Most people have never seen a tilt shift lens or even heard of one. It looks like a pretty normal lens most of the time, so even if you see one it might not register as unique. However, it is unique in 2 ways: It can tilt and it can shift.
The shift function means the entire lens can move from side to side (or rotate and move from top to bottom) while the camera is held perfectly still on a tripod. The lens points straight ahead, but it can move left and right or up and down.
I’ll write a different blog on the tilt function, but with that function the lens can be “bent” or angled so it points upward or downward (or rotated and point left or right). For now, let’s stick with shift.
Why is this lens important? The primary use is architectural. The picture at top shows the home taken with a 24 mm tilt shift lens using the shift function. Notice the home is straight, not distorted. Using an identical 24 mm lens without using the shift gives a photo like the one at right. It is easy to see the value of the tilt shift lens when you compare these photos. Only the tilt shift can provide this corrected and sharp image. If the home is straightened in photoshop it will not be as sharp and many pixels will be lost. This shift function allows a photo to be taken without the normal level of distortion seen in other lenses.
The red lines are vertical and horizontal and were added to the photos to make them easier to evaluate. Of course, normally such lines would not be needed or added, but with them the extent of the difference is even more apparent.
The way one uses the lens is to first line up the photo straight on at the subject which is how a wide angle gives the least distortion. The camera must be on a tripod so focus will be accurate and exposure accurate. Metering works in the neutral position, but not the shift position, so you set and manually focus the photo and put the exposure in manual mode Then, instead of tilting the camera up to capture the image, you shift the lens up so the upper part of the home is in the frame. The camera has not moved, only the lens shifted. It did not change the plane of focus so there is no distortion.
Bottom line…if you have a camera that can handle the lens, then tilt shift lens is a must for the architectural photographer. Though the above paragraph does tell the story, you’ll find it easier to grasp when you try the lens (you can rent them from shops like Glazer’s in Seattle). The pictures above are the most powerful argument for the utility of the lens. All the apparatus in the lens renders some metering and all autofocus operation null. Manual focus and manual settings are needed, so this is typically a professional level tool.
The shift function has landscape photography application as well. By setting the center frame and then shifting left and then shifting right, I took 3 images of Manito Park’s Duncan Gardens and used Photomerge in Photoshop to make the panorama shown. Unlike normal panoramas created by merging multiple images there is a more complete and “lined up” image created and it lacks the typical distortion seen in most panoramas. Other lenses will create a panorama, but require considerable cropping and loss of pixels. With the tilt shift there is no loss of information, all lines up perfectly, and the image is sharp throughout.