The IQ of the camera should be very good. Just make sure you check the AF accuracy.
I cannot comment on the quality of the zoom.
As to your documentary photography, brava for a worthwhile and unusual genre. You should get to Asia! The square mile that I live in was once a Hutong but it has now been flattened. The local population has been cut drastically, so it seems there are more young, serious, very white Russians than Hutong residents around here these days. The men all look quasi-military and the women all look like exotic dancers!