The Exposure Triangle: The Fundamental Elements of Exposure

The Exposure Triangle: aperture, shutter speed and ISO

When I started in the photography world, words like Aperture, Shutter Speed and ISO were foreign to me, and it took me a couple of weeks to take pictures in full manual mode after read a photography book and look in Internet to obtain more information. You might be feeling a little confused, and you may even feel like you will never get your camera out of Auto mode, because it’s just too hard to understand. But I’m sure after read this post you will start to try by yourself in manual mode and experiment the different possibilities.

What is Exposure in Photography?

In the simplest of terms, exposure for photographers refers to how an image is recorded by camera sensor and how much light is captured. Basically, it determines what the image you capture will look like.

Understanding the Exposure Triangle

ISO, Aperture and Shutter are known as the “exposure triangle”. If you know how to control or adjust these elements on your camera, taking well exposed photos will not be a problem for you. Take your time to know your camera and find each adjustment. The most important thing before all, it’s to know your controls and how to change them to have a correct exposure.

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Copyright https://www.exposureguide.com/exposure/

With the experience, you will be able to make the correct adjustment faster and faster. Finally, it has to be by intuition, as a athlete in any sport.

The three elements are:

  1. ISO – the measure of a digital camera sensor’s sensitivity to light

  2. Aperture – the size of the opening in the lens when a picture is taken

  3. Shutter Speed – the amount of time that the shutter is open

It is at the intersection of these three elements that an image’s exposure is worked out.

Most importantly – a change in one of the elements will impact the others. This means that you can never really isolate just one of the elements alone but always need to have the others in the back of your mind.

Side 1: Aperture

Aperture. Aperture controls the brightness of the image that passes through the lens and falls on the image sensor. It is expressed as an f-number (written as “f/” followed by a number), such as f/1.4, f/2, f/2.8, /f4, f/5.6, f/8, f/11, f/16, f/22, or f/32.

A wider aperture (or lower f-number) means more light will be let in by the lens, simply because the opening is larger. A narrower aperture (or higher f-number) allows less light to reach the sensor.

  • SMALL numbers (like f/1.8) = wide open aperture (large opening).

  • BIG numbers (like f/22) = small aperture (teeny opening).

Another thing that can be affected by aperture is depth of field, or how much of your picture is in sharp focus. A wide open aperture (small number) will make less in focus, and a closed down aperture (big number) will make more in focus.

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Copyright https://www.better-digital-photo-tips.com/deep-depth-of-field.html

Try to use Aperture Mode in your camera to see the difference between wide and small apertures.

Side 2: Shutter Speed

In photography, shutter speed or exposure time is the length of time when the film or digital sensor inside the camera is exposed to light, also when a camera's shutter is open when taking a photograph. The amount of light that reaches the film or image sensor is proportional to the exposure time. 1⁄500 of a second will let half as much light in as 1⁄250.

If you have a wide open aperture, your shutter speed will need to be faster, because you’re already letting a lot of light in the lens opening. If your aperture is small, your shutter will need to move slower, so there is more time for light to get to the sensor.

If you want to freeze the action, or hand-hold your camera, then a faster shutter speed is needed. If you want to create blur, then you need a slower shutter speed. 

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Copyright https://lottiesimpkinsgcsephotography.weebly.com/shutter-speed.html

You can try your Shutter Priority Mode to obtain different results. Long exposure is amazing when you take pictures by night but remember to use a tripod to have more stabilized shots. As you play with these different priority modes, notice what the camera chooses for the rest of your settings. The more you pay attention to these things, the more knowledge you’ll have to be able to set everything yourself in the future.

Side 3: ISO

ISO measures the sensitivity of the image sensor. The same principles apply as in film photography – the lower the number the less sensitive your camera is to light and the finer the grain. ...

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Copyright http://stylenoviceblog.blogspot.com/2015/07/dslr-basics-aperture-shutter-speed-and.html

By choosing a higher ISO you can use a faster shutter speed to freeze the movement. But take care about this, higher ISO means higher grain on your pictures.

