I’ve been frustrated countless times in the past when I’ve tried to experiment with the manual mode in my Canon Rebel T3i and I didn’t get the results I was hoping for. ‘Why is the sky so bright? Mmm let’s change this setting and see what happens. Oh no! Why does everything look so dark now…?’. I got tired of guessing, and after devoting some time to reading good photography blogs and magazines I’m finally starting to understand these WHYs. It all comes down to the basics, my friends.
This week I have focused on teaching myself what is called ‘the exposure triangle’ - a basic concept to understand how light enters and interacts with the camera. Knowing which settings you should use in each situation can be tricky, and a lot of practice is needed in order to understand the interaction of the three elements that form the aforementioned triangle.
Once you read the theory, put cozy clothes on, go out and…shoot, shoot and shoot! Practice is always the key to success – don’t forget that! The more you do something, the better you get. After a while, it will be very satisfying to look at your first pictures and see the evolution of your photography skills over time. I’m really looking forward to that special moment!
So let’s get down to business. The three elements that we need to understand in order to master the art of the exposure are…
It is at the intersection of these three elements that a photo is properly exposed. It hasn’t been an easy task for me to completely grasp the relationship between Shutter Speed, Aperture and ISO since there are a lot of different components involved. However, I read a metaphor about the exposure triangle on Digital Photography School that was very useful to get the big picture in mind. Let me share it with you (please note that this metaphor hasn’t been written by me, I got it from the Digital Photography School page).
Imagine your camera is like a window with shutters that open and close.
Aperture is the size of the window. If it’s bigger more light gets through and the room is brighter.
Shutter Speed is the amount of time that the shutters of the window are open. The longer you leave them open the more that comes in.
Now imagine that you’re inside the room and are wearing sunglasses. Your eyes become desensitized to the light that comes in (it’s like a low ISO). There are a number of ways of increasing the amount of light in the room (or at least how much it seems that there is. You could increase the time that the shutters are open (decrease shutter speed), you could increase the size of the window (increase aperture) or you could take off your sunglasses (make the ISO larger).
There is not a single combination of the three elements to achieve the same exposure. Different values of shutter speed, aperture and ISO can give the same exposure result. However, we need to keep in mind that every time we change one of our settings, the image will be affected in a different manner. Therefore, it is really important to understand the trade-offs of each element to know how to best play with them. In order to remember how each element can affect my shot, I carry a note like this one in my camera bag (at least for now!).
As I’m not a professional in the field (yet!) and my main objective is to help others who like me are starting to learn photography, I’ll just sum up the main concepts that I have learned during this week. However, I strongly recommend carefully reading some of the professional websites that explain in more detail each of the elements of the triangle. I’ll also post some of the pics that I took as examples during my practice sessions.
SHUTTER SPEED – how long the image sensor is exposed to light
- Impact on how motion is captured
- It is usually measured in fractions of seconds, meaning that the bigger the denominator the faster the speed (1/1000 > 1/30)
- Important question to ask yourself: how do I want to capture this movement? (freeze it or blur it?)
- To freeze movement –> choose a faster shutter speed
- To let the movement blur –> choose a slower shutter speed
- It is recommended to use a tripod to avoid camera shake when using 1/60 or slower
As you can see in the first picture, I wanted to blur the moving object (water) so I had to use a slower shutter speed. Unfortunately, I don’t own a tripod yet, so I had to rely on the lens image stabilization. I’m happy with the final result though – I barely can notice the image shake. In the second pic I shot with a faster shutter speed in order to freeze the movement.
APERTURE – how much light the lens lets in
- It is measured in ‘f-stops’ (f/2.8, f/4, f/5.6, etc) and every time we change the setting to the next f-stop it means that we are doubling or halving the size of the hole in our lens
- The larger the hole the more light that gets in, and the other way around
- Large apertures (more light gets in) –> f/stop smaller numbers (i.e. f/2.8)
- Small apertures (less light gets in) –> f/stop larger numbers (i.e. f/22)
- Depth of field (DOF): describes the distance in front of and behind a focus point that appears sharp in a photograph
- Large aperture (small number) = shallow DOF (part of the image is focused, the rest is blurry)
- Small aperture (large number) = large DOF (most of the image is in focus)
In this example you can see that with a large aperture the object in focus is the flower and the rest is fuzzy. However, in the second picture the whole image is in focus.
ISO – the camera’s sensitivity to light
- The lower the number the less sensitive the camera is to light and the less noise the image has (less grain)
- If we’re taking photos outside in sunny conditions we’ll want to use ISO of 100 or 200
- If it’s a cloudy day or evening time, then we should use a higher ISO between 400 and 800
- In darker situations (night or indoor activities) we will generally want to use an ISO of 1600 or more (the cost is noisier shots though)
When I took these pics it was still sunny outside, so you can see that using an ISO of 200 was the right choise. However, when I increased the ISO value my shot was way too bright.
Finally, we always need to keep in mind that thinking about one element in isolation from the other two of the triangle is not going to give us the perfect exposed picture. As you change one of the elements you’ll need to change one or both of the other ones to compensate.
If you are an amateur like me, my recommendation is to find some time to understand each element in detail. You don’t need to spend hours and hours reading professional blogs and magazines; just pick one that you like and read the basic concepts to get a general idea. Once you’ve done that, grab your camera and experiment by playing with the different settings. Every time that you take a shot explain to yourself why the picture is too bright or too dark, why it has so much grain or why it is so fuzzy. Try to find the logic of it and eventually you’ll understand how the three elements work together to find the perfect exposure.
That’s exactly what I’ve done this week, and even though I still have a lot of practice ahead of me, I’m having so much fun along the way! Here is the proof – Dan being goofy while I was practicing with the aperture settings.
Feel free to share your advice or criticize my work. I really appreciate when people give me their honest opinion :).