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Beyond Perspective Control

Regular readers know that I love my tilt-shift lenses. Also known as “perspective control” optics, these devices are really neat. They bring view camera movements into the world of the DSLR. And every time I connect one to my camera I’m struck by how uniquely they let me view the world.

Most folks who employ tilt-shift lenses use them for perspective control—that’s altering the optical physics in such a way as to maintain straight lines even when the sensor isn’t parallel to the subject. For instance, when an architectural photographer points her lens up at a building. This architectural use, where a tilt-shift lens is useful to help keep image elements straight and true, is perhaps the most popular use for a tilt-shift lens. But there are some other great reasons to try such a lens, from creative experimentation to practical resolution physics. Here are four of my favorites.

Canon’s TS-E 17mm tilt-shift lens

Laying Down the Plane of Focus

If you wanted to photograph a group of bowling pins arranged in a triangle, with the first pin a foot in front of the camera and the remaining nine spreading out behind, there would be almost no way to get all the pins in focus without a tilt-shift lens. You see, when the lens plane and sensor plane are parallel, the plane of focus is parallel as well. That results in the standard plane of focus that stands upright in every other scene you photograph. In these normal situations, adjustments to depth of field expand that field bringing it closer to the camera at the front, and farther from the camera at the rear. But there are limits to such depth of field, even when stopped down to f/32 and smaller. With a tilt-shift lens, however, the plane of focus can be “laid down” so that it runs through the scene more parallel to the floor than the walls. Then adjustments to depth of field via aperture extend the field up and down—ensuring the bowling pins are sharp top to bottom. When the required depth of field extends well beyond the limits of a traditional lens, use a tilt/shift to lay that plane of focus down.

Nikon’s 85mm tilt-shift lens

Depth of Field Special Effects

Speaking of depth of field, that same approach to “laying down the plane of focus” can be combined with a wide aperture of, say, f/4 to produce a thin swath of focus that runs away from the lens at a fairly acute angle. When paired with most typical subjects, this super-shallow depth of field creates a funky, artistic effect—virtually driving the viewer’s eyes straight to the center of interest. One approach is to photograph a regular city street from above, and by shifting the plane of focus and shooting at a shallow depth of field, the whole scene will appear to be a miniature model. In other cases, such as the still life shown here, the effect can isolate a sharp subject against bokeh in foreground and background for a bit of a painterly effect. It may be a funky effect, but it’s also a useful creative tool for isolating the subject and eliminating all the unnecessary ancillary details.

Wider Angle of View

Shallow depth of field
Shallow depth of field

The “shift” in a tilt-shift lens allows the lens to slide from side to side and up and down, all without moving the camera body. If you think of the area of coverage of such a lens as a tic-tac-toe grid, the normal position is the center square. Then the lens can effectively be moved to cover the top left corner, the top middle, the top right and all the remaining positions on the grid. The resulting exposures are easy to composite because the camera hasn’t moved at all. When layered together, these exposures create a significantly wider angle of view than the lens is capable of producing on its own in a single exposure. If you’re trying to make landscape images, for instance, the increased angle of view may enable you to get a shot that would be otherwise impossible. Even simply sliding the lens up and down to create three exposures and a more square composition delivers a wider view that opens up creative possibilities. The 17mm, 24mm, 45mm and 90mm tilt-shift lenses from Canon, as well as Nikon’s 24mm, 45mm and 85mm perspective control lenses, can essentially be made wider with this simple technique. It’s a technique I use all the time when photographing interiors, such as the one pictured here. To do it, simply lock the camera down on a sturdy tripod and compose as usual. Fire the first shot, then use the shift control to move the lens in one direction and lock it in place. Fire another shot then move the lens back down through the center position until it’s shifted all the way down and fire the final shot. Now you’ve created three exposures that will composite together nicely into a square format for a significantly wider angle of view. To expand the view to the sides, simply rotate the tilt-shift lens so that the shifts will now move left and right and repeat the exposures.

Higher Resolution Capture

High resolution capture
Higher resolution capture

One of the side effects of the above approach of compositing multiple frames is that it produces an image that is also significantly higher resolution than the single frame alone. For instance, let’s say you’re using a 24mm lens on a 22-megapixel sensor. By shifting up and down and adding just two additional exposures, you can increase the image size and the resolution by an impressive 40 percent. That’s the difference between a photograph that prints about 13 inches wide on the short side and an image that prints more than 18 inches wide. For photographers who want to maximize resolution, this technique practically turns a 35mm sensor into medium format. Better still, it feels like you’re using a large format view camera when you work this way. It may not work for everything, but for still life, landscapes and other stationary subjects, the tilt-shift lens has a lot to offer outside of simply correcting for distortion.

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