Copyright https://www.exposureguide.com/exposure/

Copyright https://www.exposureguide.com/exposure/

In low light conditions, you should increase your ISO to obtain a correct exposure.

Side 4: EVs and Stops

Almost all digital cameras have an Exposure Value (EV) Compensation setting. This setting is needed because the camera can sometimes make incorrect assumptions about the lighting of a photo. Changing the EV will make sure your photos are always correctly exposed.

In photography, a "stop" is a widely misunderstood concept, feared by many because it sounds so complicated. However, it's actually very simple:

A stop is a doubling or halving of the amount of light let in when taking a photo.

For example, if you hear a photographer say he's going to increase his exposure by 1 stop, he simply means he's going to capture twice as much light as on the previous shot to obtain the correct EV.

This amount of light captured while taking a photo is known as the exposure value as said previously, and it's affected by the exposure triangle - the shutter speed, the aperture diameter, and the ISO. These are all measured using different units, so the concept of "stops" was invented as a convenient way to compare them.

Forward, perhaps I will repeat some concepts but if you understand what they are the stops and how the 3 variables can affects your pictures, you will understand the exposure triangle and how to use it at any moment.

STOPS AND SHUTTER SPEED

Shutter speed measures how long your camera's shutter is left open during a shot. The longer it's open, the more light it lets in, and the greater your total exposure will be. Doubling or halving your shutter speed produces an increase or decrease of 1 stop of exposure.

Common shutter speed stops.

Common shutter speed stops.

For example, changing from 1/100 of a second to 1/200 lets in half as much light, so we can say we've decreased the exposure by 1 stop. Similarly, going from 1/60 to 1/30 lets in twice as much light, giving a 1 stop increase in exposure.

Most cameras allow you to adjust shutter speeds in increments of 1/3 of a stop, so 3 turns of the dial either way will adjust your exposure by 1 stop.

STOPS AND ISO SPEED

ISO speed describes how sensitive your camera's sensor is to the light that hits it. A more sensitive sensor will produce the same overall exposure from less light, meaning that you can use a narrower aperture or faster shutter speed in the same conditions.

Common ISO speed stops.

Common ISO speed stops.

ISO is measured using values that correspond to the ASA scale for film, with a higher ISO number relating to a more sensitive sensor. As with shutter speed, doubling the ISO number gives an increase of 1 stop, while halving gives it a decrease of 1 stop.

For example, switching from ISO 100 to ISO 200 doubles the sensor's sensitivity, producing a 1 stop increase. Moving from ISO 800 to ISO 400 is a 1 stop decrease. Most cameras let you change ISO speed in increments of 1 stop.

STOPS AND APERTURE DIAMETER

Aperture is measured using the "f-number", sometimes called the "f-stop", which describes the diameter of the aperture. A lower f-number relates to a wider aperture (one that lets in more light), while a higher f-number means a narrower aperture (less light).

Common aperture stops.

Common aperture stops.

Because of the way f-numbers are calculated, a stop doesn't relate to a doubling or halving of the value, but to a multiplying or dividing by 1.41 (the square root of 2). For example, going from f/2.8 to f/4 is a decrease of 1 stop because 4 = 2.8 * 1.41. Changing from f/16 to f/11 is an increase of 1 stop because 11 = 16 / 1.41.

As with shutter speed, most cameras let you control your aperture in 1/3 stop increments.

STOPS ARE INTERCHANGEABLE

The great thing about stops is that they give us a way to directly compare shutter speed, aperture diameter, and ISO speed. This means that we can easily swap these three components about while keeping the overall exposure the same.

Let's say you're shooting a scene using a shutter speed of 1/60 of a second, an aperture of f/8, and an ISO of 200. You find that while the scene is well exposed, your subject is turning out a bit blurry, so you decide to increase the shutter speed to 1/120 of a second.

This change of 1 stop will result in the next photo coming out dark, because you're now letting in half the total light as before. In order to correct this, you need to reclaim that 1 stop reduction from somewhere else. Now that we have a way of comparing settings, this is simple.

You could open the aperture wider to let in more light - moving from f/8 to f/5.6 is an increase of 1 stop, so we've got back to our original exposure. Alternatively you could double the ISO speed from 200 to 400, again resulting in a 1 stop increase.

