If you want to take stunning pictures of Vietnam, you have to go to Bac Son Valley, one of the most beautiful landscape in the North of the country.
I choose a private tour 2 days 1 night with driver and English speaker guide (but other languages are available) with Hello Vietnam Travel. This is the cheapest that I found but very professional. We visited the top of a mountain, where is possible to see a 360 degrees view of the valley. We stayed in the best homestay just in front of the mountain and the family was very kind. Of course, the level is under that of a hotel but the experience is more authentic. The morning we enjoyed the sunrise and go around the valley by bicycle. The place is not touristic at all. I absolutely recommend this tour.
Our stay at the Chalcedony has been a very pleasant experience - the correspondence. I had prior to our visit has been nothing but professional. I had the city day tour with a guide of Hello Vietnam Travel, who was very knowledgeable in the history of this city and a Halong bay cruise.