lens is more of a standout on Canon due to having essentially zero quality competition. The 18-50mm RF is a genuine treat as an addition here. Why? Here’s a few reasons:

Has at least a weather sealing gasket
Better build quality than RF-S lenses
Includes a lens hood
Constant F2.8 aperture
Good up close performance
Great autofocus on RF

In essence, the poor competition makes this lens a star, though frankly I still found it one of the more compelling options on these other platforms as well.

The crop factor on Canon is different than Sony or Fuji, so the zoom range works a little different. Fuji/Sony have a crop factor of 1.5x, which means that the lens goes from a full frame equivalent of 27-75mm. Canon’s APS-C crop is 1.6x, and so that changes the effective focal range to 29-80mm. You’ll miss the extra bit of width at 18mm:

…but appreciate the extra bit of reach on the telephoto end.

Sigma 18-50mm RF-Mount Build and Handling

There’s really only one significant change to the 18-50mm on Canon, and that is that the lens mount portion of the lens has to be flared out to accommodate the much larger diameter of the RF mount. You can see that difference when compared to the Fuji X-mount version on the right.

As this is now the widest portion of the lens, the lens diameter changes from 61.6mm (2.4″) to about 68mm by my measurement. I found the RF version to be just a hair shorter than the X-mount version, measuring more like 75mm than the 76.8mm of the X-mount (3″). That extra bit of girth near the lens mount also adds a tiny bit of weight, with the RF version weighing 294g (10.37oz) on my scale, which is about 10g heavier. I haven’t seen the dimensions and weight for the RF mount published by Sigma, so I’m using my own measurements.

Other than these minor physical changes to the RF version, the build is otherwise identical to either the E-mount of X-mount versions.

The 18-50mm F2.8 is a mixture of metals and “thermal composites” (high grade engineered plastics) in construction, and the construction feels quality in the hand. It is built around a metal mount.

The overall build quality just feels much higher than any of the Canon RF-S lenses that I’ve tested so far. Some of them even have plastic lens mounts. This feels like a quality lens.

There is a weather sealing gasket at the lens mount (thicker here on the RF mount than on previous versions), but, like other Contemporary lenses, there are no internal seal points.

The only thing on the barrel is the focus and zoom rings. The closest to the lens mount is is the focus ring, which is fairly narrow (10mm), ribbed, and moves smoothly. It is has light damping and doesn’t have a lot of feel, and is actually slightly compromised here by the thicker lens mount flare, which clearly wasn’t part of the original design. It crowds the focus ring a bit, and I found my thumb slightly pushed off the ring.

The second ring is the wider (20mm) of the two, and it is the zoom ring. The zoom action is very smooth, with a single inner barrel that extends about 25mm. The inner barrel is well engineered and without any wobble.

Also included is a fairly shallow petal-shaped lens hood. It has a ribbed texture section to help you grip it for removal and will reverse for storage.

There are seven rounded aperture blades inside, and these do a reasonably good job of maintaining a circular shape with the lens stopped down.

A look at the front of the lens shows a 55mm front filter thread along with a significant amount of glass inside; this is the huge advantage over the Canon kits lenses with a much smaller maximum aperture value.

Like many recent zoom lenses, there is a separate minimum focus distance for wide angle (18mm) and telephoto (50mm), with interim focal lengths being on a sliding scale between them. The highest magnification (as per usual) is at the 18mm end, where you can focus as close as 121mm. Only one problem – when the lens is mounted on the camera, the distance from the sensor to the end of the lens (without the lens hood) is 95mm, leaving only 26mm of working distance between you and your subject. Here’s what that looks like:

It is basically unusable, as even without the lens hood it is almost impossible for the lens to not be shading your subject. If you add the lens hood, you actually exceed that minimum focus distance. So, in theory, you can achieve a maximum magnification of nearly 0.36x, but you are unlikely to ever achieve that in the field. Here’s what that looks like if you were able to achieve it:

You’ll see a lot of field curvature and a very small sweet spot of focus/sharpness. My advice: back up a little and get much nicer results with more like magnification in the high 20s instead.

The telephoto end doesn’t market as well, but is much more useful. You can focus as closely 30cm there, but the resulting magnification of 0.20x is much more easily attainable.