As you can see, stops are a really easy way of adjusting our camera's settings while making sure we don't ruin the photo's overall exposure.

Conclusion: CONSIDERATIONS WHEN ADJUSTING EXPOSURE

When adjusting the three components of exposure you should be aware that each one affects your photos in other ways, which may not always be desirable:

Shutter speed - If your shutter speed is too slow your photo may blur, either from movement of the camera or movement of the subject.

Aperture - A wide aperture produces a narrow depth of field, so if you make it too wide you may have trouble keeping everything in focus. On the other hand, a narrow depth of field can help to isolate the subject, and is often something that you want; if so, you need to avoid using a narrow aperture.

ISO speed - The more you increase your camera's ISO, the more digital noise your photos will exhibit. This can make your image look grainy and reduce its sharpness.

As with everything in photography, adjusting these three settings is a balancing act. You need to decide what effects you want in your shot and choose settings that will produce them while minimising the potential downsides. Exposure stops are a really useful tool for doing this, helping you swap settings around with ease and giving you more control over your scene.

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15 Basic Photography Composition Rules: improve your photos!

Before you just step up and take a picture you should consider what you want your viewers to look at and how you should display main points of interest.

There are no fixed rules in photography, but there are guidelines which can often help you to enhance the impact of your photos.

In this tutorial, I’ve listed 15 of these guidelines with examples of each. I’ve started with the most basic ones and finished with some of the more innovating composition techniques.

Before all, I need to define the word “composition”. It refers to the way the various elements in a scene are arranged within a frame. They aren’t rules for this but guidelines as I’ve mentioned already. But we need to remember that they’ve been used in art for thousands of years and they really help us to obtain more attractive results. I always keep in mind some guidelines when I’m shooting as an instinct thinking.

#1. Rule of Thirds

The rule of thirds is very simple. You divide the frame into 9 equal rectangles, 3 across and 3 down as illustrated below.

I wrote about this basic rule in my previous post. you can follow this link for more deep information:

https://www.migueldasilva.net/blog/rule-of-thirds-start-taking-superb-photographies

#2. Balacing elements

Placing your main subject off-centre, as with the rule of thirds, creates a more interesting photo, but it can leave a void in the scene which can make it feel empty. You can achieve a balanced composition and even out the main subject's "visual weight" by including another object of lesser importance to fill the space.

Copyright Jason Row

Copyright Jason Row

#3. Centred Composition and Symmetry

After the first and second guideline where I’ve told you not to place the main subject in the centre of the frame, I’m going to tell you to do the exact opposite! There are times when placing a subject in the centre of the frame works really well. Symmetrical scenes are perfect for a centred composition.

#4. Fill The Frame / Cropping

Sometimes, leaving too much empty space within a photo can make your main character appear smaller than you’d like. Of course, this can come in handy if you’re trying to capture how small your little one is next to a particular person or thing. On the other hand, don’t be afraid to zoom in close on your subject or “fill the frame.”

#5. Frame Within the Frame

Framing is the tactic of using natural surroundings to add more meaning to your subject.  It could be anything such as bushes, trees, a window, or even a doorway like in the picture at the top of this page.  In the process of doing this you need to be careful that you don’t only focus on what’s framing your subject.  Make sure you focus on the main subject, and also it is a good idea to use a narrow aperture (high f/stop) to achieve a high depth-of-field.  It also wouldn’t hurt if the part of the picture framing the subject was darker so make sure you take your light reading on the main subject.

#6.  Leading Lines

Leading lines help lead the viewer through the image and focus attention on important elements.

When we look at a photo our eye is naturally drawn along lines. By thinking about how you place these leading lines in your composition, you can affect the way we view the image, pulling us into the picture, towards the subject, or on a journey "through" the scene.

There are many different types of line - straight, diagonal, curvy, zigzag, radial etc - and each can be used to enhance our photo's composition. Anything from paths, walls or patterns can be used as leading lines.

Take a look at the examples below.

