I'm using this code to create a blur effect inside my view:
let blur = UIVisualEffectView(effect: UIBlurEffect(style: UIBlurEffectStyle.Light))
blur.frame = CGRectMake(180, 10, 200, 750)
Since there is no other parameter in
UIBlurEffect , I think the only way is to use the CIFilter preset
CIGaussianBlur to blur the background View and use its key
inputRadius to adjust the level.
If you want to achieve the same effect as so called
ExtraLight, you can compose this filter with other filters.