MEMBERS MOMENTS | Melton Mowbray Photographic Society

KNOWLEDGE HUB

The Exposure Triangle: The Three Camera Settings That Work Together to Control Your Image.

Think of exposure as how bright or dark your final photo turns out. Get it right and your image looks natural and well-lit. Get it wrong and you end up with a photo that's too bright (overexposed) or too dark (underexposed). The good news is that exposure is controlled by just three settings — shutter speed, aperture and ISO — and understanding how they work together is one of the most useful things you can learn in photography. Together, these three are known as the exposure triangle.

The Three Sides of the Triangle

Each setting affects exposure, but each one also has a second effect on the look of your image:

Shutter speed controls how long the sensor is exposed to light. A faster shutter speed lets in less light but freezes motion. A slower shutter speed lets in more light but can introduce motion blur.
Aperture controls the size of the opening inside the lens that lets light through, measured in f-stops (such as f/1.8, f/5.6, f/16). A wide aperture (low f-number like f/1.8) lets in more light and blurs the background. A narrow aperture (high f-number like f/16) lets in less light and keeps more of the scene in sharp focus.
ISO controls how sensitive the camera's sensor is to light. A low ISO (e.g. 100 or 200) produces a clean, detailed image but needs more light. A high ISO (e.g. 3200 or 6400) works in darker conditions but can introduce digital noise — a grainy or speckled look in the image.

Why "triangle"?

Because changing one setting almost always means adjusting at least one of the others to keep the exposure balanced. They are linked. Increase the shutter speed to freeze a moving subject and the image gets darker, so you might open the aperture wider or raise the ISO to compensate. Lower the ISO for a cleaner image in bright light and the image might become overexposed, so you might use a faster shutter speed or narrow the aperture to bring the brightness back down.

How do photographers use this in real life?

Bright outdoor portrait: A photographer might use a wide aperture (f/1.8) to blur the background and separate the subject, a fast shutter speed (1/500) to keep things sharp, and a low ISO (100) because there's plenty of natural light available.
Dark indoor event: With less light available, a photographer might raise the ISO (e.g. 1600 or 3200), open the aperture as wide as it goes, and drop the shutter speed to let in as much light as possible — accepting a little noise or slight blur as a trade-off.
Landscape at golden hour: A photographer might use a narrow aperture (f/11) for a sharp foreground and background, a low ISO for a clean image, and adjust the shutter speed accordingly — possibly needing a tripod if the shutter speed drops too low.

Quick tip: When you change one setting and something looks off, ask yourself which of the other two can fix it. Most exposure problems in real shooting come down to finding the right balance between all three.

Recap: The exposure triangle is the relationship between shutter speed, aperture and ISO.

Shutter speed = controls time = affects motion blur
Aperture = controls lens opening = affects depth of field (background blur)
ISO = controls sensor sensitivity = affects image noise
Change one and you'll likely need to adjust another — that balancing act is exposure.

July 2026

ISO: The Camera Setting That Helps You Shoot in Brighter or Darker Conditions

ISO controls how bright your photo appears by changing how strongly the camera processes the light it has captured. In simple terms, a low ISO uses less amplification, and a high ISO uses more. Common ISO values are typically 100, 200, 400, 800, 1600, and higher.

Low ISO (for example ISO 100 or 200) usually gives the cleanest image quality and is best when there is plenty of light.
High ISO (for example ISO 1600, or above) makes it easier to shoot in darker conditions, but it can introduce visible noise (a grainy or speckled look).

That trade-off is the key idea with ISO: raising it can save a shot when light is low, but the image may look ‘noisy’ and lose some detail. Modern cameras handle high ISO better than older ones, but in general it is still a good habit to keep ISO as low as you reasonably can.

The images below demonstrate how increasing the ISO introduces noise.

Modern cameras offer ‘auto ISO’ which selects the ideal setting for an image. They also allow you to set a maximum setting to prevent the camera choosing a particularly high setting in especially challenging condition. Software such as Photoshop is exceptionally good at removing noise from an image but the trade-off is that the image can lose fine detail particularly in high contrast areas.

