I'm not a phone camera guy, but I'll take a shot at this.
RAW is a type of file format used in most upper end digital cameras. It's all the basic data as gathered by the sensor and is basically a digital negative that is developed by software. A RAW file isn't changed as it is modified. The changes are saved in what is called a "sidecar" file linked to it. If you don't like a change, you toss it from the sidecar and start over with the undamaged original.
Not quite. This is a description of non-destructive editing. That is possible with JPG as well as RAW. If you know video, it's the same idea as an Edit Decision List - original footage remains untouched, software performs all modifications when viewing. When exporting from iPhoto, one can decide to export the original (unedited), or a file that incorporates the edits (either TIFF, JPG, or PNG).
A "sidecar file" is a misconception. Yes, separate data is needed to apply edits to a non-destructively edited image. It is NOT part of RAW shooting. The edit
data (created by the editing program) is handled in a variety of ways. In iPhoto and Aperture, it's saved in a database. In Adobe, it's an integral component of Adobe's PSD file format.
Most phone cameras don't do RAW, just jpeg, but in reading the promo on the 5s camera from the Apple site my guess is that it does. Apple says you can add changes to photos before, during or after a shot and if you don't like the result just toss the filter effect. That sounds like some version of RAW to me.
All this indicates is that it's using non-destructive editing, which is just the way iPhoto works, both with JPG and RAW files. Undoubtedly, whatever is exported from the camera (in email images, exported to Facebook, etc.) has those edits applied as they go out the door.
The iPhone 5s spec sheet is not specific about output formats for photos, and I don't yet have a 5s, so I can't confirm or refute how the 5s stores and exports its images. However, saving as RAW would be a really big deal, something I'd expect Apple to be explicit about. I have tried the iPhone filter effects at the Apple Store, and confirmed that they are non-destructive. Any filter effect applied when shooting can be undone when viewing the shots in the Photos app. I have to take another look at the camera settings on the iPhone, to see if any RAW/JPG-related options exist.
It's been a long time since I last used iPhoto, but I don't recall it being able to recognize RAW, just jpeg. If that's still the case, then it's dumping the sidecar on import and just keeping a jpeg that it generates. It might keep the sidecar file but not be able to do anything with it so it doesn't show up. That's why your effects vanish. There's a trick for looking into the iPhoto library to see what's there, but I don't want to get into that just now.
The current version of iPhoto absolutely does support RAW.
And again, the notion of a "sidecar" being exported from the camera alongside the RAW image is not correct. RAW is what it is - a single file that contains all data from the imaging sensor. If you want a file that includes in-camera edits/modifications, you adjust your camera's settings to save JPGs. You want RAW, set the camera to save RAW. Best of both worlds, you save and export RAW + JPG from the camera. It's a memory card-eater, but at today's memory prices...
They may need to update iPhoto to keep up with the iPhone camera.
Hope this helps.
The only modification necessary, if iPhone 5s does save as RAW, would be a camera-specific RAW profile. Every new camera that saves RAW requires a new profile, which allows the editing program to properly interpret the raw data. These profiles are distributed periodically as updates by the software developer. I haven't seen an iPhoto/Aperture update that includes a RAW profile for iPhone 5s.
Overall, I doubt the iPhone 5s is saving RAW (at least, as a default setting). RAW files are quite bulky, and the iPhone's casual amateur user base would quickly burn up their phone's storage capacity. That's a cause for customer dissatisfaction. Apple's focus is clearly on the needs of hundreds of millions of casual users, not millions of camera enthusiasts. Similarly, for all users of iPhone with Windows computers, dropping a RAW file into their Pictures folder would be inconceivable - while all Macs come bundled with iPhoto, which can handle RAW, there is no RAW viewing/editing capability in Windows - a 3rd-party program is required. If that was happening, you'd already see the howling on forums like this.
