How varying camera placement affects apparent perspective.

Understanding Perspective “Distortion” in Photography

A longer focal length does nothing but magnify the image.

Except where otherwise noted — All photos herein ©Charles G. Haacker, Author. Yes, I drink instant Folgers. Wot’s it to ya?

The banner picture above was made with my crop-sensor (APS-C) Sony A6400 fitted with a Sony E PZ 18–105mm f/4.0 G OSS (27–158 FF equivalent). The lens was at 105mm, ISO 200, 1.5-sec @ f/22. A crop factor of 1.5 from APS-C to full 36x24mm causes a 105mm to perform as if it were 158mm, a decent telephoto. We call them “telephotos” since they magnify like a telescope.

This beast of kit is an excellent general-purpose outfit. If told I could keep only one body and lens, I’d choose this and a 10mm extension tube.

The setup: The jars are sixteen inches apart, center to center. The camera was sixty-four inches (five feet) from the nearer (red) jar.

In photography, there is a curiosity often referred to as Perspective Compression. I use it instinctively, from decades of practice, but what exactly is it? Is it even a real thing? (It’s not.) Why would you want to learn about it?

It’s a common misconception that the apparent phenomenon of “perspective compression” — where distant objects in a scene look closer or further away from nearer objects — is affected by changing your focal length. Conventional wisdom and your own two enchanting Mark-1 eyeballs seem to support the notion that the longer the lens, the closer the far appears to the near.

‘T’ain’t necessarily so.

Bbb-bb-but, you stammer; the far-away stuff looks closer when I use a telephoto. Yes, it does because longer lenses magnify everything in their field of view. The effect is not compression; it is foreshortening.

I recalled an assignment from school intended to teach us how focal length and camera position affect spatial relationships in a 2-dimensional rendering of a 3-dimensional scene. I tried to duplicate that exercise.

With this first group, only the focal length was changed. The similarity was achieved through careful cropping.

85mm on the left, 50mm at the center, and 24mm at the right. The difference is that the three images were cropped so the red jar would appear about the same size in each frame.

The camera didn’t move. The jars didn’t move in relation to each other or the camera. Only the focal length was zoomed back, the same as if I had changed out three primes of similar focal lengths.

Our instructors’ exercise taught us that we could prove the rule by cropping. We’d taken three photos, each with a wide-angle, a normal, and a telephoto, while not moving the camera on its tripod. The apparent spatial relationships with distant objects did not change, regardless of the lens.

Therefore, it is not the lens; it is the placement of the camera. Relationships change when the camera is moved in any direction, regardless of focal length.

In this second set, the focal length was changed, AND the camera position was altered by moving closer to hold the red jar the same relative size in each frame. Look what the green jar seems to be doing…

85mm on the left, 50mm at center, and 24mm at right.

Neither jar moved in relation to the other; they are still the same sixteen inches apart on their centers, so why does the green jar appear to be receding further from the red?

In the second group, the cropping was all done in-camera, shortening the focal length while physically moving the camera closer to hold the red jars about the same size in each frame.

That has the effect of foreshortening the perspectives. The green jar only appears farther from the red because the camera has moved closer.

Conventional wisdom often suggests you don’t need zooms because you can “zoom with your feet.” ‘T’ain’t necessarily so, though, because moving the camera changes the spatial relationships among objects in your scene. You don’t even need a camera to see it; just look at any scene while moving left and right, closer and further, while watching the relationships in the scene. It might be an ah-ha moment for you.

I worked with a matched pair of Canons, two zooms and a 28mm prime for a decade. They were outstanding!

I was an early adopter of zooms for professional work after burglars hit our studio one night and lifted my Nikon bodies and all their prime lenses. We were “between insurance,” so I had to replace them out of pocket. I chose the kit pictured above because it was what I could afford. I never looked back; been a confirmed Zoomie since 1986.

“Zooming with your feet” sounds reasonable. If you need to “zoom in,” just walk toward your subject until the finder is filled, easy-peasy. If you want more context in the frame, turn around and step further away.

Does it work? Absolutely. You can do everything with a normal Nifty Fifty or equivalent; what’s not to like?

What they don’t tell you is that every time you move the camera in any direction, you change the *perspective,* the perceived spatial relationships among all the elements in the picture, foreground to background.

Many, if not most of you, have seen the so-called “distortions” incorrectly attributed to (blamed upon) focal lengths, most especially wide angle vs. telephoto.

This animation from Fstoppers is the best I have seen

These noticeable differences lead most photographers to believe that wide angle lenses are distorting a scene while telephoto lenses are compressing a scene, but they are overlooking what is actually happening: the camera is moving. In reality, the distance from the camera to the subject is what is creating these distortions. — Fstoppers

There are only two genuine optical distortions, called barrel and pincushion.

From Learning With Experts website.

Some wide-angle lenses will exhibit barrel distortion, where parallel lines in the picture appear to bow outward, like a barrel. Many post-processing applications will have a tool to correct this. Pincushion, where parallel lines seem to bend inward, are more likely to be seen in telephoto lenses. Zoom lenses, especially cheaper ones, may suffer from both at either end of their range. I routinely use Lightroom Classic’s Lens Correction Tool on every processed picture inasmuch as I use zoom lenses almost exclusively.

But barrel and pincushion are actual optical distortions within a lens. The “distortions” and “compressions” you hear about are not optical but illusionary. (Psssst, Bob, he sez we’re seein’ t’ings…)

These pictures were both made with my crop-sensor (APS-C) Sony A6400 and Sony E PZ 18–105mm f/4.0 at 105mm.

Camera in fixed position:

I wanted to see if I could manage a portrait ringaround working alone. The first set of six below was made with the camera at a fixed distance. Only the focal lengths were changed. When the pictures were each enlarged to headshot size, you can see that the background objects did not change in relation to me or one another.

60mm. The shot on the right ← → was cropped from the one on the left.

40mm. The shot on the right ← → was cropped from the one on the left.

30mm. The shot on the right ← → was cropped from the one on the left.

The only changes were the focal length and the crop. If you try this you’ll probably get lots of grain (noise) the more you enlarge, but most post-processing apps should have de-noising tools built in. All these pictures are unretouched.

Camera moving closer to subject:

The set below was made (extremely tediously working alone) by getting up and moving the camera closer for each frame, cropping in the camera. Compare the first, made at 105mm (equivalent to 158mm on a full-frame camera), with the bottom right, made at the lens’s shortest focal length of 18mm (27mm equivalent); you are seeing the misnamed “wide-angle ‘distortion’” from the camera being too close. The apparent warping is due simply to the lens being closer to my nose than my ears.

105mm — 40mm

30mm left; 18mm right. This is why most portraits are made with longer lenses, to get the sensor farther away for better perspective.

So, if you’ve wondered why so many phone selfies look weird, it’s mainly due to their being held at arm's length, which is too close. Selfie sticks may not have been invented to make the perspective more pleasing, but they serve that function well.

📸As always, gratitude for looking in. I sincerely appreciate it! Questions in the comments will be answered promptly, so please ask.😊👍