I cannot find much information about the SPX7005 except that it is obsolete and may be the same as the 4N35.
Run some tests. Assuming you have a modern camera and digital flash guns (low trigger voltages) set up a SPX7005 with 5V + resistor on the input side and a battery + resistor + LED on output side.
If you have older equipment with higher trigger voltages I suggest buying optocouplers suitable for the voltages.