Chapter 11 — Quiz

Twenty-five questions to check your grasp of flash fundamentals — the geometry of why direct flash fails, how flash makes light, the two-exposure model, bounce and diffusion, off-camera placement and the inverse-square law, and fill flash. A mix of multiple choice, true/false-with-justification, short answer, and "what's wrong with this?" seeing questions. Answers and brief explanations are at the end; try the whole set before peeking, and treat every wrong answer as a section to reread.

Multiple choice

Q1. The main reason direct on-camera flash makes faces look flat is that: - A. The flash isn't powerful enough. - B. The light comes from beside the lens, so it lands frontally and casts no visible shadow side. - C. The flash color temperature is wrong. - D. The shutter speed is too fast.

Q2. The hard, sharp-edged black shadow stamped on the wall behind an on-camera-flash subject is caused primarily by: - A. The flash being too bright. - B. The flash source being very small. - C. A slow shutter speed. - D. The subject standing too far from the camera.

Q3. Dropping a manual flash from 1/4 power to 1/16 power changes the flash light by: - A. One stop less. - B. Two stops less. - C. Three stops less. - D. Four stops less.

Q4. In the two-exposure model, which control adjusts the ambient light but essentially not the flash-lit subject? - A. Aperture. - B. ISO. - C. Shutter speed. - D. Flash power.

Q5. You set a shutter speed faster than your camera's flash sync speed while using a normal flash. The likely result is: - A. The whole frame is overexposed. - B. A black band across part of the frame (the shutter wasn't fully open when the flash fired). - C. Severe redeye. - D. The flash refuses to fire at all.

Q6. Bouncing a flash off a white ceiling makes its light softer because: - A. The ceiling absorbs some of the power. - B. The whole lit patch of ceiling becomes a large effective source, and large sources give soft shadows. - C. The bounce changes the flash's color temperature. - D. The light travels farther, so it spreads out.

Q7. By the inverse-square law, moving an off-camera flash from 1 metre to 2 metres from the subject (nothing else changed) makes the subject: - A. Half as bright (one stop darker). - B. A quarter as bright (two stops darker). - C. An eighth as bright (three stops darker). - D. The same brightness (distance doesn't matter for flash).

Q8. For a deliberate, repeatable off-camera portrait where the light isn't moving, the better power mode is usually: - A. TTL, because it adjusts automatically. - B. Manual, because once dialed in it stays identical frame to frame. - C. High-speed sync, because it's the most modern. - D. It makes no difference.

Q9. You want a single subject to glow out of a dark room, with everything behind them staying shadowy. You should: - A. Move the off-camera flash far from the subject. - B. Move the off-camera flash close to the subject (steep falloff darkens the background). - C. Raise the ISO until the background brightens. - D. Use the widest aperture you have.

Q10. For a backlit subject against a bright sky, the correct fill-flash approach is: - A. Expose for the subject, then turn the sky down with flash. - B. Expose for the bright sky/background first, then add flash to lift the subject to match. - C. Use full-power flash so the subject is much brighter than the sky. - D. Avoid flash; just brighten the subject in editing.

Q11. A "diffuser cap" (small dome) on a flash, aimed straight at the subject with no bounce, mainly: - A. Makes the light dramatically soft on its own. - B. Scatters light around the room (useful with bounce) but only modestly softens a direct beam, because it's still a small source. - C. Increases the flash's power. - D. Eliminates the need to get the flash off-camera.

Q12. The reason a flash freezes a moving subject sharply even during a fairly long exposure is: - A. The flash is very bright. - B. The flash burst is extremely short, so it exposes the subject only during that tiny instant. - C. The shutter syncs to the motion. - D. Flash automatically raises the shutter speed.

Q13. Which is the single most valuable feature when choosing one external speedlight for better people-pictures? - A. The highest possible guide number. - B. A head that tilts and swivels (so you can bounce). - C. A built-in optical slave. - D. The fastest recycle time.

True / False — justify your answer

Q14. Flash always makes a photograph look cheap and snapshot-like.

Q15. Raising the ISO brightens the flash-lit subject and the ambient background together.

Q16. A flash with a bigger guide number is more powerful than one with a smaller guide number.

Q17. Fill flash should be obvious in the final image — the brighter the better.

Q18. Bouncing a flash off a wood-paneled wall is a great way to soften light for a portrait.

Short answer

Q19. State the two-exposure model in one or two sentences, and name which dial controls the ambient and which controls the flash.

Q20. Explain why a close off-camera light gives steep, dramatic falloff across a subject while a far light gives flat, even light. Use the idea of proportional distance.

Q21. Your flash-lit subject is perfectly exposed, but the room behind them is too dark and you want to bring it back without changing the subject. What one dial do you adjust, which way, and why is the subject safe?

Q22. Name the two geometric problems with direct on-camera flash, and the one fix that addresses each.

What's wrong with this? (seeing questions)

Q23. A reader shoots a wedding reception on full-auto with the pop-up flash. Every photo shows a guest lit and sharp in the foreground, but the entire warm, candle-lit room behind them has gone pure black, so you can't tell it's a reception at all. Diagnose the cause in two-exposure terms and prescribe the fix.

Q24. A reader gets one flash off the camera at last, but places it about 4 metres back "to light the whole scene evenly." The result is flat and dull: the subject doesn't stand out, and the background is just as bright as the subject. What did they get wrong about light placement, and what should they do instead?

Q25. A reader's outdoor noon portrait has the subject's eyes lost in deep black shadow under the brow, even though the rest of the face is bright. They have a small flash but think "it's already sunny, I don't need flash." What technique are they missing, how should they set the flash, and what's the one-sentence rule for getting it right?

