I didn't know Ortlieb had a DSLR bag, I will look into that first and foremost. Thank you for that information.

Secondly, yeah, I might someday forego the DSLR but as of now, I've got the dubious title of Group Photographer, where everyone loves getting their picture taken. So this is something I definitely want to bring.

My backup options are:

#1- wearing the case strapped to my chest with a chest harness. Not crazy about this in the heat.

#2- wrapping the case in my sleeping bag in my Ortlieb rear pannier. I'm ultralight, as I mentioned, so my pannier has room to spare for such an endeavor, but I don't love stopping and taking 3 minutes just to access the camera.

I am going to try leather straps like what was mentioned over Velcro, or just webbing compression straps. I do want to be able to detach it to take it with me, so the camera never leaves my side. But the Ortlieb handlebar bag might solve everything.

Thanks for the responses, extremely helpful.