ora vejam só… eu não sabia: dá pra navegar nos synths usando teclado  :)   aqui vao algumas dicas:

Scroll wheel
Scrolling the mouse wheel zooms you in or out. The zooming is centered around your current mouse position.

+ or -
Zoom in or out around the center of the window.

← or →
Move left or right to a neighboring photo, when one is available.

↑ or ↓
Move inwards or outwards to a neighboring photo, when one is available.

u or j
Move up or down to a neighboring photo, when one is available.

mais algumas legais:

Fun with the Point Cloud

Ctrl
Holding the control key down temporarily hides all photos allowing you to see the point cloud in all its glory. Dragging a halo with the control button down lets you spin around the entire point cloud. Try it!

P
Switches among three modes: points, images, both.

a lista completa está aqui: Photosynth Blog : Photosynth Guide: Viewer Keyboard Shortcuts

e se você quiser testar os vários synths que eu fiz aqui em Sampa…. divirta-se (eu usei o tag euamosampa): http://photosynth.net/Search.aspx?query=euamosampa