Tell me about photography. Photography is the controlled recording of light. A camera collects light through a lens, limits how much light reaches the recording surface, decides how long that light is collected, converts the result into an image, and then uses optical, electronic and computational processes to shape what the viewer finally sees. Understanding photography means understanding light, lenses, exposure, focus, colour, timing, composition and the difference between a scene and a photograph of that scene.

People searching for how photography works usually encounter disconnected settings: aperture, shutter speed, ISO, focal length, white balance, autofocus, dynamic range, RAW, JPEG and megapixels. These terms become easier when they are organised around a small number of questions. How much light is available? From what directions and wavelengths does it arrive? What part of the scene should appear sharp? What motion should be frozen or shown? What perspective and field of view should be used? What information can the sensor record, and how will the final image be interpreted?

This guide explains photography from first principles and then turns those principles into practical decision-making. It covers camera obscura geometry, lenses, apertures, shutter time, sensor sensitivity, noise, depth of field, autofocus, motion blur, exposure metering, colour, dynamic range, composition, portraiture, landscapes, phones, computational photography, image editing, ethics, archiving and troubleshooting. The goal is not to memorise settings. It is to understand the image-making system well enough to choose settings deliberately and diagnose why a photograph looks the way it does.

Photography in 50 Seconds

A photograph begins when light from a scene travels into a camera. A lens bends that light so rays from different parts of the scene form an image on film or an electronic sensor. The aperture controls the size of the opening in the lens. The shutter controls how long light is collected. ISO changes how strongly the captured signal is interpreted or amplified in the imaging pipeline. Focus determines which distances are rendered most sharply. Focal length and sensor size influence field of view and framing.

The sensor records a limited range of brightness and colour information. A processor then converts raw measurements into an image by demosaicing colour-filter data, applying tone curves, sharpening, noise reduction, white balance and other adjustments. A phone may merge several exposures, align frames, detect faces and locally brighten shadows before the user sees the result. Photography is therefore both optics and computation, but the foundation remains simple: control how light becomes information.

1. First Principle: A Photograph Is a Map of Light

Every visible object either emits light or reflects light that came from somewhere else. A lamp emits. A face in daylight mostly reflects. A red apple appears red because the light reaching the observer or camera has been filtered by the illumination and by the apple’s material properties. Photography records that interaction. The camera does not directly record “an apple,” “a person” or “a sunset.” It records patterns of light intensity and wavelength that software and human perception interpret as those things.

This distinction explains many photographic surprises. A white shirt photographed under warm indoor lighting may appear yellow because the light itself is warm. A face can look flat at noon because overhead light creates different shadow geometry from a low window. A dramatic sunset can become pale if the camera chooses an exposure that protects dark foreground detail at the expense of sky colour. The scene is not one objective brightness map; it is a distribution of light filtered through the camera’s limits.

The practical habit is to look for light before looking for subjects. Ask where the strongest source is, how large it appears from the subject, how hard or soft the shadows are, what the brightest highlights are, what reflections exist, and whether the colour of the illumination is consistent. The subject matters, but light determines how the subject is described.

2. From Pinhole to Lens: How a Camera Forms an Image

A dark box with a tiny hole can form an image because rays from each point in the scene travel through the opening in constrained directions. The image appears inverted on the opposite wall. Make the hole extremely small and the image can become sharper, but much dimmer. Make it larger and more light enters, but rays from each point overlap and blur.

A lens solves much of this trade-off by bending light. It accepts light through a much larger opening and redirects rays so they converge near a focal plane. Real lenses are combinations of glass or other optical elements designed to control aberrations such as distortion, chromatic fringing, spherical aberration and field curvature. No lens is perfect; optical design balances sharpness, size, aperture, focal range, cost and manufacturing complexity.

Focus means placing the sensor where light from a chosen subject distance converges most accurately. Objects at other distances may still appear acceptably sharp depending on aperture, viewing size and enlargement. This leads to depth of field, one of photography’s most useful creative controls.

3. Exposure: The Quantity of Light Recorded

Exposure describes how much light reaches the recording medium. In practice photographers control exposure with aperture and shutter time, while ISO influences how the captured signal is rendered and how exposure decisions are made. The three are often called the exposure triangle, although the metaphor can obscure an important point: aperture and shutter time physically control light collection, while ISO changes the relationship between sensor signal and output brightness within the camera’s system.

