How face shape changes in photos according to lens

Taking photographs is a way to capture special moments and create lasting memories. However, the captured images do not always correspond to our real appearance, especially when we evaluate the shape of the face registered in the selfies. This can generate frustration and, over time, even lead some people to seek unnecessary aesthetic procedures, due to a distorted self-perception.

One of the main factors that influence how you look in photos is the lens choice, which can generate perspective distortions and affect how we perceive face and body shape. In this article, we'll explore how focal length and lens choice can influence appearance in photos and how to avoid unwanted distortion.

Understanding Perspective Distortion: What It Is and How It Occurs

A perspective distortion it is an optical phenomenon that occurs in all lenses, including the most expensive and sophisticated ones. It is a direct consequence of the laws of optical physics and lens geometry, and becomes more evident with the types of fixed focal length lenses present in smartphones – which are the devices massively used to take pictures today.

The phenomenon is caused by the difference in distance between the photographed objects and the camera lens. When an object is close to the lens, it will appear larger than objects farther away, creating a sense of distortion in the image. This is what happens with selfies, in which the distance from the camera is limited by the size of the arm of the person taking the picture and, to make the proper framing, manufacturers choose a lens wide-angle, which has a shorter focal length to increase the field of view.

With a larger field of view, the lens is able to capture more elements of the scene, including those closest to the camera. This makes perspective distortion more evident in photos taken with wide-angle lenses.

To minimize the effects of perspective distortion, it is important to pay attention to the distance between the photographed objects and the camera lens, and choose the most appropriate focal length for each situation. Additionally, some lenses are specifically designed to minimize perspective distortion, such as Tilt-Shift lenses, which allow you to adjust the position of the lens relative to the camera sensor to correct distortion.

The different types of lenses and how they affect the captured image

Camera lenses are also classified according to focal length, which can vary from ultra wide angle a telephoto. By default, the focal length of the lens considers a camera type full frame, whose sensor is equivalent to a 35mm photographic film — those of analog cameras. Each type of lens has its own characteristics and effects on the captured image, learn how they are classified:

• Ultra wide-angle: these lenses have a focal length of less than 24mm on a full frame camera, allowing the captured image to include a large amount of scene in a single frame. They have a wide perspective, which can result in barrel distortion (straight lines that appear curved away from the center of the image). Ultra wide angles also tend to elongate objects near the edge of the frame.
• wide-angle: these lenses have a focal length of between 24mm and 35mm on a full frame camera. They have a wide field of view, but less extreme than ultra-wide angles. They can also exhibit barrel distortion, but to a lesser extent than ultra-wide angles. Wide angles can help create a sense of depth in a scene.
• Standard: these lenses have a focal length of between 35mm and 85mm on a full frame camera. They are the closest to the natural perspective of the human eye. Standard lenses have little or no noticeable distortion, and are often used for portraits.
• Telephoto: these lenses have a focal length greater than 85mm on a full frame camera. They allow the photographer to isolate distant objects or compress the perspective of a scene. Telephoto lenses can help soften facial features and backgrounds in portraits. However, they tend to compress the scene and flatten nearby objects.

It is worth remembering that the real focal length on smartphones is smaller than on cameras. full frame, due to the small size of the sensor. The focal length values ​​reported by cell phone manufacturers are not real, but the equivalent of full frame.

Choosing the right lens can make a big difference in the final result of the captured image. It is important to consider the purpose of the image and the desired perspective before choosing the appropriate lens for the situation.

The different categories of lens distortion and their visual effects

Just as there are lens categories for types of expected results in terms of image composition, there are also different types of lens distortions. It is interesting to note that for each type of lens, there is a corresponding type of distortion, namely:

• Barrel Distortion: This distortion makes straight lines appear curved outwards, as if they are curving towards the edges of the image. It's common on wide-angle type lenses and can be useful for shooting indoor architectural work, but can distort faces when used for portraits.
• Pillow Distortion: Unlike barrel distortion, this distortion makes straight lines appear to curve inwards, as if forming a cushion. This is common with telephoto lenses and can be useful for portraits, but can cause problems with architectural images.
• Perspective Distortion: This occurs when perspective is changed by the position of the camera relative to the subject. For example, when a person is photographed from the bottom up, it may appear larger than it actually is. This can be useful for creating a dramatic effect, but it can also distort a person's appearance.
• Field Distortion: appears when the lens is unable to keep the entire image in focus at the same time. This is common with wide aperture lenses and can create an artistic effect, but it can also cause problems in group shots where some people may appear out of focus.
• Coma Distortion: This occurs when point lights appear as comet-shaped spots. This is common with wide-aperture lenses and can be useful for shooting stars at night, but can cause problems with portrait shots.

