Studlagil was discovered only a few years ago. It was created since the waterlevel dropped when a dam was built. You can view it from both sides of the river. To be able to walk inside of it you have to park on the east side of the river and walk for about 40 minutes. 
Before you drive here, make sure to put this pin into google maps: 
https://goo.gl/maps/BuCreKJhz6twFJ8k9

There's no phone signal in the valley so you need to have the correct pin before you enter. The pin will lead you to the first parking lot (at the bridge). You can continue driving over the bridge for another 10 minutes, then you find the main parking lot and from here it's 40 min walk to the canyon.