Lighting, EXIF, Focusing

Lighting is very important. Indoor digital photography is the most difficult. Outdoor pictures are usually pretty easy. 

Digital cameras have a tough time dealing with fluorescent and incandescent light. The more natural light the better. The better the lighting, the higher the f-stop your camera might use. The higher the f-stop, the greater the depth of field thus giving you better focus throught your picture. 

I always use flash indoors unless there is a complelling reason not to. Make sure you do not try and take a picture of something that is further away than your flash can reach. 

As I understand it, auto focus needs light to focus. With most digital cameras, low light will cause your auto focus to be less accurate. Some of the newer cameras, when having trouble focusing, will send out a burst of light from the flash to help with the focusing process. As others have said, in low light, you will always want to try and use a tripod and manual focus. If you can manually set the shutter speed the tripod is not as important.

I have also found that sparkly lights such as lit houses or a Christmas tree may give you focus problems. All of these little points of light seem to cause some cameras to misunderstand the lighting conditions. Higher shutter speed and f-stop may help this. 

Most digital cameras these days allow you to depress the shutter button half way to to set the auto focus and the auto camera settings like shutter speed and f-stop. You can then move the camera to a final composition and snap the picture. This works real nice in some cases. 

The newer cameras use EXIF.

Exchangeable Image File: the file format used by most digital cameras. For example, when a typical camera is set to record a JPEG, it’s actually recording an EXIF file that uses JPEG compression to compress the photo data within the file.

Within these EXIF files, the camera stores bunches of information about the individual photos you take. Most newer digital photo editing software allows you to view the EXIF information about your photos. Here is an example of the EXIF information on a photo from my camera. 

Make - Canon
Model - Canon EOS 10D
Orientation - Top left
XResolution - 180
YResolution - 180
ResolutionUnit - Inch
DateTime - 2004:03:21 10:16:41
YCbCrPositioning - Centered
ExifOffset - 196
ExposureTime - 1/30 seconds
FNumber - 8.00
ISOSpeedRatings - 100
ExifVersion - 220
DateTimeOriginal - 2004:03:21 10:16:41
DateTimeDigitized - 2004:03:21 10:16:41
ComponentsConfiguration - YCbCr
CompressedBitsPerPixel - 3 (bits/pixel)
ShutterSpeedValue - 1/30 seconds
ApertureValue - F 8.00
ExposureBiasValue - 0.00
MaxApertureValue - F 5.60
MeteringMode - Multi-segment
Flash - Not fired
FocalLength - 300 mm
UserComment - 
FlashPixVersion - 100
ColorSpace - sRGB
ExifImageWidth - 3072
ExifImageHeight - 2048
InteroperabilityOffset - 2330
FocalPlaneXResolution - 3443.95
FocalPlaneYResolution - 3442.02
FocalPlaneResolutionUnit - Inch
SensingMethod - One-chip color area sensor
FileSource - DSC - Digital still camera
CustomRendered - Normal process
ExposureMode - Auto
WhiteBalance - Auto
SceneCaptureType - Standard 

This might help with some glossary terms: http://www.microsoft.com/windowsxp/digitalphotography/glossary/default.asp