Zooming in close on photos?

I recently uploaded a large panorama shot to my iPad to view. When zooming in, I was quite surprised to find out that I could zoom in far at all - and the panorama remained a small band on the screen. I tried two other apps beside the default Photos app, but they all seem to apply the same API, as zooming behaviour was identical.

So my question is: Is there a photo viewing (and managing) app that let's the user zoom in close to pictures? With close I mean at least 1:1 with regards to pixels, or even closer.