As promised, here are a few photos and comments about the Mindshift Firstlight 40L.
Bear in mind that this is the first and only rucksack/backpack I have ever bought so I cannot offer legitimate comparison to other makes.
I think it's great. It is expensive but overall I am very please with it.
The thing is quite large, but not ridiculously so, and whilst it holds all my current kit, it does have sufficient spare capacity for maybe an extra 3 slow lenses, or 1 fast and 2 slow lenses. That being said, I have shown the rain cover/ground sheet pouch stored inside the bag which is pretty silly of me as I would have to put the bag down to take it out! It makes more sense to place that pouch in one of the outside mesh pockets which would free up more room inside.
Realistically I will probably only get another one slowish 360 or 480 lens which will leave sufficient room for filters and the like. On the right-hand-side there is a bladder pocket which might make a nice store for the Lee wide angle hood. If I did manage (to afford!) to fill the thing I could always expand with the rather nice matching Filter Hive.
So far I have arranged it to accommodate the following:
Wilderness V 10x8 (positioned upside down as the locking screw knobs stick a little wide and fit the natural midpoint 'swell' of the bag)
Apo-Symmar 240mm f5.6
Dark cloth
Sekonic L-508 in pouch
Rain Cover/ground sheet in pouch
Wista loupe
2x 2-off double darkslides. Each pair in rather thick laptop sleeves with one sleeve inside the main compartment and the second in the front pocket
Cable release
Lens spanner/key
Gitzo GT2542 + GH2780QD

All of the above fitted pretty snugly but I think things would be a little easier by reducing to 3x DDS or getting less padded sleeves.
On the back it feels pretty good, after following the instructions to get the weight on the hips and not the shoulders, with the all-up weight at around 14.5kg (32lbs).
There are, of course, a load of spare dividers which will never be used so will need to be stored somewhere.
if anyone has any questions or wants more feedback after I have been for a hike with it let me know and I will do my best to answer as honestly as possible.

...Sweep

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