Did the leaves fall off? Something not working right? Let us know how we can improve the Photosynth experience.
I can't zoom in any more... How should I do?
This is a known problem. Unfortunately those geotags are right on top of eachother.
We are working on a fix for this though
Switching to Bing Maps 3D lets you get close enough.
The same problem sometimes happens when you have Bird's Eye View turned on and the fixed camera position is slightly too far from the geotags, but it's easy enough to drop back to the 'Aerial' (Satellite) imagery and zoom down in.
There's also this: http://photosynth.soulsolutions.com.au/