so yea i just purchased a sigma 10-20 and i love the hell out of it but these photos i took got distorted i know thats normal with wide angles but how do i fix it.
Photoshop has a distortion correction tool that works pretty good. You'll have to use trial and error to find the right values for that lens.
Isn't one of the reasons to use ultra wide is to get distorted perspectives? I don't see anything wrong with the pics in regards to distortion or perspective.
If you want straight lines, use DXO and run all your pics in batch to correct distortion. You don't have to do a thing as it is an automatic correction.
You don't need to lose all that much image even with such stretched perspectives as this.
Two tips on how not to lose too much image:
1. Make the canvas bigger before you do the correction. Otherwise some of the image falls off the edge of the canvas.
2. After cropping you are left with two missing triangles. You can fake with a bit of content-aware fill or simple cloning.
So here is my attempt at the first image. It took several minutes. It isn't perfect but a bit more work would make the cloning invisible to the eye.