An exposure can be numerically brighter or darker without being aesthetically better. The useful question is whether important highlights and shadows contain the information you need. A silhouette intentionally places a person in deep shadow. A high-key portrait may keep much of the frame bright. A night photograph may include areas of near-black. Correct exposure is not a single average brightness; it is an allocation of limited recording range.

Aperture

The aperture is an adjustable opening inside a lens. It is described with f-numbers such as f/2, f/4 or f/8. Smaller f-numbers correspond to larger openings for a given focal length. A wider aperture lets in more light and usually reduces depth of field. A narrower aperture lets in less light and usually increases depth of field, although very small apertures can reduce fine sharpness through diffraction.

Shutter time

Shutter time is the duration over which the sensor collects light for an exposure. A short exposure such as 1/1000 second can freeze many kinds of motion but collects less light. A long exposure such as one second collects far more light but records movement as blur unless the camera and subject remain sufficiently still. Shutter time therefore controls both exposure and the representation of time.

ISO

ISO is commonly treated as camera sensitivity. In digital cameras it is better understood as part of the signal-processing and exposure system. Raising ISO can make the output image brighter for a given aperture and shutter time, but it does not create photons that were never captured. If less light is collected, the signal-to-noise ratio is usually worse. Modern cameras can perform remarkably well at high ISO, yet the deepest cure for noise is often to collect more useful light when the scene and desired motion rendering allow it.

4. Stops: A Simple Language for Exposure Change

A stop is a doubling or halving of exposure. Doubling shutter time from 1/250 second to 1/125 second collects one stop more light. Opening the aperture by a full-stop step also doubles the light passing through. ISO values are conventionally arranged in similar doublings. Stops are useful because they let photographers compare different controls using one language.

Suppose a photograph at f/4 and 1/250 second has the desired brightness, but the photographer wants greater depth of field and closes the aperture to f/8. That is two full stops less light through the lens. To maintain similar exposure, the shutter could be slowed by two stops to 1/60 second, provided motion blur remains acceptable, or ISO could be raised, accepting its consequences. Exposure decisions are trades among light, motion, depth of field and noise.

5. Focal Length and Field of View

Focal length is an optical property of a lens, usually stated in millimetres. On a given sensor size, shorter focal lengths show a wider field of view and longer focal lengths show a narrower field. A wide-angle lens can include more of a room or landscape. A telephoto lens can fill the frame with a distant subject.

Focal length is often said to change perspective, but camera position is the direct cause of perspective relationships. If the photographer stays in the same place and changes focal length, the geometric relationship among near and far objects remains the same; the framing changes. In practice photographers move when changing lenses, so perspective changes too. A close wide-angle portrait exaggerates near-versus-far facial distances because the camera is close. A longer lens used from farther away produces different proportions because of the new viewpoint.

This distinction is useful because it tells you what to change. If a nose looks disproportionately large, stepping back changes perspective. Simply cropping later can mimic the framing of a longer lens if the original resolution is sufficient, but it cannot undo perspective caused by camera position.

6. Depth of Field: Why Some Distances Look Sharp

Only one distance is perfectly focused in the strict optical sense, but a range in front of and behind that plane may appear acceptably sharp. That range is depth of field. It depends on aperture, focal length, subject distance, sensor format, final display size and the standard used for acceptable sharpness.

Wide apertures such as f/1.8 often produce shallow depth of field, especially at close distances and with longer focal lengths. Narrower apertures such as f/8 or f/11 often produce more depth of field. Moving closer to the subject reduces depth of field substantially. This is why macro photography can have very thin focus even at relatively narrow apertures.

Depth of field is not automatically a quality measure. Shallow depth can isolate a portrait subject from a busy background. Deep focus can connect a foreground rock to distant mountains. The correct choice follows the visual argument of the photograph: what information should be sharp enough to matter?

7. Focus and Autofocus

Autofocus systems estimate how to move lens elements so the chosen subject forms a sharp image on the sensor. Modern cameras may use phase-detection, contrast-detection or hybrid methods. They can track faces, eyes, animals, vehicles or other learned subject categories. These systems are powerful, but they still require the photographer to define intent.

A common failure is not “bad autofocus” but bad target selection. A camera may lock onto a high-contrast background instead of a low-contrast face, or it may track the wrong person in a crowd. The diagnostic questions are: what focus mode was used, what target area was active, was the subject moving, was there enough contrast or light, and was the shutter time fast enough to distinguish focus error from motion blur?

