yes i'll use rayswitch material, never think about that solution.. thanx :) but I hope that's just a temporary solution not the only solution. because I don't experience this with other renderer.
check the attachments, its the scene file.
btw, why 1000 lm in photometric light isn't show the same brightness like 1000 lm in coronalight?
and I saw that in photometric light 1lm is equal with 1.025cd, and in coronalight 1lm is equal with 0.318cd. will appreciate if there is non-science explanation about this.