Suspension & Brakes - Does tire size change your camber?

I decided to take my 18 inch rims off and autocross with my old 7 inch tires and rims. I have the Strabo koni setup and I have it aligned with -1 camber. However my understeer was ridiculous with the 17 inch tire and got worse as the day went on. Just wondering if my new alignment is off or is it the tire swap.

not in the least. camber is a suspension angle, tire size has nothing to do with it.

Maybe they left something loose on the alignment. Before the alignment the car pulled to the Right. After the alignment, the car pulled to the right even worse. This was with the 18inch tires. Now with the 17's The car sometimes pulls hard to the left and sometimes to the right. I'm not sure what to think. I even pulled over on the side of the road thinking I hadn't tightened the lug nuts.

not in the least. camber is a suspension angle, tire size has nothing to do with it.

Oh yeah, this also implies the vice versa of not needed an alignment when upgradiing to larger wheels and tires. I really need to know because I'm either going to buy a pair of auto cross tires for my rear on my 17 inch wheel. Preferable or buy some for my 18 in wheels.

I've had an alignment done with 245/50/16 all around and 275/40/17F // 315/35/17R. My alignment guy wondered why I brought it back. Specs came out near identical as the last time he put it in.

Old + 7 inch tire = less traction