Metering
Written by Abin Alex and Anu Joseph.
Abstract
Metering is the measurement of light in a scene so that an exposure can be set, by the camera or by a hand-held meter. A camera meter reads reflected light and aims to render the scene as middle grey, so very bright, very dark or high-contrast scenes can mislead it. This guide distinguishes reflected from incident metering, describes the matrix, centre-weighted, spot and partial modes, and shows how to meter backlit and high-contrast scenes. It explains why a camera may render snow as grey. It is written for photographers and cinematographers.
Keywords: metering; matrix metering; spot metering; middle grey; incident light
- What is metering in photography?
- What is the difference between reflected and incident light metering?
- How does a camera measure light?
- Why does my camera make snow look grey?
- What are the metering modes in a camera?
- How does matrix (evaluative) metering work?
- What is centre-weighted metering?
- When should I use spot or partial metering?
- How do I meter a backlit or high-contrast scene?
- How do I focus on one area and meter from another?
- How do I correct a wrong meter reading?
- How is light measured in cinematography?
- How can I practise metering?
- Which metering mode suits each kind of photography?
What is metering in photography?
Short answer. Metering is the measurement of the light in a scene, so that the camera or the photographer can choose an exposure. The meter judges how bright the scene is and proposes an aperture, shutter speed and ISO that should give a well-exposed picture.
- A meter measures light. It does not know what your subject is.
- In the automatic modes the camera uses the reading to set the exposure. In manual mode it shows you the exposure scale and you set it.
- The metering mode decides which part of the scene the meter pays attention to.
- The reading is a suggestion. You decide if the picture should be brighter or darker.
A simple picture to remember: the meter is a helper who looks at the scene and says, "this much light, so use these settings." The helper is right in an average scene and wrong when the scene is far from average. The rest of this guide shows how to tell the difference.
Cham tipThe meter measures light, not meaning. You choose what should be bright and what should be dark.
Cham taskSet your camera to manual. Point it at a window and then at a dark corner, and watch the exposure scale move.
Check yourself: Does the meter know what your subject is?
No. It only measures the brightness of the area it reads. You decide what that brightness should look like.
What is the difference between reflected and incident light metering?
Short answer. A reflected meter measures the light that bounces off the scene towards the camera. An incident meter measures the light that falls on the scene. The meter built into every camera is a reflected meter.
- Reflected metering reads how bright things look, so it depends on their colour and shine.
- Incident metering reads the light that reaches the subject, so a white shirt and a black shirt give the same reading.
- A hand-held incident meter has a white dome. You hold it at the subject and point it towards the camera.
- Because camera meters are reflected, very bright or very dark subjects can fool them.
| Type | What it measures | Where you find it | Strength | Weakness |
|---|---|---|---|---|
| Reflected | Light bouncing off the subject | Inside the camera, or a hand-held spot meter | Reads only the part you aim at, even from far away | Fooled by white, black or shiny subjects |
| Incident | Light falling on the subject | Hand-held meter with a dome | Not fooled by the colour of the subject | You must stand in the same light as the subject |
Table 1. Reflected and incident metering compared.
Cham tipCamera meter: reflected. Hand-held dome meter: incident. The dome catches the light that falls, so the colour of the subject does not matter.
Cham taskPhotograph a white sheet and a black sheet in the same light in an automatic mode. Both come out a similar grey. Why?
Check yourself: Which type of meter is built into your camera?
A reflected light meter. It reads the light that comes back from the scene through the lens.
How does a camera measure light?
Short answer. The camera reads the light that comes through the lens. A DSLR has a small metering sensor in the viewfinder path. A mirrorless camera has no mirror, so it works out the exposure from the image on its own sensor.
- In a DSLR, light passes through the lens, hits the mirror and is sent up to the focusing screen and the metering sensor.
- In a mirrorless camera there is no mirror. The camera reads the image from the sensor and calculates the exposure from it.
- The camera meters through the lens, so a filter on the lens is already part of the reading.
- The camera usually meters when you press the shutter button halfway.
It is often said that the mirror flips up so the sensor can be exposed. That is true for a DSLR. It does not apply to a mirrorless camera, which has no mirror.
Cham tipIn a mirrorless camera, what you see on the screen is already a measurement. Turn on the exposure preview and watch it change.
