Is that the medium size? It looks plenty big enough for my purposes. I hadn't noticed the black wasn't pannier black until you had mentioned it though.
I've just gone and grabbed it and it might actually be a small :/
(and have now just realised you can change measurement units on the ortlieb website so apologies for measuring in inches, was just following their lead)
rain jacket, sunglasses, nuts, more I think. More than I thought it could take.
^ that's at maximum unfurledness