@4V29LN0n
Aside from the photography backgrounds, almost every scene has this weird angle, it looks like a photograph rather than a drawing, most manga drawing have a high angle views (imagine standing next to some people sitting down and you view them as you pass by, etc), this manga has a center view (your eyes are at the same level as the people you are watching; photographs use this angle).
I'm guessing the artist is using photographs as the basis for the scenes, and since many scene happen at a campsite, it makes me think he is getting them from camping magazines, since the drawings viewing angle centers around people sitting down at a camp side, but puts emphasis on the equipment. Also, the characters are always posing!
Plus, many of the equipment and the clothing is unusually detailed, yet the characters faces are not as detailed; which is very odd. Why put emphasis on everything, but the characters faces? This is why I think the artist is tracing.