budget doesn't really matter within reason. i'll just save till i have enough. i'd rather buy something decent for a bit more, rather than something shit, which is cheap.
what's something to look out for in terms of lenses?
There are heaps of different fields of engineering. It's abojut designing things, to benifit society I guess. Have a look at various Uni websites to read up on the different types, and see what you like.
And yes, lots of maths.