Low Light Photography
Great gray owl at sunset
There are numerous variables that you need to balance when taking images of wildlife in low light. At these times you are working to gather the most light you possibly can while having a fast enough shutter speed so your images are not blurred. ISO, shutter speed, and aperture must be balanced to get the optimal conditions in low light.
First and foremost you have to have your aperture set as wide open as possible. Whatever the lens you have, you need to have the aperture wide open. So lens choice is important and it is one of the BIG advantages of prime lenses, such as the 400mm f2.8 or the 600mm f4.0. The bigger the aperture opening, the more light that reaches the sensor, and conversely either the faster shutter speed you can use or lower ISO setting. Getting lenses with large apertures are expensive. While most people choose zoom lenses for the wide range of distances they can cover and their affordability, the more light a lens can gather whether in good light or low light the faster the camera will focus and the sharper the image will be. This is why prime lenses are outstanding in terms of image quality, but also very expensive.
Coastal brown bear photographed after sunset using a 400mm f2.8 allowing for much lower ISO and faster shutter speeds
In terms of shutter speed with animals that are moving in daylight hours, you want a shutter speed of at least 1/1000, if it is moving fast at least 1/2000, and birds in flight depending on species between 1/1600 - 1/3200. There is simply no way you can have those types of shutter speeds in low light. With those kinds of shutter speeds, you will have very high ISO and noisy and unusable images. Aperture as discussed is already as wide as possible, so the balance comes between ISO and shutter speed. Ideally, you want to keep your ISO below 5000 if at all possible. This is high already but still, images are useable especially with programs now like Topaz DeNoise. If you can get the ISO even lower then that is even better!
Porcupine in low light shutter speed 1/400 so some blur on the paw but a useable photo
Consider your subject and what shutter speed you need. If the animal or bird such as an owl is not moving you can try a range of shutter speeds from 1/100 - 1/400. The balance is between the shutter speed and ISO. As you increase your shutter speed you will increase the ISO and introduce more noise. On the other hand, the slower the shutter speed the more risk you run of blurred images. You need to take a lot of images in low light as the reality is you will get blurred images, but there should be some that are useable and more the higher the shutter speed. You will need to lower shutter speed to allow more light to reach the camera's sensor to decrease the ISO and allow the camera to focus. Hence here is the balance. Generally, as the light continues to drop you need to continue to lower the shutter speed. The darker it gets, the harder it is for the camera to focus and as the light continues to drop the camera eventually will not be able to autofocus.
If I am photographing an animal moving in really low light I will go to 1/400 and may even bump the ISO above 5000, you are going to have some blurred photos and you are going to have some noisy photos, the hope always is that there is a good one in there. With owls in flight I use 1/640, owls are slower in their wing movement, you will have some blurred wings and some that are not, but if you can keep the owl's face focused, motion blur on the wings is common and an increasing style you are seeing more and more. There simply will come a point in time when you cannot photograph an animal moving as the shutter speed needed will make the ISO way too high as you continue to lose light. At this point, you have to look for opportunities to take compelling portraits.
Great gray owl in low light in flight
When you are to the point you can no longer take moving images and only portraits tripods can be helpful, this helps minimize some of the blur versus handholding the camera. With a tripod you can even drop the shutter speed to 1/60 or if the subject really is not likely to move and can be stationary for some time such as an owl you can go even lower.
Low light takes a lot of time and practice in the field. In summary, set your aperture wide open, use the shutter speed that is the highest for the subject needed
- portraits you can start at 1/250 and you can go quite low 1/60 or lower if needed with a tripod
- animal moving 1/400
- an owl in flight 1/640
Try to keep ISO at 5000 or lower. As the light drops continue to drop your shutter speed until your camera can no longer autofocus.