Astrophotography
Battery Charger Speed
NiMH (Nikel Metal Hydride) vs. Nikel Cadium (NiCD) Batteries
Independent Channel Chargers vs. Non Independent Chargers
Learn About Digital Photography from Hewlett Packard
Step Up Adapter Ring vs. Step Down Adapter Ring
Telephoto Lens
Wide Angle Lens

Astrophotography
To accomplish astrophotography with your digital camera easily, take a look at these special adapters.

Battery Charger Speed
To determine the approximate time it takes for a particular charger to charge a particular battery, take the mAh of the battery and divide it by the output mA of the charger (e.g. 2300 mAh battery divide it by charger output of 750mA = 3.07 hrs). That calculation is going by a completely drained battery. Typically, by the time you need to recharge the batteries, they will still have approximately 1/4 to 1/5 power left, so the recharge time is usually quicker than the calculation above.

Independent Channel Chargers vs. Non Independent Chargers
Non independent channel chargers typically have 4 battery slots and two lights, requiring you to charge at least 2 batteries at a time. Some may even have a switch that you need to set between charging 2 or 4 batteries. If one battery is completely drained, while the other is half way charged, when the half way charged battery is fully charged, the completely drained battery will only be half way charged. With the benefit of independent channel chargers, since each battery slot is its own channel with 4 lights, you can charge either 1, 2, 3 o 4 batteries at a time. So, it does not matter if one battery if fully drained, while the other is half way charged, they will all be charged fully in the end.

Learn About Digital Photography from Hewlett Packard
The ability to change your point of view when taking a picture is one of your most powerful creative controls. Today, most point-and-shoot digital cameras have one intrinsic limitation: They have only one lens. Many cameras now come with good built-in zoom lenses. But when you want to expand your creative power (to capture a dramatic wide-angle perspective, for example) that's where add-on lenses come in, and most cameras will require a lens adapter ring or tube. Visit Hewlett Packard to get more information on this subject.

NiMH (Nikel Metal Hydride) vs. Nikel Cadium (NiCD) Batteries
NiCD has a memory effect, where you should discharge it completely first, prior to charging it fully, or else, it will not hold a full charge that the battery is capable of. NiMH does not have a memory effect, where you can charge it at any time, without needing to discharge it first.

Step Up Adapter Ring vs. Step Down Adapter Ring
To determine is you need a step up or step down ring, you always start from the camera side, to the side of the accessory that you are trying to attach the camera to. (e.g. If the camera has a 52mm filter thread, and you are trying to mount an auxiliary lens that has 58mm mounting threads, you will need a 52-58mm step up ring, or vice versa)

Telephoto Lens
A telephoto lens is to bring far away subjects closer, without you having to move closer to the subjects. To figure out how much a particular telephoto lens will increase the magnification of the camera, just take the optical zoom power of the camera and multiply it by the telephoto lens magnification (e.g. Camera 8x optical zoom X 2x telephoto lens = 16x optical zoom). To figure out the mm of the lens, each 1x optical zoom is equivalent to approximately 35mm (e.g. If you have a total of 16x optical zoom, multiply 16 by 35 = 560mm). If you are looking for a even higher power zoom capability, as an example, let's use the add-on 8x telephoto lens (Sharpshooter 8x and LX 8x), if your camera have a 10x optical zoom, by adding the 8x telephoto lens, which will turn it in to an 80x optical zoom, which will be approximately 2800mm equivalent. Now, that is some MAJOR zoom for capturing distant subjects, great for birds, other animals that you just are not able to get close enough to, surveillance, etc. As you may have noticed, we only go by optical zoom, and NOT digital, since digital is only software enlargement, where the camera takes the center of the image, and enlarging it by the power you specify, that is why they do not come out as clear/sharp as optical zoom. Using digital zoom, is pretty much the same as taking the picture using optical zoom only, transfer the picture to your computer and opening it with your photo editing program, then enlarging it within the software, which again, does not look sharp at all.

Wide Angle Lens
A wide angle lens allows you to squeeze in more of the subject, without having to move back. Useful for landscape, cityscape, small rooms, etc. How much more area will a particular wide angle lens allow you to squeeze into the frame? (e.g. First, the lower the number, the wider the lens is. So, if a lens shows .75x, that will approximately allow an extra 50 percent more of the scene, while a .5x will be 100 percent, and so on)