Whether inside or outdoors, parties often involve moving subjects, so it's important to make sure that your camera is set to the best party photography settings.
To capture the fast-paced movement of a dance floor without flash, you'll need to ensure your shutter speed is fast enough. Shutter priority (Tv) mode enables you to specify the shutter speed, while the camera selects the aperture and ISO for a correctly exposed image. A minimum shutter speed of about 1/160 or 1/250 sec is best for movement, although faster movement may mean you need to go up to 1/1000 sec. If you're in Manual (M) mode, make sure your aperture is relatively wide open (lower f-number) to compensate for the faster shutter. Start with Auto ISO, but if your image is too dark, try setting a moderate or high ISO, such as ISO 3200 or ISO 6400.
If the party is more of a sit-down gathering, Aperture priority (Av) mode enables you to select your depth of field. In calmer environments, you can assess your camera settings based on the light available. For example, a 1/80 sec shutter is fine for slow-moving portraits or group photos – it will allow more light to hit the sensor, giving you some leeway with your aperture and ISO values.