The Exposure Triangle

Key takeaways

• A small f-number describes a large opening and more light
• Each full stop doubles or halves the light passing through the lens
• Wide apertures create shallow depth of field; smaller apertures increase the acceptable focus range
• Bokeh describes the character of out-of-focus rendering, not only how blurred it is
• Many lenses improve in technical sharpness one or two stops down from maximum aperture
• Very small apertures can reduce fine detail through diffraction
• Stopping down near f/11–f/16 can create a sunstar from a point source; its shape and ray count depend on the aperture blades

Practical example

An individual portrait at f/2 can separate the subject from the background. A group arranged in three rows may need f/5.6–f/8. Bring the rows closer together, step back, and focus about one-third into the group's physical depth rather than automatically choosing f/16. Good subject arrangement often preserves both sharpness and usable shutter speed better than an extreme aperture. When low sun is partly hidden by a building edge, tree, or ridge, try f/11–f/16 for a sunstar. Keep the sun small in the frame, watch highlight clipping, and shade the lens if unintended flare lowers contrast.

Key takeaways

• Doubling exposure time adds one stop of light
• Fast shutter speeds freeze action; slow speeds can express motion deliberately
• A tripod removes most camera shake but does not stop movement inside the scene
• Panning uses a slow speed while the camera follows the subject
• A short flash duration can freeze motion, subject to synchronization limits
• Electronic shutters may bend fast subjects through rolling-shutter distortion
• Intentional camera movement (ICM) and zoom bursts use slow exposures to turn camera or zoom-ring movement into an abstract effect

Practical example

Football may require around 1/1000 sec to freeze a player. For a cyclist panning shot, begin near 1/30–1/60 sec, follow the subject before pressing the shutter, use a short burst, and continue rotating after the exposure. If everything is sharp, slow the shutter; if the subject is unrecognizably blurred, increase speed or improve the tracking movement. For ICM, try a vertical sweep through trees at roughly 1/4–1/15 sec, keeping the motion smooth and choosing a scene with clear lines or color blocks. For a zoom burst, stabilize the camera, use around 1/4–1 sec, and rotate the zoom ring continuously during the exposure. Keep one stable anchor, such as a bright center or tree trunk, so the result is intentional rather than random blur.

Key takeaways

• Use low ISO when sufficient light and shutter time are available
• Raise ISO when needed to protect shutter speed or depth of field
• A sharp, slightly noisy photograph is usually more useful than a clean blurred one
• High ISO commonly reduces dynamic range and highlight flexibility
• Auto ISO works best with a deliberate minimum shutter speed and maximum ISO
• Judge noise at the final display or print size, not only at 200% magnification
• In A/P with Auto ISO, set an ISO ceiling and ISO AUTO Min. SS for subject movement; try 1/250 second for a walking person. On the A7C this threshold is not a hard shutter lock: the camera may go slower after reaching the maximum ISO.
• M + Auto ISO retains your selected aperture and shutter while varying ISO within limits. At the upper or lower ISO boundary the result may underexpose or overexpose; check the meter, histogram, and EXIF rather than trusting AUTO alone.

Practical example

Indoors, moving from ISO 400 to 1600 allows 1/60 sec to become 1/250 sec at the same aperture. That two-stop change may turn a blurred speaking subject into a sharp one. At a performance, f/2.8 and 1/250 sec at ISO 3200 may be the correct compromise. Apply moderate noise reduction later without erasing hair and skin texture.

