How to stitch photos into a panorama online

Stitch a panorama in six steps

1. 1

   Shoot or collect overlapping frames

   Stand in one place and turn, rather than walking along the view. Overlap each frame with the next by a third or more, keep the camera level, and lock the exposure and white balance if your camera allows it, so the frames match. Portrait orientation gives a taller panorama.

   To follow along, download the three sample frames from the top of this page. They were made to match frames taken turning about 20° between shots, with the camera tipped and tilted by about a degree each time, as handheld frames are. Their corners are slightly darker than the middle, as with most lenses, and their brightness differs by up to about half a stop (the middle frame is the brightest), as when the camera sets the exposure for each shot. Each overlaps the middle frame by about half its width.

   

2. 2

   Put all the frames in one document

   Open the frames with File› then Open… (Ctrl+O or ⌘O). Auto-Align lines them up whatever the order, but open the middle frame, valley-pano-2.jpg for the sample, first and on its own (files picked together open in the picker’s order): each frame opens in its own tab, the tab furthest left becomes the panorama, and its layer stays at the bottom of the stack. Seamless tones and colors in step 5 evens out the other frames’ brightness against this bottom layer.

   Click the second tab (the left frame) and choose Layer› then Duplicate Into Other Document. Then do the same from the third tab (the right frame). The layer is copied into the first of the other open documents, the tab furthest left, so both copies end up in the middle frame’s document. Click that tab to continue there; you can close the other two.

   

3. 3

   Select all the layers

   The Layers panel of the first document now holds three layers: Background and two copies, all stacked over each other. Click the top layer, then hold Shift or ⇧ and click the bottom one, so all three are highlighted. Auto-Align and Auto-Blend work on the selected layers only.

   

4. 4

   Line them up with Edit › Auto-Align

   Choose Edit› then Auto-Align. Lil Cactus finds the features the frames share, works out how each frame has to move, tilt or skew to match its neighbors, and transforms the layers into place. The canvas grows to fit them all: on the sample it goes from 720 × 960 to about 1630 × 1217 px, and the side frames are tilted into a bow-tie shape.

   One frame stays where it is and the others are fitted to it. To choose that reference yourself, usually the middle frame, select it alone and click Lock position (the four-arrow button) in the Layers panel first; only one selected layer may be locked. Auto-Align fits frames with a perspective transform, so it can also tilt or skew a frame (keystone) when the camera turned between shots.

   

5. 5

   Hide the joins with Edit › Auto-Blend…

   With the three layers still selected, choose Edit› then Auto-Blend… Pick Panorama, leave Seamless tones and colors ticked so the frames’ brightness is evened out, and click Blend. With more frames, each one is matched through the frames it overlaps.

   Each layer gets a mask that shows it only where it is the best source, with the joins placed along the overlaps. The layers stay separate, so you can paint on a mask to move a join, for example away from a person who moved between frames.

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6. 6

   Crop the edges and save

   Choose Marquee Select (M) in the toolbar and drag a rectangle that stays inside the photo everywhere, clear of the transparent wedges. Then choose Image› then Crop to Selection. The largest rectangle that fits is about 1540 × 965 px.

   Check the joins at full size with View› then Actual Size (100%) (Ctrl+1 or ⌘1; some browsers use that shortcut to switch tabs): on the sample they can’t be found. Export with File› then Export› then JPEG…, or keep the layers and masks with File› then Save As› then Lil Cactus Project… (Ctrl+Shift+S or ⇧⌘S). File› then Save on this document writes the flattened panorama back into the middle frame’s JPEG, valley-pano-2.jpg for the sample; the first time, the Save Image dialog asks for its quality.

   

   

Fix common problems

Duplicate Into Other Document put a frame in the wrong document

It always copies into the tab furthest left among the other documents. Click the tab that received the copy and undo there, then close the other tabs to the left of the panorama’s tab, choosing Don’t Save (reopen any frame you still need to copy), and copy again.

Auto-Align or Auto-Blend is grayed out

Select at least two visible layers; text, shape and Smart Object layers must be rasterized first. Auto-Blend also refuses a layer locked with the padlock button (Lock layer) in the Layers panel; Lock position is fine.

A visible line or a doubled object along a join

Something moved between frames, or the overlap was too small. Select the layer’s mask and paint white or black with a soft brush to move the join to a quieter place.

What to do next

• Crop to a final shape: how to crop an image.
• Merge several exposures instead of several directions: how to merge HDR brackets.
• Move a join by hand: layer masks.
• Resize the panorama for the web.

Coming from another editor

Photoshop

File › Automate › Photomerge…, or Edit › Auto-Align Layers… followed by Edit › Auto-Blend Layers… In Lil Cactus the same job is Edit › Auto-Align and Edit › Auto-Blend…

Panorama stitching: questions and answers