The wide open sharpness and contrast there is not off the charts, but is good enough to produce nice real-world results like this:

There is no optical stabilization on the lens, unfortunately. I happened to test on a camera that had in body image stabilization, so I didn’t miss it, but many of Canon’s smaller APS-C cameras don’t have IBIS.

As noted, on other platforms the Sigma is a rather plain lens in terms of features and build. Because of so little competition on Canon, however, it feels next level in terms of build and handling. It’s a nicely made little lens that follows a familiar, well-executed Sigma formula.

Autofocus and Video

Sigma continues to utilize a stepping focus motor (STM) in these smaller lenses as the elements are smaller and lighter than lenses and don’t require the higher torque that some of their large aperture full frame or sports oriented lenses. Autofocus is something that Canon does very, very well, and it is clear to me that Sigma has received access to the focus protocols and algorithms, as the 18-50mm RF definitely handles like a first party lens.

The STM motor provides fast, quiet, and accurate autofocus. Eye detection works well, and I was able to get nice “people” photos with quick and easy autofocus.

Autofocus speed was excellent, near instantaneous both indoors and outdoors, and utterly reliable and accurate.

I got well focused results when I took some photos of Nala (working hard).

Even without a trackable subject in frame I was able to get good focus. Here’s some foliage in the evening light.

I’ve got zero complaints about the autofocus for stills; I got a lot of well focused results without any drama. This is a seamless transition to Canon RF.

On the video front my findings were also excellent. My autofocus pulls tests were smooth and confident, with none of the settling or pulsing that I saw on Fuji.

On a positive note focus breathing is fairly low.

My “hand test” (where I block the view of my face with my hand and then move the hand to allow focus to pop back to the eye) also went well. Focus transitioned confidently from my hand to my test and vice versa.

Unlike on Fuji, I also saw smooth focus results when zooming in and out while recording video. There was none of the shattering effect and focus readjustments, which shows again how far behind Fuji’s autofocus is.

This is a great lens all around when it comes to autofocus; a fantastic performance on Canon.

Sigma 18-50X Optical Performance

Sigma has given the 18-50mm F2.8 DN an optical design of 13 elements in 10 groups, and this includes 1 SLD element and 3 Aspherical elements. The MTF charts show a good performance in the center of the frame, fairly strong mid-frame results, and a dip into the corners.

In this section I will be reusing my results from the 40MP Fuji X-Trans sensor. It is higher resolution than anything Canon currently makes (current resolution points are between 24 – 33MP. Fuji’s images are also harder to sharpen than Canon, so you will have no problem getting beautiful results on Canon bodies. It has no problem producing beautiful images.

We’ll start by taking a look at distortion and vignette. Distortion is essentially identical to what I saw on Sony, with some strong barrel distortion at 18mm.

While Sigma lenses do receive good correction profile support on Canon, I turn off those corrections and do a manual correction so that I can see what’s being compensated for. I used a +24 to correct for the barrel distortion, but you can see that there is a mild mustache pattern left over.

Expect less vignette on Canon than what I saw on Fuji, with results more in line with what I saw on Sony. I had to use a +52 to correction vignette at 18mm on Sony. On Fuji? A whopping +92! The good news is that the profile correction does a good job with both distortion and vignette. This F2.8 image has received no addition correction, but you can see that there is no visible shading on the snow.

As you progress through the zoom range the distortion starts to invert and eventually becomes a pincushion style distortion that is more strongly pronounced at 50mm.

I needed to dial in a -11 to correct the pincushion distortion, though it was nice and linear and cleaned up well. Vignette remains heavy, however, requiring a +88 to correction (again, about +40 more than on Sony).

There are longitudinal chromatic aberrations (LoCA), but they aren’t particularly strong. I mostly see them in the form of a blue-green fringing after the plane of focus:

You will see a light fringing around specular highlights as well:

Likewise there is a bit of lateral chromatic aberrations (LaCA) that show up near the edges of the frame. You can see them in the transitions from black to white.

The LaCA is easy to clear up by clicking the “Remove Chromatic Aberrations” button in software or in camera for JPEGs or video.

Chromatic aberrations are a little more visible at a pixel level on high resolution cameras for the simple reason that the fringing occupies more pixels and gets more highly magnified at a pixel level, but they aren’t any more obvious when viewing the image as a whole.

So how about the main event? High resolution cameras also expose any lack of contrast or a lens’ inability to resolve fine details because those flaws are more highly magnified. Here’s a look at our test chart.

