Some of us may think of ourselves as hard cases, but I mean those tough plastic boxes for carrying delicate stuff.
I bought a case to carry my reflex nikkor and some accoutrements, but I found using a shoulder strap to be too uncomfortable. So I did a bit of research on carrying systems to convert a case into a backpack. I came up gold with the Baggex conversion system. I bought mine on Amazon, but it also on eBay. $55, free shipping.
I am very impressed. My B&W case is at the smallest end of the range of suitable cases, but it still works.
Sorry if this is old news for some people, but I really wanted to share this cheap, and good, product.
https://www.amazon.com/dp/B07QJX1K8H?psc=1&ref=ppx_yo2_dt_b_product_details