Cham taskHalf-press the shutter on a bright wall and then on a dark cloth. Watch the exposure scale move.
Check yourself: Does a mirrorless camera need a separate metering sensor?
Usually not. It reads the exposure from its imaging sensor.
Why does my camera make snow look grey?
Short answer. A camera meter assumes the scene is an average middle grey, and it sets the exposure so that whatever it measures comes out as middle grey. That is why white snow turns grey and a black cat turns grey too.
- Traditional teaching puts middle grey at 18 percent reflectance. Many meters are calibrated lower, at roughly 12 to 16 percent, a difference of about half a stop (Art Adams, 2012).
- A bright scene is made darker than it should be. A dark scene is made brighter.
- The fix is exposure compensation: plus for bright scenes and minus for dark scenes.
- In Ansel Adams’s Zone System, the meter reading is placed on Zone V, middle grey, and the other tones fall above and below it (Ansel Adams, 1981).
- If you meter from a grey card, hold it in the same light as the subject, out of shadow and away from coloured reflections. Do not point it square at the camera. Estimate the angle between the main light and the camera, then turn the card away from the camera by about a third of that angle. An approximate adjustment is enough (Präkel, 2009).
| Scene | What the meter does | Result | Starting fix |
|---|---|---|---|
| Snow, white wall, bright sand | Tries to make it grey | Too dark, grey snow | Plus 1 to plus 2 |
| Black cat, night street | Tries to make it grey | Too bright, washed-out black | Minus 1 to minus 2 |
| Average mixed scene | Close to its own assumption | Near the right exposure | None |
Table 2. How the meter treats bright and dark scenes. The compensation values are starting points. Check the picture each time.
Cham tipWhite things need plus. Black things need minus. Check the picture and adjust.
Cham taskPhotograph a white wall in an automatic mode. Is it grey? Add plus 1 and shoot again.
Check yourself: You photograph a white wall in an automatic mode and it looks grey. What do you do?
Add plus exposure compensation, about plus 1 to begin with, and check the picture again.
What are the metering modes in a camera?
Short answer. A metering mode tells the camera which part of the frame to read. The four common modes are matrix (also called evaluative or multi), centre-weighted, partial and spot, running from the whole frame down to a very small area.
- Matrix, evaluative and multi are one idea with three names. Nikon says matrix, Canon says evaluative and Sony says multi (Canon, n.d.; Sony, n.d.).
- Centre-weighted reads the whole frame but gives more importance to the centre.
- Partial reads a small area at the centre and spot reads a smaller one. On the Canon EOS R5, partial is about 6.1 percent and spot about 3.1 percent of the screen (Canon, n.d.).
- The sizes differ from camera to camera, so check your manual. Some makers add more modes, such as the highlight mode on Sony cameras (Sony, n.d.).
| Mode | Area it reads | Good for | Watch out |
|---|---|---|---|
| Matrix, evaluative, multi | Whole frame, in zones | Most everyday pictures | One very bright or very dark area can still fool it |
| Centre-weighted | Whole frame, centre counts most | Portraits and steady results | Subject away from the centre |
| Partial | A small area at the centre, about 6 percent on one Canon | A subject against strong light | Not on every camera |
| Spot | A very small area, about 3 percent on one Canon | A small bright or dark subject, backlight, the moon | It reads only one tone |
Table 3. The four common metering modes. The percentages are from one Canon camera (Canon, n.d.).
Cham tipIf you are unsure, start with matrix. Change the mode when the picture goes wrong in the same way twice.
Cham taskFind the metering setting in your camera. Write down the names it uses for the modes.
Check yourself: Are matrix, evaluative and multi metering different?
No. They are different makers’ names for the same idea: the camera reads the whole frame in zones.
How does matrix (evaluative) metering work?
Short answer. The camera splits the frame into zones, reads each one, and then judges the scene as a whole. It takes brightness, colour, distance and the focus point into account before it picks an exposure. This is the default mode on most cameras.
- Each zone is read separately, so the camera knows where the bright and dark areas are.
- The focus point often gets extra importance, because the subject is usually where you focus.
- Makers add their own rules. For example, Nikon compares the scene with a database of stored pictures.
- It works well for evenly lit scenes, for travel and for quick shooting.
Matrix metering is clever, but it is still a guess. If one part of the scene is very bright, like a window behind your subject, the guess can be wrong.