Manual focus remains useful in macro work, astrophotography, controlled studio work and situations where autofocus repeatedly chooses the wrong plane. Magnified live view and focus peaking can make manual focusing far more precise than older viewfinders allowed.

8. Motion: Freezing, Blurring and Panning

A photograph integrates light over time. Anything that changes position during that interval can blur. The amount of blur depends on subject speed, direction, distance, focal length, shutter time and the motion of the camera itself. There is no single “fast enough” shutter speed for all motion.

To freeze a fast bird in flight, a photographer may need a very short exposure. To show the silky movement of a waterfall, the photographer may deliberately use a long exposure and a tripod. Panning uses a slower shutter while the camera follows a moving subject. If tracking is successful, the subject can remain relatively sharp while the background streaks, communicating speed.

Image stabilisation helps reduce blur caused by camera movement, not movement of the subject itself. This distinction matters. Stabilisation may let you hand-hold a static building at a slower shutter speed, but it cannot freeze a running child. To control subject motion, shorten exposure time or change the way movement is represented.

9. Sensors, Pixels and Why Megapixels Are Not Image Quality

A digital sensor contains millions of photosensitive sites that convert incoming light into electrical signals. Pixel count influences spatial resolution, but final image quality depends on much more: lens sharpness, focus accuracy, motion, noise, dynamic range, demosaicing, processing, viewing size and the amount of light captured.

Two cameras with the same megapixel count can produce very different results. A larger sensor may collect more light for a comparable framing and exposure configuration, depending on conditions. A better lens may resolve more detail. Strong computational processing may improve perceived sharpness or reduce noise. Conversely, excessive sharpening can create halos and an artificial texture that looks detailed at first glance but contains little additional real information.

Megapixels matter when printing large, cropping heavily or resolving fine detail, but they are one link in a chain. The weakest link can dominate. A 60-megapixel file that is out of focus does not become a sharp photograph by virtue of file size.

10. Dynamic Range: Highlights, Shadows and the Limits of Capture

Scenes can contain a wider brightness range than a camera can record cleanly in one exposure. A sunlit window and a dim room may differ by many stops. If exposure is set for the room, the window may clip to featureless white. If exposure is set for the window, the room may fall into deep noise or black.

Photographers manage dynamic range by choosing exposure priorities, adding light, reducing contrast, using graduated filters, blending multiple exposures or relying on high-dynamic-range computational methods. Modern phone cameras routinely capture several frames and merge them to retain bright skies and shadow detail.

The critical concept is clipping. Once a channel has reached the system’s maximum recordable value, detail above that threshold cannot be recovered from that exposure. Deep shadows may retain information but with poor signal-to-noise ratio. Histograms and highlight warnings help diagnose where the captured information sits relative to these limits.

11. Colour, White Balance and the Colour of Light

Light sources have different spectral distributions. Daylight, shade, tungsten lamps, fluorescent sources and LEDs can make the same white object produce different sensor signals. Human vision adapts strongly to illumination, so a sheet of paper often still seems white under different lights. Cameras need an estimate of the illumination to render neutral colours plausibly. This is white balance.

Automatic white balance can work remarkably well, but mixed lighting is difficult. A person may be lit by warm indoor lamps on one side and cool window light on the other. No single global white-balance setting can make both sources neutral. The photographer can embrace the contrast, change the lighting, move the subject or correct regions selectively during editing.

Colour is also shaped by camera profiles, display calibration, output colour spaces and editing choices. A photograph does not contain colour in isolation; it contains encoded values interpreted by a colour-management pipeline. This is why the same image can look different on two uncalibrated displays.

12. RAW and JPEG

A RAW file usually preserves sensor data with relatively little irreversible image rendering compared with a JPEG. It gives the editor more freedom to adjust white balance, tone, highlight recovery, shadow rendering and noise reduction. A JPEG is already processed, compressed and mapped into a standard image format. It is smaller, widely compatible and often ready to share.

RAW is not automatically “better” for every purpose. If a camera or phone produces a JPEG or HEIF that looks good and the image will not require heavy editing, the convenience may be valuable. RAW matters when capture conditions are difficult, when maximum editing latitude is needed or when the photographer wants precise control over rendering.