How does lens distortion affect self-image in selfies?

With the popularization of selfies, it is increasingly common for people to use the front cameras of their smartphones to take pictures of themselves. However, as mentioned earlier, the perspective distortion produced by front-facing camera lenses can have a negative effect on people's self-image.

According to a study conducted by researchers at the Rutgers University and the Boston University, perspective distortion from the front cameras can make people's faces appear up to 30% larger than they actually are. This can lead to dissatisfaction with appearance and, consequently, to a search for aesthetic procedures such as facial harmonization and fillers.

Another study carried out by University of Toronto and Ryerson University found that people tend to rate their appearance more negatively in selfies taken up close (less than an arm's length away) than in selfies taken from afar. This suggests that perspective distortion from front-facing cameras can significantly affect people's self-image.

How to minimize perspective distortion in selfies?

It is important to remember that perspective distortion is an intrinsic feature of the lens and, therefore, cannot be completely eliminated — but it can be mitigated, mainly, by increasing the distance between the camera and the face. However, with some techniques and adjustments, it is possible to minimize it and obtain images that are more harmonious and faithful to reality. To reduce lens distortions in your photos, check out our tips:

Use a selfie stick (or selfie stick)

The main factor to consider to avoid lens distortion is the distance from the camera, and when taking selfies we are limited to arm's length. To increase this distance, the classic selfie stick can be used and, in this way, it improves the aspect of the photo. You can find the Docooler model, with bluetooth trigger, by R$ 39.99 on Amazon.

use a tripod

The advantage of the selfie stick is being able to take the photo using the front camera, which allows you to view the framing of the image in real time. However, this lens remains a wide-angle lens that provides greater distortions when advancing towards the edges of the photo. To reduce distortion, just turn the phone around and use the main camera, but then we have another problem: it is necessary to move the camera further away to frame, and at that time the use of a tripod comes in handy.

With the tripod, you can take pictures at any distance, being perfect for making a good framing of what should be photographed. With the use of the timer or a remote trigger — available on most smartwatches and smartbands — you can take a beautiful photo, avoiding distortions in the final image. You can find the I2GO Basic model by R$ 21,90 at Amazon.

Avoid positioning your face at the edges of the photo

If you're going to shoot using a wide-angle lens at close range, forget about the rule of thirds — the one that positions the subject in the left, right, top or bottom third of the image. Wide-angle shots, as we've already seen, have a wider field of view, and distortion increases as we get closer to the edges of the image.

To avoid these distortions, keep the subject centered in the image, avoiding using the edges — see how the model's arms become elongated as they approach the side limits of the photo, and faces far from the center appear in an elongated format.

Use lenses with longer focal length

Human vision is “equivalent” to an approximate focal length between 50 and 80 mm. This range comprises the main cameras of part of current smartphones, such as the telephoto line Galaxy S23 with 70mm and iPhone 14 Pro e Pro Max, with 77mm. It is worth noting that the iPhone 14 e 14 Plus they only have a wide-angle (26mm) and ultra-wide-angle (13mm), which are not the most suitable for portraits — in this case, it is necessary to take the photo at a greater distance and apply a zoom, with the possibility of losing quality.

If you are using a camera with interchangeable lenses — such as a DSLR ou mirrorless — see if your lens fits within this range of focal lengths. It is important to note that if you are using a full frame lens on a camera APS-C — or cropped — you'll need to multiply the focal length by the form factor. For the APS-C sensor from Canon, for example, the form factor is 1,6x, and when using a 50mm full frame lens on a crop sensor camera, the effective focal length will be 80mm.

Use image editing programs

When all possibilities are exhausted before taking the photo, you can work with adjustments in post production, in programs such as Adobe Photoshop and GIMP, its open source (and free) “equivalent”. Using filters built into the programs, you can adjust perspective and lens distortions. The process is made easier by using the Adobe Lightroom: when identifying the lens used, the program can automatically apply the specific correction for that lens, even for batch processing.

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Sources: Dan Vojtěch, PhotographyLife, Newsweek, HowToGeek

Text proofread by: Pedro Bomfim (April 26, 2023)