Convert DNG to JPG

DNG is not one thing. Some cameras write it as their native format — Leica, Pentax and Ricoh bodies, most consumer drones, and iPhones shooting ProRAW. In those files the embedded preview was made by the camera at capture, at full resolution, exactly as a CR2 or an NEF would be.

Other DNGs are conversions. Adobe DNG Converter takes a CR2, NEF, ARW or ORF and repackages the sensor data into DNG, and the preview it writes is generated by the software using whatever raw processing settings applied at that moment. It is also offered at medium or full size, and whoever ran the conversion picked one. That is why two DNGs can behave differently on this page for reasons that have nothing to do with the camera.

Adobe published DNG in 2004 to solve an obvious problem: every manufacturer invented its own undocumented raw format, most were reverse-engineered rather than specified, and a format nobody can read in twenty years is a poor place to keep photographs. DNG is documented, standardised as ISO 12234-2, and not tied to a company that might stop supporting a camera line.

So people convert archives to it deliberately, and some cameras skip the intermediate step. If you have been handed a folder of DNGs, somebody probably made an archival decision, and the corollary is that the file you are holding is meant to be the master. Extract the JPG and leave the DNG where it is.

DNG has an unusual property among the formats here: there is no magic number that identifies it. A DNG is a TIFF that carries a DNGVersion tag, and that tag is two bytes — searching a file for two particular bytes finds them in most ordinary TIFFs by chance. There is no honest way to write a signature for it.

That is why software identifies DNG by extension and container structure rather than by sniffing the first few bytes, and it is one reason a stray DNG occasionally gets mistaken for something else by tools that guess from content. It has no effect on this conversion, which scans for embedded JPEGs regardless of what the container claims to be.

An iPhone shooting ProRAW writes a DNG that has already had a great deal of computational work applied — multi-frame merging, tone mapping, noise handling — and the embedded preview reflects that. Developing the raw yourself from scratch will not reproduce it, and will usually look worse.

Drone DNGs are similar in spirit: the camera’s rendering includes lens corrections that a generic raw developer may not apply. For both, extracting the preview is not a compromise. It is the picture the device’s own processing produced, which is the thing you were buying.

The DNG holds sensor readings at up to 16 bits, with the highlight and shadow latitude that makes raw worth keeping. The extracted preview is an 8-bit rendering with a tone curve already applied. A clipped sky in the preview usually still has detail in the DNG; the JPG will not let you reach it.

That is the argument for keeping the DNG rather than replacing it. Converting produces a second file and takes nothing away, so there is no decision to regret — and since the DNG was probably created as an archival master in the first place, deleting it would undo somebody’s deliberate work.

Nothing here forces the metadata out: the preview is already a JPEG, so it could be handed over byte for byte with the whole EXIF block — camera or phone model, lens, exposure settings, capture time and any GPS coordinate. What survives by default is less than that. "Remove metadata" is on, so the EXIF and IPTC blocks are edited out before the file reaches you; what always survives is the ICC colour profile, which is the one piece you would not want dropped.

That default is aimed squarely at these files. A drone DNG records where it flew and a phone DNG records where you stood, and both tag far more reliably than a dedicated camera does. When you do want the information — a survey flight, a documented site visit, an archive where the capture data is the point — turn the option off and the block comes through intact. Setting a maximum width is not the way to remove it any more; that only worked because a resize forces a re-encode, and it costs quality to do what the option does directly.

The converter keeps the largest embedded JPEG above 640 by 480 and rejects anything below that, on the grounds that a thumbnail is not a conversion. Some DNGs written by software with previews disabled, and some produced by conversion tools set to minimum, fall under the line and fail with a message.

When that happens the fix is a raw developer — Adobe Camera Raw, Lightroom or darktable all read DNG properly, which is the whole point of an open format. It is the one case in this bundle where the alternative is genuinely easy, because DNG support is not manufacturer-specific.

Drop the whole folder. Each file is scanned and its preview copied out, with the set available as a ZIP at the end. For a JPG target at the default settings there is no re-encoding at all, so a large archive goes through quickly.

The free tier accepts files up to 100 MB each. DNG sizes vary enormously — a 12-megapixel phone file is around 25 MB, while a 16-bit DNG converted from a high-resolution camera can be much larger — so this is the one format in the bundle where checking a file size before a big batch is worth the ten seconds.

Browsers do not display DNG, Windows needs a codec, and macOS handles many but not all producers. If you have been sent an archive and cannot see any of it, that is the ordinary experience rather than a fault at your end.

This page needs nothing installed: the extraction is JavaScript running in the tab, so it works on a locked-down laptop, a borrowed machine or a phone, and the files stay where they are while it happens.