Here is a closer look at roughly 180% crops from the center, mid-frame, and lower right corner at 18mm, F2.8:

The center looks great, the mid-frame acceptable sharp, but the corner looks quite low contrast. Stopping down to F4 provides a little more contrast and detail, and F5.6 looks better still, but the corners never get exceptionally sharp.

Real world images look great in the center and mid-frame, but the corners don’t look as crisp.

F8 is a lateral move (not really any sharper than F5.6) due to diffraction starting to soften the image (diffraction comes very early on a high resolution body). After F8 the image will show more obvious softening, and by the minimum aperture of F22 the image looks very soft in my tests.

$27-Diffraction$

At 24mm the image shows improvement across the frame, but in particularly in the corners, which are radically sharper.

It’s easier to get sharp landscape images at 24mm due to the more consistent sharpness profile.

28mm is largely the same as 24mm, with a very consistent sharpness profile across the frame.

At 35mm there is a dip in contrast relative to the high water mark of 24-30mm.

Sharpness and contrast do improve if you stop the lens down, however, and by landscape apertures like F5.6 the results look good.

Things rebound a bit at 50mm, and, if they aren’t the peak of sharpness like 24mm, the results look quite good even at F2.8.

When stopped down the lens can produce very nice landscape images with strong contrast.

Here’s another 50mm that looks nice at F2.8, with a nice depth of field that highlights the subject. Contrast at a pixel level isn’t incredibly high, but viewed normally the image looks great.

The quality of the bokeh is mostly good. Zoom lenses like this rarely create the most creamy bokeh, and the Sigma 18-50mm is no exception. At the same time, however, I felt like images looked pretty good. The bokeh here is actually really nice, particularly in the top half of the image.

This shot shows a bit of outlining in some of the defocused textures, which does detract a bit from the bokeh.

This shot is somewhere in between, but overall I feel like it looks pretty nice.

One final example at a little further distance. In some ways this image is a little more impressive, as background isn’t quite as out of focus. The 18-50mm avoids any nervous looking textures in the transition zones, and there is a reasonable amount of 3D pop on the subject.

The look of sunbursts is nice but nothing special. The blades don’t have the distinction of straight blades, but it is nice enough to add a little extra touch to images.

Flare resistance was also fairly good, with only minimal ghosting artifacts showing up in real world images.

Contrast remained strong, however with only a bit of a flare pattern showing in some images.

I was able to test for astrophotography during my review of the E-mount version of the lens, and found a bit of coma smear in the corners along with a bit of generalized fringing on the brightest points of light.

I was able to get nice looking Milky Way images with a lot of asteroid action, too.

Before closing this section, I think it is important to put the Sigma’s overall performance into perspective. The Tamron 17-70mm F2.8 is much larger, and yet it doesn’t really hold up better on the Fuji 40MP sensor. When I compared the two on the wide end, the Sigma clearly had the sharper center of the frame along with a slightly better mid-frame, though the Tamron showed a little better in the corner.

On the telephoto end there is some give and take, with the Sigma looking slightly sharper in the center and the Tamron looking a bit sharper in the corner. The Sigma’s mid-frame is clearly better, however, with more contrast and detail visible.

The fact that the Sigma delivers slightly more sharpness on the 40MP despite being so compact is very impressive. Here’s a gallery of a few more images taken on Canon RF.

Conclusion

I was very encouraged by what I saw from the Sigma 18-50mm F2.8 DC DN on Canon RF mount. It feels like a seamless port over other than the slightly odd lens shape due to the much larger RF mount. Autofocus was fantastic, image quality looks great, and the lens remains very impressive despite its small size.

This is a great little general purpose/travel lens, as it affords enough flexibility in the focal length to shoot many scenes, and the constant maximum aperture of F2.8 gives you more flexibility in different lighting situations.

It’s great to see Canon’s RF mount starting to open to these third party offerings, and very quickly we will see the amount of lenses available for RF-S (APS-C) tripled due to Canon’s move to open the protocols. This lens isn’t cheap, per se, at $599 USD, but I’d rather spend a few hundred extra bucks to buy this lens over the current Canon options any day of the week.

