· 4 min read
If your camera is set to RAW + JPEG, every frame writes twice. A 30 MB Sony ARW next to a 8 MB JPEG. A 100 MP Fuji X-T5 RAF next to a 12 MB JPEG. For a wedding photographer with 3,000 frames per shoot, that's 90+ GB per gig — and most of it is sitting on your local SSD long after the JPEGs were the only ones you actually used.
A Sony ARW and its in-camera JPEG are visually identical but their file bytes are completely different. Standard checksum-based tools (MD5, SHA-256) treat them as unrelated. Tools that only do perceptual matching within a format never even compare them.
The signal you actually want is "these two files contain the same image." That's what Dup computes — a perceptual hash on the decoded pixels, regardless of the source format.
HEIC is also matched against JPEG / RAW — useful if you shoot iPhone alongside your main body and want to dedupe location-event photos across devices.
Drop the folder on the app, or browse to it. Works on external drives — useful if you offload to a Samsung T7 and want to clean before importing to Lightroom.
Dup groups every frame with its sibling. You see the resolution, file size, and format side by side.
Tell Dup once whether your workflow is RAW or JPEG-first. Auto-Keep marks the keeper across thousands of groups in seconds. Review, then delete.
Deletions go to a staged folder before the system Trash. Restore any file within the 30-day window.
Every comparison happens on your Mac. No file content, thumbnails, or metadata leaves the machine. This matters specifically for unreleased shoots — Dup will never upload anything to a cloud service, full stop.
Try it on one shoot
Free up to 250 MB of deletions without a Pro license — enough to test on a real folder.