A hair tie
Obviously this is only really applicable if you have longer hair; even if you do manage to hold your hair out of every shot, it’s still very annoying!
A spare memory card
I keep an old 2Gb card in my purse (I’m English, I mean my wallet) ‘just in case’. It’s been used more than once!
An energy bar
If you’re in the middle of a shoot and everything is going perfectly, the last thing you want is to have to stop and eat (or start getting snippy with people because you skipped breakfast).
A bottle of water
See above but for drinking. The water is also useful if you need to add some droplets of water to something to give it an extra dimesnsion.
A macro lens
Even if you’re out with the intention to shoot a landscape or a wedding; a macro lens is great for an alternative view (and can be a great way of overcoming difficult lighting conditions such as harsh midday sun).
You never know who you might meet when you’re out shooting with your camera – even when it’s just snapshots with the family. You don’t even have to go to the expense of professional printing – I’ve seen amazing ones done using a home printer (and a dozen cards at a time is plenty).
I’m often screeching to a halt in the car because I’ve spotted something I have to photograph and and as such need to use arcane parking meters – having some coinage to feed them is very helpful! (And you can always use it to buy sweeties if you don’t end up parking anywhere).
Chances are you’ll either a) need to know how to get to somewhere or b) want to know where it was you were when you took that amazing photo, so a mobile device with GPS enabled, or even a paper map will be very handy.
There’s all sorts of scenarios where you’ll wish you had a way of writing something down – the email address of that photogenic stranger who you promised to send a JPG to, the name of the street with the cool graffitti that would make such a great backdrop for your next portrait session, George Clooney’s phone number… you just never know!
Just. In. Case.
Can you think of more? Is there something you just can’t be without when you’re out with your camera?