Why down the line, and why behind the ball

Down the line is the view a coach stands in. It shows the club's path into the ball, the plane of the shaft, your posture and whether you keep it, and the first part of the ball's flight. It is also the only view where a line you draw at address (the shaft, a vertical through the ball) means the same thing in every clip of the session, because the camera never moves. Face-on has its own uses, which the guide on down the line vs face-on covers; if you only film one view, film this one.

Set up in seven steps

1. Pick a target. A flag, a net post, a sign or a distant tree: something far away you aim at. It decides the line.
2. Set up the shot first. Place the ball and stand as you will for the swing. Do not move the ball after the camera is placed.
3. Walk back behind the ball. Put the phone on a tripod or a range stake, 10 to 15 feet (3 to 5 m) behind the ball and at about hand height at address, waist to chest. Closer than 8 feet and the club leaves the picture at the top of the swing; much farther and the ball is a speck.
4. Look through the ball, then at the target. The ball should sit on the middle line of the screen near the bottom, and the target on the same line far up in the picture. If the target is left or right of it, slide or turn the phone. The Camera app's grid, or the faint center line in Impact Reel's recorder, is there for this.
5. Frame the swing. Hold the phone upright. Leave room above the ball for the club at the top of the swing and for the first of the ball's flight, with the whole golfer in the picture and room on both sides. The ball about a quarter of the way up from the bottom works well.
6. Make it level. Do not tilt the phone up or down more than you need to: a tilted phone bends every line you draw later.
7. Record the whole session. Start before the first ball and stop after the last. Take one practice swing, look at the clip, and adjust the height or distance before you hit for real.

Camera settings

Impact Reel's Record a session films at the highest frame rate your iPhone has and, at that rate, the highest resolution, with sound; the label at the top of the camera shows what it chose, for example 1080p at 240 fps. There is nothing to set. If you film with the iPhone's Camera app instead, and choose the video from Photos afterwards, set these once:

• Settings > Camera > Record Video: the highest frame rate you can: 1080p HD at 240 fps if your phone offers it, otherwise 4K at 60 fps or 1080p HD at 60 fps. More frames per second means a sharper ball at impact, smoother slow motion and easier tracer marks.
• Auto FPS: Off on the same screen, on phones that have it. Auto FPS lowers the frame rate in low light, which is exactly when a late-afternoon or night range needs it most.
• Grid: On, so the middle lines help you line up the ball and the target.
• Formats: High Efficiency, for smaller files at the same picture quality.
• In the Camera app, touch and hold the ball until AE/AF Lock shows, so the focus and exposure do not change when the golfer walks into the frame.
• Use Video mode. Cinematic and Action mode crop and re-process the picture. Do not use Slo-mo mode for a long session: it is built for short clips, and a shared Slo-mo file has its own problem, covered below.

One thing an app cannot do: choose the frame rate of the iPhone's own Camera screen. If you open the Camera from inside Impact Reel with Go to Camera, it films with whatever Settings > Camera > Record Video says, so set that first.

Which frame rate?

The frame rate decides how much of the swing you can see when you slow it down. The club moves through impact in a few hundredths of a second, so more frames show more of it.

Frame rate	What you get
240 fps	The smoothest slow motion. Impact Reel's Auto speed plays it at ⅛ speed, the same as iPhone Slo-mo. The best choice for seeing the club and the ball at impact.
120 fps	Smooth slow motion at ¼ speed. A good choice when the light is low.
60 fps	Fine at normal speed and frame by frame; slowed down, it starts to look jumpy.
30 fps	Standard video. Slow motion looks choppy; Impact Reel slows it to ½ and tells you so.

Higher frame rates need more light and make bigger files: a 240 fps recording runs to several hundred megabytes a minute. On a bright afternoon, 240. Under lights or at dusk, 120. If a frame rate is not offered on your phone, the next one down is fine; the setup matters more than the number.

