A basic understanding of the physics of light can help us to achieve the best possible photographic results. Here are some very simplified explanations of how what we learned in school science lessons can affect what we do with our cameras.

There’s a lot more to light than meets the eye. Okay, so that’s an awful pun, but it is both metaphorically and literally correct. Not only is it a more complex subject than we need to know in our everyday lives, there is a lot more light hitting you than your retina can convert into nerve impulses that are sent to the brain. There is less light than that landing on your camera sensor that gets turned into an electronic signal and transmitted to the camera’s processor.

In other words, our eyes can’t see all the light there is, much of it is invisible to us, but they see more than our cameras.

Get to Grips With Your Camera’s Dynamic Range

On a bright day, you will see most of the details in both the bright highlights of the sky and the deep shadows under objects on the ground simultaneously. Your camera, with a single exposure, can’t see as wide a range of tones. However, modern sensor technology has improved dramatically and, as you can see from the image above, they have the ability to see both highlights and details in darker areas. It wasn’t that many years ago when I would have had to bracket the exposures of that scene and then combine them to create a high dynamic range (HDR) image to be able to see the top of the lighthouse when pointing the camera directly at the sunrise.

As we get older, our eyes gradually lose our capability to see as wide a range of tones as we did in our youth. Nevertheless, we should see between 18 and 20 stops of tonal range between black and white. Top-of-the-range cameras are between 12 and 15 stops, although a recent sensor developed this year claims 24.6 stops. Don’t worry too much about that, though; your camera will still take fabulous pictures.

The Importance of Our Visible Spectrum

What we call visible light is a tiny fraction of the total electromagnetic spectrum that we and our cameras can see. I find it quite incredible that we can differentiate the different colors of the spectrum that occur in a range that’s only 320 nanometers wide. In other words, we can tell apart all seven colors that comprise white light plus all their combinations.

We are fortunate that most of the photons that hit the earth fall into the bandwidth from 380 to 700 nanometers. It is a happy accident resulting from our planet being in the Goldilocks zone, exactly the right distance from the right type of star. Plus our atmosphere has an ozone layer that filters out the ultraviolet light that would cause us sunburn and worse. If we were bathed in more energetic particles, such as UV or gamma radiation, we would not last long before we were cooked. At the other extreme, if the wavelengths reaching us were a bit longer, we would need much bigger eyes and would have difficulties threading a needle.

How Bending Light Affects Our Images

As the earth spins and dawn arrives, we see the sun appear before it’s physically above the horizon. That’s because, like passing through a prism or raindrops, the light bends when it hits the atmosphere. Consequently, that bending of light, called refraction, means we can see below the horizon. It’s the same effect as when you put a spoon into a glass of water and see it bend.

White light is made up of seven different colors: red, orange, yellow, green, blue, indigo, and violet. We see these in a rainbow and on the cover of The Dark Side of the Moon album by Pink Floyd.

Each color has a different wavelength and therefore travels at a different speed. As a result, the colors bend at different angles, which is what makes the white light split into its component parts. Red light slows the least and is therefore diffracted less. At the other end of the spectrum, violet light is slowed down the most and is refracted more. This process of splitting the light is called dispersion. The more refraction there is, the greater the dispersion. Unsurprisingly, diamonds have the highest refractive index, which is why they sparkle with colors.

That splitting of light is usually unwanted in photography. The last thing we need from a lens is it making rainbows. When it happens, we see it as color fringing or chromatic aberration around high-contrast edges. Cheap lenses are prone to this fault. A perfect lens would have no aberrations and all the different wavelengths would converge on a single point on the sensor. To get close to this, lens manufacturers have multiple glass elements within the lens that help bring the different wavelengths together. Modern lens technology is getting constantly better and contemporary professional lenses exhibit no visible aberrations.

Diffraction also occurs as light hits an edge. Imagine ripples on water hitting an obstruction, they will bend around it. The same applies to light.

Why We Usually Avoid Very Small Apertures

Stand outside on a bright day and look at your shadow. You will see that the outer edges of it are not quite as dark as the middle. That lighter edge is caused by the light bending around you. Incidentally, that dark part of the shadow is called the umbra, and the lighter edge is the penumbra. The farther from the light source you are, the larger the umbra is in proportion to the penumbra, and the sharper your shadow becomes. That’s something to consider when using flash and studio lights.

