Hi
I don't know where you will be traveling to in Guatemala and what type of trip you have planned---- alone, with a group etc. Safety depends on so many situations in Guatemala. I also don;t know how serious you are about photography. You can do a lot with the G7.
Antigua is probably the safest- even though you need to keep your eyes out- will you be photographing with a tripod? That also makes a difference.
Chichicatenango is superb- the church, the marketplace, the colors...
At Atlitlan I would be more careful. The interior of the country as well. For Tikal and the ruins it's safer as there are more tourists around.
Guatemala is an amazing country with fantastic photographic opportunities. You have to organize yourself so as not to be in a vulnerable situation.
I am planning another trip there next year and will actually hire a "bodyguard" as I will be traveling with two cameras and several lenses...
Lots of luck and most of all, enjoy!
camilla