LOKSAK aLOKSAK Large Waterproof Bags 12 x 12, 13 x 11, 16 x 24" (Multi-Pack)

Storage, Dehumidification, Custom Weather Cover

I've used LokSaks for many years for other purposes. I recently realized they also make great bags for transporting camera gear in wet/dirty conditions, when dehumidifying bodies and lenses after wet exposure (seal gear in a bag with a with a desiccant pack), and they can even be fashioned into a working rain cover with a little creativity and self-adhering Velcro (if one is cost conscious). Align the bag seams vertically, push the lens+hood into the bottom corner tightly and trace the cut line with a Sharpie. Cut the hole, then use Velcro on the outside edge to create an adjustable collar. The 12x24 bags are fine for storage, transport, and drying equipment, but you really need the 16x24 bags to conveniently fit a large body and up to a 100-400mm lens plus extender with plenty of room to get your hands in the drooping  “zipper edge” of the cover. The Loksak fabric is durable enough to clamp the lens foot into the tripod mount over the bag. It's not a custom fit, but you can see ALL camera displays and reach all camera/lens controls. The only real downside is the extra material (which I rolled up and secured with gafftape will create drag if you're working in a high wind environment.