The basics
What is a PEF file?
PEF is the raw format of Pentax cameras. It goes back to Pentax's first digital SLR, the *ist D of 2003, and is still offered by current K-mount bodies such as the K-3 Mark III. Pentax's camera business is part of Ricoh Imaging, which now makes the cameras and their software.
Like every camera raw format, a PEF holds what the sensor measured, before the camera's processing. Each value is the brightness under one coloured filter. A raw developer interpolates full colour for every pixel, applies white balance and a tone curve, and only then do you have a photo. Because PEF files keep 12 or 14 bits per value, you can recover highlights and shadows and set white balance afterwards, which a JPEG doesn't allow.
The catch is the usual one for raw files: a freshly opened PEF can look flatter and duller than the camera's JPEG, because the editor hasn't applied the camera's look. That's a starting point, not a fault.
Anatomy
What's inside a PEF file
Pentax doesn't publish the PEF format, but it's an ordinary TIFF on the outside, so its layout is well known from reverse engineering. This outline combines PRONOM's signature for the format (fmt/1781) with ExifTool's documentation of the Exif and Pentax tags. Tags shown are ones the documentation lists for PEF files; their positions and the full tag set vary by camera. It isn't a dump of a real file, and none is offered for download.
IMGP0001.PEF: structure outline (positions vary by camera)
offset bytes part
000000 4D 4D "MM": big-endian
000002 00 2A 42: a standard TIFF header
000004 xx xx xx xx where IFD0 starts
IFD0 ordinary TIFF tags
0103 Compression 65535 = "Pentax PEF Compressed"
010F Make the maker; "PENTAX" appears early in the file
0110 Model
0111 StripOffsets → the sensor data
8769 ExifOffset → Exif IFD
Exif IFD exposure, lens, date and time
927C MakerNote → Pentax maker notes
maker 41 4F 43 00 "AOC\0": Pentax maker-note header
notes 4D 4D their own byte order ("MM")
0003 PreviewImageLength
0004 PreviewImageStart → a JPEG preview
0008 Quality 4 = RAW, 7 = RAW (pixel shift enabled)
0405 large data block found in PEF and DNG, not JPEG
… many more camera settings
raw the sensor data: one value per pixel, 12 or 14 bits,
data stored with Pentax's own compression- 1
4D 4D 00 2AA real TIFF header
MM(big-endian, from Motorola) and the number 42: the same first bytes as a big-endian TIFF. PRONOM's signature for PEF starts with exactly these bytes, which is why a generic tool may report a PEF as a TIFF. - 2
IFD0Standard tags first
Image size, make, model and pointers to the data, as in any TIFF. The camera name appears here as text; PRONOM uses the string
PENTAXto recognise the format. - 3
0103 Compression 65535Pentax's compression
TIFF has no standard code for raw sensor compression, so cameras use private values. ExifTool lists 65535 as Pentax PEF Compressed. Pentax doesn't document the method; raw decoders implement it from reverse engineering.
- 4
41 4F 43 00The maker-note header
AOCand a null byte open Pentax's maker notes, followed by their own byte-order mark. The maker notes hold hundreds of Pentax-specific settings that only Pentax's software and tools like ExifTool decode in full. - 5
0003, 0004The JPEG preview
The length and position of a JPEG the camera made. Thumbnails, quick viewers and the camera's playback screen show this, not the raw data.
- 6
0008 QualityWhat kind of shot
Value 4 means a normal raw file, 7 a raw file shot with Pixel Shift, where the camera combines several frames with the sensor moved slightly between them.
- 7
raw dataThe sensor readings
One value per photosite, each under a red, green or blue filter. Nothing has been demosaiced, white-balanced or tone-mapped yet: the raw developer does all of that.
Two raw formats
PEF or DNG: why Pentax cameras offer both
Most camera makers save raw files only in their own format. Pentax is an exception: since the K10D of 2006, one of the first cameras to support DNG natively, many Pentax SLRs let you choose between PEF and DNG in the menu. The K-3 Mark III Monochrome's specification, for example, lists RAW (14bit) as PEF or DNG. Ricoh's GR III and GR IIIx compacts go further and record raw only as DNG.
| PEF | DNG from the camera | |
|---|---|---|
| Owner | Pentax/Ricoh, unpublished | Adobe, published specification |
| Structure | TIFF-based | TIFF-based |
| Sensor data | The same readings | The same readings |
| Pentax maker notes | Yes | Yes: ExifTool finds Pentax maker-note tags in both |
| Software that reads it | Raw editors that support that camera model | Most raw editors, often even before they add the camera |
The practical difference is compatibility. A DNG carries the colour information a raw developer needs inside the file, so software that understands DNG can usually open a new camera's files without an update. A PEF needs software that knows that specific camera. If you're unsure, DNG is the safer choice; if you already have a library of PEF files, there's no need to convert them while your software reads them.
Pixel Shift and special modes
Files shot with Pentax's Pixel Shift Resolution mode hold several frames. Some software supports only the normal raw files of a camera, or only one of the two formats for these modes; Apple's raw list, for instance, has footnotes for such limits. Test with your own editor before relying on it.
