Choice of camera bag is a very personal thing and I alternate between 3 different bags depending on what and where I am shooting. Here is a breakdown of the bags I use and why.
So What Camera Bag Do I Use???
Requirements.
There are a few things that I need any bag to do as a basic requirement
Be comfortable to wear
Store my kit in a safe manner (hard for anybody to access)
Protect my kit (well padded)
Waterproof
Flexible
Well made
No too flashy
Suitable logical storage for the bits I need to have with me
Small Option Bag: 11 Litres
Used For: Restricted luggage travel i.e. Flight option, Weekend trips where I want to shoot with minimal kit.
What's in the bag:
Nikon D850
12 - 24mm
24 - 70mm
70 - 200mm
Spare Batteries
Spare cards
Those odd bits that you carry with you (See what odd things I carry with me - LINK)
Overview This is a small bag that is carried over one shoulder and a key aspect of the design is the ability to rotate the bag around you body and access your kit without removing the bag and this works well. It does create a slight issue that you carry the weight on one shoulder. An added bonus of rotating the bag is that it changes the orientation in such a manner that you can use the bag as an arm rest while shooting for extra stability. Getting the kit listed into the bag is a tight fit but it can be done. The waterproof cover is neatly integrated into the build of the bag and stored in the base out of sight. It does become a little unbalanced however if you fix a tripod onto the bag however this is dependent on how big a tripod you need.
Medium Option: 17.2 Litres
Used For: Serious Photo trips , London trip, Weddings, Commercial shoots, Standard go to choice
What's in the bag:
Overview This is a mid sized bag that is carried via two shoulder straps and is accessed via the rear panel against your back which keeps your kit secure. In theory if you have the waist belt fastened you can rotate the bag around your waste for access however I have generally found this difficult and uncomfortable. Getting the kit listed into the bag is easy and as can be seen it offers good flexibility depending on what I am shooting that day. The waterproof cover is neatly integrated into the build of the bag and stored in the base out of sight. Side pockets are good for a water bottle, attaching a tripod is easy and I find that I can fix a light jacket across the top of the bag. One thing I have noticed is that my bag is quite old now and the newer model does not appear to be as robust?
Large Option: 36 Litres
Used For: Landscape Photography, Complicated shoots, Storage of kit at home
What's in the bag:
Nikon D850
12 - 24mm
24 - 70mm
70 - 200mm
Spare Batteries
Spare cards
Those odd bits that you carry with you (See what odd things I carry with me - LINK)
Two from this list of lenses
85mm prime
105mm prime
50mm prime
Irix 11mm prime
Nikon 300mm prime
Mindshift Filter Hive (for storage of filters) LINK
Mindshift memory Card Wallet LINK
Lunch
Spare tops/waterproofs
Overview This is big and holds a huge amount of kit. It is amazingly comfortable to wear and very adaptable in design as sections can be removed. The build quality is exceptional and the way it integrates with the other Mindshift kit is very well considered. You need to take care that you don't put all your kit in and make it too heavy. The versatility means you can take anything you need. The waterproof cover is not integrated into the build of the bag and stored in a separate pouch but is small and as such not an issue. Side pockets are good for a water bottle, attaching a tripod is easy. The section of the bag that contains your kit can be removed and carried separately and is regulation flight size so you can put the outer cover in the hold and keep you expensive kit in the cabin with you. For my full review of this bag see LINK
I hope this helps your bag selection and gives some real insight into these options.