Keyframes

What we ran

Six short films, all keyframed, 53 takes analysed. Each film has one set of pinned stills and a bin of takes that sweep the number of pins (10, 5, 4, 3, 2) and the duration (20s, 15s, 10s, 5s), plus structural variants: hard cuts, smash cuts, a locked-off frame, a loop where the first pin is also the last, deliberately uneven beats, and a metamorphosis.

Every take stores the exact pin schedule, so there is no guessing about where a pin was meant to land. FLUX.3 runs at 24fps; a 20-second take is 481 frames and the pins sit at named frame indices — frame 0, 60, 120, and so on. I pulled all 340 pinned stills off the takes, extracted the video frame at each pin's exact index, and compared them. Then I looked at 19 takes frame by frame against their pins, and at four of them second by second across the whole run.

Scoring below is normalised greyscale correlation between the pin and the frame at its timecode. It is a blunt instrument, so I checked it by eye: 0.75 and up means the pinned picture is on screen, 0.5 to 0.75 means the right idea in the wrong picture, below 0.5 is a miss. Fog and heavy grain drag the number down on takes that visually landed, and I've flagged those where it matters.

One take from the board, K7b — the even-spacing control for The Vault — wasn't in the local set. It's the single most useful comparison in the family, so I pulled it down and analysed it alongside the rest.

What happened

The two ends are honoured. The middle is not. Across 49 measured takes the first pin scores a median 0.96 and the last 0.97. Interior pins score 0.61. Put plainly: 44% of interior pins put the pinned picture on screen at the pinned second, 23% get close, and 33% miss outright.

1One object lives and dies on a potter's wheel in a single meditative shot. A wet lump of grey clay is slapped down, centered under wet hands, opened and pulled into a rising cylinder, refined into an elegant vase, dried leather-hard and trimmed, painted with a cobalt wave, reborn glossy from the kiln, cracked by a hairline flaw, shattered mid-air, and settled into a quiet cone of dust — while the camera drifts slowly clockwise around the wheel the whole time, the studio and its window light unchanged and indifferent. Each state must grow physically out of the last — continuous transformation, not cuts; hands appear and vanish naturally. 35mm film look: grain, halation, crushed warm blacks.2 3SOUND — the wheel's whir, wet clay under palms, brush strokes, kiln tick, a crack like ice, one sharp shatter, then settling dust and room tone.

Pin count governs. Spacing barely matters. This was the question, and the answer is unambiguous.

Now hold the count at ten and squeeze the duration. The gap between pins shrinks four-fold, from 2.22s at 20s to 0.56s at 5s, and interior fidelity moves from 0.64 to 0.62 to 0.54. Almost nothing. The model does not care how far apart your pins are. It cares how many there are. Ten pins is roughly twice as likely to drop a frame as four, at any length.

Order survives; the clock drifts early. Content order is mostly preserved — the story happens in the right sequence. The schedule is not. Two-thirds of interior pins are off by half a second or more, and the drift is one-directional: in the back half of a take the median pin arrives 0.29s early, and individual beats run one to three seconds ahead. K5a (n=15, Round, ten circles across 20s) is the clearest case: it delivers all ten worlds, but at 6.67s where the record was pinned it is showing the clock, and at 8.88s where the clock was pinned it is showing the record. It transposed two shots.

A dense cluster inside a slow film destroys everything after it. The Vault pinned four beats — lift, grab, alarm, flatten — into a single second at 10.0/10.5/11.0/11.5s, with a five-second freeze either side. K7a (n=35) hits its first two pins at 0.96 and 0.97, then collapses: 0.37, 0.38, 0.55 through the cluster, then 0.18, 0.04, 0.09 for the standoff, the sprint and the empty room. It never recovers. Watch it and you can see why — the heist finishes at 15.8s and the last four seconds are an empty room with the smoke settling. The model ran the whole story ahead of schedule and then had nothing left to shoot.

1Twenty-four hours on one locked-off city corner as a single time-lapse — the minimum case: only the first frame (4:45 AM blue dark) and the last (4:00 AM fog) are pinned, twenty seconds apart. The model must invent the ENTIRE day between two nearly-identical night frames: dawn, rush hour, noon, storm, downpour, golden hour, neon dusk, deep night — and return to stillness. The camera NEVER moves; fixed elements pixel-locked. 35mm film look: grain, halation, crushed blacks.2 3SOUND — a whole invented day: birds, traffic, thunder, rain, chatter, then wind and fog silence.