With photography, this light-bending effect happens when the photons bounce off and bend around the edges of the aperture blades. The smaller the aperture, the more pronounced that bouncing and bending becomes. That’s because the proportion of diffracted light to un-diffracted light is high at small apertures.

This is why photographers usually avoid the smallest apertures because the increased proportion of diffracted light causes images to be less sharp.

The Reason the Sky Is Blue

Not only does this bouncing – properly called scattering – occur when light hits boundaries, but also when light encounters other particles. Because blue has shorter wavelengths, it is scattered more easily than red, which is why we see the sky during the day as blue.

As we look toward the horizon, the sky can appear whiter. That is because there is more atmosphere for the blue light to be scattered repeatedly, which removes the blueness. Furthermore, looking obliquely through the atmosphere the extra particles scatter other colors too, plus there’s also the light reflected from the planet’s surface affecting it. 

All these factors result in the different wavelengths being mixed again and producing white light. The exception can be over the sea, where the blue of the water is reflected up into the atmosphere turning the low sky blue again.

Using a CPL Filter

The scattered light in the sky is polarised. That means that the blue light waves travel in a single direction, as opposed to randomly in all directions. This polarized movement is perpendicular to the light source. Therefore, if you fit a circular polarizing (CPL) filter to your lens, you can cut out much of the light in the sky at 90 degrees to the Sun, making the sky appear darker.

Polarizing filters are great for taking away reflections off the water’s surface, allowing you to see more clearly what lies beneath because the reflection is polarized. You can also remove glare from, say, damp, autumnal leaves, allowing their colors to become richer.

The Physics Behind Those Glorious Sunsets

As the sun gets low in the sky, the sunlight must pass through a lot more atmosphere before it reaches you. At low levels, it is filled with dust and water vapor. This scatters the blue light even more and only the reds and oranges get through to our eyes, hence glorious sunsets with warm colors.

Warm Colors Are Not Warm At All

When I say warm colors, I mean psychologically warm. We think of reds, oranges, and yellows being warm colors and blues being cold. However, in physics, it’s the other way around. Think of a blacksmith heating a piece of metal. At first, it glows red, then yellow. As it gets hotter it turns a blueish white. A welder’s gas torch is exceptionally hot and can melt steel. It burns blue.

There’s a Reason Why Your Camera Used Red, Green, and Blue

There is a question that I am often asked. Why do photographic sensors and computer screens use red, green, and blue to reproduce colors instead of red, orange, yellow, green, blue, indigo, and violet? That is the big difference between science and engineering. It is possible to achieve white by combining just those three colors, which, from an engineering perspective, is the simplest way to achieve the desired result. Finding a means of combining all seven colors of the spectrum on a camera sensor or computer monitor would be complex, and expensive.

However, like everything in photography, there is a compromise. The camera and your computer screen using the three primary colors of red, green, and blue cannot reproduce anything like the range of colors available to our eyes in the real world.

Even that isn’t as simple as it first seems. The range of colors differs depending on the device. Firstly, there is the virtual image, which is the most precise version. It’s what your camera records when shooting raw and what your editing software understands your image to be. Then there is the rather more limited version of colors that appear on your computer monitor, or your camera if you are shooting jpegs. Different again is the version that you are able to print.

What we really want is for these three different ranges to be the same. To do that, we use color management. With color management, we are defining maximum and minimum values for red, green, and blue. Whole books have been written about this, and there’s far too much information to include in this article. However, it is important to know that you should keep your printer, screen, and camera (if you are not shooting raw), set to the same color space.

The most commonly used of these color spaces is sRGB. However, Adobe RGB is another common profile that has more colors available to it and it was the standard for high-end digital printing. ProPhoto RGB has an even wider profile and provides almost all the colors possible for most printers. However, things have changed and the printers I use produce color profiles for each type of print and paper. Those give the highest possible color accuracy.

For most photographers, it is enough to remember to use a color space that is no bigger than the gamut available to your devices.

