One of the common misunderstandings in photography has to do with the focal length of a lens, or its optical distortion properties. Many photographers claim that a wider angle lens will distort facial features either because of the lens distortion, or the focal length of the lens being too short. In this article and the accompanying video (which is extracted from our upcoming Photography Life Basics Video), we will prove that focal length has nothing to do with distorting a subject’s face and the additional information on lens distortion will explain in detail exactly what gets impacted by lens distortion.
What is Face Distortion?
Before we discuss the impact of lens distortion and focal length, let’s first take a look at what face distortion is. While the word “distortion” here sounds similar to what we see on wide angle lenses that suffer from optical distortion, the two are not the same, as facial distortion is the result of perspective distortion, a phenomenon that occurs due to subject being too close to the camera. Take a look at the below subject, photographed with a short focal length lens at close distances:
We can see that in the first photo the subject is too close to the camera, which completely distorted his facial features – the face is stretched across the frame. In the vertical photo, the camera was moved away from the subject, which resulted in a lot less face distortion. However, the subject is still too close and the area outside the center frame is stretched heavily, causing the subject’s shoulders to appear very disproportional compared to the rest of the body.
While getting close to subjects can result in interesting and funny-looking photos like the ones above, this is not the way to photograph people normally.
Lens / Optical Distortion
Lens distortion, also known as “optical distortion” has nothing to do with perspective distortion mentioned above. Most lenses suffer from some type of optical distortion, but the particular offenders are wide angle lenses, which can show pronounced “barrel” distortion in images, as shown in a diagram below:
Seeing such distortion can easily trigger one to assume that facial distortion is caused by barrel distortion, since the effect is similar – the frame is stretched in a barrel fashion just like what one would see in the image samples above. However, that’s definitely not the case, because even lenses that exhibit the worst amount of barrel distortion won’t distort the subject as long as the subject is kept away from the camera.
Now, does this mean that optical distortion doesn’t play a role in distorting subjects? No, it sure does! If you use two similar focal length lenses with completely different distortion characteristics, the lens that exhibits more optical distortion will definitely make your subject appear more distorted. However, the effect is a lot less pronounced than you might think and can really only be seen at extreme close-ups. The effect of perspective distortion is far more substantial on a subject than optical distortion. For example, the Nikon 50mm f/1.4G suffers from approximately 1.4% barrel distortion, which can be easily seen when photographing anything with straight horizontal lines:
The barrel distortion on this lens practically does nothing in terms of introducing distortion to subjects. However, if the subject is placed at a very close distance, say if the subject’s face is tightly framed, we see two effects at the same time – perspective distortion and optical distortion, both of which are going to make your subject’s features appear slightly disproportional.
This leads us to focal length. Let’s take a look at what focal length does to our subjects in terms of distortion.
Focal length affects how tight our subjects appear in the frame, but it does absolutely nothing to affect the perspective. If you stand in the same spot and use a zoom lens to shoot at different focal lengths, the perspective will remain the same. This can be easily proven by photographing the same subject at different focal lengths, then analyzing the relative sizes of objects in the background. Take a look at the below comparison, shot at 24mm and 50mm focal lengths:
While the two different focal lengths resulted in differently framed images, the size of the subject relative to the background is the same. Here is the same image on the left, except this time it is cropped to have the same framing as the image on the right:
Note that using two completely different focal lengths also did nothing to distort the subject’s face or body, which proves that focal length has nothing to do with face distortion.
Take a look at another image, which I captured at 11mm on a full-frame camera (which is considered to be super wide), then tightly cropped:
At 11mm, if I placed the subjects at a very close distance to fill the frame or have similar framing as in the above image, they would appear extremely distorted. And yet at this particular distance and with this heavy of a crop, the subjects appear normal. This again proves that focal length has nothing to do with facial distortion!
To further solidify this concept, take a look at the below video:
P.S. This video was extracted from our upcoming Photography Life Level 1 Basics video product, which we are planning to launch very soon. Since it was a more advanced topic, we decided to post it for our readers in this article.
