Making People Skinnier in Photoshop Part 2: Lens Distortion and Perspective

(Missed Part 1? You can find it here.)

In our previous article we discussed making people skinnier in Photoshop and how you really shouldn’t do it…

…Except when you should.

So when IS it okay to make people “skinnier” in Photoshop? The primary instance where it’s acceptable is when you have distortion or perspective problems in your photo. These are not uncommon and can be very unflattering but have very little to do with the physical dimensions of the person who is actually in front of the camera. Because it doesn’t have anything to do with the person’s actual size in real life, I do not consider this actually making someone skinnier. It is merely correcting aberrations introduced by the camera. However, in before and after photographs, people can construe this as making someone skinnier (or sometimes larger!) because body parts will appear to become smaller (or larger.) Let’s look at some examples.

Making People Skinnier in Photoshop Part 2: Perspective

This photo was shot from slightly below plus the model is leaning her head away from the camera. This makes her body appear larger in relationship to her head. This isn’t true to her real-life dimensions. Additionally, this was for a hair ad campaign so the head needed to be the focal point. So, I made her body subtly smaller. I also altered her chin for perspective. Click for before/after animation.

 

Making People Skinnier in Photoshop Part 2: Lens Distortion and Perspective

This image had some lens distortion plus I was a bit shorter than the model. She is also leaning slightly away from the camera. Again, this amounted to an original photo where her head was not proportional to her body. The correction is so subtle you can’t see it in side by side comparison, but it does make her body proportionally smaller. Click for before/after animation.

In both of these final images, the models’ bodies look smaller than they originally did in the photographs I started with. However, the photos may not have been accurate depictions of the models in the first place. So, how do you know how to correct for things like this? First of all, a good retoucher has at least some knowledge of photography, anatomy, and perspective. You can usually make some educated guesses if you have some background knowledge. When in doubt, a retoucher should draw attention to the face. You can do this by making sure the face is proportional to the body or slightly larger. (Assume a camera position that is slightly above the subject when the photographic composition allows for it and make your changes based on that, following the rules of anatomy. Shooting a photo from a higher angle causes the head to be very slightly larger in proportion to the body. Any changes along these lines should be subtle.) It also helps to compose the limbs and torso into leading lines toward the face when possible. The face is where we most strongly identify personality.

I want to stress the “when possible” part. Never force a change if it isn’t anatomically correct or if it doesn’t stay loyal to the subject’s appearance.

Let’s delve a little deeper into these technical concepts that can lead you to make decisions about altering physical proportions in a photograph.

Leading Lines

I’m only going to touch on this since composition isn’t our main focus here, but “leading lines” are lines that direct your gaze toward something in an image. Our eyes like to follow lines and in images we typically follow lines away from the edges. Leading lines can be things like arms and legs or even fence lines, telephone wires, walls, portions of hair, or any other kind of line that leads toward the face or main image feature that the viewer is supposed to focus on. I will sometimes smooth out a bump in a line or alter a neck contour to make it into a stronger lead toward a face or other focal point. Not because these things make a person look fat, but because it focuses attention where I want it to go. I make a point not to do this because it makes someone look more attractive, but only because I want the viewer to look at, say, a person’s eyes, or their hair, or their face, or their clothes. Whatever is being highlighted.

Making People Skinnier in Photoshop Part 2: Leading Lines

You can see in this image’s composition that most lines point attention up toward the face. Red lines direct attention to the face. Secondary blue lines lead the eye to the stronger direct leading lines.

Lens Distortion

Now let’s venture into the territory where we really might want to start making people “skinnier”: distortion. When a camera distorts a body, we are no longer looking at a photo that is an accurate depiction, so we start to consider changing the dimensions we see in an original photo. Lenses play a big role in how large or small individual body parts appear in a photo. They can introduce all sorts of strange problems, whether the glass is cheap or top of the line. Especially when working with wide angle lenses, distortion is just a fact of being a photographer. Cameras do not see the way the human eye does. Consider the following examples all taken of the same model (my friend, Karen) with different lens focal lengths:

Lens Distortion

I chose to shoot a portrait here because it is a very clear demonstration of lens distortion even though it isn’t as descriptive of instances where you may be changing body dimensions to make someone appear to be “skinnier”.

Karen’s facial proportions look entirely different as we change focal length and the first images are clearly distorted. If I’d done a full body shot, it could easily be her waistline, hips, or legs that showed distortion depending on my angle and her pose. (That’s where we get into controversial retouching when dealing with audiences uneducated about the issues we’re covering today.)

When trying to correct for distortion, it really comes down to training your eye and learning about what focal lengths are most likely to introduce what problems. Wide lenses (smaller numbers) tend to make things at the center of the photo bend toward the edges of the frame and exaggerate the size of anything closer to the camera. Long lenses (larger numbers) tend to make things appear more normal or even compressed. As a retoucher, you’ll usually have less lens correction to do if your photographer shot with a longer lens.

Luckily for us, software is getting a lot more sophisticated. Sometimes, it can auto-detect the lens used and automatically correct for the distortion most typical of that lens at that focal length, though personally, I find that imperfect. It’s a good start and once in a while it will get you all the way there, but I encourage retouchers to also learn manual lens corrections, whether in ACR, Photoshop’s lens correction filter, or using completely manual transform and liquify adjustments.

