Why is Photoshop not merging my panorama?

Question

It's not something i am planning on doing often but I wanted to try to do a panorama and use Photoshop's "Merge to Panorama" feature to stitch the images. Previously I have only done this manually. I think I have a decent overlap in my images but Photoshop is unable to stitch my images. I have 2 sets of images and it stitches the middle group fine but not the first and the last image. This is similar with my other group of images where it stitches 2 middle groups and not the first and the last image. Below is a screen capture of what i usually get:

What am I doing wrong?

Answer 1

The framing of the first and last images seems to be significantly different from the others (it took a while for me to see that the top pic was the last and the bottom the first, assuming left-to-right sequence). There may simply be too much ambiguity for Photoshop to deal with in this particular sequence, since the main differentiator is colour (something PS autocorrects to a degree in stitching), with the darkness of the islands and clouds being the "anchor", and both of the pics left out have the horizon in a significantly different place than their next-door neighbors.

I don't know how the panoramic merge works in PS these days (I'm still running CS3), but this looks to me like one of those instances where manual tiling would be necessary, and I'd expect to lose (or have to synthesize) a significant part of the vertical after the stitching because of the framing issue.

Answer 2

Automatic stitching is not perfect, it works by identifying a set of salient image features, corners, junctions, dots, lines etc. and then searching for a transformation that causes a good number of features to match up with the feature set of an adjacent image.

In your case there are simply not enough features in the two unmatched images. The top image contains a large amount of featureless sky. In the bottom image, all the features are concentrated in the shoreline area - which isn't present in any of the other images, and the water is devoid of the dark ripples that I'm guessing provided the features to match the middle images.

You haven't really done anything wrong, it's just your chosen subject doesn't contain enough detail. If I were you I'd try and add the spare images manually, and try and bear in mind the need for distinguishable features when shooting panos.