The Difference Between Additive and Subtractive Light

When we mix projected light, red, green, and blue are primary colours. Combined they produce secondary colors: magenta, cyan, and yellow. This is additive light, so mixing red and green produces yellow. Mixing different proportions of these colored lights will give us the range of colors that the printer can produce.

In comparison, when we use printer inks, they remove or subtract colors from white light. The inks absorb some light and reflect others. When mixing the ink colors of magenta, cyan, and yellow in different proportions with black, we can get another, different range of colors. In color management, that range is known as a gamut.

Using a single color space, we ensure we are only using those colors where the two gamuts overlap. If we tried to view or print colors that were outside the capabilities of your screens or printers, we would get some odd results.

Color Is Not Entirely Under Your Control

On a related subject, the screen in front of you will have control buttons to change, at the bare minimum, the contrast and brightness. So will everyone else’s. Calibrating your screen is an important step to ensuring your prints’ colors and tones match what you print. Of course, when you share an image online, most other people won’t have calibrated screens. Consequently, your images may appear brighter or darker, with more or less saturation, and different contrast than it should. There is nothing you can do about that. If you are printing photos and want accurate results, or if you are sharing them with other photographers who are likely to have calibrated their screens, then calibrating your screen is essential.

Please, Go and Read More

This article is, of course, just scratching the surface of these topics and there is plenty to be learned under each topic I’ve covered. Search the other articles here at Fstoppers, there’s a wealth of knowledge in the 33,000+ articles, some of which look more deeply at the topics I have briefly covered here.

Photographer Chris Porsz hopes this photo will help him finally find a mystery woman and her leaping dog.

“In March 2019 I was sat in the Union Square, New York dog run when I spotted a lady with a pink bag on her hand (to keep her hand clean) throwing a ball to her dog which was sat down facing her. The dog then launched itself and flipped in mid-air to face me and snap,” he said.

“As you can see the lady with her hand on her head was as surprised as me and I think she is saying phew.

“I have searched in vain via the NY media to find the owner so that I can send her a copy.”

Calling all nature enthusiasts and photography aficionados. The Tennessee Wildlife Federation is thrilled to announce the launch of its ninth annual Wildlife and Landscape Photo Contest. Last year’s contest winners included a photograph from Unicoi County.

Photographed by Lauren Lyon and titled “Loving the Leaf Litter,” the image of a salamander became the featured photo for October in the federation’s 2023 calendar.

Lyon, a Ph.D. candidate at the University of Tennessee, Knoxville, in the Department of Ecology and Evolutionary Biology, has a vested interest in conserving native species in the Blue Ridge Mountains. You can see more of her photography on the Instagram account @AppRedPanda.

In order to celebrate the beauty of Tennessee’s wildlife, landscapes and natural wonders, photographers of all skill levels are invited to submit their captivating shots for a chance to win exciting prizes and be featured in the federation’s 2024 calendar.

Photos of Tennessee’s incredible wildlife and wild places can be submitted at tnwf.org/photo-contest until Aug. 31.

Whether you’re an amateur capturing the mesmerizing hues of a sunrise over the Smoky Mountains or a seasoned pro with wildlife masterpieces, this contest welcomes all nature-inspired imagery.

Photographers can submit one photo with a $5 suggested donation, up to five photos for $10 and up to 20 photos with a $20 donation. This donation helps support the federation’s mission to lead the conservation, sound management and wise use of Tennessee’s wildlife and great outdoors.

“We are incredibly excited to host this photography contest each year because it’s another way to join together with other passionate people to highlight our state’s rich biodiversity and natural splendor,” said Kendall McCarter, chief development officer for the Tennessee Wildlife Federation. “We hope this contest provides a platform for photographers to show their love for nature and wildlife, inspire a greater appreciation of conservation and foster a deeper connection with the great outdoors.”

A panel of judges will select the best photos to be featured in the federation’s 2024 calendar and across the federation’s digital platforms. Winners will also receive a variety of prizes including Patagonia gift cards up to $250, federation apparel and more.

The deadline to submit photos is 11:59 p.m. CT Aug. 31. Voting for the People’s Choice winner will open to the public on Sept. 8.

For contest guidelines, submission details and more information, visit tnwf.org/photo-contest.

