I've tried three of the apps designed to do panoramas and they all come up pretty short.
The first I tried was Pano [app store link]. It's US$2.99. This app does the best job of guiding you through the process, telling you to take the leftmost view, then another, and then if you want another image it cues you for that. You get a choice of accepting the photo, or taking a fresh one. When you are done, Pano merges the photo and you have a panorama ready to save to your phone or export to iPhoto. Some of the pictures look OK, but I noticed when I was shooting outdoors the three panels did not match very well in tone or color. There were big differences, especially in the sky. It looked a bit like the old Cinerama movies where the three cameras didn't quite match up. When shooting inside, I found the images more consistent. Steve Sande reviewed this app for TUAW back in October.
On to TripStitch [app store link]. Even at US$4.99, this was the most confusing of the apps to use. First, you can't take pictures from within the app. You must use the regular camera controls on the iPhone, then import the images into TripStitch. The problem is there is no guidance for doing that. No instructions, nothing on-screen except a '+' icon, which allows you to import the images from your camera roll. A trip to the developer web site didn't give up any secrets either. So, I took 3 images with the camera, and imported them into the program. The images just sat there. I double tapped on one of the images and saw some controls at the bottom of the screen with arrows in four directions for moving and aligning the images. There was also a cryptic animated target icon. I touched that and saw a cross-hairs and an animated reticle, but I didn't have a clue what it meant. There was an information icon which let me set auto exposure and crop the photos, but not a word about how this program works. I did manually move the images to line them up, but on the small iPhone screen it's no picnic. TripStitch does a good job of balancing the sky, but none of the images I created were worth sharing with anyone. It could be I'm missing something in how the program works, but with no info on the web site, and no built in instructions, getting this app to work well would be tough sledding.
That brings us to PanoLab Pro [app store link]. There was something in that name 'Pro' that encouraged me. The price is US$4.99. This app doesn't force me to use the built in camera controls. I can take the image from inside PanoLab Pro, or it will allow you to import from the camera roll. You can stitch vertically as well as horizontally, which most other programs don't allow. Although the program is very powerful and allows exposure settings and control of white balance, I could still see seams between the panels. A look at photos submitted by other users of the app often showed the same issues. PanoLab Pro does give you the best chance of getting the final image right, of course, because it allows more control of the merging. Even so, I really couldn't create anything I was truly excited about. If you want to give the program a try, there is a free version of this program called PanoLab, but it doesn't have all the control of the Pro version.
I spent a lot of time comparing these programs, and there may be some other ones I missed that are better or worse. Panorama [app store link] is also at the app store for US$9.99 and it got both good and bad reviews from users. I'll give it a try soon. So far, I haven't been too excited about any of the three I've tried, but PanoLab Pro comes the closest. If you take some time with the images, you have enough fine control to make them acceptable.
The quest continues.