#7. Simplicity

Simplicity is the method of keeping the information in a photograph relatively simple.  If your main subject is close, then your background should be very simple to avoid distractions.  You should try to keep everything not important much less interesting than what’s important in the frame.  Especially avoid lines or objects that lead the eye away from the subject.

#8. Change your Point of View

Before photographing your subject, take time to think about where you will shoot it from. Our viewpoint has a massive impact on the composition of our photo, and as a result it can greatly affect the message that the shot conveys. Rather than just shooting from eye level, consider photographing from high above, down at ground level, from the side, from the back, from a long way away, from very close up, and so on.

#9. DEPTH

Having fore-, middle- and background detail will add depth to your image as well as draw the eye through the picture. Compositional elements that compliment each other, for example with colour or by association, work well but do be careful with the size of objects you use and how you place them as you don't want the shot to be thrown off balance. You don't want a rock in the foreground of your landscape shot, for example, drawing the eye away from the hills and mountains in the background. Adding water to the foreground can also lighten your shot as well as adding an extra element of interest as it reflects the sky back out.

#10. Colors Combination

Choosing colors and color combinations for photography requires planning if not effort. Use of color in photography is an Art as old as photography itself but most of us don’t realize the importance of co-ordination and planning. In this guide, we will consider some tips to get the best color combinations when posing for photos. But first: we will consider the best color combinations for decorative landscape photos especially from the point of view of wall art and interior design.

As you can see in the portrait below, the green color of the dress meets perfectly with the tulips by intermediate colors.

#11. Foreground Interest and Depth

Including some foreground interest in a scene is a great way of adding a sense of depth to the scene. Photographs are 2D by nature. Including foreground interest in the frame is one of a number of techniques to give the scene a more 3D feel.

#12. BACKGROUND

How many times have you taken what you thought would be a great shot, only to find that the final image lacks impact because the subject blends into a busy background? The human eye is excellent at distinguishing between different elements in a scene, whereas a camera has a tendency to flatten the foreground and background, and this can often ruin an otherwise great photo. Thankfully this problem is usually easy to overcome at the time of shooting - look around for a plain and unobtrusive background and compose your shot so that it doesn't distract or detract from the subject.

#13. Patterns, Textures and symmetry

Texture can add a significant amount of interest in any picture.  When people see texture in pictures they start imagining what it feels like to touch what’s in the picture.  Texture is a good idea when your taking pictures of rocks, walls, surfaces, someone’s hands, or leaves.  In order to make a picture reveal a texture you must make sure the light is coming almost exactly from the side of the surface so it creates shadows in places key places.

Human beings are naturally attracted to patterns. They are visually attractive and suggest harmony. Patterns can be man made like a series of arches or natural like the petals on a flower. Incorporating patterns into your photographs is always a good way to create a pleasing composition. Less regular textures can also be very pleasing on the eye.

We are surrounded by symmetry and patterns, both natural and man-made. They can make for very eye-catching compositions, particularly in situations where they are not expected. Another great way to use them is to break the symmetry or pattern in some way, introducing tension and a focal point to the scene.

#14. Diagonals and Triangles

It is often said that triangles and diagonals add ‘dynamic tension’ to a photo. What do we mean by ‘dynamic tension’ though? Look at it this way, horizontal lines and vertical lines suggest stability. If you see a person standing on a level horizontal surface, he will appear to be pretty stable. Put this man on a sloping surface and he’ll seem less stable. This creates a certain level of tension visually. We are not so used to diagonals in our every day life. They subconsciously suggest instability. Incorporating triangles and diagonals into our photos can help create this sense of ‘dynamic tension’.

Incorporating triangles into a scene is a particularly good effective way of introducing dynamic tension. Triangles can be actual triangle-shaped objects or implied triangles.

#15. EXPERIMENTATION

It exists so many different composition guidelines or rules in art and photography that it only depends on you to search, follow them or simply try and experiment by yourself.

With the dawn of the digital age in photography we no longer have to worry about film processing costs or running out of shots. As a result, experimenting with our photos' composition has become a real possibility; we can fire off tons of shots and delete the unwanted ones later at absolutely no extra cost. Take advantage of this fact and experiment with your composition - you never know whether an idea will work until you try it.