I remember when I got my first DSLR in 2012. I set it in manual mode and forced myself to learn how to manipulate the settings to get the exposure I was looking for. Exposure is a combination of different settings with your camera. The settings you need to learn and understand are Aperture or F-Stop, ISO, Shutter Speed.
The lower the number the wider the diaphragm is, meaning the hole is bigger. Which lets in more light and reduces what is in focus. So if I want to take a picture of a person and I want the background to be blurry and have them in focus I would want to use a lower F-Stop such as 1.4-3.2. Now you can get away with a slightly higher F-Stop to isolate a subject if you have a zoom lens such as a 70-300mm and you are at 300mm. A wide aperture also comes in handy for photographing macro subjects such as flowers, which helps to isolate the subject. Sometimes to get everything in focus instead of changing the aperture you just need to select different focal points on the flower and blend in photoshop to focus stack your subject. A low aperture also comes in handy when photographing at night. With the wider hole caused by the diaphragm on a lens, you allow more light to reach the sensor of your camera.
ISO controls the sensitivity of the sensor in your camera. It also can create noise in your photos at higher settings. Low ISO is known to reduce the noise and allow for a sharper image. Sometimes you need a higher ISO to get the right exposure. For example in lower lighting situations such as when it is cloudy and you need to stop motion, you will need a higher ISO to get your shutter speed fast enough to stop the motion so it doesn't blur. Another time you will need to change ISO is for nighttime photography. Because there is less light you will need your sensor to become more sensitive to pick up more of what little light there is.
Shutter speed is an amazing part of your exposure. Shutter speed relates to how long your sensor will gather light to create your exposure. The longer the exposure the more light will be let in creating a brighter image. For example, 1" or slower is a slow shutter speed. The faster the shutter speed the less chance light has to get to the sensor of your camera. For example, 1/500th is a fast shutter speed.
A long exposure can come in handy for nighttime photography allowing you to capture details of the stars and night sky, along with allowing the foreground at night to be revealed. A long exposure is also the magic setting to blur water and make it smooth like what you would want in a waterfall photo. Think of it this way, the water is in motion for the entire say 5 seconds you have your shutter speed set for. Allowing the sensor to record all the movement of the water for 5 seconds, making it soft and smooth.
Now in reverse say you want to stop action. I like to go by the settings of my lens focal length or mm. So if I am at 500mm my shutter speed should be at least 1/500sec. Although I prefer to go slightly faster than the minimum just to make sure all action is stopped.
If you increase shutter speed, and it is to dim, try increasing your ISO, but if you would like to keep the noise down, you can try widening your aperture, aka lowering your F-Stop.
If you have any questions please feel free to contact me and I would be happy try and help you better understand exposure. Once you learn how to manipulate the settings on your camera to create the feeling you want to capture it all becomes second nature. That way when you are in the field instead of thinking F-Stop this, ISO that Shutter Speed this, it will just come naturally to you. The camera becomes an extension of who you are allowing your mind to be completely and artistically in the moment. Remember to practice anywhere and everywhere you can. In the beginning, it will be very technical and you will think about it a lot. To this day I still think about it, however knowing my camera and how to create an exposure frees my mind to always be in the artistic state of mind while in the field. I hope this helps and happy photographing!
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