The control take, K7b, is the same ten pictures spread evenly at 2.2s. It scores 0.95, 0.91, 0.72, 0.88, 0.91, 0.84, 0.94, 0.78, 0.67, 0.78 — a mean of 0.84 against 0.51 for the timed version. The board hoped uneven spacing would buy tension. It buys a broken second half. FLUX.3 has one speed and spends its runtime evenly; it will not hold for you and then sprint.

The same thing happens at the tail. K6i (n=33) back-loads five pins into the last five seconds of the loop. The first half tracks the cat beautifully, then at 15s the film cuts to a completely different, tighter lens and holds a sleeping cat for the final five seconds. Pins 9 and 10 score 0.24 and 0.23. The loop does not close. Front-loading is the exception that works — K5i (n=23), six worlds strobing past in the first five seconds and four long dissolves across the remaining fifteen, is the best ten-pin take in the entire family: nine of ten pins on screen at their second.

1A match-cut chain with warped rhythm: the first six worlds — eye, eclipse, coffee, vinyl, clock, manhole — strobe past in the first five seconds, a cut a beat; then the chain decompresses, and moon, ferris wheel, porthole and galaxy get long luxurious dissolves across fifteen seconds. Fast cutting then slow morphing in one film — the contrast is the experiment. Circle dead-center, constant scale, always. 35mm film look: grain, halation, crushed blacks.2 3SOUND — rapid percussive world-flashes that open into long oceanic drones.

It dissolves unless you crowd it. Ask for hard cuts in prose and you don't get them. K3b (n=2) says "TEN SEPARATE SHOTS with HARD CUTS between them… no gliding, no morphing, no whip pans" and produces one detectable cut in twenty seconds; at 16s the frame is a visible double exposure of the neon over the counter. The same ten pictures at 5s (n=3) produce six cuts, and Round's ten worlds at 5s (n=17) produce six. Cuts come from spacing, not from wording. Below about a second between pins the model stops interpolating and starts cutting.

Two pins can beat ten. K4g (n=11) is The Corner with only the 4:45am opener and the 4:00am fog closer pinned, twenty seconds apart, camera locked. It invents the entire day — traffic streaking through midday, crowds blurring on the corner, wet neon at night, fog at the end — in proper time-lapse language, with the frame pixel-locked throughout. Both pins score 1.00 and 0.96. The ten-pin version of the same corner (n=6) puts two of ten on screen and spends the middle of the take in grey haze.

The failure mode of two pins is a freeze. K6g (n=31) pins the same picture at frame 0 and frame 480 — a cat asleep on a windowsill — and asks for twenty unpinned seconds. The result is a twenty-second still. Nothing moves. The model read two identical endpoints as an instruction not to move, and it did not. Give it ten pins of the cat's adventure (n=25) and it performs the whole thing and lands back on the sill exactly. Pins are what create events; the gap between two pins is interpolation, not invention.

1The purest loop test: the SAME image pinned at frame 0 and frame 480 — a sleeping cat on a sunlit windowsill — and twenty unpinned seconds between. Does the model keep the cat asleep, breathing gently in the sun? Does it invent a journey and return? Anything is allowed except a visible seam: the clip must land back exactly where it began. Camera locked, room untouched. 35mm film look, warm grain, dust motes drifting.2 3SOUND — room tone, purring, distant street — identical at head and tail.

That reading holds elsewhere. K5g (n=21), a pupil at frame 0 and a spiral galaxy at frame 480, is a single unbroken zoom — no invented worlds, despite the prompt offering them — and the galaxy is fully formed by 15.8s, leaving four seconds of nothing. K8g, clay lump to shards, does invent throwing, glazing and shattering, because the shortest plausible path between those two pictures runs through being a pot. Two pins get you the shortest path. If you want a detour, pin it.

1The minimum match cut: a human eye at frame one, a spiral galaxy at frame 480, twenty seconds apart — pupil to galactic core. The model owns the entire journey between the most intimate circle and the largest; it may pass through any circular worlds it invents, but the circle must stay dead-center at constant scale from first frame to last. 35mm film look: grain, halation, crushed blacks.2 3SOUND — a single slow crescendo from a heartbeat to the roar-silence of space.

