So, you've got your spiffy new DSLR because you wanted to take your hobby to the next level. You've gone trigger happy and annoyed all your friends with that constant clicking noise and blinding light. You've taken some pretty decent shots in Auto Mode, but they don't always turn out the way you want them too. Your photos are sometimes too bright, too dark, blurry or (unintentionally) grainy.
This tutorial aims to help you to explore your camera's Manual Mode in order to improve the quality of your work and to give you much more control over the outcome.
The Exposure Triangle
The Exposure Triangle consists of three main points: ISO, Aperture and Shutter Speed. Understanding these three things is key to becoming a better photographer and getting the result you want. In my next tutorial, I will explain how these three elements influence exposure and how they can be altered to create an evenly exposed image. For this tutorial, I will just focus on these three points to help you understand how they work. I will start with my favourite: Aperture.
This refers to the opening in your lens that lets light in. The aperture size can be adjusted to let more light or less light in. When the aperture is adjusted, the depth of field changes with it. If you are not familiar, depth of field is the range of distance that appears focused or sharp in the photo. A large depth of field means that much of the photo is in focus (for example, what you would see in landscape photography), whereas a small or shallow depth of field means that only a specific subject or part of that subject is in focus (for example focusing on a single petal of a flower with the rest of the image blurred).
Have a look at these two photos:
The image on the left was taken with an aperture of f/2.2. You will notice that only the staples in the front and part of the carpet are fully in focus. The rest or the photo is strongly blurred. The image on the right was taken with an aperture of f/20. Almost everything in the photo is in focus -- except the very back. You may ask, "what is this funny figure with the 'f'?" It's called an f-stop and is used to tell you how wide your aperture is set at that moment.
Now, here's some frustrating logic: the smaller the f-stop number, the larger or wider the aperture (or lens opening). In the example above, the photo taken with f/2.2 has a large or wide aperture, whereas the f/20 photo has a small or narrow aperture. A good way to make sense of this is to not see the f-stop numbers as whole or compound numbers, but as fractions.
For example, 1/2 of a pie is much larger than 1/8 of a pie and certainly larger than 1/22 of a pie. Get it?
Here is what my old soviet lens looks like when the aperture is adjusted
(click to see the animation)
The larger the aperture, the more light gets in through the lens.
The larger the aperture, the smaller the f-stop number.
The larger the aperture, the blurrier the background.
And vice versa.
If you are interested in knowing more about the technical aspects of f-stops, then have a look at this Tedious Explanation of the f/stop.
The shutter speed refers to the length of time the shutter is left open and is measured in seconds. On your camera, you will see numbers like 1/20 or 1/125 which mean a 20th of a second or 125th of a second respectively. The longer your shutter stays open, the more light gets in.
However, leaving your shutter open longer also means that the chances of motion blur are much higher. The shutter speed is basically how long your camera takes to capture an image. If you have a moving subject and a long exposure (shutter open longer), your camera will record the movement from the moment you press the shutter release button to the time you set it to close.
Using different shutter speeds while dropping a ball of paper
In the example above, you will see that the motion blur becomes less and less until you get to the last image on the right where there is no blur at all. You will also notice that the photo keeps getting darker and darker -- this is because faster shutter speeds allow less light than slower ones. Faster shutter speeds help you to catch subjects in movement with sharper detail. It gives that lovely frozen in motion effect.
Why would you want a slow shutter speed? Sometimes motion blur is desired -- for example when capturing fireworks, you want to see the trail of light from beginning to end. Motion blur can also make an image surreal or more dramatic.
So what do you do if you don't want the blur? Are your shots sometimes unintentionally blurry? It happens to the best of us. In auto mode, your camera will often select a slower shutter speed to compensate for low light. This will cause your photos to look blurry from camera shake. Aside from using flash, there is another way to solve this problem.
There is a rule of thumb:
The shutter speed should be the same or larger than the inverse of the focal length.
For example, if you have a lens with a focal length of 50mm, then the shutter speed should be 1/50 or less (less meaning quicker). Some argue that it is better to use the formula: 1/2xFL, so if you have a focal length of 50mm, you should use a shutter speed of 1/100 for a really sharp image. Here is an article where you can learn a bit more about lenses: www.cambridgeincolour.com/tuto…
Another way to avoid the blur is to keep your shutter speed high but open up your aperture to let in more light. However, opening up the aperture reduces the depth of field, which may not always be desired. This is where knowledge of ISO comes in handy. Before I continue with ISO, here's a quick
The slower the shutter speed, the more light is let in.
The slower the shutter speed, the higher the chances of motion blur.
Faster shutter speeds are great for photographing subjects in motion, for example athletes in a game.
Rule of thumb for avoiding blur due to camera shake (if you don't have a tripod): The shutter speed should be the same or larger than the inverse of the focal length.
The ISO measures the sensitivity of your camera's digital image sensor to light. The higher the ISO, the more light it picks up and vice versa. Low ISO means smooth images with very little noise/grain. High ISO means that the image appears brighter, but it also becomes grainier. Higher ISO comes in handy in low-light situations where you would need a faster shutter speed to capture the moment.
In the first image, you can see a bit of motion blur in the fingers because of the low shutter speed. To get the image sharper, I bumped up the ISO and increased the shutter speed. You will notice that each image gets sharper. There is also more grain in the sharper images. The darker the room, the more grain you will see if you up your ISO. Here is a guide for further reading: digital-photography-school.com…
The higher the ISO settings, the more sensitive the sensor gets to light, which means sharper shooting in low-light conditions.
The higher the ISO settings, the grainier or noisier the image appears.
Very low ISO settings make an image appear very smooth, but this works better when sufficient light is available.
So, this is the end of my Exposure Triangle tutorial. I hope that it was useful to you in some way. I am no expert in photography, but learning these aspects of photography have helped me immensely in my quest to become a better photographer.
Did you enjoy this tutorial? Was it helpful? Your feedback would be much appreciated as I intend to write more of these. Thank you
Next up: Understanding Your Exposure Meter
Exposure triangle: www.kruger-2-kalahari.com/expo…
Exposure triangle DP School: digital-photography-school.com…
The Easy Guide To Understanding Aperture: www.redbubble.com/people/peter…
Focal Length Rule of Thumb: gizmodo.com/5940329/shooting-c… photo.stackexchange.com/questi…
How to Shoot in Manual Mode -- the Basics: clickitupanotch.com/2010/09/sh…
And me own experience
My Other Tutorials
Understanding Your Exposure Meter
Why I Now Always Shoot in Raw