UPDATE 11/16/2018: Support for RAW has improved in iOS 12. The major difference is that the Photos App on iOS can now edit RAW images natively. That said, Photos will still show the embedded JPEG until you enter Edit, so you still don’t see the RAW most of the time on iOS. Also, on iOS 12, it is not possible to develop a RAW Photos extension for iOS, because extensions are always passed a JPEG. I have filed a bug against Apple (with a solution). Hopefully, they will fix that some time soon.
RAW has been (minimally) supported on iOS for a long time. You could import them directly onto an iPad for example. However, when you looked at the RAW on iPad, you could only see the embedded JPEG. Apple added support for RAW decoding in iOS 10, but despite that, most of the time, you are still looking at the embedded JPEG. In this post, I will describe what is really going on and how to make the most of your RAW files on iOS.
The embedded JPEG is a camera-generated JPEG stored inside the RAW file. This JPEG uses the camera manufacturer’s algorithms and will look different from the actual RAW. Sometimes the difference is relatively subtle (color, noise reduction, or sharpness), but other times, the difference can be quite striking. For example, embedded JPEGs receive any “picture styles” set on the camera, so if you set your camera to “monochrome”, the embedded JPEG will be black and white, while the RAW will remain full color. In addition, many cameras do not produce full-size embedded JPEGs. Common sizes for small embedded JPEGs are: 640 x 480, 1920 x 1080 (2 megapixels), and quarter-resolution (e.g., for a 20 megapixel camera, the JPEG is 5 megapixels). It’s hard to judge an image when you are only looking at 10-25% of the pixel data!
Here is a link to a RAW file that demonstrates the problems with embedded JPEGs. Import it and view it in Photos.app. This is a 20 megapixel RAW from a new Panasonic G85. It makes a 1920×1440 embedded JPEG. The embedded is black and white, because I set the picture style to Monochrome. RAW Image
Apple RAW Camera added in iOS 10:
Apple added support for viewing and editing (and capturing) RAW images in iOS 10. However, applications must opt-in to RAW (for backward compatibility reasons). The built-in Photos app does not opt-in. Nor does the built-in Camera app. So by default, you cannot capture, view, or edit RAWs on iOS, even though Apple’s RAW Camera software is capable of decoding hundreds of RAW camera formats. On the plus side, RAW images get synched over iCloud, and sent properly via AirDrop.
Another confusing aspect of RAW on iOS:
As mentioned earlier, most of the time you are looking at the embedded JPEG. To preserve the illusion for apps that don’t support RAWs, Apple APIs do not return correct information about the RAW. For example, if an app requests the pixel dimensions of a RAW image through the standard ImageIO framework, Apple’s code will lie and return the size of the embedded JPEG. To get the correct size, one needs to use Apple’s RAW Camera code. This is not true on the Mac. The same ImageIO call on the Mac returns the RAW’s image size, as expected.
Working with RAW:
If you are going to import on iOS, then you will definitely want a RAW editor (like RAW Power) that natively understands RAWs. If you edit an image in the Photos library (using any app), then you will end up with two images: the original RAW and a JPEG that is the result of the editing process. iOS will also store the adjustment data so that you can edit non-destructively. Though there are two images, you can only see one at a time.
If you want to back up your data using something like Dropbox, then you will probably want to back up the RAW first. Then edit and back up the JPEG. If you are using iCloud Photo Library, then both images will be synched to the cloud for you.
If you have questions about RAW, post them here. I will update the post or respond to your comments below.
RAW + JPEG:
When shooting RAW + JPEG, both iOS and macOS will combine the pair of images into a single “asset.” On iOS, the JPEG is always the image shown and edited. On macOS, the JPEG is the image shown by default, but you can switch the display to show the RAW instead. Whichever image you are displaying on macOS is the one you will edit. RAW Power for iOS shows the JPEG by default also, but if you enter Edit, it will show and edit the RAW.