We Review the Canon RF 24mm f/1.8 Macro IS STM Lens


Canon has released a series of nice primes that are reasonably priced and in a friendly size and weight. Most of these lenses also have 1:2 macro abilities. The latest one is the RF 24mm f/1.8 Macro IS STM. Let’s find out if it’s just as great as its siblings.

I’ve been using the cheaper RF primes on occasion. I wrote about my experience with the RF 16mm, RF 35mm Macro, and the RF 85mm Macro during my scouting trip in France. I also used the RF 50mm f/1.8 for a few shoots and made a complete review of the RF 85mm Macro here on Fstoppers.

Now, Canon Netherlands has provided me with the latest sibling in the series of relatively cheap RF primes. It’s the RF 24mm f/1.8 Macro IS STM, which is a great addition when it comes to focal length. Especially for landscape photography, it’s the sweet spot. It doesn’t show the typical wide angle distortions, and a polarization filter can be used without an obvious uneven polarization effect. It’s also great for full-body portraits and wedding photos.

How It Looks

As expected, the RF 24mm looks similar to all the other lenses in this series. It has the same build quality and the same finish. Also, size and weight are comparable, except for maybe the RF 85mm. The lens has a dedicated focus ring and the programmable Control Ring. There are two switches which allow the user to turn off the autofocus or the stabilizer. These are great additions, since they prevent the need to dive into the menu system to turn them off.

Just like the other lenses in this series, it will extend while focusing. The lens becomes 1.3 centimeters longer. Although it’s not that much, looking at the overall length of 7.2 centimeters, it’s substantial. If you remove the lens while the camera is still turned on, the lens tube will remain in its position. It will only retract if the camera is powered down, unless you have deactivated the retraction of the lens in the menu, that is.

The Image Quality

With the RF 24mm macro lens, you have to rely heavily on the in-camera lens correction. With the maximum aperture opening of f/1.8, the lens performs quite well in the middle. The sharpness becomes less impressive towards the edges. Vignetting is strong at that aperture also, up to four stops.

Fortunately, the quality at the edges improves significantly when stopping down to f/4 or f/5.6. The vignetting will also decrease until it’s not that noticeable anymore. If the in-camera lens corrections are activated, the vignetting will be completely correct, even at f/1.8. This will require an exposure correction at those corners of almost four stops, which might result in a slight increase in noise levels in those areas of the image.

Besides the sharpness and vignetting, the lens shows a strong barrel distortion. This is corrected also with the in-camera lens correction. It requires some stretching of the edges of the image, which may result in a decrease in image quality again. Notice how the corrected image has some quality loss, but this becomes apparent only when the image is viewed without lens correction in post-processing software.

The Image Quality in Real Life

Looking at image quality in great detail will reveal a lot of imperfections that will be almost invisible in real-life situations. That’s why I prefer to take the lens out into the field to see how the results are with normal use.

I have made some comparison shots at f/1.8 and f/4, with and without the in-camera lens correction activated. Without the lens correction, the vignetting is prominent at f/1.8, but at f/4, almost unnoticeable. With the lens correction activated, both images show no signs of vignetting anymore.

The funny thing is, on a lot of occasions, we tend to add vignetting in post-processing to capture a viewer’s attention in the middle. Of course, this is more controllable than the natural vignetting of a lens. But it shows vignetting isn’t always a bad thing.

Also, for portraits, the corners are often less important because the subject is more center frame. If a shallow depth of field is used, the lack of image sharpness is not that important anymore. If you need a larger depth of field, you will stop the lens down to f/5.6 or f/8, in which case the sharpness is significantly better.

If the RF 24mm is used on an APS-C camera like the Canon EOS R7 or EOS R10, the field of view will be reduced to a 35mm full frame equivalent. In that case, you lose the outer part of the image circle, which is the weakest part of the lens.

Using macro

The minimum focal distance of 14 centimeters allows a 1:2 magnification. This makes the RF 24mm a macro lens, which can be considered quite unique for this focal length. It allows you to shoot macro with a wide field of view, capturing small objects together with their surroundings.

Add the f/1.8 to the equation, and it will allow nice macro landscape photography with a shallow depth of field. You will have decreased sharpness at the edges, but this will be lost in the unsharp background. I think the macro function is a great addition that makes the RF 24mm Macro a lot of fun to use.

My Conclusion

Looking at the RF 24mm f/1.8 macro IS STM from a clinical perspective, it doesn’t have stellar performance. Most of its lens defects are corrected when the in-camera lens corrections are activated, but that might reduce image quality in the far corners of the frame. Especially at the f/1.8 aperture, the sharpness in those corners isn’t that great.

Since the sharpness isn’t something that is easily corrected, I don’t think this lens is usable for images that need edge-to-edge sharpness with a wide aperture, like photographing a night sky. But for normal use, the lack of sharpness will be less of an issue. Most images with a shallow depth of field only need sharpness at the point of focus, which is seldom at the edge.

Stopping down makes the image quality much better. This makes the RF 24mm a great lens for both full-body portraits and landscape photography. Add the macro capabilities to the equation, and it’s a great lens with lots of possibilities. It may not be perfect, but that can’t be expected from a relatively cheap lens. The in-camera lens corrections will solve a lot of the issues, fortunately, resulting in a nice, clean image at the end.

The STM focus system works silently and smoothly. It’s accurate and fast. The lens also has image stabilization built in that rates up to five stops. This is quite unique for a lens with such a short focal length, but very helpful. There is no focus breathing, which is great news for filmmakers.

There is only one other downside to this lens. It costs $599. Looking at the quality and at the prices I asked for the other lenses in this series, I find it to be a bit too expensive. On the other side, since this focal length is so versatile, the RF 24mm might be used quite a lot. In that case, it can justify the price, maybe.

What I Like

  • Small and lightweight
  • Image stabilization up to five stops
  • Silent and fast STM focusing system
  • Switches for the AF and IS on the lens
  • No focus breathing
  • Excellent sharpness in the image center
  • Macro capability up to 1:2 magnification

What I Don’t Like

  • Lens barrel extends while focusing
  • Strong vignetting at f/1.8 (becomes better from f/4 onward)
  • Lack of sharpness at the corners at f/1.8 (becomes better than f/5.6 onward)
  • Strong chromatic aberration at f/1.8 (becomes better from f/4 onward)
  • No dust- or weather-resistance
  • Strong barrel distortion (fixed with in-camera lens corrections)
  • Not suitable for night sky photography
  • Although reasonably cheap, it’s still a bit too expensive

Despite its downsides, I think the RF 24mm f/1.8 Macro IS STM is a great lens nonetheless. Most of the downsides won’t be noticeable or even visible during real-life use. I can recommend this lens if you can live with the price tag.





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