Key takeaways

• One stop gained with one control can offset one stop lost with another
• Prioritize aperture when depth of field defines the image
• Prioritize shutter speed when motion defines the image
• Set ISO after aperture and shutter satisfy the intention, without treating low ISO as sacred
• Exposure compensation changes the meter target in automatic modes; it is not a fourth exposure variable
• A setting is only “correct” for a particular light, subject, and output
• Dynamic range extends from usable shadows to unsaturated highlights in a single exposure. If scene contrast exceeds capture capacity, alter the light, add fill, or combine exposures; raising Exposure later cannot restore lost data.
• DRO optimizes brightness and gradation from one capture, mainly affecting JPEG/preview rendering. It does not expand the sensor’s physical capture range, and stronger shadow lifting can reveal noise.
• On the Sony A7C, Auto HDR combines three exposures into a JPEG result, requires a relatively still scene, and is unavailable with RAW or RAW & JPEG selected. To retain RAW, bracket exposures and merge later; this differs from DRO.

Practical example

Changing f/4, 1/250, ISO 400 to f/2.8, 1/500, ISO 400 keeps brightness similar: the aperture adds one stop and the shutter removes one. The second setting freezes motion more strongly and creates shallower depth of field. For a group, f/2.8 may be too shallow; keep f/4, use 1/500, and raise ISO to 800 instead. For a bright window in a dark room, expose to retain curtain detail first. Compare JPEGs with DRO off and on: shadows may look brighter, but clipped RAW detail cannot return. If a still scene remains too contrasty, capture −2/0/+2 EV RAW frames with aperture, WB, and focus locked, then merge rather than expecting DRO to rescue everything.

Key takeaways

• A meter reading of zero is a camera recommendation, not an absolute truth
• Bright subjects often need positive compensation and dark subjects negative compensation
• A pile-up at the right edge can indicate clipped highlights
• RGB histograms reveal a single color channel clipping before overall luminance looks clipped
• Camera histograms usually come from the JPEG preview and may be more conservative than RAW data
• Exposure compensation affects automatic and semi-automatic modes, including Manual with Auto ISO
• Multi/Matrix evaluates many zones; Center-weighted favors the middle; Spot meters a small area; Highlight metering prioritizes bright areas. Choose according to what matters in the scene and verify the result.
• Zebra overlays stripes on areas reaching a selected brightness threshold. On the Sony A7C, enable Zebra Display in Zebra Setting and select a level appropriate to the picture configuration. Stripes are not recorded and do not directly measure RAW sensor data.
• Highlight clipping loses detail when one or more channels saturate. Combine playback warnings with the RGB histogram: a tiny specular reflection may clip intentionally, while important skin or white fabric should retain gradation.

Practical example

A meter may render a white wedding dress gray. About +1 EV can restore the intended brightness, but the histogram and highlight warning must confirm that fabric texture remains. A black outfit against a dark background may need negative compensation to remain dark rather than being lifted to gray. The exact value comes from a test frame, not a universal recipe. For white clothing against a dark background, Multi may overexpose the fabric, while zeroing a Spot reading from white fabric may turn it gray. Make a test exposure, add compensation to preserve its white appearance, then reduce it if important texture disappears. Zebra identifies bright areas in the frame; the RGB histogram reveals individual channel clipping.

Key takeaways

• A/Av is efficient when aperture and depth of field are the priority
• S/Tv is useful when shutter speed and motion are the priority
• Manual creates consistency when the light is stable or flash is dominant
• Program is more controllable than full Auto through exposure compensation and program shift
• Auto ISO needs a suitable ceiling and, where available, a minimum shutter speed
• Always notice when the camera reaches maximum aperture, shutter limits, or the ISO ceiling
• In-camera multiple exposures need locked exposure, white balance, and camera position before frames are combined

Practical example

For an outdoor portrait moving between sun and shade, use f/2.8, a minimum of 1/250 sec, Auto ISO, and a practical ISO ceiling. The camera can change ISO or shutter as the light changes while depth of field remains fixed. If shutter speed drops below the safety limit after ISO reaches its ceiling, respond instead of assuming the mode will solve everything. For a multiple exposure, use Manual to keep every frame consistent, then decide which bright areas in the first frame the second should occupy. Start with two simple frames: a silhouette against a bright background and a detail against a dark one. Check the camera's blend mode because manufacturers combine or prioritize highlights differently.