When I started off with my Canon 1000D Digital SLR back at Christmas 2009 I bought a small bag that carried the camera, spare battery and lens brush. The following Christmas I got the Canon EF-S 55-250mm lens which still fitted in the bag comfortably.
In 2011 I bought the Sigma 150-500mm lens. For a while I carried this around in the box-like case it came with but this meant that I did not have a way of protecting/carrying it when it was on the camera. I therefore bought a big shoulder bag but I found that this was uncomfortable on long walks even though it had straps to carry it on my back.
I therefore spent a while looking at alternatives and finally bought a Lowepro Flipside 400 AW backpack. I have been very pleased with this but it was a while before I realised that one of the reasons for the waist strap was to allow you to take the straps off your shoulder and swing the bag round to the front, open it and swap lenses etc. without having to take the bag off and put it down somewhere.
I now use it to carry everything other than my second tripod.
The only downside I can think of is that the tripod fits to the front of the bag and the top strap tends to pull it against the bag and squash things up a bit. If the strap is not tight, or if I use only the middle strap then the tripod leans back and spoils the balance when walking. It might be better if the tripod was fitted to the side of the bag so that the weight is closer to your back. I have now started carrying the tripod on the side of the bag.
So, either inside this, Lowepro Flipside 400 AW Backpack
or strapped to it, I fit all this –
Canon EOS 1000D replaced with a Canon EOS 7D in 2012
replaced with a Canon EOS7D MkII in 2018 at the Photography Show
replaced with Canon EF-S 17-55mm f:2.8 USM
with Hoya 58mm UV Filter fitted to protect the lens. I no longer use filters to protect lenses, I fit the lens hood ASAP as protection.
This filter is not normally fitted due to increased chance of “banding” on out-of-focus lines. Perhaps this is as a result of going for a cheap one. I may post about this sometime. I have noticed it on many wildlife photos on flickr and it is certainly not limited to this lens. The lens hood is deep enough to protect the lens from accidental touching. Maybe I will get the Sigma 86mm filter sometime.
LCD Display Wireless Remote
(mine is not on Amazon now but this looks like an update to it)
Spare battery for the remote release transmitter – bog standard AAA batteries.
Spare battery for the remote release receiver
Nikon binoculars replaced with Opticron 8×40
– essential when out in the evening along river banks.
Self sealing thick plastic food bag to keep the insect repellant in – I don’t want that leaking over any of the contents of the bag or even leaking on to the bag itself.
A litre bottle of water in a side pocket
Tripod seat This is something I only occasionally take with me.
Collins Bird Guide
I have occasioanlly squeezed my ASUS netbook in there too with a length of network cable and a pair of USB to CAT5 adapters that allow me to connect my camera to the netbook via USB but with the wire between them being readily available network cable. I have yet to use this in anger but it does work.