One film ignored its opening pin entirely. All four Closing Time takes (n=1–4) open on a different framing than pin 1: the pin is a wide from the doorway down the counter, and every take punches in tighter on the same set. Scores 0.59, 0.22, 0.12, 0.19. No other film is anywhere near that bad, though it isn't a clean binary: 31 of 49 takes open on their pin at 0.90 or better, and the softer misses are reframes — Round's 5s and 10s takes (n=17, n=19) re-render the eye as a different eye, and three Vessel takes drift the camera off the lump before the first frame. The pattern is that FLUX.3 will re-shoot a composition it doesn't like, and it likes deep wides with small figures least.

Metamorphosis is the thing it's actually good at. K8a (n=44), ten states of a pot across twenty seconds, is the strongest ten-pin take in the set: lump, wet hands, rising form, leather-hard vase, the cobalt wave being painted, glazed, shattered mid-air, and a cone of dust. Eight of the ten states land within a second. It skipped exactly one — the hairline crack at 15.54s — and went straight from an intact vase to an explosion. And The Vault, its opposite, fails its final pin in five of nine takes: the empty case with the sapphire gone is a small semantic difference the model will not render, no matter how few pins you give it.

Notable takes

11 | K4g · The Corner (2 pins / 20s) | Two pins and a locked frame invent a whole day of traffic, weather and neon — better than the ten-pin version of the same corner.

35 | K7a · The Vault (10 pins / 20s timed beats) | Four pins inside one second broke the film; the heist finishes at 15.8s and the last four seconds are an empty room.

1A one-room jewel heist where the EDIT is the rhythm — pins placed at their authored timecodes: slow creep for ten patient seconds (door, laser tightrope, kneel at the case, the cut, the lift), then a half-second cluster of violence — GRAB, ALARM, FLATTEN — inside a red strobing detonation, then five unbearable frozen seconds of standoff, then the sprint and the empty room. Pacing must follow the pin timing exactly: languid, explosive, held, released. One continuous shot, no cuts. 35mm anamorphic thriller look: grain, halation, crushed blacks, red strobe.2 3SOUND — near silence with breath and cloth, one glass squeak, the sapphire's tap — then a piercing klaxon and strobing hum, held tense through the standoff, then running footsteps swallowed by the vault door and the alarm alone in an empty room.

31 | K6g · The Long Way Home (2 pins / 20s loop) | Same picture pinned at both ends produced a twenty-second still. Nothing moves at all.

23 | K5i · Round (10 pins / 20s front-loaded) | Six worlds in five seconds then four long dissolves. Nine of ten pins on screen at their second — the best ten-pin take here.

44 | K8a · The Vessel (10 pins / 20s even) | Clay to dust, eight of ten states within a second. It skipped the crack and went straight from intact vase to shatter.

21 | K5g · Round (2 pins / 20s) | Pupil to galaxy in one unbroken zoom. It invented no worlds in between and reached the galaxy four seconds early.

What this means if you're prompting FLUX.3

Use four or five pins, not ten. Four pins land seven times in ten; ten pins land four times in ten. If you have ten pictures, pick the five that carry the story.

Spend your pins on the ends. The first and last frame come back almost exactly, at any duration and any pin count. Everything you cannot afford to lose should be at frame 0 or the final frame. The exception is a final pin that differs from the rest of the film only by a small semantic detail — an object gone, a door open — which The Vault shows it will quietly refuse to render.

Space them evenly. There is no benefit to authored rhythm — FLUX.3 spends its runtime at one speed. A dense cluster in the middle or at the end will rush the story, arrive early, and leave you holding dead air. The one exception is front-loading: a fast burst at the head then long gaps works, and produced the best ten-pin result in the set.

Don't write "hard cut". Below about a second between pins you get cuts; above it you get dissolves and morphs, whatever the prose says. If you want an edit, tighten the schedule.

Two pins are a real tool, but they give you the shortest path between the pictures, not a story. Two very different endpoints (clay to dust, dawn to fog) produce genuine invention. Two similar or identical endpoints produce a freeze.

Expect to be a beat early. Interior beats drift one to three seconds ahead in the back half. If timing to music or dialogue matters, pin the moment late and cut the tail.