For those new to photography, the combination of a letter and numbers like f2.8, f11 or f22 can conjure up horrible flashbacks of struggling through algebra class. It doesn’t help that the larger the number is, the smaller the aperture is. A bit backwards, I know.
But don’t worry, with a little basic understanding of what aperture is and how it affects your photography, you can be taking great pictures in no time.
In a nutshell, the aperture of your lens is the hole through which light travels. This light reaches your sensor or film, and creates your image. In this post, we will focus more on the relationship between aperture and depth of field.
Depth of field is the distance between the nearest and farthest objects in a scene that appear sharp in the image. If the subject of your photograph is in focus but everything behind and in front of it is out of focus and blurred, your depth of field is narrow. This is great for portrait photography.
If everything from the near distance to the horizon is sharp, your depth of field is large or wide. This is good for landscape photography.
Your challenge when taking photographs in the bush is to select an aperture which will provide the right depth of field for your desired photo. A wide open aperture (small aperture number eg. f2.8) will provide a shallow depth of field and a narrow aperture (large number eg. f22) will provide a wide depth of field.
Take a look at the following photographs and the different aperture settings used:
Wide open Aperture:
Wide open apertures ie. a small f-stop like f2.8, 3.2 or 3.5, provide a narrow depth of field. This is ideal for portrait photography. Having a leopard’s face nicely in focus and sharp but having its body blurred will create a beautiful photo.
In the photo above, the face of the Mashaba young female is perfectly in focus, while the branches only slightly behind and in front of her are out of focus. This draws your attention to her face immediately. Zooming in exaggerates the effect of a wide open aperture, and in this photo, the combination of a 200mm zoom and an aperture of 3.5 has done that nicely.
In this photo of one of the Mhangeni cubs grooming its sibling, my aperture was too wide. At 3.2 it made for a very narrow depth of field, and as a result, the cub that is doing the grooming is not in focus, whereas it should have been to capture the moment better. An aperture of 6.3 or 7.1 would have probably been preferable, as both cubs would have been sharp.
In this photo, both the lions and the vehicle with its occupants are in focus. I was actually focusing on the vehicle, so the lions are right on the edge of the focal area and not quite as sharp as they could be. I was zoomed out fully (70mm) and as mentioned earlier, less zoom increases the depth of field.
For this photograph of a white rhino calf scratching itself I wanted the whole calf in focus, while everything behind it and in front of it blurred. Had I used a smaller f-stop like f4 or f3.5, the back end of the rhino would not have been sharp. The medium aperture of f6.3 keeps the rhino sharp while blurring the rest.
Despite having all four Majingilane in one shot, the real point of this photo is to highlight the fact that they are on the hill opposite Varty Camp. Had I used a wide open aperture, the camp in the background, and Colbert Mdluli on the deck, would have been out of focus. I therefore had to narrow the aperture to f11 in order to increase the depth of field and have the camp be properly visible, instead of just an indistinct blur in the background.
I had zoomed in to crop some of the surrounding foliage out of the photo, but still wanted to keep all these Mhangeni cubs and the lioness in focus. Knowing that by zooming in my depth of field was going to be narrowed, I had to narrow my aperture to f10 make sure the depth of field was maintained.
At the end of the day, photography is an art form. No one can tell you what you like in a photo or not, and it is your interpretation of a scene that determines what sort of photo you will want to try and capture.
A good general rule is to have a wide-open aperture for portrait photography, a medium one for large animals like rhinos and elephants, and a narrow aperture for landscape scenes, although that is keeping it basic to the extreme. We have yet to delve into the relationship between shutter speed, aperture and ISO, what lenses do to affect depth-of field, and countless other factors that can determine what type of photograph you will capture.
For now, stick with these basic aperture suggestions and you’ll be ok. Next week we’ll explore the Exposure Triangle (aperture, ISO, shutter speed) a little more closely, and the relationships should become a little clearer.
Written by James Tyrrell
Photographed by James Tyrrell and Richard Laburn