How to
How to open, edit and convert a PEF file
- Pentax Digital Camera Utility 5: Ricoh's raw developer, included with Pentax cameras, for Windows and macOS. It develops raw files, saves JPEG and TIFF, and can convert PEF to DNG. Ricoh's updater page lists version 5.10.2 (February 2025).
- Adobe Lightroom and Photoshop (Camera Raw): open PEF files from the models on Adobe's supported-camera list.
- darktable and RawTherapee: free and open source, on Windows, macOS and Linux.
- Mac, iPhone and iPad: Photos and Preview open PEF files from the Pentax models in Apple's raw list, which goes back to the *ist D.
- Windows: install Microsoft's free Raw Image Extension, built on LibRaw, and Photos and File Explorer show PEF files.
From the command line, ExifTool can pull out the preview without developing the raw data, and show what the camera recorded:
# save the camera's JPEG preview
exiftool -b -PreviewImage IMGP0001.PEF > IMGP0001.jpg
# all metadata, grouped by where it's stored
exiftool -a -G1 IMGP0001.PEFTroubleshooting
Why won't my PEF file open?
- The camera is newer than the software. Raw support is added camera by camera. An older Lightroom, Photoshop or raw editor may reject the file or show only the preview. Update, or use Adobe's free DNG Converter, which rewrites PEF files from the cameras it knows as DNG for older software.
- Only a small or low-quality picture appears. The program is showing the embedded JPEG preview because it can't decode the raw data.
- A generic tool calls it a TIFF. It is one, structurally, but the image data is Pentax's raw sensor data. Ordinary TIFF viewers can't show it correctly.
- Next time, avoid the problem. If your camera offers DNG, recording DNG instead of PEF makes files readable by more software straight away.
Comparison
PEF vs JPEG, HEIF and DNG
| PEF | DNG | JPEG | HEIF/HEIC | |
|---|---|---|---|---|
| Processed in camera | No | No | Yes | Yes |
| Bits per value | 12 or 14 | As recorded | 8 | 8 or 10 |
| Edit white balance later | Fully | Fully | Only roughly | Only roughly |
| Readable without camera-specific support | No | Mostly | Yes | Yes |
| Good for sharing | No | No | Yes | Yes, where supported |
Keep PEF or DNG files as your originals and share JPG exports. Raw files are several times larger than a JPEG of the same shot, and nobody can view them in a browser.
Privacy
Metadata in PEF files
Pentax's maker notes are detailed. Besides the usual Exif date, time and exposure, ExifTool reads a camera serial number, lens information and, on cameras with built-in GPS or a GPS accessory, the location. All of it travels with the file.
Before sending raw files to people you don't know, check them with exiftool -a -G1 file.pef. For public sharing, export a JPEG with metadata removed instead. PEF files contain no scripts or macros; the risk of a crafted file is limited to bugs in raw decoders, so keep raw software updated.
Sample files
There are no sample PEF files on this page. Raw files come straight from the camera, so the simplest test file is one shot on a Pentax camera set to RAW with the PEF option.
Put it online
Have a PEF file? Give it a link.
Drop a Pentax raw file on 99helpers and it gets its own web address. Browsers can't display raw files, so anyone who opens the link downloads it to develop in their own software; add a JPEG if people just need to see the photo.
Questions
PEF files, frequently asked
What is a PEF file?
A raw photo from a Pentax camera: the unprocessed sensor data, a JPEG preview and the camera's settings, in a TIFF-based file.
How do I open a PEF file?
Use Pentax Digital Camera Utility 5, Lightroom, Photoshop, darktable or RawTherapee. On a Mac, Photos and Preview open them; on Windows, install Microsoft's Raw Image Extension.
Should I shoot PEF or DNG on my Pentax?
Both hold the same sensor data. DNG opens in more software without updates; PEF is Pentax's own format. If you're unsure, DNG is the more compatible choice.
How do I convert PEF to DNG?
Use Pentax Digital Camera Utility 5 or Adobe's free DNG Converter. Keep the original PEF files as a backup.
How do I convert PEF to JPG?
Open the file in a raw editor or Preview and export as JPEG. exiftool -b -PreviewImage file.pef > file.jpg extracts the camera's own preview without editing.
Why does my PEF look different from the photo on the camera?
The camera showed its own processed JPEG preview. Your editor develops the raw data with its own defaults, which are often flatter. Adjust it, or choose a camera-matching profile.
Is PEF the same as TIFF?
It uses TIFF's structure, so the first bytes are a TIFF header, but the image inside is raw sensor data that ordinary TIFF viewers can't display properly.
Related formats
Other file types explained
Keep going
Related
Sources
- PRONOM: Pentax PEF Image File (fmt/1781)
- ExifTool: Pentax tags
- Ricoh Imaging: Digital Camera Utility 5 for Windows
- Ricoh Imaging: GR III and GR IIIx specifications
- Ricoh Imaging: K-3 Mark III Monochrome specifications (Japanese)
- Apple: Digital camera RAW formats supported by iOS 26, iPadOS 26 and macOS 26
Last reviewed 27 October 2026.