The Tennessee Wildlife Federation leads the conservation, sound management and wise use of the state’s great outdoors. Since 1946, the federation has spearheaded the development of the state’s wildlife policy, advanced landmark legislation on air and water quality and other conservation initiatives, helped restore numerous species and introduced thousands of kids to the great outdoors. To learn more, visit tnwf.org.

Now in its fourth year, the Comedy Pet Awards, a photography contest looking to capture the playful, the bizarre, and the hilarious character we all know resides within our fur babies, just concluded in London.

The winner this year was Michel Zoghzoghi, who travels the world shooting pictures of big and fearsome cats among other wildlife. He took first prize when he captured his playful rescues in action, with the rambunctious Max ambushing the timid Alex.

As the winner of the top prize, Michel received £500 cash, a fantastic camera bag
from ThinkTank, and a beautiful bespoke trophy.

“This is still a very young competition in the whole scheme of things, but within a few short years we are already receiving some of the most uplifting, life-affirming hilarious images of pets in the world!” stated Tom Sullam, Co-founder of the Comedy Pet Awards.

“I couldn’t be more excited to share these with you all. Pets have played a fundamental role during the COVID years, and to be able to laugh out loud with these loveable creatures is the reason this competition exists.”

“In March 2019 I was sitting in the Union Square New York dog run when I spotted a lady with a pink bag on her hand (to keep her hand clean) throwing a ball to her dog which was sat down facing her. The dog then launched itself and flipped in mid-air to face me and snap!”

“Karin and her two dogs, don’t they look the same?

“The avenger of the poor is back, but this time as a dog and not on a horse, but in a car! The obligatory black mask is a must, of course.”

Uplift Anyone’s Day With These Cute And Hilarious Photographs… 

John Fielder, a prolific and prominent nature photographer who has lived in Summit County since 2006, died Friday, Aug. 11, after a prolonged struggle with pancreatic cancer, according to an email from his daughter, Katy Fielder. He was 73 years old.

During a career that spanned 40 years, Fielder worked to protect Colorado’s ranches, open space and wildlife. Over 50 books have been published depicting his Colorado photography. In January 2023, he donated his Colorado photography to History Colorado. The museum is the home of a collection of more than 7,000 photos distilled from 200,000 he made since 1973, and which are now available to the public for personal and commercial use.

“I have never felt that I ‘owned’ my photographs, only that I was borrowing these places to visit and record, and that I would give them back someday,” Fielder wrote in a column for the Summit Daily News talking about his donation.

His photography influenced people and legislation and earned him recognition including the 1993 Sierra Club Ansel Adams Award, in 2011 the Aldo Leopold Foundation’s first Achievement Award ever given to an individual, and in 2017 Colorado Mountain College presented him an Honorary Degree in Sustainability Studies.

He leaves behind two daughters Ashley and Katy, and six grandchildren. John lost his wife Gigi to Alzheimer’s disease in 2005 and their son J.T. to suicide in 2006.

In an effort to continue his spirit and legacy of helping nonprofit environmental organizations for the promotion and funding of their respective land-use protection initiatives, Fielder requested donations be made to Sierra Club, Conservation Colorado, Colorado Open Lands and Save the Colorado.

The family will conduct a private memorial service at a later date.

It’s difficult to see how anyone other than the photographer is responsible for a photograph they may take, although I’m sure there are some specific exceptions – but usually, if a photographer is not responsible for their photograph, then who should be?

Responsibility extends beyond taking credit or criticism if people like/dislike the work. Sometimes there are situations where a photograph has an effect the photographer did not account for, which is why it’s important to recognize the potential implications a photograph, or the method used to make one, may have.

Once you publish a photograph (especially online) your control over it vastly diminishes. This can make the decision to publish far more significant than the decision to create something in the first place. Making a photograph takes only a fraction of a second, but the consequences can echo for generations if people continue to see and relate to it. This is most obvious with “history book” photographs which make up part of our collective cultural consciousness, but it is also true of mundane snapshots we may not even realize will go on to be seen by many more people than we first expected.

The Anonymous Project is a good example of this, consisting of found slides, negatives, and prints, which are available for all to see. None of the photographers or subjects of these photographs could have imagined that decades later we would be witnessing their lives, in their living rooms or during holidays. They most likely didn’t expect anyone they didn’t personally show them to in a photo album to know anything about them at all.