Pros:

Fantastic job porting to Canon
Extremely compact and lightweight
Nicely made with a weather sealing gasket
Useful focal range with constant F2.8 aperture
Great autofocus performance
Good video AF performance
Minimal focus breathing
Good sharpness across zoom range
Nice bokeh in most situations
Fairly good coma performance
Nice build and handling than RF lenses

Cons:

No optical stabilizer
Fairly strong barrel distortion at 18mm
Some ghosting in certain lighting conditions
Flare for RF lens mount slightly interferes with MF ring

__________________________________________________________________________

GEAR USED:

Purchase the Sigma 18-50mm RF @ B&H Photo | Adorama | Amazon | Camera Canada | Amazon Canada | Amazon UK | Amazon Germany

_______________________________________________________________

Purchase the Canon EOS R50 @ Camera Canada | B&H Photo | Adorama | Amazon | Amazon Canada | Amazon UK | Amazon Germany

___________________________________________________________________

Purchase a Canon EOS R7 @ B&H Photo | Amazon | Camera Canada | Amazon Canada | Amazon UK | Amazon Germany | Ebay

————————————————————————–

Want to support this channel? Use these affiliate links to shop at: B&H Photo | Amazon | Adorama | Camera Canada | Amazon Canada | Amazon UK | Ebay | Make a donation via Paypal

Buy DA Merchandise https://bit.ly/TWIMerch

Keywords: Sigma 18-50 DN Review, Sigma 18-50mm Review, Sigma 18-50mm F2.8, Sigma 18-50mm F2.8 DN, Sigma 18-50mm F2.8 DN Review, DC, DN, F2.8, Canon R50, R100, Canon R7, RF-Mount, 33MP, Review, Hands On, Dustin Abbott, Real World, Comparison, Sharpness, Bokeh, Flare Resistance, Autofocus, Image Quality, Sample Images, Video, Portrait, Photography, let the light in, #letthelightin, DA, Weather Sealing, #SIGMA, #SIGMA1850mmContemporary, #SIGMAContemporary, #sigmadcdn

DISCLAIMER: This article and description contains affiliate links, which means that if you click on one of the product links, I’ll receive a small commission. As an Amazon Associate I earn from qualifying purchases.

Sigma 18-50mm F2.8 for X-Mount Gallery

Dustin Abbott

December 12th, 2023

I received Sigma’s first APS-C specific zoom lens for mirrorless cameras (the Sigma 18-50mm F2.8 DC DN) back in October of 2021. At that stage the Fujifilm X-mount was closed to most third party development, so the lens was released only on Sony E-mount and Leica L-mount. That started to change in 2022, so Sigma has been slowly rereleasing some of its DN (Sigma’s designation for mirrorless designs) lenses on Fuji’s X-mount. I’ve considered this move worthy of a second look at many of these lenses because of two reasons. The first is that the competition is quite different on Fuji than it is on Sony, with more (and more premium) options as Fuji has been solely focused on APS-C rather than investing most of its energy on full frame. The second is that Fuji has the industries highest resolution APS-C sensor, the 40MP X-Trans monster found in cameras like the X-H2 that I’m doing this review on. That creates a very different optical challenge for lenses than the 24MP Sony sensor I did that review on. How does the Sigma 18-50X (as we’ll call it here) handle these new challenges? You can find my thoughts in the video review below or in my text review of the lens.

Thanks to Gentec (Sigma’ distributer in Canada) for sending me a review loaner of this lens. As always, this is a completely independent review. *The tests and most of the photos that I share as a part of my review cycle have been done on the 40MP Fujifilm X-H2 that I reviewed here.

__________________________________________________________________________________________________

This review of the 18-50X is not a whole new review, but rather an update on how it compares to the competition on Fuji along with reviews of the autofocus and sensor performance on this new platform.

The 18-50x is one of six lenses released by Sigma for APS-C mirrorless now, and all of these lenses are now available on Fuji. You can click on any of the list to see my reviews. Here’s a look at the DC (APS-C) DN (mirrorless) lineup thus far.

Sigma’s DC DN lenses have all fallen under the umbrella of their Contemporary lineup, and while Sigma has proven willing to experiment with new features and design elements within the ART and Sport lineups, the Contemporary lenses have all stuck to a fairly rigid design formula. That continues to be the case here, so this little zoom mostly looks and handles pretty similarly to other lenses in the lineup.

