Camera settings should answer the picture you are trying to make. Decide first whether movement should be sharp or blurred, how much of the scene needs to appear sharp, and which tones must retain detail. The exposure controls then become practical choices rather than a test of photographic status.
The examples in this chapter are starting points. Light level, subject speed, distance, sensor size, lens, output size and your own handling change the result. Check a frame and adapt. A successful setting on yesterday's walk may fail in today's shade.
Aperture shutter speed and ISO
Aperture controls the opening in the lens. With other variables unchanged, opening from f/8 to f/5.6 admits roughly twice as much light. It also changes depth of field: a wider aperture generally gives a narrower range of apparent sharpness for the same camera position, focal length and focus distance.
Shutter speed controls how long light is recorded. Moving from 1/250 second to 1/500 second halves that time. It can reduce subject movement blur, but also halves the light gathered when the aperture and illumination stay the same.
ISO affects how the captured signal is handled and the brightness of the rendered result. On a digital camera, raising ISO does not make the sensor collect more photons. In automatic modes it may allow the camera to choose a shorter exposure time or a smaller aperture. Noise, highlight headroom and processing vary with the camera, so judge the actual files rather than fearing a particular ISO number.
This distinction matters in a dim street. If someone is moving, a sharp photograph at a higher ISO may serve the picture better than a cleaner but blurred frame. If the subject is still and you can steady the camera, a longer exposure may gather more light. The important decision is what kind of blur you can accept.
Stops in a real scene
Suppose a walking subject gives a usable exposure at 1/250 second, f/5.6 and ISO 800. To try 1/500 second while keeping the aperture, doubling ISO to 1600 gives a similar rendered brightness on a typical camera. Alternatively, opening the lens to f/4 compensates for the shorter time, but reduces depth of field.
If two people are at different distances, opening the aperture may lose the second face. If the moving hand is central to the picture, slowing the shutter may lose the gesture. The exposure triangle becomes useful when you understand what each compromise does to this specific frame.
A stop is a doubling or halving of a relevant setting. Common full aperture steps include f/2.8, f/4, f/5.6, f/8 and f/11. Each smaller opening transmits approximately half as much light as the previous one. Use the scale to reason about adjustments; you do not need to calculate every frame in the street.
Choosing an exposure mode
In aperture priority, choose the depth of field and watch the resulting shutter speed. Auto ISO with a suitable minimum shutter speed can make this a responsive setup where the camera supports it. Check what happens at the configured ISO limit: some cameras then allow a slower shutter speed, which can defeat your intention to freeze movement.
In shutter priority, choose the treatment of motion and watch the aperture. If the lens has already reached its widest or smallest opening, the camera may be unable to achieve the exposure it wants. Read the warnings and inspect the result.
Manual exposure gives direct control of shutter speed and aperture. With fixed ISO, it is useful when the light on your subject stays consistent while bright and dark backgrounds would confuse the meter. With Auto ISO, it can maintain your chosen shutter and aperture as the light changes. Exposure compensation in that combination is camera-dependent, so test it rather than assuming it works.
Program mode is also a legitimate choice. Knowing how to use program shift or exposure compensation can give fast control. The camera mode is a means of working; viewers respond to the photograph, not the letter on the dial.
Reading light with the meter
The meter measures reflected light and proposes a brightness. Large dark or bright areas can influence that proposal. A person in a dark coat against a dark doorway may be rendered lighter than you intend; bright paving can lead to the opposite problem.
Use exposure compensation to move the camera's proposal towards your intention in a supported automatic mode. Try a modest change, check the face or important highlight, and continue. Spot metering is useful when you understand what the measured patch represents. Pointing it anywhere on a face is not a guarantee of correct exposure.
Histograms and highlight warnings can help identify clipping. Remember that they usually describe a processed preview, even when you record raw. A tiny reflection from chrome may reasonably be white. A large area of featureless skin is a different problem. Decide which highlights matter instead of trying to preserve every glint at any cost.
Do not routinely underexpose every picture because you have heard that shadows can be rescued. Lifting a severely underexposed file can reveal noise and weak colour or tonal transitions. Give important tones sufficient exposure while protecting highlights that matter to the image.
