Time for our second guest post – this is another one written by my dad, for use when he’s teaching digital photography courses. I’ve done a bit of editing to bring it up to date, so any typos are probably my fault…
Digital cameras are totally dependant on a source of electrical power and the more facilities and functions that a camera has, the more electrical power it will require.
Web cams may contain batteries so that they can function away from the computer but are more likely to draw their power from the USB socket.
At the cheaper end of the digital camera market, many cameras take AA or AAA batteries; these can be non-rechargeable or rechargeable but check your cameraâ€™s manual as to what types are advised (rechargeable batteries deliver a slightly lower voltage and some cameras may not work with them – almost all do now, but it’s worth checking).
Non-rechargeable types are either zinc carbon (cheap but with little staying power) or alkaline batteries which will deliver a higher current, when required, and work for longer. Always carry a spare set although they are widely available provided you are close to a suitable shop.
Rechargeable batteries, of AA and AAA (and other) sizes, are available in two common types â€“ nickel cadmium (NiCd – pronounced â€˜ny cadâ€™) and nickel metal hydride (NiMH). NiCd are a little cheaper although there is not a lot of difference.
NiMH are generally better, having a higher capacity (they can work for longer) and suffer much less from â€˜memory effectâ€™. They are also available in a range of capacities â€“ the higher the better although they will be more expensive. NiMH capacities are measure in mAh (milliamp hours) and whereas 1000 mAh was a good AA battery a few years ago, 2400 mAh and higher are now available. Always carry a spare set since these batteries are less widely available and need charging before use. Your spare set could be alkalines.
The â€˜memory effectâ€™ occurs when rechargeable batteries are partially discharged and then recharged rather than being used until â€˜flatâ€™ and then recharging. The battery can â€˜rememberâ€™ its smaller discharge-charge cycle and this then becomes the norm, reducing its usefulness. Always try to run NiCd rechargeable batteries completely down before recharging although an occasion â€˜top-upâ€™ is unlikely to cause a problem. NiMH and Li ion batteries are fine with being partially discharged and recharged regularly.
Lithium non-rechargeable batteries are used in some, usually more expensive, cameras. They are available in special camera sizes (2CR5, CR123A etc.) and AA size from some outlets. They are expensive but do have a high capacity and are often called lithium photo batteries.
Cameras which are particularly compact or which draw a lot of electrical power are usually supplied with a lithium ion (Li ion) battery. These are rechargeable and have a very high capacity for their size. They are also widely used for video cameras. A lithium ion battery may be unique to your camera and they are quite a bit more expensive than the other types. They are also only available from specialist retailers and may need to be ordered. If you are likely to use your camera for extended periods such as many times in one day, a spare battery is well worth considering. Spare Li ion batteries are expensive but shop around and seriously consider buying an independent make rather than one by the manufacturer of your camera â€“ they can be as much as 50% cheaper but still expect to pay Â£10 – Â£20.
Cameras that take these types of batteries are becoming more and more common now – even towards the lower end of the market, AA and AAA batteries are becoming uncommon.
Charging batteries may be done with them in the camera (sometimes inconvenient if you want to continue taking pictures) or in a separate charger (something else to take on holiday) or both options may be available.
Some cameras may also have a mains adaptor (supplied or as an option) which can be used to save battery power, and avoid the risk of the camera shutting down, when transferring your images to the computer.
If you want to know more about batteries, visit BatteryUniversity for comprehensive information and guidance.
Non-rechargeable â€“ alkaline are best unless you can use lithium photo.
Rechargeable standard types (AA, AAA etc.) â€“ NiMH are best.
Rechargeable non-standard types â€“ Li ion are best.
Examples in photo, top to bottom… Alkaline (AA), NiCd (AA), NiMH (AAA), Lithium photo (2CR5) and Li ion (Canon specific).