Cham tipMatrix is a good start. Do not trust it with a bright window or a bright sky behind your subject.
Cham taskTake a picture of a person with a bright sky behind, in matrix mode. Does the face look too dark?
Check yourself: Besides brightness, what else can matrix metering look at?
Colour, distance and the position of the focus point, depending on the camera maker.
What is centre-weighted metering?
Short answer. Centre-weighted metering reads the whole frame but gives most weight to a circle in the middle, with the corners counting far less. It behaves steadily and predictably, which is why it suits portraits.
- The centre gets most of the weight, often put at 60 to 80 percent. The exact figure differs between cameras.
- Some cameras let you change the size of the circle. Nikon has a custom setting for it (Nikon, n.d.).
- The background has less effect on the reading, so a bright background does not spoil the face as much.
- It gives more consistent results than matrix, because it follows one simple rule.
Cham tipPut your subject in the centre when you meter, lock the exposure, then recompose.
Cham taskShoot a portrait against a bright window in matrix and in centre-weighted. Compare the faces.
Check yourself: Why does centre-weighted give steadier results than matrix?
It follows one simple rule, the centre counts most, so the same framing gives the same result.
When should I use spot or partial metering?
Short answer. Choose spot or partial metering when one small part of the scene matters more than the rest. The camera reads only that area, so a small bright or dark subject is not thrown off by its surroundings. The rest of the picture may then come out too dark or too bright.
- Spot reads a very small circle, about 3 percent of the screen on one Canon camera. Partial reads a larger circle, about 6 percent on the same camera.
- Spot works best on a mid-tone. Put the spot on a mid-tone such as skin or a grey patch, lock the exposure, then recompose.
- It suits backlit subjects, a face under a stage spotlight, a far-away bird and the moon.
- On some cameras the spot moves with the focus point, and on others it stays at the centre. Check yours.
- You can lose the rest of the picture. Check the highlights and shadows after every shot.
| What you spot meter | Result without compensation | What to do |
|---|---|---|
| A mid-tone: grass, a grey card, average skin | Close to right | Use it as it is |
| A white shirt or snow | Grey and too dark | Plus 1 to plus 2 |
| A black dress or a black dog | Grey and too bright | Minus 1 to minus 2 |
| The moon | Close to right, and the dark sky does not fool the reading | Check the detail on the surface |
Table 4. What a spot reading gives on different tones. The values are starting points.
Cham tipSpot meter on something middle in tone. If you spot a very bright or very dark thing, add or subtract.
Cham taskPhotograph a person against a bright window, first in matrix and then in spot on the face.
Check yourself: You spot meter a black dog’s fur and the picture looks too bright. Why?
The meter turns what it reads into middle grey, so black fur is brightened. Use minus compensation, about minus 1 to begin with.
How do I meter a backlit or high-contrast scene?
Short answer. Decide what matters, meter for it, and accept that the rest may clip. Meter the face with spot or centre-weighted, or use matrix with plus compensation, then check the highlight warning. In a very high-contrast scene a single picture may not hold everything.
- First, choose the part of the picture that must keep detail.
- Then meter that part with spot or centre-weighted, or use matrix and add plus compensation.
- Check the screen and the histogram for clipped highlights.
- If the sky and the face cannot both fit, add light with a reflector or a flash, or choose a silhouette on purpose.
| Situation | Try this |
|---|---|
| Person against a bright window | Spot on the face, or matrix with plus 1 |
| Subject in shade, background in sun | Centre-weighted or spot on the subject |
| Stage spotlight | Spot on the lit face |
| Sunset silhouette | Meter the bright sky next to the sun and keep that exposure |
Table 5. Metering choices for high-contrast situations.
Cham tipNever try to meter for everything. Pick the one thing that must be right.
Cham taskTake three shots of a person against a bright window: matrix, spot on the face, and matrix with plus 1. Which keeps both the face and the window?
Check yourself: In a strongly backlit scene, what do you meter for?
The part that must keep detail, usually the face. Accept that the bright background may clip, or add light to the face.
How do I focus on one area and meter from another?
Short answer. Use AE lock. Meter on the area you want, press the AE lock button to freeze the exposure, then move the camera, focus and shoot. While the exposure is locked, the viewfinder shows a symbol, a star on many cameras.
