Canon EYECUP ER-KE

I was skeptical about the size at first, but the asymmetrical shape actually makes vertical shooting much more comfortable. It stays put on the R5 Mark II without any slipping.

The larger asymmetrical design really makes a difference when I'm shooting portraits vertically—my eye doesn't slip off like with the standard cup. It fits snugly on the R5 Mark II and blocks out glare perfectly.

I was skeptical about the asymmetrical design at first, but it actually makes framing vertical shots much quicker when I'm wearing glasses. The larger size blocks out side light perfectly without being uncomfortable against my eye.