Exposure Triangle

Three settings, four visible effects

Choose a subject above the image: Running dog, Landscape · focus at infinity, or Hummingbird · fast-moving wings. The lighting dropdown and camera controls work with all three.

Choose Tv (Shutter Priority), Av (Aperture Priority), or M (Manual) above ISO. Hover over a button to see its full name. In Tv, choose shutter speed and the simulator selects aperture. In Av, choose aperture and it selects shutter speed. The automatic dial is labelled Auto and cannot be dragged. M leaves both dials under your control. ISO can be manual or Auto in all three modes. With Auto ISO in a priority mode, the automatic dial is first selected for ISO 100, then ISO rises if needed within the available range. Limits can still leave exposure too bright or dark.

The page starts in M. Selecting a camera example or changing subjects returns to M and applies that example or subject’s settings.

ISO: Increasing ISO makes the rendered image brighter at the same aperture and shutter speed. The simulator also adds more visible noise. ISO does not increase the amount of light collected by the sensor; actual noise depends on the camera, the light captured and processing.

Move the ISO slider one step left of ISO 100 to select Auto ISO. The displayed value shows the ISO chosen for your aperture, shutter speed and lighting. In Auto, the thumb stays at the Auto position and a blue bar fills to the selected ISO level; manual ISO uses green. Auto ISO chooses the nearest manually selectable ISO by exposure-stop distance: 100, 200, 400, 800, 1600, 3200, 6400 or 12800. Rounding can leave up to half a stop of exposure difference; at either limit the image can be further too bright or dark, and the control explains the limit. Moving right to ISO 100 or higher returns to manual ISO. The running dog and hummingbird start in Auto ISO; the landscape starts at ISO 100. Changing subjects restores that subject’s balanced defaults. Balanced / reset also restores this ISO mode; the other camera examples apply their displayed manual ISO settings.

Shutter speed: A faster shutter freezes more movement, but collects less light. A slower shutter makes the dog blur along its direction of travel, or smears the hummingbird’s rapidly beating wings while its hovering body stays steadier. The landscape is static, so changing shutter speed affects brightness without introducing subject motion blur. The camera stays still in every scene.

Aperture: A smaller opening means a higher f-number. Moving from f/2 to f/16 increases depth of field while admitting less light. With the dog or hummingbird, focus stays on the animal and a wider opening softens the background. The landscape contains only distant mountains, lake and shoreline, with no nearby foreground. Focus stays at infinity and the entire view stays in focus even at f/1.4; changing aperture still affects brightness.

Try these comparisons

Start with Sunny 16 lighting and Balanced / reset, then make only the shutter faster. The dog becomes sharper and the image becomes darker. Open the aperture or raise ISO to recover brightness.

The balanced defaults are ISO 100, f/8 and 1/500 s under Sunny 16 lighting, and ISO 100, f/2.8 and 1/250 s for golden hour. Sunny 16 remains the name of the lighting preset; its default aperture here is f/8.

Above f/8, the Aperture label turns red and shows a diffraction softening link. The new Diffraction Calculator page is under construction. This is a reminder; diffraction blur is not rendered in the preview.

The Balanced / reset, Freeze action, Shallow focus and High ISO buttons adapt their camera settings to the selected lighting. Each example applies all three displayed settings, whereas moving a slider changes just that control (with ISO compensation if Auto ISO is selected). Each example gives approximately reference brightness, with a different balance of motion blur, depth of field and noise. The settings are shown on each button. Compare the dog’s outline, the distant trees and the grain to see what changes even when brightness stays similar.

If an example is selected, changing to Golden hour or Night time · street lamps automatically applies that example’s settings for the new light level. At night, freezing the dog needs a wide aperture and high ISO; the Freeze action example uses ISO 12800, f/1.4 and 1/1000 s.

Moving any camera slider leaves the selected example. With manual ISO, changing lighting then keeps your settings so you can see the image darken or brighten. With Auto ISO, the ISO adjusts to the new light level while aperture and shutter stay fixed. Click an example to return to an adapted exposure. Balanced / reset restores a balanced starting point for the current lighting without changing the selected EV.

Choosing a different subject restores its balanced defaults; its example buttons adapt to that subject. For the hummingbird, Freeze wings uses 1/8000 s, since the illustrative wing movement is much faster than the dog’s movement. Under the night preset, even ISO 12800 and f/1.4 leave this example about 3 stops dark. The button and meter show that limitation; you need more light or must accept some wing blur. For the static landscape, the corresponding examples are labelled Fast shutter and Wide aperture; the distant scene remains fully in focus in both.

Lighting and the exposure meter

Choose from three scene-light presets:

• Night time · street lamps: ≈ EV100 4. An illustrative dim street-lit scene.
• Golden hour: ≈ EV100 11. An illustrative lower-light outdoor scene near sunrise or sunset.
• Sunny 16: EV100 15. The rounded bright-sun reference used by the Exposure Calculator.

These are teaching presets, not universal readings. Golden-hour light varies with the sun’s position, weather and subject direction; street lighting varies with lamp brightness and distance. Nikon’s sunrise and sunset photography guide discusses changing light around these times. Meter your actual scene.

The selected EV stays fixed while you change camera settings. At EV100 15, ISO 100 and f/16, the exact matching shutter time is 1/128 second; the familiar 1/125 setting is about 0.03 stops brighter. The meter displays the difference from the selected lighting. Positive values mean brighter; negative values mean darker. Slider changes with manual ISO do not trigger automatic compensation. With Auto ISO, brightness is balanced within the available ISO range. The marker stops at the ends of the ±6-stop scale, but the numeric reading shows the full difference.

Brightness difference in stops = selected EV100 − [log₂(aperture² / shutter seconds) − log₂(ISO / 100)]

One stop corresponds to doubling or halving the exposure-related brightness before display rendering. For calculated settings and other lighting conditions, use the Exposure Calculator.

About the simulation

The preview is an illustration, not a prediction for a particular camera or lens. Each subject uses the same source scene across lighting choices, with brightness adjusted for the selected EV; sunset colours, street lamps and changes to shadows are not rendered. Noise, motion blur and depth-dependent softness are stylised. The dog moves sideways at a fixed illustrative speed; the hummingbird’s raised wings are blurred with a feathered mask and rotational averaging, rather than a biological wingbeat model. The distant-only landscape stays entirely in focus at all apertures; no defocus is applied. The camera, framing and focus stay fixed for each subject. Lens focal length, sensor size, precise focus distances, diffraction, camera shake and detailed sensor behaviour are not modelled. Small apertures increase depth of field in this demonstration without simulating diffraction softness. Extreme settings can crush shadows or clip highlights.

For the underlying relationships, see Nikon’s guide to the exposure triangle and explanation of ISO sensitivity.