Focus and depth of field
Single autofocus can suit a stationary subject. Continuous autofocus can track a moving one. Face and eye detection can help, but may select the wrong person or lose a face behind an obstruction. Practise changing the focus area without looking through menus.
For a close portrait, inspect whether the intended eye is sharp. For several people, decide whether they occupy a similar plane or need greater depth of field. Stopping down cannot make every distance sharp in every situation. Small apertures also demand more light or a slower shutter, and very small openings can soften fine detail through diffraction.
Pre-focusing means setting focus on a place where you expect the action. Zone focusing uses a chosen focus distance and aperture to create a useful range of acceptable sharpness. The edges of that range depend on the output and your standard of sharpness, not just the engraved scale on a lens.
Test your zone in ordinary conditions. Photograph subjects at several known distances and inspect the results at your intended display size. Back-button focus is an optional way to separate focusing from releasing the shutter. It is useful if it simplifies your actions, unnecessary if it adds another thing to remember.
Freezing motion and allowing it
For an ordinary walking person, 1/250 or 1/500 second may be a reasonable handheld starting point. Faster motion, closer distance or movement across the frame may require more. Stabilisation can reduce the effect of your hand movement; it does not freeze a moving person.
For deliberate blur, try a slower time and decide what should remain recognisable. With panning, follow the moving subject smoothly before, during and after the exposure. Starting around 1/30 or 1/60 second can make the effect visible, but subject speed and your tracking determine the result. Expect many failures while learning.
A tripod and a longer exposure can hold architecture still while people blur through it. Use a stable permitted position and avoid obstructing others. A neutral-density filter can make longer exposures possible in bright conditions. Do not confuse an exposure made over several seconds with an instantaneous account of who stood where.
A short burst can help with a fast gesture. It cannot decide your viewpoint or repair a weak arrangement. Compare the whole sequence and select the frame in which expression, limbs and background align. Do not discard the surrounding frames immediately; they may explain what happened and provide useful context.
Raw JPEG and the preview
Raw is a family of camera formats containing sensor data and metadata for later processing. Raw files may be uncompressed or compressed, sometimes losslessly. They are not automatically untouched records of every possible detail, and a converter must interpret them to produce a viewable picture.
A JPEG has already been rendered, including choices about tone, white balance, sharpening and compression. It is convenient and can look excellent, but has less latitude for extensive changes. Raw plus JPEG can offer a practical combination if storage and the camera's performance allow it.
A monochrome preview on a conventional colour-sensor camera generally leaves the colour data available in its raw file. This does not apply in the same way to a dedicated monochrome sensor, and software handling differs. Test your own camera and converter before relying on the workflow.
White balance influences colour rendering and can affect a later monochrome conversion from colour channels. It is not a substitute for setting exposure, and changing it does not repair clipped sensor data. For raw work it can usually be adjusted later with considerable flexibility. A JPEG gives less room for large corrections.
Special techniques with clear descriptions
Multiple exposures, zoom bursts, HDR merges and simulated miniature effects can be interesting experiments. Keep them separate from a claim that the picture records one unaltered instant. Bracketing records separate exposures; HDR processing merges them. They are related operations, not interchangeable names.
Photographing a moving crowd with a multi-frame process can create ghosting or misleading combinations. Optical tilt changes the plane of focus; shift adjusts framing relative to the sensor and can help manage architectural composition. A blurred band added in software imitates a look, not those optical functions.
If an electronic shutter is available, test it under the lighting and movement you encounter. Some systems show banding under artificial light or distort moving subjects through rolling readout. Quiet operation is useful only if the file remains suitable for the picture.
Assignment and review
Photograph one safe, ordinary movement at three shutter speeds. Then photograph a static scene at three apertures, checking that exposure remains comparable. Compare the results and note what changed, including the background.
Build one reliable starting setup for a daylight walk and another for dim light. Write down the limitation of each. Familiar settings should reduce hesitation while leaving you able to respond when the street asks for something different.