Determination of the stop loss should be known at least some of the following:
Trend direction
If you take a position in line with the trend then you can set a stop loss on a direction away from the opening position, but if you open a position against the direction of the trend, obviously you have to be prepared to secure your capital because you're counterattack against the market, so in this case you must be prepared and must put a stop loss close to your opening point.