Lens Review – Canon EF 40mm f/2.8 STM

Having had two weeks break for the London Olympic Games, I am back and writing this new review. Canon EF 40mm f/2.8 STM is a brand new pancake lens from Canon. In fact, it’s the first EF pancake lens for Canon since the launch of EOS system back in 1987. I always have split views of these little things. I love them because they are small and good for travelling and walkabouts, but I hate them because they don’t normally give me the best image quality compare to normal bigger primes. Pancake lenses are nothing new and they have been around for over a century. Over time, almost all lens manufacturers have tried to clone and modify the original design by Paul Rudolph, the famous Tessar, and to launch their own versions. Some later examples come from Pentax for their DSLRs and more recently Olympus and Panasonic for their M4/3 cameras.

Because of their design limit, they can be soft when shoot wide open, which isn’t so good if you want to use them in low light. Stopping down makes thing better but that defies the purpose of the relative large aperture for these little things. I own and have tried the Nikon 45mm P lens and I am not impressed at all. It’s soft when shoot wide open and things just don’t improve even when stops it down to f/6.3, its sharpness still can’t match the standard 50mm f/1.8 prime shot at wide open. I am not joking. Panasonic’s famous 20mm pancake seems to be the best around when launched a couple of years ago but it is all for the M4/3 cameras and there are no other full frame offerings.

That’s changed when Canon announced the new Canon EF 40mm f/2.8 STM in June. I was surprised and started wondering. First Canon already has enough primes to cover any possible range in SLR photography and why would they need a new pancake? Canon isn’t known for its portability anyway so why now? Ok, the STM, the new stepping motor focus technology, promises to be much quieter than traditional focusing motor, might be the selling point of this. But I wasn’t even too bother about the noisy motor of my trusty old Canon EF 35mm f/2. Canon said that this type of focusing is beneficial for video but unfortunately, video isn’t my thing yet and my 5D Mark II doesn’t do focus tracking and it means things have to be pre-focus anyway so noise doesn’t come into play at all if I wish to shoot video with it. The only Canon DSLR that does focus tracking is the latest Canon EOS 650D anyway. Well, ok, Canon’s new mirrorless Canon EOS-M might be the reason but it needs a new mount. So it’s a puzzle that I cannot answer.

All the test shots here are photographed in Hong Kong during my trip and straight after I acquired the lens.

So why this lens?

I was asking myself that question. When I first picked it up, for some strange reasons, I felt in love with it. I have had better looking pancake lenses but the Canon does have something about it. It’s like an Oreo cookie, kind of cute and looks yummy. But as a photographer, you cannot judge a lens by its look but it certainly helps.

One reason you would want this lens is that you want something that you can carry everywhere with ease. This is the strength of any pancake lens. When it is mounted on my 5D, my kit suddenly shrinks. I am really a fan of my 35mm f/2 because it’s small and light. But the 40mm is in a totally different league. When you look from above the camera, it’s so small that it doesn’t protrude further than the camera handle. All… just like a lovely lady that I am always dreaming about, small enough to feel her presence, pretty to look at but doesn’t bling enough to attract unnecessary glances. It’s so light that you can carry it all day long without feeling the strain around your neck. It’s a perfect travelling partner and its f/2.8 aperture is also large enough to so some low light photography. Read on to see how this lens performs.


I am used to all the professional ‘L’ construction so anything less ‘expensive’ usually means no good to me. However, I do have a few non-L lenses such as the Canon EF 35mm f/2 and Canon EF 100mm Macro USM. The 35mm certainly feels cheap even though it has a metal mount. The macro lens was better but the plastic was shiny and feels hollow.

For the price, you will be pleasantly surprised just how well built this little pancake lens is. Its polycarbonate body certainly feels more solid than any of my non-L lenses. Even though it is light, you can certainly feel the weight of the glass. Metal mounts ensures durability and that ultra smooth focusing ring is definitely something to shout about. It’s as smooth as Charlize Theron’s body.

Using it in practice, good and bad

Right this is the crunch bit. You can love the look of the lens if you are a poser but for a serious photographer, the most important thing is image quality. I am very proud to say that this 40mm lens delivers and in a BIG way! Why? For a start, it’s sharp and not just the normal sharp. It’s sharp even at wide open. For a second if you do pixel peeping, you will see this lens is actually sharper than my Canon EF 24-70mm f/2.8L USM lens! But sharpness isn’t everything either. To me, what makes a lens special is its character and this pancake is not shy of showing off its characters. Leica shooters will know what these characters mean. They give a certain look to a photo. I have used many many Canon lenses before, so far, only two lenses give me these good characteristic feeling. They are: Canon EF 85mm f/1.2L II USM and this little gem, Canon EF 40mm f/2.8 STM.

So much about its greatness but has it got any weakness? Well, that depends on how you like you lens. It does vignette quite a bit when it is wide open but just half a stop smaller, it’s almost all gone. I was shooting wide open virtually religiously in Hong Kong because the vignette, couple with the rendering, gave me that character that I loved. So if you don’t like vignetting, then this isn’t your lens. The new STM motor is definitely quiet but no match to USM. It’s hundred times quieter than my grinding machine (the 35mm f/2).

The focus mechanism is electric driven and the front element will move back and forth during focusing. This isn’t great when your lens is sleeping or camera is powered off. Unlike the more mechanical 35mm f/2 lens, if your lens is fully extended, you cannot retract it back to its ‘flat’ position by turning the focusing ring, even when set to manual focus. I am not too bother about this but I have heard people making a big fuzz out of it.


There isn’t a perfect lens that suits everyone or every situation. You pick a lens that suits your needs. For me, this new pancake lens exceeds all my expectations (because I had none to start with). And it’s definitely a much better lens than my trusty 35mm f/2 and this Canon EF 40mm f/2.8 STM can definitely replace it as my new street star. It is sharp and more importantly, it has character. You can never reproduce or replicate a lens’ character  so for that reason, it is very special. It may not be perfect but it makes perfect pictures for me, and that’s more than enough already!

Update: Canon just said that they will have a new firmware by end of August  to fix a phenomenon when the front element is pressed, the lens will stop functioning. I haven’t encountered such problem myself but I don’t intend to force it to test the theory. I will update the firmware but so far I am a happy bunny.

All the products mentioned here can be bought from Amazon via my links below. Help support my work and thanks for sharing your views

Canon EOS 5D Mark II Body

Canon EOS 650D Body

Canon EF 35mm f/2

Canon EF 40mm f/2.8 STM

Canon EF 24-70mm f/2.8L USM

Canon EF 100mm f/2.8 Macro USM

Canon EF 85mm f/1.2L II USM

Canon EOS-M


5 responses to “Lens Review – Canon EF 40mm f/2.8 STM

  1. Pingback: В поисках идеального штатного объектива… « Фото и путешествия·

  2. Pingback: LENS REVIEW – LEICA SUMMILUX-M 1:1.4/35 CLASSIC (PRE-ASPH) | talktog·

  3. Pingback: Review Canon EF 40mm f/2.8 STM. В поисках идеального штатника… « Фото и путешествия·

  4. hey man, is this lens good for landscapes and street photography?
    btw awesome review and amazing pictures!

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