In Icelandic, to express that you are doing something so that a certain outcome happens or someone else can do something, you use the phrase til þess að ("so that" or "in order to").
When the action in the purpose clause has a different subject than the main clause, til þess að introduces a subordinate clause. Crucially, the verb in this new clause must be in the subjunctive mood.
When talking about setting up a film shot, you will frequently use the verb vera (to be) to describe the desired state of the set. The third-person singular present subjunctive of vera is sé:
| The director films outside so that the light is natural. | Leikstjórinn kvikmyndar úti til þess að ljósið sé náttúrulegt. |
| We move the spotlight so that the background is dark. | Við færum kastarann til þess að bakgrunnurinn sé dökkur. |
Other verbs also shift into the subjunctive in these clauses. For many regular and strong verbs, the third-person singular present subjunctive ends in -i. For example, geta (can) becomes geti, and sjá (see) becomes sjái:
| You must stand here so that the cameraman can find the focus. | Þú verður að standa hér til þess að tökumaðurinn geti fundið fókusinn. |
| I do not film it so that the spectator does not see the error. | Ég kvikmynda það ekki til þess að áhorfandinn sjái ekki villuna. |
Notice how the subject changes in each sentence—one person performs the main action so that the next person or object can do theirs:
| The cameraman adjusts the focus so that the actress directs well. | Tökumaðurinn stillir fókusinn til þess að leikkonan leikstýri vel. |