Hi

I am doing a lot of ambient sound recording for my videos,with a Fostex FR-2 digital field recorder.
In the countryside I am using an Audio Technica AT825 with real good results.
However, in the city, I think I need a shotgun to cut off undesired surrounding sound... I was proposed Sennheiser MKH416, and Audio Technica's 835B and 835ST... wich one, (or other), do you think will work best for me ??

Does anyone have an insight on this ?

both are good mikes really. At the end backnoise/ambience sound can be created with worse mikes, so that is fine. Remeber to buy a windshield as well to get rid of windy 'PPP' sounds. THe more bass your mike can record the better, the fuller the sound is and the more you can do with it afterwards in pre-editing.