What's the diffences between digital cameras that uses AA batteries and its own battery packs?

I've noticed that some digital cameras uses its own battery packs especially the portable ones and others advanced models like EOS uses 4 AA's batteries? Why is that? Are there any difference when it comes to performance?

Taking into consideration that I use rechargable AA batteries not the disposable ones...

Battery packs are more effective over time (while AA rechargeable batteries maximum capacity starts decreasing after a few recharging cycles). Also the recharging units work faster (while in the AA recharge case, the fast recharging units contribute tremendously on the thing above, batteries losing maximum capacity).

This is why advanced SLR systems provide a dual option: the camera uses a battery pack, but a grip unit allows for either extra pack or AA rechargeable.

Pack are overall lighter and better fit for travel, they are not as easy to lose as AA's.

However, regular battery packs don't pack a high a capacity as the average AA rechargeable (around 1700 mhA compared to 2500mhA for the AA, on the average) but they are also cheaper.

Well having it's own battery pack is cheaper and more convienent...

digatal camera r digital and much better=P

The one with tis own Battery Packs are slimmer then the one that uses AA batteries.

There is no difference when it comes to performance.
The cameras that have AA batteries have to be changed every now and again (referring to the batteries) as they run out of juice. The cameras with their own battery packs just need to be plugged into the wall and charged up - which is cheaper yet more time consuming than the cameras that take AA batteries.

I don't know if I am understanding you completely but I think it's because you can recharge portable ones.

the batteries that come with the camera are better quality than AA

battery packs are litium ion and will last generally better than the best AA's

AA's are best if you use rechargables and get a recharger

Usually the one's that have their own battery pack are made from a different chemicle and last longer than 1.5v batteries that you buy from any shop and dispose of once they've ran out. but you can also buy rechargable batteries for them which will have more or less the same good quality of cameras that come with their own battery packs

dont know

As far as the quality of the pictures the camera will be able to take, there is no difference. You will just have to decide which fits your photography style more. As others have stated, the smallest, sleekest, thinnest cameras will have there own rechargeable battery pack as a space saver. In the long run a camera that uses a rechargeable battery pack will probably be cheaper if you use it often because batteries get expensive. However, if you need your camera (to be on) for long periods of time, you might be better off to go with something that you can simply replace the batteries on. Compact digicams tend to pull juice out of batteries quickly and if you aren't near a wall outlet when that happens, your camera is useless. If, on the other hand, you mainly want to take snapshots of friends or parties or events or such, a sleeker camera might be better. Remember you can always buy rechargeable AA batteries as well.

Some battery packs will allow the camera designer to create a slimmer package. The cameras that allow you to use either a battery pack or AA batteries do so for you convenience. While the battery pack will usually last longer than alkaline or ni-cad AA's, in a pinch, you can purchase AA's almost anywhere in the world.

The battery packs are usually lithium ion. I've noticed with my digital camera that's only a couple of years old, that I have to replace the batteries ALL THE TIME!! It's such a hassle! If I would go out for the day to somewhere cool, I would bring 6 batteries (it takes 2 at a time) and usually go through 4. I'm so happy I got a camera that has it's own battery!

cameras which use AA batteries are cheap

the battery packs usually last longer
but, are more expensive