In the video, we demonstrated that at the right distance, the model’s facial features appeared normal. But once we moved closer to the model, we saw the immediate effect of perspective distortion on the subject. Here is the same model at 35mm at two different distances:
We moved the camera, but the model remained in the same place. You can see a drastic change in the way her face appears in the two images, with the one on the right showing a much more stretched face, bigger nose and eye. Putting the two images together and aligning them reveals this drastic change in facial features:
This is something to expect when the subject is framed too closely with a wide angle lens.
Some people might argue that the focal length impacts distortion indirectly, because a wider lens requires one to get closer to the subject to keep the same framing on the subject. That’s definitely true, but that again has nothing to do with the focal length of a lens itself – it is the changed distance that causes such distortion issues. Here is another example, this time wih the subject framed the same, but captured at different focal lengths:
Now this is a classic case of perspective distortion – look at how going from 300mm to 14mm changed not only the perspective, but also the model’s facial features and her body.
a photo is just the 3D world projected on a 2D camera plane, with any amount of basic high school optics knowledge you would know only the distance can affect the so called “perspective distortion” since the if you take the photo close up the ratios of different parts of the object vs. the focal length vary much more than when the photo is taken far away. I don’t know why it’s called “distortion” because it’s not. It’s how the object should be viewed by your eyes, this is what’s realistic.
Technically there is no distortion at all.
A photo taken close up should be viewed close up.
A photo taken from far away should be viewed from far away.
By viewing at the incorrect viewing distance for any lens or subject distance you can perceive distortion.
However, when the photo is viewed at the correct distance, everything suddenly looks normal.
For example take a photo with a fisheye lens.
Totally weird and distorted?
Hang on… hold the fisheye image right up close to your eye and hey presto! No more distortion!
Excellent article! Nasim, you do a fantastic job at explaining these common questions/issues I have in in my head regarding photography. It’s very enlightening when reading your posts.
One thing you need to bear in mind when viewing wide-angle shots is your viewing distance to the image. If you view such an image from the same relative distance as the camera was from the subject (i.e. with the distance scaled down from life-size real-life distance) you may find that a lot of the ‘distortion’ is corrected. I’ve only noticed this with objects at the periphery of wide-angle shots that tend to get elongated, but a similar effect may well occur with the model’s face in these pictures.
In situations where the camera may be said to be ‘too close’ to the subject, it can sometimes also be said that the viewer is ‘too far away’ from the image. Admittedly it can be tricky viewing a picture from a couple of inches away…
I agree that distance to camera distorts. I disagree its only due to perspective. Take the last 2-pics example in the article. Perspective distortion cannot explain why her face looks elongated and her body looks slimmer. I came to this article after a day of frustration taking selfies and one arm length (wide lens) and selfies at several feet (same wide lens zoomed in). My face always looks elongated and slimmer at one arm length and more round at several feet zoomed in. I don’t think this can be explained with “perspective” since the horizontal and vertical widths of my face are at the same distance to the camera.
I am a regular reader of your posts which help me a lot.
Regarding focal length and distortion, i have a question.
Is there any general rule which gives information about the minimum distance between object and lens (focal length) so that image will not have optical distortion.
Especially distortion which comes due to incorrect distance between object and camera.
I have learned so much by reading your posts and counter comments from your readers. I am an amateur stepping into the field of wedding photography for supplemental income. I’ve been surfing the net and reviewing several different equipment packages to get started but it’s all quite confusing. Not quite sure which will be my best bet. Could you kindly make a recommendation that will be economical and effective.
Thanks in advance,
Nasim, thanks again for another great article. I just purchased a Tamron 15-30 for my Nikon D-750 and to me it presents kind of a Catch 22. In order to frame the subject properly at an extremely wide setting, I have to get too close resulting in a lot of distortion. If I stand at a far enough distance to eliminate the distortion, the subject matter is much too small. Either I don’t need that wide of a lens or I just need to learn how to better utilize it. My previous experience has been with a Nikon 24-120 which seems perfect for about 90% of my shots.
At what focal length does lens distortion no longer play a part in the image? ie, at what focal length do you no longer get lens distortion?