Review Canon 50 mm f/1.8 STM @ 5Ds


With the arrival of the Canon EF 50 mm f/1.8 STM, we met the successor to a legendary lens, which was introduced a full 25 years ago. The Canon 50 mm f/1.8 II is a popular, affordable, bright lens that serves perfectly on a camera with a full-frame sensor as a universal standard lens that can also be used in low light for all possible subjects. But since the introduction of digital cameras, there have been a great many innovations in the design of lenses. A sensor thus reflects a part of the light, while that was not the case with analog film. Lenses that are designed for digital cameras thus get extra coatings in order to ensure that any internal reflections do not decrease the contrast or create disruptive ghosts. For video, smooth and silent AF is important. And digital cameras make higher demands in terms of resolution than analog cameras do. Those were all aspects on which the Canon 50 mm f/1.8 II was beaten by 50 mm lenses from other brands. To what degree will the Canon 50 mm f/1.8 STM change that?

Canon 50 mm f/1.8 STM? Finally!


Build and auto focus

The lens design is simple and unchanged with respect to the lens design of the Canon 50 mm f/1.8 II: this lens consists of 6 lens elements in 5 groups. The shortest focal distance is just 35 cm, and the maximum magnification is 0.21x. At 160 grams, a length of less than 4 cm and a weight of 160 grams, the Canon 50 mm f/1.8 STM is a terrifically compact lens. In order to save weight, the housing is made of plastic, but the mount is fortunately metal. There is just one switch on this lens: AF/MF. You do not have built-in image stabilization available. Manual focusing with the Canon 50 mm f/1.8 STM is nicer than with the Canon 18-55 mm STM standard lens; the focusing ring is just a bit wider. Certainly for video, the STM motor is an enormous step forward relative to the AF of the slightly noisy AF of the Canon 50 mm f/1.8. The stepper motor creates pleasantly smooth auto focus during video. With a focus time of 0.3 seconds, the Canon 50 mm f/1.8 STM is not terribly fast, but for most applications, it is more than fast enough. If you half-depress the shutter, you can always overrule the AF manually, without having to make use of the AF/MF switch. Great. {insertgrid ID = 289}

Distortion and vignetting


At f/1.8 and f/2.8, the vignetting is visibly present, as you can see in the practice shot below. Even so, this degree of vignetting is actually unexpectedly good for a bright lens on a camera with a full-frame sensor. Canon cameras have an option to correct for vignetting in jpg files that are saved in the camera.

vignet Canon 50mm f/1.8 STM + Canon 5Ds @ f/1.8Canon 50 mm f/1.8 STM + Canon 5Ds @ f/1.8

If you make use of the in-camera lens correction option, or use the lens correction profiles in Lightroom or Photoshop for RAW files, then you will not have problems from visible vignetting or distortion. The shot on the left is uncorrected. 

Flare & chromatic aberration


The Canon 50 mm f/1.8 STM is—just like all modern Canon lenses—equipped with Super Spectra Coatings, which do their job very well, preventing flare and ghosts that result from internal reflections. A lens hood is not included standard, but for most backlit shots, you will still have few problems with flare. That might be in part because of the small number of lens elements in this lens and because the front lens is hidden deep inside the lens housing.

You can see from the chromatic aberration that this is an older lens design. Without correction for chromatic aberrations, you can get visible colored edges at sharp contrast transitions in the corners of the image. 


We tested the Canon 50 mm on a Canon 5Ds, which with 50 megapixels places the highest demands (aside from the Canon 5DsR) on a lens of all Canon cameras that are currently for sale. If you take pictures with this combination at f/5.6 or f/8, then you will be rewarded with very sharp images. At full aperture, the contrast is low, and even the center sharpness clearly has room for improvement. At f/4, the center sharpness is nearly twice as high as at f/1.8. You do not have to carry out an Imatest measurement for that. Even a beginner can see it. Starting at f/8, the center sharpness begins to decrease again as a result of diffraction. At f/11, the sharpness across the entire image is constant.  


 T0A0390Canon 50 mm f/1.8 STM + Canon 5Ds @ f/1.8

Bokeh Canon 50 mm f/1.8 STM

One of the reasons for the popularity of 50 mm f/1.8 lenses is that they have a much higher brightness and much nicer bokeh than a standard kit lens, while they are just as attractively priced. In comparison with its predecessor, the number of aperture blades has increased from 5 non-rounded to 7 rounded lamellae, which benefits the bokeh. That is a step forward for the bokeh of the Canon 50 mm standard lens, bringing it back into the pack, since far and away most lenses are now outfitted with 7 rounded lamellae. Only the more expensive lenses have 9 lamellae.  

bokehCanon 50 mm f/1.8 STM + Canon 5Ds @ f/1.8
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Conclusion Canon 50 mm f/1.8 STM review with Canon 5Ds

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Look in our overview of reviewed lenses in order to compare this lens with other lenses.

ECWYSIWYG score: This table shows the performance of this lens if you store the files in the camera as jpg, where you have applied all available in-camera lens corrections. This score gives you for this lens/test camera combination: “What you see is what you get”.

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ECPure RAW score: This table shows the performance of this lens if the file is saved in the camera as a RAW file. This score approaches the intrinsic quality of the combination of lens and test camera. If you use Photoshop, Lightroom or SilkyPix for converting RAW files, then the RAW scores are the same as the jpg scores. {insertgrid ID = 309}


  • Universally applicable focal distance for a camera with a full-frame sensor
  • Attractively priced, certainly given the high brightness
  • STM AF motor for video
  • Compact and light
  • High image quality


  • No built-in image stabilization
  • Image quality at full aperture is not optimal

Secretly, you hope that if a manufacturer has had 25 years to design a successor, that they will come out with a spectacular new lens design. That is not the case with the Canon 50 mm f/1.8 STM.

The Canon 50 mm f/1.8 II has been a very successful with an outstanding price-to-quality ratio. The same applies for the Canon 50 mm f/1.8 STM. The Canon 50 mm f/1.8 STM is improved relative to its predecessor on a number of points. If you are disturbed by noisy AF, like to focus manually and/or like making video recordings, then the choice between the Canon 50 mm f/1.8 STM and the even less expensive Canon 50 mm f/1.8 is easily made: buy the 50 mm STM and you will also have less trouble from flare. If you do not care as much about that, then the 50 mm f/1.8 II or the much less expensive Yongnuo 50mm f/1.8 is also an option. 

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