Hi,
i'm not familiar with the photo area but you can find fews good site which can help you to find a job in Japan, and i remember saw some postion regarding photographer.
you have gaiijinpot , careercross, workininjapan , and more,
if you have a good Japanese i will suggest you to contact directly some big magazine here (send them a resume and some photo sample) or you can also try the Hello Work (but for that you need to have a valid working visa)
you can check they offer online (Only in Japanese)
https://www.hellowork.go.jp/
Bye and good luck.
PS: if you need some information about Visa in Japan i just wrote a news on my site here about Japanese Visa :
How to get a Japanese Visa? | Akiba4you.com