Exposure is the combination of shutter speed, aperture, and ISO. Depending on the light in your environment, these values will change in order to achieve a balanced exposure. When your camera is set to Auto, the camera makes the decisions for you depending on the reading from its lights sensor. However, if you are on Manual, Aperture Priority, or Shutter Speed Priority, it is important how these three values interact and relate.
Shutter Speed: The amount of time that the shutter is open. A camera has a shutter that blocks the light from the sensor. When a shot is taken, the shutter opens for the specified amount of time. The longer the shutter speed, the more time there is for light to be exposed to the sensor.
Aperture: Controls the depth of field, in other words, the range of focus. With a small aperture, only a small distance remains in focus whereas with a larger aperture, more of your field of view stays in focus.
ISO: Light sensitivity. Depending on the level of light you have in your environment when you are shooting, you will want to adjust the ISO to reduce the amount of noise that ends up in your photo.
Putting it all together! Exposure
Aperture Priority (AV) On this setting, the camera chooses the iso and shutter speed values depending on the aperture that you choose. Use this when you are trying to achieve a specific depth of field. Usually when you want the background and foreground to have different levels of blur. - portraits - architecture - nature Shutter Priority (TV) The camera selects the aperture and iso allowing you to control the shutter speed. Usually this mode is used when your subject is in motion and there isn't enough time to set all three manually for each shot. - sports - long exposure - low light settings
Long exposure photos are taken with a long shutter speed. With the shutter speed open for a long time, any movement that happens in the shot will be preserved in the image. This often produces a blurry look for moving objects in the frame while the still objects remain clear.
1. Star Trailing
2. Waterfalls
3. Cars at night
4. Ocean
5. Sky/Clouds
Reflectors can help a photographer manipulate the light source by changing its direction, providing a specific "glow" and adjusting its strength. This technique comes in handy when you are trying to set up a photograph and are dealing with natural or studio light.
White: reflect light, soft light
Silver: reflect light, harsh light
Gold: reflect light, warn glow
Black: absorbs light, creates shade
Semi-transparent white: diffuses light, creates a softer light source
Across from the light source: light is redirected back to the subject
At an angle: varied amount of light that gets reflected
Parallel to the ground: for portraits to fill in and remove unwanted shadows
source: https://expertphotography.com/how-to-use-light-reflectors/