Ive been shooting with my 90D for about three years now and honestly I love the thing for wildlife and sports because that extra reach is great but man I am hitting a wall with my landscape stuff lately. I just booked a trip to Glacier National Park for next month and I realized my gear is seriously lacking on the wide end. I mostly use my nifty fifty and the 70-200 f/4 for everything but when I tried to do some interior shots for a friends house last week I realized my widest lens is the 18-135 kit lens and it just felt... soft? Or maybe just not wide enough. I always forget about the 1.6x crop factor until Im actually standing in a cramped room or looking at a massive mountain range and realizing I cant fit the peak in the frame without backing up into a lake lol.

Im looking for something thats actually sharp and maybe fast enough to try some Milky Way shots while Im out there. I was looking at the Canon 10-18mm because its cheap and has IS but the build quality looks a bit like a toy and Im worried about the f/4.5-5.6 aperture for night stuff. Then theres the Tokina 11-20mm which everyone talks about for the f/2.8 but Ive heard they flare like crazy when the sun is in the corner of the frame. Has anyone used those on a high-res sensor like the 90D? Im worried that 32.5 megapixel sensor is gonna show every single flaw in an older lens design. My budget is around 600 bucks maybe 700 if I stretch it but Id prefer to buy something that stays in my bag for a long time.

Should I just stick with EF-S glass or is it worth looking at a used EF lens even though itll be huge and heavy? I just need something that actually feels wide and doesnt turn the corners into mush...