Have you noticed that when shooting tall buildings from a lower level, the base of the building tends to look disproportionately broader than the top? This is perspective distortion, and it is inevitable when shooting with a conventional lens. To capture an entire building with straight, parallel lines, you will need to use a tilt-shift lens. Learn more about what this special category of lens can do for architectural shots, and find out how to make the most of the Shift function. (Reported by: Ryosuke Takahashi)

 

What is a tilt-shift lens?

When you photograph an architectural structure, the camera angle can make perspective distortion look more obvious. For example, the tip of a building might look tapered if you shoot it from ground level.

A tilt-shift lens (known as TS-E lenses in Canon's lineup) is a special category of lenses that allows the photographer to move optical elements in the lens so that the distortion is corrected. These lenses generally consist two functions:

- Shift function: This uses a mechanism that slides a part of the lens elements along the optical axis. It helps to eliminate perspective distortion; and is good for photographing architecture, portraits, products and any other scenes where it is important to capture the subject’s shape accurately.

- Tilt function: Uses a mechanism that inclines the lens at an angle. This adjusts the area in focus in a way not possible with conventional lens. The most well-known effect of this is probably the miniature/diorama effect, where only a part of the image is focus.The tilt function also capable of the opposite:If a scene has a lot of depth, it can ensure that everything from the foreground to the background is in focus.

In this article, we shall focus on the Shift function and how it helps prevent distortion in architectural photography.

 

How does a tilt-shift lens work?

First of all, let’s take a look at what happens to an image if we don’t use the Shift function on a tilt-shift lens. This is the same as shooting with a conventional lens. Notice how there is a tapered effect toward the top of the building in the image below.

 

Without using Shift function

EOS-1D X Mark II/ TS-E24mm f/3.5L II/ Aperture-priority AE(f/5.6, 1/1000 sec)/ ISO 100/ WB: Auto/ Shift amount: 0mm (without using shift function)

Generally, when we photograph a tall building with a conventional lens, we need to point (tilt) the camera upward, and this causes the top portion of the building to appear disproportionately narrower than the lower part.

 

The optical axis without shift correction

The tapered effect occurs due to a change in the image magnification: When the lens is inclined, some points on the subject are further away from the camera while others are closer. This is due to the principles of optical perspective, which states that “nearby objects appear larger and distant objects appear smaller”.

 

With shift correction

EOS-1D X Mark II/ TS-E24mm f/3.5L II/ Aperture-priority AE(f/5.6, 1/1000 sec)/ ISO 100/ WB: Auto/ Shift amount: 5mm (up)

 

The optical axis with upward shift correction

When you use the Shift function to capture a tall building, you shift the optics upward. The optical effect that this creates is similar to moving the camera to a higher position while keeping the angle of the lens level with respect to the building. The vertical lines of the building will therefore appear parallel.

 

Why it works

As the image circle formed by a tilt-shift lens is larger than the image circle of conventional lenses, you can simply use the Shift function to slide the lenses off-centre, hence changing the part of the scene that is captured in the image.

 

How to get the best results from the Shift function

To fully utilise the Shift function, keep in mind these two essential principles:

1. Ensure that the camera is vertically and horizontally level
Tools such as the in-camera electronic level display will help you to check and adjust.
(See: Architectural Photography #1: 3 Basic Concepts)

2. Compose your shot with some additional allowance
Remember that when you use the Shift function, the part of the scene that is in the frame will shift as well.

For focusing, I recommend using the Live View function and shooting in manual focus (MF). You can magnify the Live View display to check the details of the image, such as whether your aperture setting is giving you ideal results.

 

Step 1: Adjust the camera settings

Before starting the shoot, tailor your camera settings for use with a tilt-shift lens. Some useful functions:

- The Live View function, which offers 100% coverage—perfect for ensuring that distortions are corrected.
- The electronic level, grid display, and any other tools that can help you ensure that the image is level, is best suited when photographing with a tilt-shift lens.

Of course, you can also shoot through the viewfinder. However, depending on the shift amount, light through the lens may be partially blocked and cause the exposure to fluctuate. Shooting in Live View is ideal as it provides a good preview of the final image.

 

Step 2: Mount the camera on the tripod and ensure that the image is horizontally and vertically straight

1. Mount the camera onto the tripod and switch on the camera. (1st image)
2. Use the electronic level to ensure that the image is horizontally and vertically straight.
(Note: Even if the ground surface appears level to your eyes, it may in fact be slanted. Always use the electronic level to be sure.)

Once you have ensured that the camera is upright and level, you may find the top part of the image is cropped off (2nd image). This will not be a problem after shift is applied.

After you have set up the camera, you might want to take a few test shots both with and without the shift to familiarize yourself with the effect.

 

Step 3: Shift the lens to correct the distortion

Once you have ensured that the image is perfectly straight, turn the shift lock knob to unlock it. Then, rotate the shift knob to shift the lens upward. Adjust the image until you can see the entire building in the Live View preview. 

For this shot, I shifted the lens upward by 5mm. The shift amount to use depends on the focusing distance and the height of the building you are photographing.

Use the grid display to help you “see” and adjust the balance between the sky and the ground. Finalize your composition, and take the shot when you are ready. 

 

Which Canon tilt-shift lens to choose?

Canon offers a diverse lineup of tilt-shift lenses with different focal lengths, and each of the lenses varies in character. 

The shift function is useful not only for photographing architecture, but also for portraiture, product photography, and any other scenes where you need to eliminate perspective distortion and capture the shape of the subject accurately.

Meanwhile, the tilt function for adjusting the area in focus comes in extremely handy for special uses not possible with a conventional lens, such as capturing striking landscapes or creating miniature effects with only a part of the image in focus, or producing shots of a table full of dishes that is in focus throughout from the foreground to the background.

All TS-E lenses have the same shift and tilt functions and feature the “TS rotating system”, which allows the tilt and shift angles to be rotated up to 90° in both directions.

 

 

Learn more about the TS-E50mm f/2.8L Macro, TS-E90mm f/2.8L Macro and TS-E135mm f/4L Macro here:
Canon Announces 3 New TS-E Tilt-Shift Lenses

For more on architectural photography, check out:
Pro Tips for Improving Your Street-level Architecture Shots
6 Ways to Perfect your Architectural Photography with a Kit Lens
Architectural Photography and Lighting Techniques

 

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