The problem: Aperture isn't syncing. I thought this was an iPhone problem, but apparently, it's a system wide thing. Let me explain:
I'm running Aperture 3.2, but I've had this problem for a while now - probably since upgrading to Lion.
In Aperture, I have a smart album that contains any photo I've rated five stars. Currently, there are 180 photos in it. In iTunes, I've selected to sync certain things from Aperture to my iPhone. If I click on that 5 Star smart album, it only shows that there are 21 photos. Huh? So, as a test, I opened iPhoto (which I never use). In the File menu, I clicked "Show Aperture Library" and I selected my 5 Star smart album. Sure enough, iPhoto only sees 21 photos in there. But if I click over to Aperture, I see that smart album contains 180 images.
What's going on here?
I should also note that a search of the forums here at Apple support show lots of people have been having similar problems, but most only notice they're missing photos when they sync their iPhone. Clearly, the problem is deeper than that. Aperture sees 180 photos in my 5 Star smart album. iTunes, iPhoto and my iPhone are only able to sync 21 of them?
And how weird is this? In Aperture, I have a smart album of shots that were taken with my iPhone and rated 3 stars or higher. There are 115 shots in that smart album. iTunes and iPhoto only see 38.
Somewhere, for whatever reason, Aperture is telling the rest of the system that it has far fewer images than it does. How do I figure out where the problem is and how do I fix it?
OK. I think I solved it. Here's what I did:
In Aperture preferences > Previews. I selected "Always". It's important to make sure Aperture is generating previews to share with iLife, iPhone, etc.
Next, I quit Aperture.
Then, I went to my Aperture library. For most people, it's in the Photos folder in your home on your Mac, but I moved mine years ago to a much larger hard drive. In fact, I bought an external drive specifically for Aperture. ANYWAY... Go to your Aperture library. It looks like a file. Right Click on it and, in the menu, select "show package contents." In there, you'll find a folder called iPod Photo Cache. Delete it and empty your trash.
While you're at it, you might as well do the same thing for iPhoto.
Next, launch Aperture again. In your Library within Aperture, click Photos (on mine, it's the icon beneath Projects, above Places). Got it? Great. Now, in the menu, under Photos, click "Update previews for library."
Now, go to work, go to bed, just go, because this is going to take a while.
Once Aperture has generated a new preview for all of your photos, plug in your iPhone. In iTunes, slelect your iPhone, then select the Photos tab. Tell iTunes to sync your iPhone with something OTHER than Aperture (I chose iPhoto). Then, tell iTunes to sync your iPhone with Aperture again. By doing this, you're forcing iTunes to rebuild your iPod Photo Cache within Aperture. And, this time, it should get it right.