Here are some common real-world situations:

Bright sunshine: Start with a low ISO such as 100 for the cleanest possible image.
Cloudy weather or indoors near a window: You may need ISO 400 to 800 to keep the photo bright enough.
Low light, evening, or fast action indoors: A higher ISO such as 1600 or above can help you use a faster shutter speed and avoid blur.

Quick tip: ISO is one part of the exposure triangle, alongside aperture and shutter speed. If you raise ISO, your image gets brighter, which can let you use a faster shutter speed or a narrower aperture. If you lower ISO, you may need more light by using a wider aperture or slower shutter speed to keep the same exposure.

Recap: ISO helps you manage brightness in different lighting conditions, but higher ISO usually means more visible noise. Use the lowest ISO that still lets you get the shot you want.

June 2026

Shutter Speed: The Camera Setting that Controls

Sensor Exposure Time

Think of shutter speed as how long the camera’s “eyelid” stays open when you take a photo. The shutter opens, light reaches the sensor, and then it closes again. Shutter speed is measured in seconds or fractions of a second, such as 1/1000, 1/250, 1/60, 1 second or longer. In general, a faster shutter speed lets in light during a short amount of time, while a slower shutter speed lets in light over a longer period. To summarise:

Fast shutter speed (e.g., 1/1000) = the shutter is open for a shorter time = less light and less motion blur
Slow shutter speed (e.g., 1/30 or 1 second) = the shutter is open for a longer time = more light and more motion blur

Shutter speed doesn’t just affect how much movement is captured, longer shutter speeds also let in more light, which might be useful when the environment is darker.

Motion rendering describes how movement looks in a photo. In general:

Fast shutter speeds freeze motion, so moving subjects such as runners, pets or cyclists appear sharp and crisp
Slow shutter speeds allow movement to blur, which can create a sense of speed, energy or softness in things like traffic, waterfalls or people walking

The images below show a fan using different shutter speeds which clearly demonstrate how shutter speeds impact the image.

So how do photographers use this in real life?

Sports and wildlife: Photographers often choose a fast shutter speed (for example 1/500, 1/1000 or even 1/4000) to freeze quick movement and keep the subject sharp
Waterfalls, light trails and night scenes: Photographers often use a slow shutter speed (for example 1/15, 1 second or longer) to blur movement and create a more dramatic or artistic effect
Everyday handheld photos: A moderate shutter speed such as 1/125 or 1/250 is often a safe starting point for keeping ordinary subjects sharp while shooting without a tripod

Quick tip: If you make your shutter speed faster and the image becomes too dark, compensate by opening the aperture or raising ISO. If you use a slower shutter speed, be careful of camera shake—using a tripod can help keep the parts of the image that should be sharp looking clear.

June 2026

Aperture: the camera setting that controls
light and background blur

Think of aperture as the camera’s “pupil”: an opening inside the lens that widens or narrows to control how much light reaches the sensor. Aperture size is described using f-numbers (like f/1.8, f/5.6, f/16). Here’s the part that often feels backwards at first:

Small f-number (e.g., f/1.8) = a bigger opening = more light
Large f-number (e.g., f/16) = a smaller opening = less light

The diagram below shows how the opening changes as the f-number changes.

Aperture doesn’t just affect brightness—it also changes how much of your photo looks sharp. This is called depth of field:

Depth of field describes the range in front of and behind your focus point that appears acceptably sharp. In general:

Wide aperture (small f-number) creates a shallow depth of field, so only a thin slice of the scene is sharp and the background/foreground blur more.
Narrow aperture (large f-number) creates a deep depth of field, so more of the scene stays sharp from front to back.

The photos below illustrate the difference in depth of field at different aperture settings. (Other factors—like how close you are to your subject and your lens focal length—also affect depth of field, but aperture is the easiest place to start.)

KNOWLEDGE HUB

The Exposure Triangle: The Three Camera Settings That Work Together to Control Your Image.

