What’s the Best Aperture to Use in a Wildlife Photo?
Often, when first entering the field of wildlife photography, people hear comments along the lines of “you must use the widest aperture possible for wildlife images”. But is a bigger and wider aperture really better?
Yes and no. A wider aperture does let more light into the lens and allow you to use a faster shutter speed, which is essential for capturing fast moving subjects. It can also provide you with a beautifully diffused background. What is often missed and overlooked about using a wide aperture though, is the issue of key elements of an animal’s body being out of focus due to the shallow depth of field.
This can often happen when using a telephoto lens to take a face-on portrait. Take a look at this Atlantic puffin. Whilst its eyes are in focus, the beak is completely out of focus because the depth of field is too small. The aperture for this image was f/4.
A smaller aperture would have brought the beak into focus, and the diffused background would have been retained due to its distance from the puffin. The out of focus beak detracts greatly from the image. It is important to ensure the entire head is in focus. It can be hard to check which elements are sharp when working in the field, so pausing briefly to zoom in on the LCD screen is often time well spent. There is nothing worse than returning home to find below par photographs and wishing you had adjusted a setting.
The problem is not solved for every situation just by shooting at a slightly higher aperture. I will use puffins again to illustrate this point. If you are photographing one puffin at 10 metres away and the head is fully in focus, but you then take an image of a puffin 5 metres away using the same settings, you could well find the beak is out of focus once more. This is because the closer your subject is to your camera, the smaller the depth of field.
I would be very surprised if there was any professional wildlife photographer that had never made an error with depth of fields in their career. It is so easy to leave the camera in aperture-priority mode at its widest setting, that sometimes we forget to alter it (especially when photographing something really exciting).
So a bigger aperture is not always better. If this thought has not occurred to you before, it would be very beneficial to pay close attention to your aperture value. When you are next shooting, alter the aperture value and try to get a better feel for the difference a slight change can make.