Golden hour · EV 12
drag the dial
Tap a setting, then drag the dial. Keep the meter needle on 0 for a correct exposure.
CDG Digital Media · Knowledge Series
Exposure Lab
Learn manual mode by doing it. Pick a setting, turn the dial, and watch what it does to the picture.
Tap the dial, LCD or shutter
Challenges
Each one forces a tradeoff. Guess first, then make the shot.
How it works
Three settings, one brightness
Shutter speed, aperture and ISO all change how bright the picture is. Each one also has a side effect, and choosing between those side effects is what shooting in manual is really about.
| Setting | Brighter by | Side effect |
|---|---|---|
| Shutter | Slower: 1/500 → 1/250 | Moving things blur |
| Aperture | Wider: f/4 → f/2.8 | Background goes soft |
| ISO | Higher: 100 → 200 | More grain |
Every step on the dial is one stop: double or half the light. Make the picture one stop darker with one setting and one stop brighter with another, and the brightness stays the same while the look changes. Try it: in M, go one step slower on the shutter, then one step smaller on the aperture (a higher f-number). The needle doesn't move, but the water and the background do.
Reading the meter and histogram
The scale on the LCD runs from −3 to +3 stops. When the needle sits on 0, the camera thinks the exposure is correct. Plus means too bright, minus means too dark. If the needle blinks at the end, you are more than three stops off.
The histogram in the corner of the viewfinder shows how many pixels sit at each brightness, dark on the left and bright on the right. A pile against the right edge means highlights have turned pure white and the detail is gone for good. A pile against the left edge means crushed shadows.
The modes: M, Av, Tv, P and Auto
M (Manual): you set all three. Av (aperture priority): you set the aperture and the camera picks the shutter speed. Tv (shutter priority): you set the shutter speed and the camera picks the aperture. P (Program): the camera picks both and you set ISO. Auto sets everything, including ISO.
Av and Tv are the names this camera uses. Other brands call them A and S. In the priority modes, watch the AUTO tag move between the settings so you can see which ones the camera is choosing.
The math behind the needle
Each combination of settings has an exposure value (EV):
EV = log₂(f² ÷ t) − log₂(ISO ÷ 100)
where f is the f-number and t is the shutter time in seconds. Each scene also has an EV, set by how much light is in it: about 15 in bright sun, 12 at golden hour, 9 at dusk and 5 at night under streetlights. The needle shows the scene's EV minus the camera's EV. Any combination that gives the same camera EV gives the same brightness.
The marked values (1/60, f/5.6, 1/125) are rounded. Real cameras use exact powers of two behind those labels, and so does this simulator, which is why every step is exactly one stop.
About this scene
The fountain is drawn by the simulator. Brightness, highlight clipping, motion blur, background blur, camera shake and sensor noise are all calculated from your settings.
The waterfall is real 4K footage, stabilized and cropped. Its motion blur is real too: a slow shutter adds up light over time, so averaging consecutive frames of video gives the same result. A 1 sec exposure is 60 frames averaged, and 1/4 sec is 15. The clip was recorded at about 1/120 and is 2.2 seconds long, so speeds faster than 1/125 or slower than 2 sec look the same as those limits. Background blur on the waterfall is added from a hand-drawn depth map.