The important misconception is that RAW is an untouched picture of reality. It is data that still requires interpretation. Different software can render the same RAW file differently because demosaicing, tone curves, colour profiles and noise reduction involve choices.

13. Composition: Organising Attention

Composition is the arrangement of visual information within the frame. It is not a list of mandatory rules. The rule of thirds, leading lines, symmetry, framing, negative space, repetition and foreground layering are useful because they describe recurring ways of directing attention, balancing visual weight and creating depth.

A stronger first principle is hierarchy. What should the viewer notice first, second and third? Brightness, contrast, colour saturation, sharpness, faces, text, size and position all influence attention. A photograph becomes confusing when several elements compete equally without a clear relationship. Simplification can be more powerful than adding.

Edges matter. A distracting bright object at the edge can pull attention out of the frame. A limb cut at an awkward joint can feel accidental. A horizon barely tilted may look careless unless the tilt is clearly intentional. Good composition includes scanning the entire frame, not only staring at the central subject.

14. Perspective, Distance and Background Control

Photographers often try to improve a picture by changing camera settings when the most powerful improvement is moving. A step left can remove a pole from behind a head. Kneeling can place a child’s face against a clean background. Moving closer can eliminate empty clutter. Stepping back can compress facial perspective and include context.

Background quality depends on geometry as much as aperture. A background farther behind the subject is easier to blur. A clean wall close behind the subject may remain recognisable even with a wide aperture. Long focal lengths combined with appropriate camera-subject-background spacing can make backgrounds appear larger and smoother.

Before changing gear, change viewpoint. Photography is spatial problem solving. The scene contains many possible images; camera position chooses which relationships become visible.

15. Worked Example: A Portrait in Window Light

Suppose you want a natural portrait indoors. Place the subject near a large window rather than directly under a small ceiling light. The window acts as a large light source relative to the face, producing softer transitions between highlights and shadows. Turn the subject gradually and observe how the shape of the light changes across the cheeks, eyes and nose.

Choose a background several steps behind the subject if possible. Use a focal length that allows a comfortable camera distance and avoids exaggerated perspective. Open the aperture enough to reduce background distraction, but not so far that one eye becomes sharp while the other falls outside acceptable depth of field if the face is angled. Focus on the nearer eye.

Now check shutter time. If the subject moves slightly, a very slow exposure may create softness that looks like missed focus. Raise ISO if necessary to maintain a suitable shutter speed. Finally, watch the highlights on skin and any bright window area. The portrait is a balance among light quality, viewpoint, focus, motion and exposure—not one magic lens setting.

16. Worked Example: A Landscape With Near and Far Detail

Imagine a foreground rock leading toward distant mountains. The goal is to keep enough of both near and far elements sharp while preserving detail in a bright sky. Choose a viewpoint first, because moving even half a metre can change how the rock overlaps the mountains. Then choose an aperture that provides sufficient depth of field without stopping down unnecessarily far into diffraction.

Focus somewhere that distributes acceptable sharpness across the important distances rather than automatically focusing at infinity. If shutter time becomes long, use a tripod or stabilisation. Check the histogram for clipped highlights. If the contrast exceeds what one exposure can comfortably record, consider a graduated filter or bracketed exposures, provided the scene permits.

The result depends less on owning a “landscape lens” than on understanding depth, dynamic range and spatial arrangement. Gear enables; decisions create.

17. Worked Example: Photographing Fast Action

For a runner, bird or football player, start with motion rather than with image brightness. Choose a shutter time fast enough for the desired degree of freeze. Use continuous autofocus and an appropriate tracking area. Set the aperture for enough depth of field to tolerate small focus errors while still gathering sufficient light. Then raise ISO as needed to support those constraints.

Burst shooting can increase the probability of catching a decisive moment, but it is not a substitute for anticipation. Watch patterns. Athletes repeat movements. Birds often launch in a direction related to wind or perch position. A child jumping from a step has a predictable apex. Timing improves when the photographer models what will happen next.

If images remain soft, distinguish the cause. Are stationary objects sharp but the subject streaked? That suggests subject motion. Is everything directionally smeared? That suggests camera movement. Is the background sharp while the subject is uniformly soft? That may indicate autofocus target error. Diagnosis prevents random setting changes.

18. Smartphones and Computational Photography

Phone cameras have small lenses and sensors compared with many dedicated cameras, yet they produce impressive images by combining optics with computation. A phone may capture multiple frames before and after the shutter press, align them, reduce noise, merge highlights and shadows, detect faces, simulate shallow depth of field and apply local tone adjustments.