- Put the metering area on the part you want and press the shutter halfway. Then press the AE lock button.
- The exposure stays fixed while you recompose.
- On some cameras the lock is lost if you change the focus point afterwards. Take the reading again and lock it again.
- Back-button focus is the other fix. Set a rear button, often called AF-ON, to focus, and let the shutter button meter. Then you can focus and meter in different places.
Cham tipMeter, lock, recompose, shoot. Learn where AE lock and AF-ON are on your camera before an important shoot.
Cham taskFind AE lock and AF-ON on your camera. Meter on a grey wall, lock, then shoot a different framing.
Check yourself: What does AE lock stop the camera from changing while you recompose?
The exposure. The camera keeps the settings it chose from your first reading.
How do I correct a wrong meter reading?
Short answer. Use exposure compensation, or set the exposure by hand in manual mode. If the picture is too dark, add plus. If it is too bright, add minus. One step of compensation is one stop.
- Exposure compensation works in the automatic modes. It tells the camera to expose brighter or darker than its reading.
- In manual mode you move the exposure scale away from zero.
- Look at the picture, the histogram and the highlight warning, then adjust.
- Exposure compensation is explained in the Exposure guide.
| What you see | What to try |
|---|---|
| Too dark, and the scene is bright | Plus compensation |
| Too bright, and the scene is dark | Minus compensation |
| Highlights blink on the screen | Minus compensation, or meter for the highlights |
| Face dark, sky fine | Plus compensation, or spot on the face |
Table 6. Reading the picture to correct the meter.
Cham tipChange one thing at a time. Add plus 1, look, then decide.
Cham taskPhotograph a white wall and a black cloth. Correct each with compensation until it looks right.
Check yourself: A picture of a snowfield looks grey. Do you add plus or minus compensation?
Plus. The meter is turning the snow into middle grey, so you tell it to expose brighter.
How is light measured in cinematography?
Short answer. A cinematographer takes readings with a hand-held incident meter and a spot meter, then checks the picture on a monitor with zebras, false colour and a waveform. On a planned shot the camera's automatic reading is rarely trusted.
- An incident meter reads the light on the actor’s face. The DOP then sets the stop to match.
- A spot meter measures bright and dark parts, so the DOP can see how many stops apart they are.
- Zebras show stripes on parts of the picture at a chosen brightness. Canon suggests setting zebra 1 at 70 IRE for skin and adjusting the exposure until the skin shows stripes (Canon Singapore, 2025).
- False colour paints brightness in colours. In the Canon guide, green marks 18 percent grey, pink marks one stop above it, red marks clipped white and purple marks clipped black. The colours differ between cameras, so read the legend (Canon Singapore, 2025).
- A waveform plots brightness against the width of the image, so you can see where the highlights sit.
| Tool | What it shows | Use it to |
|---|---|---|
| Incident meter | Light falling on the actor | Set the stop for the scene |
| Spot meter | Brightness of one small area | Compare a window and a face |
| Zebra | Stripes above a chosen level | Protect highlights and skin |
| False colour | Brightness as colours | Check the whole frame at once |
| Waveform | Brightness along the frame | See clipping and contrast |
Table 7. Exposure tools used on a film set.
Cham tipSkin is a useful guide, but skin tones differ. Canon puts lighter skin near 60 to 70 IRE and medium to darker skin near 40 to 60 IRE, so judge each person on the monitor (Canon Singapore, 2025).
Cham taskIf your camera has zebras, set them to 70 and see which parts of a face show stripes.
Check yourself: Why can one zebra level not suit every skin tone?
Lighter skin sits higher on the scale than darker skin, so one level cannot be right for both.
How can I practise metering?
Short answer. Photograph the same still subject four times in the same light, changing only the metering mode. Let each mode meter for itself, note the settings it chose, and compare the pictures. Then repeat in bright, dark and mixed light.
- Pick a still subject that is different in tone from its background. Frame it and do not move the camera.
- Use an automatic mode with a fixed ISO. For each shot, set the metering mode, meter, and note the shutter speed the camera chose.
- Shoot spot, matrix, centre-weighted and partial in turn.
- Do the four shots in bright light, in dark light and in mixed light. That is 12 pictures for one subject.