July 2026

ISO: The Camera Setting That Helps You Shoot in Brighter or Darker Conditions

ISO controls how bright your photo appears by changing how strongly the camera processes the light it has captured. In simple terms, a low ISO uses less amplification, and a high ISO uses more. Common ISO values are typically 100, 200, 400, 800, 1600, and higher.

Low ISO (for example ISO 100 or 200) usually gives the cleanest image quality and is best when there is plenty of light.

High ISO (for example ISO 1600, or above) makes it easier to shoot in darker conditions, but it can introduce visible noise (a grainy or speckled look).

That trade-off is the key idea with ISO: raising it can save a shot when light is low, but the image may look ‘noisy’ and lose some detail. Modern cameras handle high ISO better than older ones, but in general it is still a good habit to keep ISO as low as you reasonably can.

The images below demonstrate how increasing the ISO introduces noise.

Here are some common real-world situations:

Bright sunshine: Start with a low ISO such as 100 for the cleanest possible image.

Cloudy weather or indoors near a window: You may need ISO 400 to 800 to keep the photo bright enough.

Low light, evening, or fast action indoors: A higher ISO such as 1600 or above can help you use a faster shutter speed and avoid blur.

Recap: ISO helps you manage brightness in different lighting conditions, but higher ISO usually means more visible noise. Use the lowest ISO that still lets you get the shot you want.

June 2026

June 2026

Shutter Speed: The Camera Setting that Controls

Sensor Exposure Time

Fast shutter speed (e.g., 1/1000) = the shutter is open for a shorter time = less light and less motion blur

Slow shutter speed (e.g., 1/30 or 1 second) = the shutter is open for a longer time = more light and more motion blur

Shutter speed doesn’t just affect how much movement is captured, longer shutter speeds also let in more light, which might be useful when the environment is darker.

Motion rendering describes how movement looks in a photo. In general:

Fast shutter speeds freeze motion, so moving subjects such as runners, pets or cyclists appear sharp and crisp

Slow shutter speeds allow movement to blur, which can create a sense of speed, energy or softness in things like traffic, waterfalls or people walking

The images below show a fan using different shutter speeds which clearly demonstrate how shutter speeds impact the image.

So how do photographers use this in real life?

Sports and wildlife: Photographers often choose a fast shutter speed (for example 1/500, 1/1000 or even 1/4000) to freeze quick movement and keep the subject sharp

Waterfalls, light trails and night scenes: Photographers often use a slow shutter speed (for example 1/15, 1 second or longer) to blur movement and create a more dramatic or artistic effect

Everyday handheld photos: A moderate shutter speed such as 1/125 or 1/250 is often a safe starting point for keeping ordinary subjects sharp while shooting without a tripod

Quick tip: If you make your shutter speed faster and the image becomes too dark, compensate by opening the aperture or raising ISO. If you use a slower shutter speed, be careful of camera shake—using a tripod can help keep the parts of the image that should be sharp looking clear.

June 2026

Aperture: the camera setting that controls light and background blur

Think of aperture as the camera’s “pupil”: an opening inside the lens that widens or narrows to control how much light reaches the sensor. Aperture size is described using f-numbers (like f/1.8, f/5.6, f/16). Here’s the part that often feels backwards at first:

Small f-number (e.g., f/1.8) = a bigger opening = more light

Large f-number (e.g., f/16) = a smaller opening = less light

The diagram below shows how the opening changes as the f-number changes.

Aperture doesn’t just affect brightness—it also changes how much of your photo looks sharp. This is called depth of field:

Depth of field describes the range in front of and behind your focus point that appears acceptably sharp. In general:

Wide aperture (small f-number) creates a shallow depth of field, so only a thin slice of the scene is sharp and the background/foreground blur more.

Narrow aperture (large f-number) creates a deep depth of field, so more of the scene stays sharp from front to back.

The photos below illustrate the difference in depth of field at different aperture settings. (Other factors—like how close you are to your subject and your lens focal length—also affect depth of field, but aperture is the easiest place to start.)

June 2026

Aperture: the camera setting that controls
light and background blur