Canon’s Shifty Lens
If you aren’t aware of tilt-shift lenses, they allow you control over perspective distortion and selective focus. If you are aware of tilt-shift lenses, then you probably also know that anything you can do with them, you can also do in Photoshop. Canon’s new 17mm TS-E f/4L lens seems like an anachronism: tilt-shift lenses are ancient mechanical technology all but abandoned, there is no autofocus, and tilting or shifting affects light readings effectively meaning that exposures are manual only.
So essentially buying a tilt-shift lens means giving up most of the automatic conveniences of a modern DSLR, all for something you can do in Photoshop or many photo programs anyway. So, of course, I had to get one…
The most important thing for this lens is understanding the shift (in my opinion the tilt is not as important on a wide angle). The easiest way to visualize the effect of shift is to imagine having taken a really big picture with a sensor much bigger than that in your DSLR. Now imagine that you can only display part of that picture through a window — the rest will be cropped out.
The shift functions just like that, it is a crop window for a much bigger picture that you can move about. If you are having trouble visualizing this or understanding this, it is probably because you are overthinking it… it really is as simple as the illustration suggests (just use the force, Luke).
So now you are underwhelmed; the magic is gone, the mystery dispelled. So why bother? Well, let me show you a real world example, I went to photograph the garden of statues with the palm trees in the background at the Huntington Library. I’m at one edge of the garden and can’t back up further to fit it all in, so I point my camera upward a bit to frame it:
The statues and the palm trees are fully in frame, this makes us happy, right? Well, except for the fact that everything is leaning back and into the center of the photo. This is because I pointed the camera up, so the perspective vanishing point is above the photo, in the middle.
So I’m not happy, and I’ll retry that photo, keeping the camera level this time:
Ok, now I *really* did solve the problem, right? Well, except that the palm trees are missing, and there is a *lot* of boring grass in the frame.
So now let’s use the “shift” feature. Here I kept the camera level, as with the previous shot. I use the shift knob to shift the lens up, just like the “Shift Up” in the first example photograph:
Now you see why this matters! The photo looks a lot better — it is framed, the trees aren’t falling backwards, and you’ll also notice that the proportions are actually correct (in the first photo, the trees look a lot shorter than they really are).
Something else I learned here about using the lens: just point at the horizon (or at a point the same height of your camera for a nearby object), and shift. That’s all there is to it: point so that verticals are straight, then shift into position. I’d make a video and draw a diagram, but it is too simple to deserve it — point, then turn the knob. Done.
You may know you can do that in Photoshop by using the distortion feature of the Lens Correction filter, and they can do it a lot cheaper than buying a new lens, and you’d be right. So let’s try that. Here is my “normally” shot photo of a building with a 17mm wide angle:
Sorry about the flaring, it happened because I was pointing the camera up and sun got into it – I didn’t notice it until I got home (although perhaps a small point in the shift lens’ favor). Here is what it looks like to process it in Photoshop:
You’ll notice how the shape now becomes trapezoidal. This is unavoidable, and now I have no choice but to crop it in order to maintain a rectangular shape. The result becomes this:
So let’s try the same photo again, but do the shift in the lens instead of Photoshop, with the same 17mm wide angle lens:
You can see the difference, I have a photo exactly as I framed it with no distortion (outside of a slight color adjustment, this photograph is uncropped and unaltered in any way). Here are the advantages:
- I can fully use the wide-angle, not just some cropped portion.
- Proportions are exactly maintained.
- I could see exactly what the framing of the photo would be right when I took the photo, I didn’t have to guess what I could accomplish in Photoshop.
- I got rid of distortion in a few seconds by turning a knob, no lengthy Photoshop work required.
- The picture is not stretched or interpolated in any way, which means the full resolution and detail the camera can produce is preserved.
Here is what I learned in using the lens:
- Keep the camera level, use the shift to get the right framing.
- Ideally use a grid focusing screen, and/or a bubble level.
A tripod is also a good thing to have, although the shift feature of the lens is suprisingly easy to use handheld.
Here is a photo of the Ferris Wheel at the Santa Monica Pier I don’t think could have ever been captured except by the 17mm TSE lens (even a 14mm wide-angle with Photoshop):
I did fiddle with the colors (hey, this isn’t about color) and some slight cropping, but the framing is basically what I took with the camera, and the Ferris Wheel does NOT look like it is falling backwards. The space was tight too, so I did not have the option of using a longer lens and standing back.
Here is another photo, handheld and uncropped:
You may think this is new-tech; in actual fact most antique cameras had this same basic capability — you’ve seen old cameras with bellows, right? It was only recently with the introduction of SLR’s and fixed lens point-and-shoot cameras that this ancient technology disappeared for most photographers. Shift lenses are used a lot in making movies still, though, for exactly the reasons given.
And specifically about the Canon 17mm TS-E lens: it is much sharper than my 17-40mm zoom at 17mm, in fact it is pin sharp. The contrast and detail are excellent. Lines are straight, I don’t perceive any distortion. My biggest complaints are really something the engineers at Canon can’t do anything about simply because of the nature of the lens: the front glass element portrudes out the front of the lens and no lens hood or UV filter can be used — the lens is unprotected, making it vulnerable. Using it outdoors is nerve-wracking. Also there is no auto focus, and for all practical purposes you need to use manual lighting — the tilt and shift will mess up light readings.
In practical terms the lack of autofocus is not really an issue. The hyperfocal range (focus distance at which everything out to infinity will be sharp) for a wide angle lens like this is quite close. You should however meter the light without a tilt or shift and dial these settings in (or buy a light meter). Also it is really hard to determine if your picture is level, so consider using a bubble level.
You don’t need a lens like this to go out and have fun photographing nature and buildings. Correcting perspective distortion in Photoshop or any other photo program, and using a standard wide-angle lens will still work. If you can, simply standing a lot farther back and cropping can produce the same result. For me time will tell if it is worth it — I don’t sell any photos, it is just a hobby, and buildings and tall landscapes are only a niche within that hobby. I am, however, fascinated by the mathematics of this lens, and aesthetically I find being able to exactly frame a photograph on the spot refreshing.
Tilt-Shift lenses are WYSIWYG in a way no other type of lens can be, which makes them very appealing but by no means essential. Using such lenses, in particular a wide angle version, is a revelation in how to compose a shot. Knowing what your photo will look like is a lot better than guessing how it will look after processing in Photoshop.
My review: the Canon 17mm TSE is an amazing tack-sharp prime lens where lines remain straight, with the drawback that the front element seems quite vulnerable. The lens requires a lot of learning — everything is manual, and you ideally will want to carry a bubble level and tripod with you. This lens isn’t for most people, however for nerdy amateurs like me (or I assume professional architecture photographers) it is worth it.