The Nova mini is Lowepro’s second smallest bag in the Nova line, just a bit larger than the micro. It is billed as a bag large enough for a camera with lens attached and a few small accessories. I found that with the size of the Olympus OM-1 I can fit that and a few small primes in to the bag. Its is cramped and can’t carry much, but it is the perfect bag if you are traveling light. I haven’t tried every combination so far, but the two setups that I’d likely to be loading in to it fit. I can fit an OM-1 along with a 24/2.8, 50/1.4 and 135/3.5. Alternately an OM-1, 28/1.8, 50/1.4 and 85/2 will fit. There is enough extra room that another small lens such as a 40/2 or other small prime might fit in that bag with either setup. You might be able to fit something like a 135/2.8 or 100/2 in the bag instead of the 135/3.5, but I don’t think that is likely due to the diameter of the lens. A 100/2.8 would definitely fit in leu of the 135/3.5 as it is the same size as the 85/2. There isn’t much room for a flash unless it is a smaller one, such as a T20 (my Vivitar 285hv will not fit)
In the front pocket there is room for a couple of filters, hoods, shutter release and a few rolls of film. I haven’t tested its limits, but it is only a bit smaller than the front pocket on the Nova 2 in which I can typically cram a 49mm and 58mm polarizer, 1ft shutter release, 3.3ft flash synch cable, 49mm hood and 6 rolls of film. I’d expect if I dropped the flash synch cable I could fit all of the same with 4-6 rolls of film in there. In the main body of the bag I could probably fit another 4-5 rolls, though it would make getting lenses in and out a bit trickier.
The bag has an all weather cover just like the rest of the Nova AW line. It covers the top and front of the bag, leaving the backside uncovered, though that rests against you and the material is water resistant as it is. The top of the bag also has a front zipper pocket which is shallow. I generally use it on either bag, but you could probably fit a small map or a filter or two in there (I do sometimes slip a cokin 2 stop split ND filter in there on the Nova 2, not sure if it will fit in the Mini). The inside top of the bag has a small zippered mesh pocket that can fit something flat, again possibly a couple of filters, map, etc. The one on the mini isn’t larger enough to be particularly useful, but the Nova could fit a small folded reflector in it.
My two main uses for the bag are for backpacking and for traveling light with primes. The later I pack my Sigma 28/1.8, Zuik0 50/1.4 and 85/2. For backpacking I pack my Sigma 24/2.8, Zuiko 50/1.8 and 135/3.5. It is especially nice for backpacking as the bag is very light and small. I can hang it off the side of my hiking pack with a carabiner and a short 3ft strap (so 18in when buckled to itself). It’s easy enough to reach to my side and pull the bag around to get the camera/lenses out so I don’t have to stop to get the bag/camera out of the top of my hiking pack when I go backpacking. For general light traveling it is nice because the bag is smaller and lighter than my Nova 2, which isn’t a large bag, but when you want to go light, smaller is better.
Lowepro has discontinued the old Nova AW line and in its place is the Nova 120-200 AW line. In it the Nova 140 corresponds roughly to the Mini. One of the major changes in the Nova line is that the bags have smaller/thinner front pockets, which isn’t terrible if you shoot digital, but for a film user it makes it harder to cram film cannisters in to the front pocket.