Implications of shooting HEIF on the iPhone or iPad and how to control the format

HEIC is the new, space saving format introduced by iOS 11. A HEIC image or HEVC video will only need half the storage on your iPhone or iPad as the more compatible JPEG or H.264 video at the same quality. This is a compelling reason to stick with the space saving format on the mobile devices, if they do not have much storage. By default the Camera.app will take the the images in the space saving format. This Apple knowledge base article explains the settings available to control, how the Camera.app and the Photos.app on mobile devices will handle the format: Using HEIF or HEVC media on Apple devices

Settings Controlling HEIF an Mobile Devices

There are two Setting on the mobile devices, that are controlling the handling of HEIF:

• Settings > Camera: You can set the format either to High Efficiency (for HEIC and HEVC) or Most Compatible (for JPEG and H.264)
• Settings > Photos > Transfer to Mac or PC: Select "Keep Originals" to have the items transferred in the original format or "Automatic" to have them automatically converted to a most compatible format.

These settings may seem to be straight forward, but can have unexpected consequences on other devices, when we are downloading the photos and videos to a computer.

It may not be feasible to shoot HEIF at all, if our computer or other mobile devices are stuck with an older system version and cannot be upgraded, or if we need to share the images online, and the sites do not support HEIF. Consider the compatibility, the storage needed, the sharing options in the Media Browser.

Compatibility and Transferring to a Computer

Consider the system versions on your other devices, before setting the camera to shoot in HEIF. It will depend on the system version on your devices if HEIF is useful for you or not.

• All mobile devices (iPhone, iPad, iPod touch) need to be running at least iOS 11 to be able to handle macOS 10.13 High Sierra. Some older mobile devices may be stuck on older system versions.
• A Mac will need to be running macOS 10.13 High Sierra or later to have system wide support for HEIC. Some older Macs cannot be upgraded to High Sierra.

Are any of your devices too old, to be updated? Or are there devices, that you want to keep on older system version, even if the upgrade were possible?

• All devices are running a system that supports HEIF - the perfect combination: You can keep the default camera setting and shoot in the HEF format and save 50% of storage on all devices and in iCloud and the Photos > Transfer to Mac or PC on "Keep original". Only if you need to share a photo, it will have to be converted, if a JPEG is required. See the paragraph about the Media Browser and Sharing below.
• If one of your computers cannot handle HEIF, but the mobile devices can: This is a problematic situation. You will have to decide, if you want to keep the mobile devices on HEIC but transfer the items as JPEGs or refrain from using HEIF at all.
  • The easier solution would be to refrain from using HEIF, because the items on your iPhone and the computer will be in the same format, and the computer can recognise, if an item has already been downloaded and only download new photos.
  • If you need to take HEIF media to save storage on the iPhone, and you download the photos in a more compatible format to the computer, the computer can no longer recognise automatically, if the items have already been imported or are new items. You will need to select the new items manually.

I would avoid the second option, because it will be very difficult to manage and disable the HEIF format. You can convert the photos that have already been taken as HEIC files with the online converter at https://heictojpg.com

Photos for Mac, Sharing Photos and the Media Browser

When you import the HEIF files into Photos for Mac, you will save storage in the Photos.app. When you want to share them on social Media Sites, the photos will need to be converted into JPEGs, if the site does not support HEIF. Usually the Media Browser will do this for us. It will depend on the system version, how this is handled.

• Photos 4 on macOS 10.14 Mojave: The Media browser is automatically creating JPEG previews for the HEIC files, that have no adjustments applied, and storing them in the user library. This way we are able to see the HEIC files when uploading to web sites or when we want to use them in other applications, and the HEICs will be converted to JPEGs. You can see the previews in your User Library cached at ~/Library/Containers/com.apple.MediaLibraryService/Data/Library/Caches/com.apple.iLifeMediaBrowser.ILPhotosTranscodeCache This cache can be quite large. My Photos Library contains roughly 7000 HEIC files and the .ILPhotosTranscodeCache on my Mojave Mac with the previews has a size of more than 25GB, much larger than the total size of the space saving HEIC files in my System Photo Library. In Photos 4 on macOS 10.14 Mojave ist is easy to use the HEIC files when sharing, but we do not save any storage on the Mac, by using HEIC in our System Photo Library.
• Photos 5 on macOS 10.15 Catalina: On Catalina the huge ILPhotosTranscodeCache is missing from the user library. But now we may not be able to upload the HEIC images using the Media Browser. Only JPEGs can be selected for uploading, see: Problem in Photos 5 on Catalina: Grey Filenames in the Media Browser - Apple Community

As you can see, you will be able to save storage using the HEIF format on a Mac with Catalina, but currently the Media Browser is not allowing us to select HEIF files for uploading. You will not save any storage with HEIC on a Mac with Mojave, you may need even more storage than before., but you can see them in the Media Browser But this applies only to the System Photo Library, which is visible in the Media Browser. There are no Media Browser previews cached for the items in additional Photos Libraries.