TRACON Controller providing OJT described a conflict event between two IFR aircraft complicated by a photo mission operation nearby and less than adequate briefings provided to the Controller workforce.

Narrative

I was providing OJTI on the satellite position. The Developmental had a Dash 8 depart on a 270 heading climbing to 4;000 FT. She RADAR [identified] him and then climbed to 5;000 FT in her airspace. The Departure Controller turned the CRJ north off the left of the Dash 8. The jet was at 5;000 FT; the Dash was at 4;600 FT. The Developmental immediately called a Traffic Alert and told the Dash to descend to 4;000 FT. The Dash got visual with the jet. The jet would have never been at 5;000 FT if there were not picture takers to the south of the airport during a departure bank. There were also excessive departures off another nearby airport because of a new procedure to have reduced separation off the airport. Vectoring off the RNAV and having visual separation. There has to be procedures briefed to controllers prior to implementing them. Vectoring off the RNAV and reduced separation was not briefed but sent in an e-mail from Union Representative. Also; picture takers should be briefed and have some sort of plan and should be monitored.