This changes the meaning of a single “photo.” The final image may be a synthesis of several moments. Night modes can stack exposures to create a cleaner low-light result. Portrait modes estimate depth computationally and blur regions judged to be behind the subject. High-dynamic-range pipelines may treat bright skies differently from faces.

Computational photography does not abolish photographic fundamentals. Direction of light still matters. Camera movement still matters. Perspective still comes from viewpoint. Composition still organises attention. The algorithms extend what can be recorded; they do not decide what is worth saying with the image.

19. Editing: Developing the Capture, Not Rescuing Everything

Editing can adjust exposure, contrast, colour, crop, local brightness, sharpening, noise and many other characteristics. It is analogous to darkroom work in film photography, although digital tools are more flexible. The best edits usually begin with a reasonably good capture because information lost to severe clipping, missed focus or excessive motion may be impossible to recreate faithfully.

A disciplined editing sequence starts with technical corrections: lens profile if appropriate, white balance, exposure and tonal range. Then refine composition with crop and geometry. Then use local adjustments to guide attention. Sharpen for the final output size. Noise reduction should remove distracting noise without erasing meaningful texture.

Editing also carries an ethical dimension. In art, heavy manipulation may be part of the work. In documentary, scientific or journalistic contexts, alterations can change meaning and may violate professional standards. The same software action can be acceptable in one genre and misleading in another. Context determines the ethical boundary.

20. Misconceptions and Diagnostics

“More megapixels always means a better camera.”

Resolution is only one component of image quality. Lens performance, sensor behaviour, autofocus, dynamic range, processing and technique can matter more.

“A wide aperture is always more professional.”

Wide apertures are useful for low light and shallow depth of field, but excessive blur can remove context or leave important parts of a subject soft. Aperture should serve the image.

“High ISO causes noise by itself.”

Noise is strongly linked to the amount of useful light captured and the sensor/electronics pipeline. Raising ISO often accompanies low-light situations where fewer photons were recorded. The relationship is more nuanced than one slider causing all noise.

“Blurry means out of focus.”

Blur can come from missed focus, subject movement, camera shake, optical softness, atmospheric effects or aggressive noise reduction. Look at the pattern before changing autofocus settings.

“The camera sees what the eye sees.”

Human vision continuously adapts, moves, fuses information and interprets context. A camera records within fixed optical and dynamic constraints. Photographic skill partly consists of anticipating that difference.

21. A Practical Photography Diagnostic

If a photograph fails, inspect it in layers. First ask whether the subject is visually clear. If not, the issue may be composition, background or light direction rather than exposure. Second, inspect sharpness. Determine whether blur comes from focus or motion. Third, inspect tonal range: are highlights clipped or shadows unusably noisy? Fourth, inspect colour: is the white balance plausible and is mixed lighting creating unwanted casts? Fifth, ask whether processing has exaggerated the problem.

For portraits, also inspect expression, eye direction, posture and timing. For landscapes, inspect horizon, edge distractions and depth. For action, inspect the moment and subject separation. For architecture, inspect verticals and perspective. Technical perfection cannot rescue a photograph with no visual priority, while a powerful moment can sometimes survive technical imperfection.

The diagnostic principle is to change one variable for a reason. Randomly changing aperture, ISO, white balance and focal length at once destroys information about what caused improvement.

22. Practice System: Learn Photography Faster

Run small experiments. Photograph the same stationary object at several apertures while keeping framing constant. Compare depth of field and diffraction. Photograph a moving fan or bicycle wheel at different shutter times. Shoot the same scene at several ISO settings while controlling exposure. Photograph a face near a window, then move it progressively farther from the window to see how light softness and falloff change.

Use contact-sheet thinking. Instead of judging only the best image, compare a sequence and ask why one frame is stronger. Did the background simplify? Did timing improve? Did the head angle catch better light? Did the horizon move? Did a gesture create a clearer shape? Photography improves when selection becomes analytical rather than merely emotional.

Limit equipment during practice. One camera and one focal length for a day can teach viewpoint more effectively than constant lens switching. Constraints force the photographer to solve problems by moving, waiting and observing.

