Blog Photography 101 : Understanding ExposureAug 15 2015
At the beginning, I aimlessly shot with my camera at beautiful scenery and colorful backdrops, without actually knowing what photography is or how it works. Of course, the results were not as good as I had hoped. So, I took a step back and started focussing on the basics and figured out how the core of photography works; and slowly the quality of my photos started improving. I strongly believe that understanding the fundamentals creates a strong foundation for developing any skill. If the basics are thorough, it is a lot easier to pick up new concepts, methods and trends along the way.
So far, I have written a handful of posts about photography in the context of blogging. Today, I want to get down to the most important and fundamental concept to photography – Exposure. This concept is useful in just about any context – blogging, casual photography, iPhone photography – you name it. Learning this is like learning the alphabet; once you master it, you can start creating words, then sentences and soon, with some other skills, you can be the shakespeare of photography 😉
What is Exposure:
Exposure is essentially the amount of light entering your camera. We usually refer to exposure in terms of how dark or light a photo is. Although it seems pretty straightforward to take a photo with the correct exposure, in reality it can be quite tricky to achieve.
There are three main ingredients that come to play when we talk about exposure – Aperture, Shutter Speed and ISO. Each of these determine the amount of light entering the lens and its interaction with the camera.
When you choose the auto mode on your camera, the camera automatically sets the values for these three elements. Hence, you have almost zero control on your photograph. However if you use manual mode, you have full freedom to set these values yourself and hence you get complete control of how you want your photo. I can assure you, there is going to be a phenomenal difference in your photos once you start using the manual mode. Actual photography happens in the manual mode, so switch today and don’t ever look back!
Here’s a simple analogy to help you understand the exposure triangle: Aperture, Shutter Speed and ISO and their relationship with each other. Think of your camera as a window. The window has blinds that open and close to let light enter the window.
P.S: To demonstrate the differences effectively, I haven’t edited any of the photos below.
Now, aperture is like the size of the window. The larger the window is, more light can enter through it and smaller the window, lesser the light that can enter. Similarly, higher the aperture, greater the light entering the camera and therefore brighter the image. Aperture is essentially the opening of the lens and is measured in a unit called f-stop. f-stop values or f-numbers look like this: f1.8 , f2.2, f4.8, f5.6 etc. The greater the f-stop value, lesser the aperture. So an f-stop of 1.8 denotes greater aperture (hence more light) than an f-stop of say 5.6!
In the comparison below, the shutter speed is fixed at 1/200″ and ISO at 400 to see the effects of aperture on a photo. As you can see, the photo on the left with a low aperture f4.5 is way darker than the one on the right with aperture f2.2.
A note on Depth of field:
Have you noticed those dreamy photos with a blurry background and a sharply focussed subject in the foreground? This effect can be achieved by varying the “depth of field”: the distance between the nearest and the farthest objects that a sharply focussed in a photograph. Smaller f-stop leads to smaller depth of field, or more blurry background. You can see in the above photo that the background petals are more blurry in the photo with f2.2 when compared to the one with f-stop: 4.5.
Back to our window analogy, shutter speed is like the amount of time the blinds of the window are open. So longer the blinds are open, more light enters and vice-versa. Shutter speed is measured in seconds. So, higher the shutter speed, greater the light entering the camera, brighter the photo. Shutter speed values generally look like 1”, 1/20”, 1/100”, 1/400” etc. In fractions, greater the denominator, lesser the shutter speed. So a shutter speed of 1/100” means more light than a shutter speed of 1/400”.
In the comparison below, the aperture is fixed at f2.5 and ISO at 400 to vary the shutter speed. The photo on the left, with 1/400″ shutter speed, is way darker than the one on the right with shutter speed 1/200″.
Now imagine you are sitting behind the window with a pair of sunglasses on. You will be more sensitive to the light coming from the window when you wear a lighter shade of sunglasses, and less sensitive when you were dark sunglasses. ISO sets the shade of sunglasses that the camera lens is wearing. Lower the ISO number, lower the sensitivity to light and darker your photo. One thing to keep in mind is that, even though higher ISO offers more sensitivity to light, it comes at the cost of a grainer photo.
In the photo below, the shutter speed is fixed at 1/200″ and aperture at f2.5 to observe the effects of ISO. The photo on the right with ISO 400 is way brighter than the one on the left with ISO 100.
Putting it all together:
Achieving the perfect exposure is a bit tricky and takes practice and time. The Aperture, Shutter speed and ISO together decide the exposure of a photo and its all about juggling the three to get the perfect amount of light. A change in one of these will always impact the other two – so it is important to keep this in mind while altering their values.
For example consider this case: If you want to decrease the depth of field to achieve a blurry background, you need to decrease the f-stop. When the f-stop decreases, the aperture increases and your photo may become too bright. To decrease the amount of light and balance this out, you can decrease the shutter speed or decrease the ISO.
Just playing around with the settings and observing the effects on the photos is the best way to figure things out. It can be intimidating at first, but I assure you – everything will get easier with time and practice!
What are your biggest struggles when it comes to Photography?