Let's have a look at the Canon 40mm f/2.8 STM, a tiny little pancake lens from 2012. Is it any good? Yes! Although it was dogged by controversy when it came out and had a surprisingly short life. Not because there was something wrong with it but because it puzzled a lot of people.
See, back in 2012 the big new things in photography were digital SLR videography and compact mirrorless rangefinder cameras. They both took the camera industry by surprise. When Nikon added a simple video mode to their D90 it felt like an afterthought; ditto Canon with the 5D MkII. But professional cinematographers immediately flocked to those cameras because they produced high-def video with a cinematic look, at a fraction the cost of hiring a professional digital cinema camera.
And so the 5D MkII ended up capturing a niche as a portable cinema camera for action shots in big-budget movies. It was used to shoot parts of Captain America: The First Avenger, Iron Man 2, Black Swan, a whole episode of House, all of Birdemic, the list goes on. A whole industry sprang up around the 5D and cameras like it.
But from a consumer perspective neither Nikon nor Canon had any lenses that could autofocus quickly and silently while shooting video. Especially not cheap lenses. The 40mm f/2.8 STM was supposed to fill that niche, by introducing a new focusing system that used a stepper motor instead of Canon's regular mechanical focusing system, but the reviewers were generally unimpressed.
I have to admit I can't pass judgement on STM video focusing because my 5D MkII doesn't properly support it. For regular stills photography it works just fine. In any case the focus travel is really short. For the shots of Battersea Power Station I used it with an ancient Canon 1Ds:
I was hoping that the security guards would pat me on the back and say "awesome camera" and "you're alright" and "yes" and "I wish I was your brother" and "yes" but this did not happen. I also tried it with an old EOS 50E film camera, which came out in 1995, and it functioned without any problems. The 50E was one of a handful of Canon SLRs with eye-controlled focus - you could switch the focus points by looking at them. It works surprisingly well, but the 50E only has three focus points so it's slightly pointless.
The 40mm f/2.8 only focuses if the camera is turned on, which is a throwback to the earliest days of the EOS range. It takes 52mm filters, and the inner lens barrel sticks out a teeny-tiny bit at close focusing distances. Apparently if you bash the barrel the autofocus system gets confused and you have to turn the camera off and on again. I can't say I've noticed.
With a 40mm f/2.8 lens almost everything from a dozen feet or so is in focus, and if you want to blur out the background this is not the lens for you:
That was shot wide open, at a fairly close distance. Most of the rest of the shots in this article were taken at f/8. It's very much a point-and-shoot-without-messing-about lens.
The second big thing in 2012 was the compact mirrorless rangefinder. Such as the Olympus EP-1 and Panasonic's miniature-SLR-looking cameras. As with video, the success of cute little rangefinders took Nikon and Canon by surprise. In particular Canon had nothing remotely similar for years afterwards, until the RF system came out, which still isn't all that compact.
Although Canon didn't explicitly market the 40mm f/2.8 as a rangefinder rival, it came across as an inadequate attempt to hide the relative bulk of Canon's SLRs by making the lens smaller. As you can see, despite the 40mm's tiny size it does not turn an SLR into a compact camera:
I'm not complaining, mind. It's a moderate wideangle that takes up very little space, with fast, accurate autofocus. It's perfect for grab shots. Curiously it's a full-frame lens, despite being sold alongside a new range of APS-C cameras. It was joined a couple of years later by the Canon 24mm f/2.8 STM, which in contrast is APS-C only.
Perhaps coincidentally the 40mm f/2.8 has the same field of view as the Panasonic 20mm f/1.7, which was one of the star lenses of the Micro Four-Thirds system. It also has the same specification as all of those old rangefinder cameras from the 1970s, such as the Ricoh 500 ME or the Konica C35 etc. They all had 40mm f/2.8 lenses as well. I assume the design is easy to make in a compact package.
What's it like on an optical level? Sharp in the middle at all apertures and sharp all over at f/8, with a fair amount of vignetting wide open, but less than I expected. Contemplate the following two images:
That's f/2.8 at the top and f/8 at the bottom. As you can see f/2.8 is just slightly glowy, less contrasty, but it's fine. This is the full image at f/2.8:
I have nothing against the people of Athens. The problems that affect Athens aren't their fault. They are pawns in a game of chess that is being played by an NPC inside a massively multi-player role-playing game that you are only tangentially aware of. Like Bayonetta. Is Bayonetta a role-playing game? No, it's some kind of fighting game. I've never played it.
When I was in Athens I wondered what the Ancient Greeks such as Don Quixote and Tyco Brahe he has a crater on the moon named after him would have thought about modern Athens. On the positive side McDonalds barely has a presence in the city, so the hamburger gases that cloud the city are Greek hamburger gases, but on the other hand everything is broken and wrong. Except for the people, who are uniformly sophisticated and good-looking, and have elevated sprezzatura to a fine art.
People of Athens, especially the women, you're okay. Take it from me. This is the corner of the image at f/2.8 and f/8:
At f/8 the image is essentially sharp across the frame. The extreme corners are just slightly soft at f/5.6, slightly more at f/4. It struck me that the only way to fix Athens would be to demolish every other city block, but where would the people go? And so, yet again, vast underground cities are the only solution.
Vast underground cities. The 40mm f/2.8 STM had a surprisingly short life. It was discontinued in 2021, just nine years after it was launched, amidst a general cull of digital SLR lenses. The third big thing in photography in 2012 was the smartphone, which wasn't exactly new - 2012 was the heyday of the iPhone 4 - but smartphone cameras were naff until the 2010s. They have only got better since then, while digital SLR sales have declined, and stratified. Furthermore 40mm f/2.8 is a dull specification, and an odd focal length on an APS-C camera, and it overlaps with the 50mm f/1.8, so I can understand if it didn't sell well.
And that's the 40mm f/2.8. Objectively great, but it occupies a bit of a niche; Canon's 35mm f/2 is faster and wider and has image stabilisation, but it's also much larger and more expensive. Control over depth of field is one of the most compelling reasons to own a full-frame camera, but unless you get real close a 40mm f/2.8 tends to have everything in focus.
And yet it takes up virtually no space and almost doubles as a body cap, and it's cheaply available on the used market, so why not?