On Fuji there are three primary competitors: the Tamron 17-70mm F2.8 VC RXD (the lone shared competitor from Sony), the Fujifilm XF 16-55mm F2.8 R LM, and the “kit lens” Fujifilm XF 18-55mm F2.8-4 LM OIS lens. The weaknesses of the 18-50X compared to this field are 1) a smaller zoom range than any of the competing lenses 2) No image stabilization (the Tamron and Fuji 18-55mm have stabilization and 3) Fewer features than some competitors. The Sigma strengths are 1) Cheapest price 2) Smallest size and lowest weight 3) Higher magnification than any competing lenses. Here’s a breakdown of the specs by comparison:

We’ll explore those differences a little further in the build and handling section below.

This is an extremely useful range, allowing you to go from moderately wide angle (27mm full frame equivalent) to short telephoto (75mm equivalent). Here’s a look at a scene from the various marked positions on the zoom range (18, 24, 38, 35, and 50mm):

The Sigma 10-18mm F2.8 DC DN carries a price tag of $599 USD. Should this lens jump to the top of your list when you are looking for a wide angle zoom lens for your camera? Here’s the original review for more information.

Images of the Sigma 18-50mm X-Mount

Images Taken with the Sigma 18-50mm X-mount

__________________________________________________________________________

GEAR USED:

Purchase the Sigma 18-50mm F2.8 DN @ B&H Photo | Adorama | Amazon | Camera Canada | Amazon Canada | Amazon UK | Amazon Germany

————————————————————————-

Purchase the Sigma 10-18mm F2.8 DN @ B&H Photo | Adorama | Amazon | Camera Canada | Amazon Canada | Amazon UK | Amazon Germany

——————————————————————–

Purchase the Fujifilm X-H2 @ B&H Photo | Adorama | Amazon | Camera Canada | Amazon Canada | Amazon UK | Amazon Germany

Purchase the Fujifilm X-T5 @ B&H Photo | Amazon | Camera Canada | Amazon Canada | Amazon UK | Find it Used at KEH

Purchase the Fujifilm X-S20 @ B&H Photo | Adorama | Amazon | Camera Canada | Amazon Canada | Amazon UK | Amazon Germany | Ebay

————————————————————————–

Want to support this channel? Use these affiliate links to shop at: B&H Photo | Amazon | Adorama | Camera Canada | Amazon Canada | Amazon UK | Ebay | Make a donation via Paypal

Buy DA Merchandise https://bit.ly/TWIMerch

Keywords: Sigma 18-50 DN Review, Sigma 18-50mm Review, Sigma 18-50mm F2.8, Sigma 18-50mm F2.8 DN, Sigma 18-50mm F2.8 DN Review, DC, DN, F2.8, Fujifilm X-H2, X-Mount, 40MP, Review, Hands On, Dustin Abbott, Real World, Comparison, Sharpness, Bokeh, Flare Resistance, Autofocus, Image Quality, Sample Images, Video, Portrait, Photography, let the light in, #letthelightin, DA, Weather Sealing, #SIGMA, #SIGMA1850mmContemporary, #SIGMAContemporary, #SIGMADCDN

DISCLAIMER: This article and description contains affiliate links, which means that if you click on one of the product links, I’ll receive a small commission. As an Amazon Associate I earn from qualifying purchases.

Sigma 18-50mm F2.8 DN X-Mount Review (40MP)

Dustin Abbott

December 2nd, 2023

I received Sigma’s first APS-C specific zoom lens for mirrorless cameras (the Sigma 18-50mm F2.8 DC DN) back in October of 2021. At that stage the Fujifilm X-mount was closed to most third party development, so the lens was released only on Sony E-mount and Leica L-mount. That started to change in 2022, so Sigma has been slowly rereleasing some of its DN (Sigma’s designation for mirrorless designs) lenses on Fuji’s X-mount. I’ve considered this move worthy of a second look at many of these lenses because of two reasons. The first is that the competition is quite different on Fuji than it is on Sony, with more (and more premium) options as Fuji has been solely focused on APS-C rather than investing most of its energy on full frame. The second is that Fuji has the industries highest resolution APS-C sensor, the 40MP X-Trans monster found in cameras like the X-H2 that I’m doing this review on. That creates a very different optical challenge for lenses than the 24MP Sony sensor I did that review on. How does the Sigma 18-50X (as we’ll call it here) handle these new challenges? You can find my thoughts in the video review below…or just keep reading.

Sigma 18-50mm F2.8 DC DN X-mount Review | Better than the Competition?