24mm? To ordinary people that measurement means nothing. To
Canon gear nerds photographers, that measurement brings one thing to mind – twice. 24mm lenses are not extremely popular. If polled, most photographers would likely say that they use their 50mm, 85mm, ulta-wide angle (UWA), and 70-200mm – any of these lenses – more than anything in the 24mm range. If someone were to ask for a suggestion for a professional lens wider than the 50mm ƒ/1.2L but not as wide as say the 16-35mm ƒ/2.8L (or perhaps they want a faster lens…) then they might be referred to the Canon 35mm ƒ/1.4L or even the Sigma 30mm ƒ/1.4. It’s true – the 24mm lenses are usually “forgotten” in Canon’s offering line-up.
Canon offers two very unique 24mm lenses (actually Canon offers 6 lenses in the 20 – 28mm range when talking about primes). One lens is the 24mm ƒ/1.4L II and the other is the TS-E 24mm ƒ/3.5L II (and of course there are first generations of both lenses though they are discontinued at the time of this writing). The first lens mentioned, which I will just call the 24L II, is fast. It auto-focuses fast and the huge ƒ/1.4 aperture makes taking photos in the lowest of light possible. Because of the generally accepted 1/<focal length> rule for shake-free, hand-held photography, you could take a photo down to 1/20 – 1/30 sec shutter without worrying much about shake. Combine that with an aperture of ƒ/1.4 you can imagine how much light this thing will gather. Combine that further with modern camera ISO performance and the 24L II makes almost any photograph possible in almost any amount of light. We’re talking real, real low light here!
So what of this other weird lens? The TS-E 24mm ƒ/3.5L II is surely a weird looking lens even if you are not very familiar with photography. The first thing you notice is the TS-E in front of the name. This stands for Tilt and Shift. A what? Well, the mechanism in this lens allows you to tilt the front element away from the camera’s sensor plane – this lets you turn the “plane” of focus – or, rather, if you think of things being in focus as a “toward or away” then what the tilt allows for is a focus “toward or away while at an angle”. It allows for wider aperture to maintain larger depth of field – it can also allow for “selective focus” – you can creatively isolate objects in the frame by tilting. The “shift” part is a little more confusing and I will be honest I don’t know why it works – but, what it does is shift the entire lens up or down, left or right parallel to the sensor plane. This allows for “perspective correction” – when using wide-angle lenses you will notice that buildings and other vertical objects can look distorted and lean back in an image. Shifting the lens allows these lines to stay parallel.
So, what’s the difference? Well obviously one is a ƒ/1.4 max aperture and the other is a ƒ/3.5 max aperture – but that’s just the obvious differences. More subtle is the fact that the TS-E 24mm is a manual focus lens while the 24L II is a very fast very accurate auto-focusing lens. The TS-E is geared more toward architecture, landscapes, and product photos while the 24L II is a wide angle “take the picture easily” lens. The truth is that both lenses serve two specific and different purposes – but, that’s only if you listen to articles and forum posts. The reality is that both lenses are amazingly good lenses and offer a photographer two different 24mm experiences. On one hand the 24L II can gather inordinate amounts of light through its huge aperture and auto-focus the scene. On the other hand the TS-E 24mm, though with a slower aperture and manual focus, can offer one of the sharpest, most distortion-free images out of any wide angle lens.
The neat thing about the 24mm range is that on a full frame 35mm camera a 24mm is a “wide angle”. On a crop body it’s a “wide” maybe “wide-normal” lens. The field of view crop is narrower proving an approximate field of view of that of a 38mm lens on a full frame 35mm body. 38mm is still considered a “wide angle” on the 35mm film/sensor standard – so it offers an approximately-equal view as the 35mm ƒ/1.4L but offers modern coatings and better glass design offering lower distortion, a sharper image, and less ghosting and chromatic aberration when compared to the much-older-in-design 35mm ƒ/1.4L.
So, what does the field of view look like when comparing a full 35mm frame and a crop body (1.6x) frame? I took these four images to demonstrate each lens on each body (5D Mark II and 7D). The images are too small to really notice the sharpness differences and all of the shots were at ƒ/3.5 so the depth of field advantage (or disadvantage, depending on your taste) of the ƒ/1.4 aperture on the 24L II is not made apparent, but you get the idea. The images below are in order – 5DII w/ TS-E 24L II, 5DII w/ 24L II, 7D w/ TS-E 24L II, and 7D w/ 24L II, respectively:
Hopefully some will find this useful! I know it’s not a test of sharpness, vignetting, ghosting, aberration, or any of those other technical aspects of lenses, but there is plenty of that out there. For instance, I recommend the reviews over on www.The-Digital-Photo.com if you care to see ISO 12233 crops or critical review.