Canon EF 40mm f/2.8 STM Lens Review

Video Review

You can watch my video review of this lens on YouTube at the following link:

Canon EF 40mm f/2.8 STM Pancake Lens Overview & Review

Sample Images

A selection of photos taken in Thailand and Vietnam with the Canon EF 40mm f/2.8 STM lens.

Canon EF 40mm f/2.8 Pancake | Canon EOS 40D | ISO:100 | Aperture: f/2.8 | Shutter Speed: 1/50s

With the simple addition of an extension tube to reduce the minimum focusing distance, the already very sharp Canon EF 40mm f/2.8 is turned into a very competent and useful macro lens.

Canon EF 40mm f/2.8 Pancake | Canon EOS M6 | Canon EF-EOS M Mount Adapter | Canon 25mm Extension Tube | Gitzo GT2541EX

These images have been resized for the Internet, but they have not been cropped. It would be possible to make them a lot larger, or to crop a small section from the image, and still retain the same level of detail.

Canon EF 40mm f/2.8 Pancake | Canon EOS M6 | Canon EF-EOS M Mount Adapter | Canon 25mm Extension Tube | Gitzo GT2541EX

Introduction

When I first wrote this I was about to make a major house purchase and shouldn't have been buying any camera gear at all. At the time I was desperate to replace my ageing 40D with a 5D Mk3 but the funds simply weren't there.

However, this didn't stop me buying the Canon EF 40mm f/2.8 Pancake. For many years now, every new lens that Canon announces has had great image quality, and this lens is no exception. The pancake design of this lens makes it very easy to carry around, and the low price means that it won't put a dent in anyone's budget.

If you are considering buying a $6,000 dollar lens you need to do lots of research because it's a big capital investment and if you make the wrong decision it could be an expensive mistake. However, purchasing the Canon EF 40mm f/2.8 STM is a no-brainer because it is so cheap.

Most people will find a use for it and even if you don't find a use and sell it second-hand, you will likely only lose a few dollars. What isn't there to like about it? It is small, light and has very good, if not outstanding, image quality.

In terms of physical size, it falls roughly between the Canon EF 12mm and Canon EF 25mm extension tubes, and it is quite a bit smaller than the Canon EF 1.4x II extender.

It was a very comfortable lens to use on my old Canon 40D. It really is tiny. I now use the Canon EOS M system and initially I only used the native EF-M lenses.

I have the Canon EF-EOS M Mount Adapter, therefore, I can use EF and EF-S lenses with the EOS M. Most of my EF lenses feel too heavy, bulky and unwieldy on the EOS M, but the small EF 40mm pancake is the exception.

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Focusing

The lens uses new stepper motor (STM) technology for its autofocus mechanism. This is all part of Canon's drive to implement silent continuous autofocus tracking in movie mode. To do this requires an appropriate body, such as the EOS 650D with a hybrid CMOS sensor and contrast detection AF technology, and a lens with an STM designation.

In addition, the STM autofocus system is backwards compatible with all EF mount Canon cameras.

I imagined that the autofocus mechanism would be completely silent, but it isn't. There is a discernable noise, even though Canon claims that continuous focusing in movie mode with an STM lens will be silent.

The autofocusing is fairly quick but doesn't feel quite as rapid as some of my other lenses. I can hear the AF going to the correct place, rather than simply 'snapping' into position as do some of my other lenses with ring-type USM motors.

It's still fast enough for my purposes, it focuses accurately, and it seems OK in lowish light. Obviously, the camera body you are using will make a difference here too.

It also appears to work perfectly well when the camera is in AI Servo mode tracking an object coming towards the camera. I tested this on passing motorbikes and the results were quite good.

There is no direct physical connection between the manual focusing ring and the internal focusing mechanism as there is on other lenses. If you turn the ring with the camera off nothing happens.

Turning the ring sends a signal to the stepper motor which then focuses the lens electronically.

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Bokeh

If focusing at a short distance and using the widest f/2.8 aperture, the bokeh effect created by the seven bladed diaphragm is fairly smooth and creamy. This adds to the appeal of the lens for portraiture, especially on crop bodies where the effective focal length of the lens is 64mm.

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No Image Stabilisation

Presumably the design brief for this lens was to keep it cheap and to keep it as small as possible in order to achieve the desired 'pancake' form. Including IS would have run counter to both objectives.

Opinions on IS vary. Some people want it on every lens, while other people say that it isn't even necessary on lenses such as the Canon EF 400mm f/5.6L. I disagree with the latter thinking and would love to see an EF 400mm f/5.6 with IS.

Conventional wisdom says it is only needed on long lenses, yet Canon have included it in a couple of recent wide angle lenses - the EF 24mm f/2.8 IS and 28mm f/2.8 IS. Surprisingly, the latest EF 24-70mm f/2.8L II doesn't have IS.

I haven't missed IS on the 40mm STM pancake and am confident handholding shots at 1/40s, or even lower.

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With The EOS M

When using the Canon EF-EOS M mount adapter, any EF or EF-S lens can be attached to an EOS M body. That is a fact, but in real life terms it is completely impractical, especially if using the LCD to compose the shot. You will have to hold the camera at arms' length to compose and focus, and holding the camera in such a way is not conducive to using lenses with a focal length over 200mm.