23. Photographing People Responsibly

Photography involves people, privacy and power. Legal rules vary by country and context, and ethical expectations can be stricter than legal minimums. A person may technically be visible in a public place while still being vulnerable, distressed or placed at risk by publication. Children deserve particular care. Commercial use, medical settings, schools and private venues may introduce additional requirements.

Consent is not only a form. It is an understanding of how an image will be used, where it may appear and what consequences publication may have. Documentary value must be balanced against dignity, safety and context. Removing identifying details may sometimes be appropriate; in other cases the identity is central to the story and requires explicit agreement.

Digital manipulation adds another layer. Generative edits can create events that never occurred. Face replacement, object removal and synthetic backgrounds may be harmless in fantasy art but misleading in evidence-oriented contexts. A trustworthy photographer knows when disclosure matters.

24. Archiving Photographs So They Still Exist Later

A photograph has no value if it disappears when a phone breaks. Good archiving means keeping multiple copies on different storage systems, maintaining understandable filenames or metadata, and occasionally checking that files remain readable. Important photographs deserve more than one physical location.

Original files matter because later software may extract more from them than today’s tools can. Keep RAW files when future editing value justifies the storage. Export high-quality standard formats for sharing and access. Preserve dates, locations and captions when they matter, because context can become harder to reconstruct than pixels.

Backups are a process, not a purchase. A drive connected to the same computer can fail with theft, fire or malware. Cloud storage can fail through account loss or accidental deletion. Redundancy means no single failure destroys the archive.

25. Frequently Asked Questions About Photography

What does aperture do?

Aperture controls the size of the lens opening. It changes light transmission and affects depth of field and optical behaviour.

What does shutter speed do?

Shutter time controls how long light is collected and therefore how motion is rendered. Short times freeze more motion; long times can show blur.

What does ISO do?

ISO affects how the sensor signal is translated into image brightness and influences exposure strategy. Raising ISO does not replace missing light and usually makes limited-light noise more visible.

What is the best camera?

The best camera is the one whose capabilities fit the task, budget and willingness to carry and use it. For many people a phone is sufficient; specialised action, wildlife, studio or large-print work may benefit from dedicated systems.

Why are my indoor photos blurry?

Low light often causes the camera to use a longer shutter time. Subject movement or hand movement then becomes visible. Use more light, a wider aperture, higher ISO, stabilisation for camera shake, or a shorter shutter time depending on the cause.

Why is the sky white in my photograph?

The sky may be overexposed relative to the rest of the scene. Reduce exposure, change lighting balance, use exposure bracketing or accept the sky as a high-key element if that suits the image.

Why do phone portraits sometimes blur hair incorrectly?

Computational portrait modes estimate subject boundaries and depth. Fine hair, transparent objects and complex edges can confuse the segmentation model, producing artificial blur errors.

Should I shoot RAW?

Shoot RAW when you expect significant editing, difficult lighting or archival value. Use processed formats when convenience, storage and immediate sharing matter more than maximum editing latitude.

What makes a photograph professional?

Professionalism is not one visual style. It includes reliable technical control, intentional communication, ethical practice, consistent delivery and fitness for the client’s or project’s purpose.

Can editing fix an out-of-focus photo?

Sharpening can increase edge contrast and modern AI tools can infer detail, but genuinely missing optical information cannot always be restored faithfully. Accurate focus at capture remains preferable.

26. The Big Picture: Photography Is Selection

A camera can record enormous detail, yet a photograph is always a selection. It chooses one position, one direction, one moment, one field of view, one exposure and one rendering. What lies outside the frame is excluded. What happens before and after is compressed into context or forgotten. This is why photography is both evidence and interpretation.

Technical mastery matters because it expands the range of selections a photographer can make intentionally. Aperture can decide what remains sharp. Shutter time can decide how motion is described. Exposure can decide whether a face or a sky receives tonal priority. Lens and position can decide what spatial relationships dominate. Editing can decide how the recorded information is translated for a viewer.

The strongest photographer therefore does not begin with “What setting should I use?” but with “What do I want the viewer to notice, feel or understand?” Settings are then tools in service of that decision. Photography becomes clearer when technique answers meaning.

Useful Routes

• Tell Me About Light — photons, colour, reflection, refraction and optics.
• Tell Me About Computers — the digital systems that store and process images.
• What Is Robotics? — sensors, control and machines in the physical world.
• Library of Congress Prints and Photographs — a major historical image collection.
• Smithsonian Institution — collections and resources spanning art, history, science and visual culture.