"I'm a natural light photographer. I don't shoot with artificial lights. I don't like the look of strobe-lit portraits." That's fine, but why are your post-processed images look so unnatural?
I don't like the term "natural light photographer." If you add a white reflector does that make you a slightly artificial light photographer? What about negative fill? Does it make you a slightly negative-light photographer? You get my point. Whenever I photograph portraits I use the light that suits best the situation, and the client. I make two types of portraits: ones that look lit and those that look natural. I don't limit myself to the way I execute the project. Lit and non-lit-looking portraits can be made both with strobes and without strobes. In case you wonder, I tend to use strobes most of the time. In this article I will focus in a couple of images I photographed with only natural light and without any modifiers.
Pros And Cons of Natural Light
Shooting with strobes on exterior locations has one big disadvantage: you have to carry a lot of extra gear. You need light stands, strobes, heavy batteries, light modifiers, sand bags, you name it. If the available light is perfect you can simply carry your image-recording device, the camera.
The problem with natural light is that we like certain qualities of it at certain times of the day. The famous golden hour lasts for a short interval and it's not always possible to photograph your models at that time. The other problem is the dynamic range of the cameras. Although they got better from what they were 10 years ago, they still don't offer the perfect natural image we see with our own eyes. Yet they are much closer. If we don't have the perfect natural light we have to either use modifiers to shape it, or try to fix it in post. If you are serious about using light shapers to alter natural light you will find that sometimes you have to carry more gear than a simple strobe with a softbox on a light stand.
What You Are Allowed to Fix in Post
Fixing it in post is alright when you have done the best the camera can capture on location. What you are expected to do is to remove distractions you couldn't remove when shooting, remove some, but not all, imperfections from the model, and eventually take advantage of the dynamic range of the modern cameras. For the last part you need to shoot in a raw format.
Changing Light Direction in Post
This is one of the most frequent problems I see in post processing of naturally-lit photographs. The light is coming from one direction shaping the model in a certain way and instead of moving the camera or the model, people photograph what they see and in post they try to change the shadows and highlights completely. Many times this is applied only over the face, leaving the rest of the environment, even the rest of the body of the model, with a different light direction. The proper way to do execute a portrait is to keep the final image with the same light direction, while you can slightly dodge and burn some parts. You made the choice to use that light direction in camera. Stick to that choice in post.
That's the most often case I see. People are without noses, without shadows under the eyes, without shadows under the cheekbones. Their faces look flat. Everything on the face is very bright, and often too bright, while the background is the only natural thing in frame, having both shadows and highlights. That's often what Instagram filters do. Women like it, because it hides all their imperfections, but it also hides their beautiful features.
Fake Light Flares
I like flares. I like fake flares when they don't look fake. Adding flares in post has to be motivated by the environment. If there was no sun in the frame or close to the edges of the frame, please, I beg you, do not add any light flares. For the love of naturally-lit portraits, aesthetics, and laws of physics: do not add flares on the opposite side of the frame where light does not come from. Please, don't. In the following photograph the light is naturally coming from the right side, while the fake flare is on the left. Even if the flare was added on the right, it is not needed, because the sun was not that bright that day and warm flares do not look good on overcast blue and green tinted background. If there were natural flares, the background would be with a different color temperature, not just the flares.
Retouching Only the Face
Dodging and burning only the face is going to make the photograph too fake. I understand that there's a lot of information in the raw files you can take advantage of, but do not focus only on the face. If you lighten the dark parts of face, lighten the dark parts of the background too.
Overexposing is Not Always Bad
If you photograph a back-lit portrait you will find that you can either have the background or the face properly exposed. You can't have both unless you use extra lights (or modifiers). If you want to shoot without modifiers, you have to make a compromise. In these cases it's fine to let some of the background to blow out, even if you can bring back the details in post. Sometimes having detail everywhere looks unnatural. Do not get too much overwhelmed with photographers' opinions about overexposed or underexposed parts of the background. Keep the final result natural to your eyes. Sometimes it even looks better to overexpose in post certain areas of the image even more, just as I did in the following example:
Leave Some Imperfections
I have seen more unnaturally retouched faces of naturally-lit photographs than such with strobes. It's usually the shadows that outline the imperfections. Leave some of them. You will be amazed how better your photographs would look. Not every shadow is an imperfection. Do not get rid of them all.
Capturing a Proper Image to Work With in Post
In order to make naturally-looking post processing you have to capture the image in the most natural-looking way possible. It's up to you if you're going to use extra reflectors, negative fill, diffusions, or mirrors. Sometimes you have to make a tough decision what to overexpose and what underexpose in order to make the right compromise, just like in the case of a back-lit portrait. Always think about the most important information you have in frame. If you photograph a back-lit model, you can have the face a stop or two underexposed. Try to limit the overexposed or underexposed important parts of the image within two stops at most. This is well-controlled when you shoot in manual mode and you read your internal camera's light meter. If you don't know how to determine the number of stops, read my article about how to understand the internal light meter of your camera or even better, check out Joey Wright's: Swimwear photography tutorial where he predominantly shoots with natural light.
If you want to be keep it natural in the way you photograph, keep it natural in the way you retouch too. My advice is to not limit yourself with the gear you use. It's the final result that matters as long as it looks realistic.