Two cameras, one wedding, one clock

Checked against CullTone on 18 Oct 2026.

The second shooter's ring exchange turns up four minutes after the first toast, because her camera never moved to summer time and nobody noticed until the cull. Every culling tool, Lightroom included, sorts by the time the camera wrote into the file. If the clocks disagree, the day is told in the wrong order.

What a wrong clock breaks

Sorting is the obvious casualty. The quieter one is grouping. Most culling tools, CullTone included, decide that two frames belong to the same burst partly by how close together they were taken. In CullTone, a frame joins the burst before it when it was shot within 2 seconds of the previous frame and looks nearly the same, and a 90-second gap with no frames starts a new scene.

So the size of the error matters:

• Off by minutes, the second camera's frames land in the wrong scene. A scene can look covered when it isn't, and the rule that keeps at least three frames per wedding scene counts the wrong groups.
• Off by a few seconds, the two cameras' frames interleave in the wrong order. A frame from her angle can sit between two of yours and split one burst into two.
• Off by under a second, nothing you'd notice. You don't need better than that.

On the morning

1. Pick one reference clock. A phone is ideal: it takes its time from the network.
2. Set every body's time zone, summer time setting and clock to match it, to the second. Several makers' phone apps can set the camera clock over Bluetooth; if yours can, use it, then check it actually did.
3. At the start of the day, photograph the phone's clock with every camera, seconds showing. This is the frame that saves you later.
4. Do it again at the end of the night if you can. Two reference frames tell you whether a clock drifted, not just where it started.

Step three is the one people skip. It's also the one that matters, because a clock set carefully at breakfast can still be wrong by lunch: a body left without a battery long enough can lose its time, and a shooter who changed the time zone for her honeymoon may never have changed it back. The reference frame records what the clock actually said, whatever anyone remembers setting.

Afterwards: working out the offset

Open each camera's reference frame and compare two times: the time on the phone in the photo, and the capture time the camera wrote into the file. The difference is that camera's offset.

Say the phone in the frame shows 14:02:10 and the file says 14:06:22. That camera is 4 minutes 12 seconds fast, so its offset is minus 252 seconds. If the phone shows a later time than the file, the camera is slow and the offset is positive. Read the phone's time from the photo, never from memory.

Compare the morning and evening frames for each camera. Same offset at both ends, and you have one number for the day. If it moved by a second or two, the clock drifted, and you'll have to choose: CullTone applies one offset per camera model for the whole project, so pick the value that's right where the two cameras overlap most, usually the ceremony.

Forgot the phone? Find one moment both cameras caught: a flash going off in someone else's frame, confetti leaving a hand, the first kiss. Compare the two capture times. It's less exact, a second or two, but usually good enough for scenes, if not for bursts.

Clock offsets in CullTone, and two catches

CullTone keeps a clock offset in seconds per camera model on each project, applies it before sorting and grouping, and flags every frame it moved so you can see what changed. Frames with no capture time at all go last, in file-name order, and are grouped by how they look alone, with a stricter bar for what counts as the same.

Two catches worth knowing before the wedding, not after.

The offset is matched by camera model name, as the camera writes it into the file. If you and your second shooter both carry the same body, CullTone can't tell your cards apart by model, and one offset applies to both. There's no per-body correction afterwards, so set those two clocks properly in the morning.

The beta also shows offsets on a project but has no field to type them into yet. Until it does, the reliable fix is the one above: get the clocks right before the first frame.

Fixing the files themselves

If you'd rather correct the files than the project, Lightroom Classic can shift capture times (Metadata, then Edit Capture Time, with "Shift by set number of hours" for time zones or "Adjust to a specified date and time" for the rest), and ExifTool can do a whole folder with a command such as exiftool "-AllDates-=0:0:0 0:4:12" DIR for a camera running 4 minutes 12 seconds fast. Do it on copies. A wrong batch edit on the only copy of someone's wedding is a long week, and CullTone never changes your originals for the same reason.