Digital cameras are 100% dependent on good batteries and unlike some film cameras there are no mechanical models.

Getting a set of batteries to last the day's shoot can be a problem but it need not be. More can be done before the shoot than carrying a spare set, particularly if they have not been properly charged.

Basically there are two types - disposable and rechargeable. Whichever the photographer chooses avoid cheap alternatives - they may not last the day! The more expensive are usually more reliable, particularly those bearing a recognisable name renowned for specialising in batteries, or those with the name of the camera manufacturer. Although it is unlikely they are made by them, a camera manufacturer is not going to add their name to a battery in which they have no faith.

Rechargeable batteries are normally more expensive, but worth the additional outlay. Recent developments now allow recharging at any time, it is no longer necessary to wait until they have run down. On a shoot lasting several days it is considered good practise to recharge the batteries every evening.

Depending on quality and reliability, rechargeable batteries will not last for ever. If they start to prove unreliable - replace!

Note: The quickest way to exhaust any battery is to leave an image displayed on the camera's screen! Also, turning a camera off and on repeatedly does not help, best to allow a camera to go into sleep mode whilst on a shoot.