No such excuse exists today with photographers sharing their work digitally online, where the objective is to be noticed, and stand out above the rest. I doubt people are sharing things in order to blend into the noise, and in photography-sharing spaces it is often a central goal to have the work noticed and discussed, not ignored and forgotten.

This objective, to produce outstanding, memorable work overlaps with a fundamental social issue that is similarly tied to the nature of the Internet: privacy. In the physical world, public and private spaces tend not to be ambiguous, although there are always cultural differences worth recognizing. On the Internet demarking public and private can be less easy, as even secure, encrypted information seems to make its way out of its own channels and into the public sphere all the time. Someone sharing their personal life moment on a private, restricted social media page may still find themselves made into the next viral meme, via screenshots/recordings made by anyone to who they do grant access.

Street photography (and a few other genres) takes this conversation a step further, as the candid aspect means that it’s possible for someone to go viral without ever even knowing the photograph exists, let alone having an opinion on it. The potential negative consequences of a photograph can be anything from mild discomfort to ending a career, or a relationship, or even a life. This can sound like hyperbole, but also remember how many photographs in the past have shaped opinions on wars, or exposed a scandal – or on the positive side how many photographs have helped campaign on issues that have saved lives, improved relationships, and inspired change for the better.

Street photography at its best reflects society at a certain place at a certain time. It is a document of changes and constants, with the potential to take on different meanings and connotations as time passes and our relationship with the stories and characters in those images changes.

The potential negative consequences that can arise from a photograph are reason enough for some to incorporate strategies into their workflow to protect the strangers in their images from that hypothetical fate. The simplest path is to anonymize identifiable features, like faces, hair, clothing, tattoos, and so on before publishing the image. The classic method for this is a simple black bar, or blur, which is censorship after the fact and can be added to any image. This method has its own connotations, as there is an association with criminals/victims often being concealed in this manner, which may not be what you want to invoke in your photography.

Another route is to incorporate self-censorship into your actual photographic approach, composing so as to not include elements, or to use exposure to render people as shadows and silhouettes rather than people with features that can be identified. While this may have a result of protecting an individual’s identity I think it has the greater consequence of removing individuality, reducing a person down to, at worst, an archetype, or stereotype.

Decisions to portray your subjects as somehow “in hiding” have a severe impact on what that photograph actually ends up communicating. Faces obscured behind shadows or hands may imply they are hiding in shame, or something similar. Of course, if that’s the intentional vibe you are going for then great, but if it’s incidental from your style and not in service to what you want to say, then the work will suffer, not benefit.

I think humanistic photography highlights the aspects of an individual that “shine through” – even when documenting a cohesive group it will be individual differentiating expressions that stand out, not uniformity. Rendering a subject of a photograph as a silhouette deliberately makes them uniform with every other silhouette – for example with this photograph I made in Washington DC I chose to capture the soldier as a silhouette, because it specifically isn’t about the soldier as an individual, it’s about the idea of a soldier, an archetype.

In this instance, it was an active choice in service of the story, not done to protect an identity, or for pure aesthetic, but to convey an idea.

This photograph on the other hand is not about the idea of a Hindu Priest, it’s about this Hindu Priest in particular, there is no benefit to hiding any aspect of him – obscuring him would not be in service to the story.

However, from the same project, this image is focused on a detail of loose thread, with the face of the member of the congregation hidden by shallow depth of field and exposure. This is an aesthetic choice in this case, but obscuring the individual works for the story, it’s not about them in particular but about the detail of the thread.

If you are photographing purely for enjoyment of the craft then maybe there’s something to be said for limiting the potential of negative consequences – but if you are working to document something specific then I think it’s worth illustrating the story in service of the story. I try not to let doctrine and tick boxes influence my photography without a specific reason to include them, a purpose for them to serve.

About the author: Simon King is a London-based photographer and photojournalist, currently working on a number of long-term documentary and street photography projects. The opinions expressed in this article are solely those of the author. You can follow his work through his documentary collective, The New Exit Photography Group, and on Instagram.

Image credits: Photographs by Simon King