My daughter is a working artist (painter, mixed media) in Atlanta and needs to photograph some of her paintings for a website and for clients. She has a Nikon D5200 with 18-55 kit lens but she says it is soft. I would like to get her a better lens that she can use with her 5200. Thinking of a normal/wide zoom that would allow framing in limited space (studio) for 2 ft to 8 ft wide paintings. Needs to have good flat field performance. Suggestions would be appreciated.