Spell Focus has no requirements at all, even level 1 Fighter could take it. Spell Focus is a Feat in Pathfinder: Kingmaker.Feats can give your character various bonus or allow them to perform all sorts of actions. Your spells of that school are more potent than normal. Each time you take the feat, it applies to a new school of magic. Spell Focus ( Player's Handbook v.3.5, p. 100) Choose a school of magic, such as illusion. Spell Focus (Transmutation) @ 11 Greater Spell Focus (Transmutation) @ 13 Spell Perfection (Slow) @ 15. Choose a school of magic. Your magical specialties are particularly effective. Unfortunately though, because of the rules you have quoted, Augment Summoning would not work for Preservationist, because technically it only works for spells (and, due to Summoner, SLAs).

Add +1 DC for all saving throws against your spells …

But on Choosing a Spell says, "To cast a spell, you must be able to… manipulate the material components or focus (if any)" necessary for casting the spell. So, casting Quickened Persistent Slow in a 5th level slot at a level 7 save DC, and haste on the party in the same round. Required for. Prerequisite. Benefit: Choose a school of magic you already have Spell Focus in. Casting any of your focus spells costs you 1 Focus Point. You automatically gain a focus pool of 1 Focus Point the first time you gain an ability that gives you a focus spell. Any spells you cast of that school are more difficult to resist. Unless the GM can be convinced that the PC can manipulate the material or focus components with his mouth, the PC'll likely need an empty hand to manipulate any of the spell's material or focus components.

The bonus to save DCs provided by Spell Focus and Greater Spell Focus for that school increases by 1. Benefit: Add +1 to the Difficulty Class for all saving throws against spells from the school of magic you select.. Special: You can gain this feat multiple times.Its effects do not stack. Currently, this wizard is level 10, with focus and greater focus in conjuration, wielding battlefield control and haste. Prerequisite(s): Spell Focus. You replenish all the Focus Points in your pool during your daily preparations. I've seen mentioned in multiple guides around the internet the possibility of optional spell focus components - the most common of which is using a flask of acid with the Acid Splash spell to increase the damage by 1 point. However, I can't seem to find actual rules on this anywhere, it's not on the spell itself nor on the item.