Nail the aperture – and you can control your photos big time!
Aperture is one of the three core pillars in photography, to expose the image correctly, together with ISO and Shutter speed. If you haven´t read the summary about the three – you will find them here.
We often refer to aperture as f-stops, and “being wide open” or “small”. You will commonly see aperture marked with f/ – followed by a number.
In the middle of your camera, there is a sensor, capturing light. Once you press the shutter button, a curtain slides open in your camera body, and lets light pour in through the attached lens. After a given time, that curtain slides down, and stops light from entering the sensor. Shutter speed controls the duration between the opening and closing of the curtain, and aperture controls the size of the opening in the lens itself. The smaller the opening, the less light gets in, and the bigger the opening, the more light gets in. You can compare this to how you eyes work. Your pupils gets smaller and larger, depending on how much light is around you. Low light calls for large pupils, and on a bright sunny day your pupil will get smaller. If there is to much light, you will have to squint to prevent the light from hurting your eye.
The opening in the lens is adjusted by a series of small blades, closing in, or opening up, towards the center, or edges, of the lens.
Aperture has, like shutter speed, two main functions. Aperture controls the amount of light let through the lens, as well as “depth of field”. Easily explained depth of field means how much of the image that will be in focus. With a large aperture, letting in loads of light, the depth of field will be small. If you shoot a subject with a wide open aperture, the background will be blurry, and soft, while the subject will be in focus. On the other hand, you can focus on the background, and make the foreground subject blurry, out of focus.
If you shoot the subject with an small aperture, or a small opening, the background will be sharper. Most cameras have apertures between 3,5-20something, but this is very different from lens to lens. Anyhow – At the wide f-stop, the blur will be most visible, and at around f/ 11 and upwards, most of the image will be sharp. The fist image below is shot with f/ 1,8 – which is wide open, and as open as the attached lens allowed for. The second image was shot at f/ 13 – a much smaller opening, letting the background get in focus as well.
When to use what aperture?
There really is no correct answer to that question. Sometimes you want a blurry bakcground, or foreground, and sometimes you want the whole image to be crystal clear. But I feel like I can give you a few pro tips to take along.
Large apertures works very well for images where you want the subject to stand out. With the blur that comes, there is no question what you want to highlight in your image. Portraits, photos of food and plants are perfect places to start experimenting. Be aware of the amount of light that comes into the camera, often calls for a fast shutter speed. In low lights I would always recommend using a quite big aperture, to catch as much light as possible.
There are cons to large apertures as well. If you shoot a model, and get the focus wrong, the model will quite possibly turn out blurry and the whole image will look bad. There is no way to fix that later.
That leads me toooooo
Small apertures are great for shots where you want to be sure you get as much as possible in focus. Landscapes are the best example I can think of. With beautiful scenery, I would hate to have a blurry background. In cases like that, you want to show everything, front to back, in focus. It can also help when shooting moving objects, to make sure they are in focus all the way, even if they move closer, or further away from you, letting you avoid to shift focus all the time.
Cons to smaller apertures are of course that you might let attention away from that subject, letting loads of details from the background interfere with the main subject. Also the small aperture lets in less light, and makes shooting in dim lights harder. If you need the front to back focus, in low lights, have a look at the shutter speed and ISO. Can you slow down the shutter, or increase the ISO?
You have no idea how many shots I have ruined, because of large aperture, and missing the focus, just ever so slightly. That way, I´m not able to sell them to the customer, and I maybe lost potential income. That su*ks.
At least you now know what it is, and how you can be creative with aperture. And keep in mind, that the greater the distance from your subject to the background, the greater the blur you´ll get – even at fairly small apertures.
When it gets so blurry, that lights in the back starts turning to balls of lights and colors, we call it Bokeh. Now, there are few better ways to make a photo look better than introducing some bokeh 😉 Use the biggest opening possible – and go nuts!
I hope this was understandable, and that you now are ready to run out there photographing like a crazy person 🙂
Should you have any questions, or comments, feel free to leave them below, or send me an email. I´ll answer all, and if you have any good ideas for other posts like this you would like to know more about – let me know 🙂
Happy shooting guys! – See you out there!