Canon 40mm f/2.8 STM review

June 15th, 2012

Let me save you some time: If you’re a Canon shooter and you’re thinking about buying this lens, buy it.

Canon recently launched their first pancake lens, and one of the first two lenses to feature a new focusing motor called STM (Stepping Motor). This new focusing motor is aimed for smoother (and hopefully quieter) focusing during video. At the moment the only camera available that takes full advantage of the new STM focusing system is the new Canon 650D/T4i.

But this lens also works brilliantly on other cameras. I got lucky and found one at Fireside Camera here in San Francisco and decided to go for it. I’ve recently been using the 50mm 1.8 on my 5D Mk II more than my other lenses, especially for street photography. But I was looking for something smaller, more discreet and lighter.

The 40mm 2.8 STM is small and on larger bodies may look like a fat body cap. Though it’s only $199, it feels very solid and well built. The metal mount is a nice addition and is something the 50mm 1.8 is missing.

# Picture Quality

Many lenses are pretty soft when wide open, but the 40mm is respectfully sharp at f/2.8. Here’s a 100% crop of a post in the Marina district, just look at the texture detail, amazing.

100 Crop

1/6400 | f/2.8 | ISO 200

There is however noticeable vignetting on the 5D Mk II when shot wide open. Some might not like the vignetting, but can be remedied with an aperture change or post processing fixes.


1/2500 | f/2.8 | ISO 250

# Bokeh (-liciousness)

In the words of Kai from DigitalRev, I find the bokeh to be smooth and creamy, like a delicious cheese. The 40mm is comparable to the 50mm 1.8 in terms of smooth bokeh, but with the 50mm 1.8 you gain a shallower depth of field which makes me wish that Canon gave this little 40mm an f-stop of 2 or even a 1.8. But that might just drive the price up a little bit.


1/40 | f/2.8 | ISO 320

# Build Quality

As mentioned above, the build quality for this little lens is superb, especially for the $199 price tag. Even though the lens is plastic, it doesn't feel cheap and the metal mount adds to the build quality.

The focus ring is nice and smooth, and the STM system really shows when it’s autofocusing. One thing to note: If you’re shooting video in a quiet environment and using the on-board microphone, you will hear the focus motor when you’re manually focusing.

Kitten by Jarques Pretorius (Jarques) on

1/30 | f/2.8 | ISO 1600

Lights by Jarques Pretorius (Jarques) on

1/60 | f/2.8 | ISO 320

# Conclusion

I won’t lie, I started liking this lens from the first few shots I took after walking out of the camera shop. It’s sharp even wide open, colors are great, it’s lightweight and above all it’s a good bang for your buck. At $199 I would definitely recommend this lens to any Canon photographer, whether you like street photography or architectural work, this lens will serve you well. Will it replace my 50mm? I haven’t had the 50mm back on my camera since I picked it up, but the 1.8 of the nifty fifty will always have me go back to it.

Canon introduced one helluva small lens with performance that out does many more expensive lenses. Go buy it now.