Do not lock the exposure between the shots. If the exposure stays locked, the four pictures get the same settings and the metering mode makes no difference.
| Light | Spot | Matrix | Centre-weighted | Partial |
|---|---|---|---|---|
| Bright | ||||
| Dark | ||||
| Mixed |
Table 8. A log sheet for the metering exercise. Write the shutter speed and a note in each empty cell.
Cham tipWrite the shutter speed down for each mode. The numbers teach more than the pictures.
Cham taskDo the bright-light round today: four modes, one subject, four shutter speeds in your log.
Check yourself: Why must you not lock the exposure between the four shots?
A locked exposure gives all four pictures the same settings, so the metering mode would make no difference. Let each mode meter on its own.
Which metering mode suits each kind of photography?
Short answer. Choose the metering mode by how much of the frame matters. Matrix reads the whole scene, centre-weighted favours the middle, and spot reads one small area. Treat every line below as a starting point.
- Birds. Spot or centre-weighted, with plus compensation for a bird against a bright sky.
- Animals and pets. Matrix. Add plus compensation for a white animal and minus for a black one.
- Reptiles. Matrix. Use spot on the head when the animal sits on a bright background.
- Insects and macro. With flash, the flash sets the exposure. Check the histogram and adjust the flash power.
- Portraits. Spot on the face, or matrix with a check of the highlights.
- Fashion. An incident meter or spot on the skin in the studio. Matrix on location.
- Wedding and events. Matrix. A white dress and a dark suit in one frame fool the meter, so check the highlights.
- Product. A grey card or an incident meter on a tripod. A white product on white needs plus compensation.
- Automotive. Matrix. Use spot on a body panel for glossy paint, and watch bright reflections.
- Photojournalism. Matrix as a default. Spot when the subject is backlit.
- Sports and action. Matrix. Spot or centre-weighted for a player under bright lights against a dark crowd.
- Landscape. Matrix, then check the histogram. Bracket when the sky is much brighter than the ground.
- Street and documentary. Matrix. Fix the exposure for the light once, then watch for changes.
- Night and astro. Spot on the brightest light you want to keep, with minus compensation. Or set manual by the histogram.
- Cinema. An incident meter on the actor and a spot meter on windows and lamps. Then check the monitor.
Questions beginners ask
What is metering in photography?
Metering is measuring the light in a scene so the camera, or you, can choose the exposure.
Which metering mode should a beginner use?
Matrix, also called evaluative or multi, for most pictures. Switch to centre-weighted or spot when the subject is small, or much brighter or darker than its surroundings.
What is the difference between spot and partial metering?
Both read a small area at the centre of the frame. Spot reads the smaller area. On the Canon EOS R5, spot is about 3.1 percent of the screen and partial about 6.1 percent.
Do I need a hand-held light meter?
Not for most photography. The camera meter, the histogram and the highlight warning are enough. In film and studio work an incident meter is more reliable, because the colour of the subject does not change the reading.
What does AE lock do?
It freezes the exposure the camera chose, so you can move the camera and recompose without the settings changing.
References
- Adams, Ansel (1981) The Negative. Boston: New York Graphic Society. See the chapters on the Zone System.
- Adams, Art (2012) ‘Reflected light meters: what are they really saying?’, ProVideo Coalition, 30 November. www.provideocoalition.com/reflected_light_meters_what_are_they_really_saying/
- Canon Singapore (2025) ‘Videography FAQ: False Colours, Waveform, and Zebras’, Snapshot, 26 August. snapshot.asia.canon/en/article/videography-faq-false-colours-waveform-and-zebras
- Canon. (n.d.) Metering Mode. Canon EOS R5 Advanced User Guide. cam.start.canon/en/C003/manual/html/UG-03_Shooting-1_0400.html
- Nikon. (n.d.) Custom Settings Menu: b5 Center-Weighted Area. Z 8 Reference Guide. onlinemanual.nikonimglib.com/z8/en/psm_metering_141.html
- Präkel, D. (2009) Basics Photography 07: Exposure. Lausanne: AVA Publishing. See the section on reflected and incident light meters (pp. 92–105).
- Sony. (n.d.) Metering Mode. ZV-E10 Help Guide. helpguide.sony.net/ilc/2070/v1/en/contents/TP0001116979.html
How to cite this guide. Alex, A., & Joseph, A. (2026). Metering: A guide for photographers and cinematographers. Creative Hut Academy. https://creativehut.org/library/how-metering-works/
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