But yeah, it is a really awesome backpack. As my other two F-stop bags, the quality is top notch. The Guru is smaller than the Loka, and pretty much perfect for day trips especially in urban areas where you just need an extra jacket or something similar. As a day pack for use in the outdoors I don't feel that it's quite big enough, if you want to bring food, clothes and things like that. But if you take out the ICU (Internal Camera Unit) it would be, but for me that would be to go against the whole point of buying a camera backpack of this sort, but it's still an option though and easy to do.
For anyone not being familiar with F-stop bags, the following is a summary definition. Kinda...
All bags in F-stop's Mountain Series can be described as being empty shells, and then you use a separate camera unit called ICU (ICU = internal camera unit) that comes in different shapes and sizes.
This means that you can customize how you want your backpack to be depending on how much camera equipment versus other equipment you have or want to bring.
For the Guru I've chosen a Small Shallow ICU for my Fujifilm cameras, because I want to bring other things than just camera gear, bigger one would mean nearly no space left for other things inside of the main compartment.
An ICU has removable inner walls so that you can customize it, like camera bags normally have and are as good as any other that I've tried.
The Guru follows international luggage dimensions, but you can easily take out the ICU and bring it into the cabin if you would need to check in your backpack on a flight.
Well, on with the description of the Guru. In the main compartment (where the ICU goes) there's also a pocket that can be used to store an iPad or a smaller, maybe 13" MacBook or similar laptop (check F-stops website for exact info on that), or to hold a hydration system like Osprey or CamelBak. I have an Osprey Hydraulics 2L, but I haven't tried if it fits, I might do that eventually and update this review, but since I have this backpack for more urban use and not nature hikes, I simply haven't tried that. It should be used with the optional waterproof bag that can be bought and hung inside the backpack (for extra leakage protection). A special opening marked H2O where you pull the hose out and attach to the right shoulderstrap through some mesh and a velcro loop.
You've got an extra (large) compartment with different pockets to keep daily general stuff or extra batteries, cleaning cloths, filters and those things. There's also a key holder in there. On top of that there's an outer compartment to store, well anything, but would hold something like a rain jacket for example. In addition there are two exterior mesh pockets, one on each side where you can have water bottles or put down tripod feet into.