While a camera is a bit different than the human eye, when it comes to perspective, a traditional lens comes pretty close to capturing what we see as we see it. If you are standing in the middle of a road for example, the road appears to shrink as it heads off in the distance. Snap a photo of the same road, and you’ll get that same look. That’s what helps us perceive depth in a two dimensional image.
But, that’s with a traditional lens. Add a tilt shift lens to the front of your camera, and you open up possibilities for altering that perspective. So, what is a tilt shift lens, exactly? And what are the best uses for one?
First, a quick refresh on how a traditional camera lens works. A lens captures a circular image, but since it’s projected onto a rectangular sensor, it renders a rectangular photo. Normally, the lens’ imaging circle is fixed in relation to the camera sensor’s position.
So what is a tilt shift lens? A tilt shift lens allows the photographer to change the position of that imaging circle. By tilting the lens, you change the center of that imaging circle, which can straighten the lines that appear to converge in the distance. The camera body remains in the same position, but the tilt shift adjusts the lens’ perspective. That makes tilt shift lenses a big help for architectural photography. Walls that are straight may actually look crooked because of the lens’ perspective; tilt shift lenses can change that perspective, making those walls straight again.
In the CreativeLive course, Nature and Landscape Photography, John Greengo expertly demonstrates this difference:
Most lenses capture a circle that’s just big enough to cover the sensor, but a tilt shift lens casts a much larger circle. That’s a necessity so that you’re still getting an image when the lens is tilted. It has another benefit too though. Where most lenses have degraded image quality at the edges, a tilt shift lens, even when pointed straight ahead, tends to have more uniform image quality.
The ability to change the position of the imaging circle has more than one application. In architecture, it means straightening out lines that appear crooked because of the perspective. A tilt shift lens will also make a building appear more imposing by straightening out that perspective. Often, it’s impossible to get far enough away from a building in a crowded city to photograph the structure without pointing the camera up. Adjusting the angle of a tilt shift lens can reduce the feeling of looking up at that building.
While architecture is the most obvious use of a tilt shift lens, many other subjects can benefit from what a tilt shift has to offer. When shooting a sequence of images to stitch together a panorama, a tilt shift lens prevents the parallax error where the horizon appears to bend.
Tilt shift lenses also allow for greater control over an image’s depth of field. Traditionally, anything the same distance from the camera as the subject will appear in focus—that’s because those objects lie on the same focal plane. On a normal lens, the focal plane is parallel to the camera. Tilt the lens, and the focal plane tilts as well, becoming a diagonal line, instead of one that’s parallel to the camera. This creates the appearance of a much deeper depth of field than shooting a traditional lens at the same aperture. With the focal plane as a diagonal, it’s also possible to have two objects that are parallel to one another, with one item in focus and another not.
Tilt shift lenses have also become popular for creating a “toy town” effect, or making real objects look like fake miniature replicas. Toy towns are often created with the camera pointed down and the lens pointed up, often from a high vantage point.
Of course, adjusting the position of the lens has a few more simpler uses as well. If you can’t get the right perspective to crop an object out of the frame, like a fence or railing, tilting the lens can get that perspective even without moving your feet. That same perspective control can be applied to shooting a reflective object without getting a reflection of yourself in the photo.
To some extent, lines can be straightened in Photoshop and toy town effects mimicked. But, many shots taken with a tilt shift lens are not possible using a normal lens and editing software. Typically, minor perspective adjustments are possible (though more time time consuming), but extreme perspective adjustments can’t be recreated in post-processing.
Tilt shift lenses are popular additions to photography kits, particularly for photographers who shoot architecture or that simply want more control over the depth of field. Canon tilt shift lenses are designated with a TS-E in the name, while Nikon marks their tilt lenses with a PC-E. Schneider also makes several high-end tilt shifts, and Lens Baby makes a few affordable options targeted more towards enthusiasts than serious pros.
Tilt shift lenses allow photographers to adjust the perspective of the lens, without moving the camera. They’re a necessity for professional architecture images, and fun to experiment with for hobbyist photographers.