Answer Key

Show answers and explanations **Q1 — B.** Front (on-axis) light lands evenly with no visible shadow side, so the face loses its three-dimensional modeling (§11.1). Power, color, and shutter aren't the cause. **Q2 — B.** Hard, sharp shadow edges come from a *small* source; the flash tube is tiny (§11.1, and Chapter 5 §5.1). Brightness and shutter don't determine shadow *edge hardness*. **Q3 — B.** Each power step is one stop. `1/4` → `1/8` is one stop; `1/8` → `1/16` is another — two stops total (§11.2). **Q4 — C.** Shutter speed gathers continuous ambient light but can't gather more from the already-finished flash burst, so it moves the ambient only (§11.3). Aperture and ISO move both; flash power moves the flash. **Q5 — B.** Above sync speed the shutter forms a moving slit and is never fully open at once, so the brief flash lights only a strip — the rest is a black band (§11.2). Fix: shutter at/below sync speed, or use HSS. **Q6 — B.** Bounce turns the large lit patch of ceiling into the effective source; large source → soft shadows (§11.4). It's about *apparent size*, not absorption, color, or travel distance. **Q7 — B.** Inverse-square: doubling the distance quarters the light = two stops darker (§11.5). (Halving distance would *quadruple* it.) **Q8 — B.** Manual holds a fixed power, so a stationary setup gives identical exposure every frame and you can stop fighting the meter (§11.5). TTL is for fast-changing distances. **Q9 — B.** A close light has steep falloff — much brighter on the subject than on the farther background — so the subject glows and the background stays dark (§11.5). Far light spills evenly and lights the room. **Q10 — B.** Expose for the bright background first so it keeps color and detail, then fill the subject up to match (§11.6). This is the two-exposure model outdoors. **Q11 — B.** A small dome is still a small source, so it only modestly softens a direct beam; its real value is scattering light to combine with bounce (§11.4). Softness comes from apparent size. **Q12 — B.** The flash burst is extremely brief, so the flash-lit subject is exposed only during that instant and comes out frozen regardless of the longer shutter (§11.2–11.3). **Q13 — B.** A tilt/swivel head enables bounce — the biggest free quality upgrade in the chapter (§11.2, §11.4). Guide number, slave, and recycle all matter less for everyday people-pictures. **Q14 — False.** *Direct, on-axis, bare* flash looks cheap; flash that is bounced, diffused, or moved off-camera is the most powerful creative light in the book (§11.1, §11.4–11.5). The fix is the *position*, not abandoning flash. **Q15 — True.** ISO amplifies the whole frame — ambient and flash alike — so it moves both together (§11.3). (Only shutter speed and flash power isolate one from the other.) **Q16 — True.** Guide number rates raw flash power; bigger = more powerful/more reach (§11.2). It's best used as a shopping comparison, not field math. **Q17 — False.** Good fill is *subtle* — typically a stop or two below full subject lighting, so the photo looks naturally lit, not flashed (§11.6). Obvious fill is a mistake. **Q18 — False.** Wood is colored; it tints the bounced light orange and casts that color on skin (a color cast, Chapter 5 §5.3). Bounce off *white/neutral* surfaces for people (§11.4). **Q19.** Every flash frame is two exposures in one — the ambient and the flash — added together. **Shutter speed** controls the ambient; **flash power** controls the flash; aperture and ISO affect both (§11.3). Workflow: set the background with shutter/ISO/aperture, then add flash for the subject. **Q20.** Falloff depends on the *proportional* change in distance across the subject. A close light: the near and far sides of the subject differ by a *large* proportion of the total distance, so the near side is much brighter — steep falloff. A far light: near and far sides are nearly the same proportional distance away, so they're lit almost equally — flat, even light (§11.5). **Q21.** Slow the **shutter speed** (e.g., `1/200` → `1/30 s`, staying at/below sync). It gathers more ambient light, brightening the room, but the flash burst already ended, so the flash-lit subject is unchanged (§11.3). **Q22.** (1) *Frontal direction* (light beside the lens → flat, formless face, redeye) — fix: **move the light off-axis** (bounce or off-camera). (2) *Small source* (→ hard shadows, the wall-shadow) — fix: **make the source bigger** (bounce off a big surface, or use a large diffuser/softbox) (§11.1). **Q23.** In auto, the camera picks a fastish shutter and lets the flash do the work, so the near subject is lit but everything beyond the flash's reach — the whole warm room — gets no exposure and goes black. Fix: take manual/shutter-priority control and *slow the shutter* (e.g., to `1/30`–`1/15 s`, at/below sync) to invite the ambient candle-light back in, then add just enough flash for the faces; ideally bounce the flash to keep it soft (§11.3–11.4). **Q24.** They mistook "far" for "even and good," but far light is *flat* light — it spills onto the background as much as the subject, so nothing stands out. Bring the light *in close* and let the inverse- square law darken the background relative to the subject; closer is more dimensional and separates subject from scene (§11.5). **Q25.** They're missing *fill flash*. Set the camera's exposure for the bright daylight scene as normal, then add the flash at *low* power (e.g., flash exposure compensation −1 to −2 stops, or low manual power) aimed at the face to open the eye-socket shadows. The one-sentence rule: **expose for the ambient first, then add subtle fill — good fill is invisible** (§11.6).

Topics to review, by question

  • Q1–2, 22, 23 (why direct flash fails): §11.1
  • Q3, 5, 12, 13, 16 (how flash works: power, sync, duration, gear): §11.2
  • Q4, 15, 19, 21, 23 (the two-exposure model): §11.3
  • Q6, 11, 18 (bounce and diffuse): §11.4
  • Q7, 8, 9, 20, 24 (off-camera and the inverse-square law): §11.5
  • Q10, 17, 25 (fill flash outdoors): §11.6