This is the continuation and concluding part of my previous article series on Perspectives. I have covered the four basic techniques of creating perspective namely:
I. Blocking, overlap or obstruction
II. Relative Size
III. Linear, Rectilinear and Vanishing Point
IV. Lack of Sharpness, Color Quality or Contrast
You can read the first part of the article here:
Now let’s get into some of the advanced concepts and clarify a few myths regarding perspective.
I. Framing vs. Perspective
Many of my friends believe that they need a wide angle lens to create “exaggerated” perspective in a photo (i.e. create an illusion of a normal size closer object to appear much larger). Similarly a telephoto zoom lens “compresses” perspective (i.e. creates an illusion of actually distant objects coming closer together). While this technique is not wrong but the theory behind this process is incorrect. Let me explain.
In the above example we think focal length of the lens determines the perspective of exaggeration/compression. Before commenting on the validity of this assumption, let’s try a quick experiment.
Stand at one place, focus on a subject (make sure you have lots of other objects in your frame) with focal length of 24mm, 50mm and 85mm. Change your lenses if you have to.
Now compare the results.
Here’s the samples (Note: I have cropped the photos taken at focal lengths 49mm and 24mm so that you can compare the relative size of the different objects easily)
focal length = 80mm
focal length = 49mm
focal length = 24mm
You can see that the relative size of the objects in the photo is UNCHANGED. In the Part I of this discussion, I had defined Perspective as -
“Perspective in photography can be defined as the sense of depth or spatial relationships between objects in the photo, along with their dimensions with respect to the viewpoint (camera lens or the viewer).”
Now if changing focal length does not alter the relative size of the objects, then how can we say that focal length affects perspective. To further illustrate this idea let’s continue with the experiment.
With one fixed focal length (say 40mm) let’s take 3 photos of the same objects but now moving closer ~5ft after each shot. What we are doing here, is to change the viewpoint by changing the distance between the lens and different objects in the frame.
Now let’s compare the results.
Here are the samples (Note: Like previous set of photos I have cropped the images so that you can better judge the difference in the relative size of the objects in the photo) with fixed focal length of 39mm.
Distance 2.5ft from the subject
Distance 4ft from the subject
Distance 7ft from the subject
You can see in the above photos that the relative size of the subject does CHANGE with respect to the other objects in the photo (surroundings) as you move closer to it. (In photography terms, this is called “foot-zooming”).
Bingo! We have changed the perspective!
So changing lenses (focal length) didn’t change the perspective of our scene while changing our position. This bring us to the conclusion that the Perspective is determined solely by the relative distance between the objects and lens, but not by the focal length of the lens. Hence the perspective doesn’t change when we move from wide angle to telephoto lens. Or in other words, a wide angle lens has nothing to do with perspective. Hence wide lens does not exaggerates or distorts perspective, and telephoto lens does not compresses it. It’s a myth.
Now from theory to practice – what is important to understand here is when you actually change position, you CAN change perspective.
Amateur photographers are prone to standing at the most “convenient” spot and vary focal lengths merely to be able to frame a subject. They probably don’t even realize that there is a dramatic composition advantage in finding a better vantage point for the shot. And this is the motto of this whole article. Not changing your location (camera position) might keep you from obtaining the best shot of the subject and their surroundings that you can ever have. So in effect, it is the framing that is affected by a change of Focal Length without change of camera position.
So when you are about to take the photo, assume that you have a fixed focal length lens (also called prime lens) and BEFORE you zoom, first choose a spot, then experiment with the focal length. Golden rule of composition: Get the perspective first and then frame the shot.
II. Playing with Perspective
Now a good photographer’s task is to show a good rendition of the subject’s form and shape, so that the viewer gets the sensation of volume, space, depth, and distance. This is well elaborated in Part I of this article.
But to make things look different (or funny!) the photographer can choose to manipulate perspective to change the illusion of space and distance in such a way that unrealistic special effects can be achieved.
A lot of example photos can be found at the website dedicated for the such perspective shots:
Funny Photos taken at unusual Angles at hongkiat.com
The closer part of the object (feet)in the above photo is abnormally bigger and more dominant. Thus the effect of exaggerated perspective is created.
When we take photographs of buildings, this problem of distorted perspective is most commonly seen, While sometimes the effect of distorted perspective does add an additional “interest point” in a photo, in my opinion, in most cases it can degrade the general impression of the image. The distortion in an image can be used only when the distortion adds a purpose to the photo’s main theme. In the next section I will explain distortions and their corrective options.
III. Distortions and their Corrections
As described in section I, there are no such things as “wide angle distortion” or “telephoto compression”. But then why we are able to get a distorted photo when we use the wider side of a lens? Well, the answer is because a wider lens will ALLOW you to focus on very close object. By “close” I mean closer to your lens. This “closeness” or the distance between the lens and the subject is what creates perspective distortions and not the focal length of lens.
The above photo illustrated a perspective projection distortion which is an inevitable phenomenon. It occurs in photos when the sensor plane is not parallel to lines that are desired to be parallel in the photo.
So how do you control/fix perspective issues in the photo.
One of the ways is to use perspective correction lens. (which are of course expensive). These are called “Tilt and Shift” lenses.
Fortunately, in this digital world, with the help of Adobe Photoshop or similar image editing tools, you can correct distortions by using Transformation tools. The process is really simple and fast.
The Photoshop tutorial in itself will take another separate discussion, but to give you a jump start, you find the menu options “Perspective”, “Skew” and “Scale” under Transformation Sub-Menu under Edit. The goal is to make all straight lines, which are vertical in reality, vertical on the photo and all parallel lines (such as four horizontal edges of a cubic room) cross in one point. You can watch my 5 minutes quick tutorial on the “basics” of using the options in Photoshop to fix the perspective projection distortion here:
But the perspective distortion in portraits caused by placing the wide-angle lenses too close to the subject can cause “big nose” or “big forehead” effect which is really difficult to fix in post-processing.
A lens with focal length from about 85 through 135 mm is generally considered to be good portrait lens for 35mm (24mm x 36mm sensor) camera. This is to FORCE you back by 8-10 feet from the subject which gives a good framing and perspective both at the same time. Moreover for a “shy” model, this is a comfortable enough distance.
In this whole engaging discussion about perspective, I deliberately left out the “background blur” effect which might be the “side-effect” of trying to control the perspective by altering the distance between the subject and the lens or due to framing by changing the focal length. Watch the above 3 sets of the photos closely to compare the background blurring and how both changing distance and focal length affected the Depth-of-Field. This needs in-depth “stand-alone” discussion on the topic of DOF.
This concludes my discussion on perspective covering the following topics:
I. The Four Techniques of Perspective Control
II. Framing and Perspective
III. Playing with Perspective
IV. Perspective Distortion Corrections
About the author
Sudipta Shaw is a Software Professional and a Self-made Photographer. He likes to mentor and teach. He is the founder of the site www.pleasurephotography.com
See also: Photography Tips