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Nikon High Efficiency NEF (HE and HE*) on Mac and iPhone
Nikon's High Efficiency NEF files (HE and HE*) used to be the classic case of a listed camera whose RAWs still wouldn't open on a Mac or iPhone: Apple supported recent Z bodies for lossless compressed files only. Apple's current lists no longer carry that restriction, and on macOS 27.0.1 we opened HE and HE* files from a Z8 and a Z9. Apple hasn't said so in plain words, though, so if you edit on Apple devices, shoot lossless compressed or test your own HE files first.
What HE and HE* are
Nikon's newer Z bodies, starting with the Z9 and Z8, offer three ways to compress NEF files. In Nikon's words, from the reference guide's RAW recording page:
| Option | What Nikon says |
|---|---|
| Lossless compression | The largest files |
| High efficiency★ (HE*) | Compares favourably in quality with lossless, and higher in quality than High efficiency |
| High efficiency (HE) | The smallest files |
As a rough guide to the savings, sample files from a Z9 on raw.pixls.us come to about 58 MB lossless, 36 MB HE* and 25 MB HE. Your files will vary with the scene and ISO. HE and HE* aren't lossless, but for most photos the difference is hard to see, and the smaller files mean longer bursts and more shots per card.
Why HE files wouldn't open on a Mac
Apps on Apple devices don't usually decode RAW themselves. Photos, Preview, Raw Smith and many other editors use the decoder built into the operating system, so if Apple's decoder can't read a NEF variant, none of them can.
For several years Apple's list carried a note on these cameras. On the version 18 list, Digital camera RAW formats supported by iOS 18, iPadOS 18, macOS Sequoia and visionOS 2, the Z5II, Z50II, Z6III, Z8, Z9 and Zf were all marked "Lossless RAW format only". HE and HE* files gave an unsupported-format error, and photographers who shot them were stuck. Have Camera Will Travel's guide, How to Open NEF Files on a Mac, describes exactly that trap for Z8 owners: lossless files opened in Finder and Preview, HE files didn't.
Where things stand today
| Apple list | Nikon Z entries |
|---|---|
| Version 18 | Z5II, Z50II, Z6III, Z8, Z9, Zf: "Lossless RAW format only" |
| Version 26 | All Z bodies listed with no note, including the ZR |
| Version 27 | All Z bodies listed with no note |
A missing note isn't the same as a promise, so we tested. On a Mac running macOS 27.0.1 we decoded public sample files from raw.pixls.us with Apple's RAW decoder:
- Nikon Z9: lossless, HE* and HE files all decoded and rendered normally.
- Nikon Z8: lossless, HE* and HE files all decoded and rendered normally.
What we haven't tested: iOS, iPadOS and macOS 26, and the other HE-capable bodies. Apple's lists for 26 and 27 cover iPhone, iPad and Mac together, so the same result on iPhone and iPad 27 is likely, but we'd rather you check than take our word for it.
How to check your own HE files
- Update your Mac, iPhone and iPad to the latest version they can run.
- Shoot one frame in each compression you use: lossless, HE* and HE.
- Open each in Preview on the Mac, or import them into Photos on an iPhone or iPad and tap Edit. A supported file opens at full resolution and responds to edits. An unsupported one won't open, or may show only the small JPEG the camera embedded.
- Or import them into Raw Smith, which tells you plainly when the decoder can't read a file instead of showing that embedded preview.
If your HE files don't open
Shoot lossless compressed
The simplest fix for future shots. Every Z body on Apple's lists has been supported for lossless compressed files from the day it was added, so this works on older OS versions too. You give up some card space and burst depth.
Convert to DNG
Adobe's free DNG Converter for Mac and Windows turns NEFs from the cameras Adobe supports into DNG, which Apple devices read. Adobe Camera Raw has read the Z9's High Efficiency files since version 14.3, according to a 2023 list of HE-capable converters, and the DNG Converter shares Camera Raw's camera support. Have Camera Will Travel warns that the DNGs can come out much larger than the HE originals, which undoes some of the point of HE. Keep the NEFs either way.
Export from NX Studio
Nikon's free NX Studio for Mac and Windows reads every NEF its cameras make, including HE and HE*. It doesn't export DNG, though. Its export formats are JPEG, 8-bit or 16-bit TIFF and HEIF, according to Nikon's NX Studio help. A 16-bit TIFF keeps plenty of room for editing, but it's a developed image, not a RAW: white balance and the demosaic are baked in, and files are large. Use it when you need to finish a set of HE files on an older OS, not as a long-term archive.
Enhanced decoding and Nikon files
Version 27 adds RAW 9, Apple's machine-learning demosaic and noise reduction, for a subset of cameras. In Raw Smith it shows as the Enhanced switch in Detail, wherever Apple offers it for a file. In our macOS 27.0.1 test, Apple's decoder didn't offer it for the Z8, Z9 or Zf sample files, in any compression. Coverage can change with updates, so look for the switch on your own files. Apple's RAW 9 Enhanced decoder has the details, and How to reduce noise in high-ISO RAW covers the standard controls.
How Raw Smith fits
Raw Smith is a RAW editor and library for iPhone, iPad and Mac built on Apple's decoder, so it opens HE and HE* NEFs exactly when your OS version does, and can't add a format Apple doesn't decode. When it can't open a file, it names the camera and says so plainly, which saves you guessing whether the file is damaged.
When the files do open, you import them from a card reader or the camera over USB with Import RAWs, and every edit is rendered from the NEF. On the Mac the files stay where they are; on iPhone and iPad they're copied into Raw Smith's folder in Files. Sharpening and noise reduction are set during the decode in Detail, and Lens Corrections in Optics uses the lens profile your NEF carries. Edits sync between your devices through your own iCloud.
Raw Smith is a free download with a free tier and a 14-day trial; Pro is a one-time purchase or a yearly plan. It's in public beta on TestFlight, so you can try your own HE files before you change how you shoot.
Questions
Can a Mac open Nikon High Efficiency NEF files?
For a long time, no: Apple supported recent Nikon Z bodies for lossless compressed NEFs only. Apple's version 26 and 27 lists no longer carry that note, and on macOS 27.0.1 we opened HE and HE* sample files from a Z8 and a Z9. Apple hasn't announced it, so test your own files.
What is the difference between HE and HE* on Nikon cameras?
Both are Nikon's High Efficiency NEF compression, which makes much smaller files than lossless compressed. Nikon says High efficiency★ (HE*) compares favourably in quality with lossless and is higher in quality than High efficiency (HE), which makes the smallest files.
Which NEF compression should I use if I edit on iPhone or Mac?
Lossless compressed is the safe choice: Apple has supported it for every recent Z body. Use HE* or HE if you need smaller files and longer bursts, once you've checked that your OS version opens them.
Can NX Studio convert HE NEF files to DNG?
No. NX Studio exports JPEG, 8-bit or 16-bit TIFF, and HEIF. If you need a RAW file Apple can read, Adobe's free DNG Converter is the usual route.
Does Raw Smith decode HE NEF files itself?
No. Raw Smith uses Apple's system RAW decoder, so it opens HE and HE* files exactly when your OS version does, and says plainly when it can't.