Filming a whole range session

The habit that makes swing video useful is one long recording per session, not one clip per ball. You hit the bucket the way you always do, and the sorting happens afterwards. A few things make that work:

• Space. Check that the phone has a few gigabytes free before you start. A 30-minute session at 240 fps is a large file.
• Battery. A fully or mostly charged phone is typically fine for a range session. In Impact Reel's recorder the screen goes dark while it films, which saves battery and keeps the phone cooler; tap it to see the picture for a few seconds. A small battery pack is only worth bringing for a long session or a phone that is already low.
• Heat. Keep the phone out of direct sun. A hot iPhone slows down and eventually stops filming. Impact Reel's recorder stops by itself when that happens and keeps everything it filmed up to then.
• Sound. Impact Reel finds each swing by the sound of the strike, so the phone needs to hear it: within about 15 feet of the ball, microphone uncovered, not behind a fan or in a strong wind. A neighbor's strike is quieter and further away; the app sets those aside in its Uncertain tab rather than mixing them in.
• Between bays. If you move to another bay, stop the recording, move the phone, line it up again and start a new recording. Two recordings are easier to sort than one with a gap.
• Do not touch it. Picking the phone up to check a swing moves the line. Review the clips when the bucket is done.

Light, sound and steadiness

• Light: more light means a faster shutter and a sharper ball. Put the sun behind or beside the phone, never in front of the lens. On a night range, the bay under a light is the one to pick.
• Steady: a phone on a stake or tripod, not held by a friend. Even a steady hand drifts, and every drift moves your lines.
• Left- or right-handed: the phone stays behind the ball on the same line; nothing changes.

The Slo-mo export trap

An iPhone Slo-mo video is recorded at 120 or 240 fps and played back with the slow part slowed in the Photos app. The file itself is still real time. Send that video by AirDrop, Messages or Save to Files, though, and the copy has the slowdown baked in: the slow part is stretched 8 times longer for 240 fps and 4 times for 120 fps, and nothing in the file says so. In any other app, one swing then lasts many seconds, and the sound of the strike is low and muffled.

The fix is to pick the original from Photos rather than the copy. If all you have is a copy, Impact Reel recognizes a slowed part by its sound, as long as it lasts at least 20 seconds, and counts its clips in real seconds; a one-swing Slo-mo clip is too short to be recognized and is treated as recorded.

Common mistakes

• Filming from beside the ball instead of behind it. The line through the ball to the target is the whole point of the view.
• Too close. Under 8 feet the club leaves the frame at the top of the backswing, and the lens distorts the shaft.
• Phone tilted up to fit a tall golfer. Move it back instead.
• Cinematic or Action mode, which crop the picture and soften the ball.
• Sun in the lens late in the day. Turn the setup around if you can, or wait for a cloud.
• Starting and stopping per ball. You will stop filming within a week. Record the session.

Do it in Impact Reel

Tap Record a session, set the phone up as above (the recorder's Tips page repeats the steps), and hit the bucket. When you stop, the recording is saved to Photos and the app cuts one clip per swing from it; you review the clips, add the lines and a tracer to the ones worth keeping, and save them to a Photos album for the session. A video filmed with the Camera app goes through the same steps from Choose from Photos.

Questions

Do I need a tripod?

You need something that holds the phone still at hand height on the line. A range stake with a phone holder, a small tripod, a monopod with a spike, or a clip on an alignment stick all work. A bag works in a pinch, but it is rarely at the right height.

Which iPhones can film at 240 fps?

Most iPhones from the last several years offer 1080p at 240 fps under Settings > Camera > Record Video. If yours lists only 120 fps, use that; the setup matters more than the frame rate.

Can I film in a simulator or an indoor bay?

Yes. Light is the limit: pick 120 fps rather than 240, turn Auto FPS off, and keep the phone close enough to hear the strike over the simulator's own sound. Mats are quieter than turf, so a clean strike sound matters more indoors.

How long can one recording be?

As long as the phone's storage and battery allow. Impact Reel is built for long recordings; videos up to a minute long also get a second pass that watches the golfer's movement for swings the sound missed.

By Austin Ambrose, founder of Impact Reel. Last updated October 24, 2026.