Before looking at the manual settings on your camera its important that you understand exposure. Exposure in photography determines how light or dark an image will appear when it’s been captured by your camera. When an image is correctly exposed it will look like what you saw with your naked eye.
- Overexposed – A photograph is overexposed when it is too bright (too much light).
- Underexposed – A photograph is underexposed when it is too dark (too little light).
Exposure is determined by three camera settings: aperture, shutter speed and ISO and is commonly referred to as the “exposure triangle“. You need the right amount of the three settings to allow the correct amount of light in to capture a good image. How you chose to manipulate and priorities these three settings however is what will allow your creativity to shine through in your photographs.
Aperture controls the size of the hole (in the shutter opening) where light enters the camera. The larger the hole the more light gets in, the smaller the hole the less light. Aperture is measured in f-stops and when you increase or decrease the f-stop you either double or half the size of the hole. So f/2 is half of the size of f/2.8 and f/2.8 is half of the size of f/4. Where it can get confusing is that a small f-stop (f/2) is a larger hole (more light) and a large f-stop (f/22) is a small hole (less light).
Why does Aperture matter?
Changing your aperture changes your depth of field (DoF). This is important in photography as it allows you to control how much of your image is in focus relative to its “depth” in the photo. If you shoot “wide open” with a low f-stop of say f/2, you will have a shallow depth of field so only your foreground will be in focus with the background blurred. You will see this a lot in portrait, food, and macro photography where the background is blurred. This is not so good in landscape photography however, as you want both the foreground and background in focus so a larger f-stop like >f/11 will be more suitable.
Good example of shallow DoF, the background which includes a shed door is blurred
Small f-stop e.g. f/1.4-f/4 = MORE LIGHT = shallow DoF (only foreground in focus)
Large f-stop e.g. >f/11 = LESS LIGHT = large DoF (foreground and background in focus)
Aperture is the hardest of the three components of the
exposure triangle to wrap your head around. So expect it to take some time and practice to understand it.
Understanding Shutter Speed
Shutter speed controls the amount of time the shutter / hole is open to allow light to hit the sensor and is measured in fractions of a second. Similar to aperture, shutter speed doubles with each change so you’ll likely see numbers like 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8 etc on your camera’s shutter dial. This ‘doubling’ is important to keep in mind as aperture settings also double with each change. So if you increase your shutter speed by one stop and decrease your aperture by one stop you should have a similar exposure level.
Why does Shutter Speed matter?
Shutter speed captures motion in an image by either keeping a moving object in focus / sharp or blurring it. A quick shutter speed will keep a moving object in focus, whereas a slower shutter speed will blur a moving object. You will want to make shutter speed a priority when movement is important or if you have low light and no tripod.
- 1/500 second or faster – keeps a moving object (e.g. dog) in focus
- ½ second – blurs waterfalls or streams
- 1 second – blurs leaves
- 8 seconds – blurs traffic
A quick shutter speed freezes the water in motion.
ISO controls the sensitivity of the cameras sensor to light. The lower the ISO the less sensitive your camera is to light and the finer the grain. At higher ISO’s you will start to get grain or “noise” in your image. People are often afraid to use higher ISO settings but cameras are getting much better at handling higher ISO’s of 6400 and above.
Higher ISO settings are often used in low light to maintain faster shutter speeds. For example when shooting sports in an indoor stadium or when you’re out taking street photographs at night. In these situations you have one of two options to get the correct exposure – slow down the shutter speed and introduce motion blur, or increase the ISO and introduce some grain. If you need to freeze motion then there is only one correct option – keep the fast shutter speed and increase the ISO. If motion is not present or if you want to blur the motion (e.g. water) then you can increase the shutter speed and keep the lower ISO. Note it’s easier to correct grain in post processing than it is to sharpen an out of focus object.
Tip: Your camera should have a setting where you can control the parameters for the auto ISO function. For example you may set it so that auto ISO cannot go above 6400.
Putting it all together:
There are three manual modes:
- Full manual (M): you control aperture (DoF), shutter speed, and ISO. You control the exposure by adjusting one or all of these. Use the exposure compensation scale in your viewfinder to balance each parameter until you have an ideal exposure. You may have an option to leave your ISO on auto so that the camera sets the ISO after you have decided on your aperture and shutter speed.
- Aperture priority (A or Av) – you control the aperture (DoF) while the camera controls the ISO and shutter speed to obtain the correct exposure. Good when you want to control your depth of field and motion is not a factor.
- Shutter priority – (S or Tv) – you control the shutter speed while the camera controls the aperture and ISO. Good when you want to control how motion is perceived in the image.
Tip: The exposure compensation scale in your viewfinder will allow you to determine if your shot has good exposure. It is a like a two sided scale where over exposed is on one side of the scale and underexposed is on the other side. Good exposure is when you are balanced in the middle.
When taking your camera out of auto mode it will take you some time to to figure out how you adjust each of the components and how that influences the final image. Don’t be afraid to experiment and get it wrong. Before long you’ll be shooting all of your images in manual and getting some amazing results.