The Tilt Shift Lens Avoids Perspective Distortion


How Does Perspective Distortion in Photography Happen?
What do we naturally do when we want to photograph something that is too tall for the normal view of the camera? We lean back and point our camera upwards, effectively tilting the plane of the sensor of the camera away from the building. Even a little tilt like this can introduce visible perspective distortion. If we're really lucky, or really in a hurry, we might not even be standing front-and-center of the building, and then we have a leaning back, leaning over, all edges wonky building in our photo, like the first one in this article. To give you some incentive for reading more, here are two photographs to better illustrate what I'm talking about, although both were taken with the same Canon 24mm f/3.5L Tilt Shift Lens, only the second one employed the Shift function of the lens.Bad: Distortion

Better: Less Distortion with a Tilt Shift Lens


Methods for Avoiding or Correcting for Architectural Perspective Distortion
There are a few different ways to avoid, or correct for the perspective distortion in real estate photography commonly seen as FOBS (Falling-Over Building Syndrome). Let's talk about the ones that don't use a tilt shift lens, first. 1. Back Up, No, Back Up Even More You can back way up, until the whole building is in your viewfinder, without having to tilt your camera upwards.- The main advantage of the Back Up, No, Back Up Even More approach is that you can use any camera, even a point and shoot.
- Disadvantages of the Back Up, No, Back Up Even More approach, however, are many.
- You might be so far across the street that your images are full of cars and pedestrians, trees and utility poles.
- You lose significant details of the building because so many of the pixels in the images are full of the stuff you didn't want in your picture (people, cars, etc.).
- The main advantage of the Stand on Something Really Tall approach is that you can use any camera, even a point and shoot.
- The disadvantages of the Stand on Something Really Tall approach are many.
- I mean, really, who carries a 20 foot ladder with them?
- How many homeowners or business are going to let you on their roof?
- How many fantastic architectural specimens or multi-story homes are across from a parking garage?
- The main advantage of the Correct in "Post" approach is that you can use any camera, even a point and shoot.
- The disadvantages of the Correct in "Post" approach are many.
- You have to edit each photo individually, to pull the top or the edges of the building back into alignment. (I'll be writing another article on this soon).
- You lose some of your resolution because your adjusted image will have wonky edges and will need to be re-cropped, which cuts out some of your data.
- Your image is unlikely to really look "right" because you're effectively compressing some of the data and expanding some of the rest, so the clarity and sharpness of detail won't be consistent.
- The main advantage of the Use an Ultra Wide-Angle Lens approach is that a wide-angle or ultra-wide angle lens like the Canon 10-20mm can be purchased for most DLSR cameras, and even the iPhone has a little lens that can be attached to increase the angle of view.
- One (significant) disadvantage of the Use an Ultra Wide-Angle Lens approach is that most wide-angle lenses have distortion at the edges. You may have avoided some of the distortion associated with FOBS (Falling-Over Building Syndrome), but you will likely introduce edge distortion and your pictures still won't look professional.
- Using a Tilt Shift Lens, or more specifically, a Shift Lens essentially makes the camera think you ARE on top of a really tall ladder, while keeping the plane of the camera's sensor parallel to the face of the building.
- It does this by shifting the lens up a few (or many) millimeters relative to the camera's sensor.
- A few millimeters mat not seem like a lot but when you figure the sensor of a full-frame Canon camera like the 5D Mark II is 24mm high, a few millimeters is actually quite a lot.

The Canon Tilt+Shift Lenses
We have a single tilt+shift lens from Canon, the TS-E 24mm f/3.5L II. This lens is a wide-angle lens that is amazingly sharp and distortion-free from edge to edge which means we can take photographs free of architectural distortion. This lens has +/- 12mm of shift capabilities and +/- 8.5 degrees of tilt. (The glorious benefits of Tilt will be the basis of another article).