A word of caution: You will never make a photo taken with a 24mm lens look like one taken with a 105mm lens. Some things have to be done in camera. You can make improvements, but you can’t totally fake extreme changes. A clear illustration: notice that you can see Karen’s ears in the photo taken with the 105mm but not the 24mm. I cannot make the first image realistically look like the last.

Human Anatomy

So, this composition and distortion info is all well and good, but when it comes down to it, how do you know how someone is “supposed to look”? Sorry, I have no easy answer. You hit the books and study anatomy. The best place to learn anatomy is drawing manuals and I’m sure there are some good online resources as well.

A crash course in anatomy for artists: We usually measure the body in “head’s lengths”. In other words, we take the height of the head, and use it to describe the proportions of the rest of the body. The average proportional height of a human being is 7.5 heads tall. (So, if a head were 1 foot in height, the person would be 7.5 feet tall. The average head is not 1 foot tall. This just describes the proportion.) This varies obviously. Women are often depicted as 6 heads in a drawing and men as 8 heads. In fashion illustration, women are sometimes depicted proportionally taller because this exaggerates long limbs, which we use to create leading lines. (I have included a fashion illustration here because I typically shoot fashion and so do a lot of my readers…also because the fractions are easy.)

The halfway point down the body is typically about groin level. ¼ is mid-chest. The knee is ¾. The arms extend below the groin 1/2 to 1 head depending on height. When we draw the average figure (not a heavier figure) we typically draw a shoulder line that is about 1.5 heads long horizontally. The hips mirror the shoulders. From here, we take the average figure and begin to vary it for body type, widening or narrowing hips, shoulders, waist, etc.

Basic Straight-On Human Anatomy

Basic Straight-On Human Anatomy

So, what doesn’t vary based on weight? What can we use as baseline references for distortion and perspective? First, a person’s height and vertical proportions don’t really change when they gain weight. The distance between chin and groin should always be approximately 3 head lengths, placing the groin about halfway down the body. See above for other vertical proportions. However, what about when you’re working with headshots or other photos that focus only on the upper body? Well, not a ton of padding gets added on the shoulder line when a person gains weight. A few inches off the bone at most. (This, of course, doesn’t account for broad shouldered people—your average linebacker is going to be a lot more than 1.5 heads wide—but you can usually recognize those types of frames visually if a person doesn’t have an average bone structure.) Additionally, the distance between the shoulder and armpit doesn’t vary all that much. This is approximately 1/2 of a head length.

Keep in mind that bodies are definitely not all exactly alike. There are many exceptions to the rules. Statistics apply here and we are talking about the average.

Perspective

An important thing to be conscious of when dealing with anatomical corrections is that camera angle will shift proportion. Looking down at a sharp angle will make body parts that are farther away appear smaller and closer together. Sometimes it is beneficial to an image to alter body proportions based on perspective, as I did in my initial retouched examples. These changes can be subtle or extreme and may vary based on the individual photographer. I know when I’m photographing people, I usually have to account for slight perspective problems caused by looking up at someone because most of my subjects are taller than me. Looking up at your subject can cause their head to appear proportionally smaller than their body, whereas we typically want the head to be the focal point and therefore either proportional to the body or ever so slightly larger…This is where taller photographers have an advantage over photographers my height.

Understanding perspective is crucial to making believable image adjustments. I highly recommend that along with anatomy, you study foreshortening and perspective. Anatomy books usually at least touch on these and I’ll include some resources below.

Perspective

Basic Perspective. Note that things that appear closer are larger and as things get smaller, they appear farther away. The pillars are also closer together as they get farther away.

That said, the basic tenets of body proportion can generally be used as reference points especially on relatively straight-on shots or photos where the perspective is only off by a little. Just remember not to force anything into EXACT proportions because they may be influenced both by body type and by perspective. You don’t need to pull out a ruler, but rather train your eye to average anatomical relationships. Know the average baseline and then keep your changes relatively minor to ensure you aren’t veering too far away from a person’s natural appearance or from believable perspective. Always work with the intention of finessing rather than strong-arming proportion when retouching to ensure better realism.

Another note about extreme changes: if you take a photo looking up at someone at a sharp angle, you will never be able to perspective correct it to look like a straight-on shot. If you try, even your best effort will look weird because you’ll be able to see the bottom of their chin. Always use discretion. That said, you can do some pretty extreme perspective corrections on non-human shots. Just don’t try it with people.

Architecture Perspective Correction

Don’t try this on a person.

In Closing

Keep in mind that the goal here is not to actually to make someone look skinnier than they really are. The goal is to make the body proportions look natural and to correct for camera and perspective issues so that your subject looks more like themselves as viewed by the human eye. (Remember that the human eye and brain fill in a lot of information that isn’t really there and can interpret visual information such that things look the way we expect them to rather than as they are. In life, our brains automatically correct for a lot of things that cameras don’t.) Changes made in the name of composition, perspective, and lens distortion may end up looking like someone has been made skinnier because you may have to shrink some body parts to make your corrections. Other times you may have to enlarge body parts, though people are less likely to balk at that.

The final effect may technically be making someone skinnier than they are in the original PHOTOGRAPH, but our intent is not to make them appear skinnier than they are in REAL LIFE. That’s the distinction. True to life, not to the photograph. Remember that photographs lie and sometimes we, as retouchers, are not trying to make them into bigger lies, but rather bring them back closer to reality.

Coming up: Parts three and four in “Making People Skinnier in Photoshop”

Recommended Resources


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All photos and illustrations by Stephanie Maulding

…please forgive my drawing skills…