Also, the whole point of the EOS M system is that it is small, light and portable. If you start using it with large, bulky EF lenses it defeats the purpose of EOS M.

Canon EF 40mm f/2.8 pancake mounted on Canon EOS M

Canon EF 40mm f/2.8 pancake mounted on Canon EOS M

Canon EF 40mm f/2.8 pancake mounted on Canon EOS M

Canon EF 40mm f/2.8 pancake mounted on Canon EOS M

I bought the EF-EOS M mount adapter with a view to using the EOS M with my EF and EF-S lenses, but most of the time I just use the native EF-M lenses. Occasionally I might use an EF or EF-S lens, but it isn't often.

An exception is the EF40mm pancake and the same would be true of the EF-S 24mm f/2.8 pancake because it is the same size as the 40mm pancake. The EF40mm and EF-EOS M mount adapter used together are just a little longer, little bulkier and little heavier than the EF-M 11-22mm wide angle zoom, and the combination is small enough to fit in the pouch I normally use for my EOS M with an EF-M native lens.

Using the EF40mm lens on the EOS M, the camera still feels balanced and is easy to handle. Another problem using large EF lenses with the EOS M is that the camera is too front heavy. The image quality is also very pleasing.

If you like the compact size and image quality, but the EOS M autofocus isn't fast enough for the type of photography you do, the little Canon SL2 DSLR body might be a good option.

I love the small size and light weight of the EOS M system and although I will still have occasion to use a large DSLR system sometimes I definitely don't want to carry a large, heavy system around me all the time for general photography - as I do with my EOS M.

A small, light DSLR body - such as the Canon SL2 - and this pancake lens seem like a good compromise between size and weight on the one side and speed on the other.

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Focal Length

Back in my full frame (film) days everyone had a 50mm 'standard' lens attached to their cameras. It was the same for me using a Canon FD 50mm f/1.8 on my Canon A1 and Canon T90 bodies.

I found this to be too long in many situations and bought a Canon FD 28mm f/2.8. This immediately became my 'standard' lens.

On a full frame digital camera, 40mm would be a useful length. On a 1.6x crop body 40mm becomes 64mm, which is getting into the realms of short telephoto.

It is good for close distance portraits and some subject matter, but too wide for a lot of general photography.

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Extenders And Extension Tubes

The lens cannot be physically connected to my Canon EF 1.4x II Extender. I would imagine it is the same for the Canon EF 2x extender. I don't know if other brand extenders, such as Kenko, can be fitted.

Extension tubes work fine. This lens already has a short minimum focusing distance, but with the addition of a 25mm extension tube I was able to roughly halve that distance and focus from around six inches.

The EF 40mm f/2.8 is a very sharp lens and combined with an extension tube to enable close focusing it becomes a very good macro lens. See samples above.

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Canon Product Advisory

Apparently, if pressure is applied to the barrel of the lens the autofocus may stop working. I haven't experienced this personally (yet), and I haven't attempted to induce the problem deliberately.

Firmware Notice: EF40mm f/2.8 STM: Firmware Version 1.2.0

The problem can be solved with a downloadable firmware update, but if you wish to do it yourself the lens needs to be fitted to a supported camera body. Alternatively, the update can be carried out at a Canon service centre (presumably for free, but I'm not sure).

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Conclusion

This lens has grown on me over the years and now I really love it. I use a mirrorless system and mainly native EF-M lenses these days because I got tired of carrying around lots of heavy DSLR equipment, especially after having children.

Nowadays, I don't tend to use my old EF and EF-S lenses very much apart from this one. Even with the Canon EF-EOS M Mount Adapter it is still small and light.

My objective is always to carry the minimum weight possible and this is one EF lens that I am very happy to take with me because it is so small and light.

If you also buy (or already have) an extension tube, this will turn the Canon EF 40mm f/2.8 into a very good little macro lens. You won't have a lot of working distance, but this might not matter depending on your subject.

Considering its price and performance, I think that it is still an excellent buy, however you can now buy the EF 50mm f/1.8 STM for a lower price and it has a faster mazimum aperture.

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Would I Buy One Now?

Definitely. Even though I now use a mirrorless system, this lens plus the EF-EOS M mount adapter is still small and light. It is fast, focuses well and delivers excellent quality.

Considering that it is also priced very reasonably, it is still a very good buy.

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Post Processing

Most original images were shot in the RAW format and converted with Adobe Camera Raw. Noise was reduced using Imagenomic Noiseware Professional. Small amounts of image enhancement were applied using Adobe Photoshop CS2 (curves, levels, saturation) before sharpening using the Smart Sharpen filter (Amount: 30% - 120%, Radius: 0.2px - 0.3px, Remove: Lens Blur).

The large JPG images that open if you click on a thumbnail were saved with a 'High' quality setting of '8' on a scale of 0-12.

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Lens Details

Weight: 130g
Filter Diameter: 52mm
Closest Focusing Distance: 0.98ft; 0.3m
Minimum Aperture: f/22
Maximum Aperture: f/2.8
Date Purchased: August 2012
Supplier: Chia Color Lab, Hat Yai, Thailand
Price: 6,900 Thai Baht
Lens Cap: E-52
Lens Hood: ES-52 (not included)
Soft Case: LP811 (not included)

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