One of the rules of P4M regards animals in enclosures - as defined in Submission Guidelines "Pictures of animals in cages or enclosures will get declined, they just don't sell . . ."
However it doesn't take much of a wander around the site to realise that a heck of a lot of animal images clearly must have been taken in cages / enclosures. So what's the trick?
It may simply be a question of finding the angle - I have many images of animals in my portfolio - a lot of them were taken of either 'free to roam' - like the deer images I have, 'free flying' as part of displays and, dare I admit it images of otters, elephants, tigers etc. that most clearly aren't famed for freely wandering about the high street.
So if you are going to take images of captives how do you go about it?
Normally it is a question of angles. Zoos are I'm pleased to say getting better at providing more natural looking environments. So often careful choice of where to stand, a little care over your angles and possibly a touch of post editing can get you a shot that has the potential to sell. Sure - we know it was likely to be in an enclosure of some sort - but the buyer can see no trace of it.
Then comes glass. Glass is a mixed blessing in as much as it often allows us photographers to get very close (sometimes too close) to animals with sharp, pointy bits - like tigers. The trick with glass is to get right up to it. Use your lens hood to help shield reflections, if possible get someone to stand over / behind you to block out even more. I keep meaning to make a simple black cloth with a couple of suction cups on it to stick to the glass and drape over the lens / camera - maybe one day.
And finally cages with bars / mesh. If your subject is a little way in to the enclosure and you are able to get right up to the cage choosing a shallow depth of field around the f5.6 mark will get rid of them. Try to get the centre of your lens between the bars / grid and there's a really good chance it'll be so far out of focus that it vanishes from the image entirely.
Finally of course be aware that attractions may have limitations to use, some for example outright ban commercial use (London zoo amongst others), some insist that you buy a licence, some ask for a credit (Tropical Birdland being an example of this), others either have no published policy. A rare few - Paignton zoo and Dartmoor zoo are very happy for you to use them and indeed recognise the value of the free publicity.
Please be aware that if you are thinking of ignoring the 'no commercial use' conditions of entry (at your own peril) many zoo animals have unique markings - and indeed some zoos have unique animals, Edinburgh and the Giant Pandas, Yorkshire Wildlife Park and Victor the only Polar Bear in England.
So in closing - make sure that if you do photograph animals in enclosures a few simple tricks may be all you need to make a saleable image.