Over the next couple of articles I’m going to cover perhaps the two biggest changes I have made to my photography technique since I took up the hobby, both of these revolutionised my wildlife photography and I think they have made me a much better photographer.
This first article I am dedicating to my very dear friend Beverley, because I can still remember the first discussions we had about this technique, and the outing we had to Craigieburn Lake where we both tried it out together, me for the first time.
To begin, let’s refresh on some photography basics. The key ingredient for our photography is light, and getting the right amount of light into our camera is key to making great images, this is usually referred to as “getting the exposure right”.
There are three things that really determine how much light makes your image, and they are often referred to as the “Exposure Triangle” (see figure 1). They are of course Aperture, Shutter Speed and ISO.
Figure 1 - The Exposure Triangle
Aperture refers to the size of the hole in the front of the lens that opens to let in light when you press the shutter. It is measured in f-stops, which can be confusing because the smaller numbers (eg f/1.4) represent a bigger hole (and therefore more light) than the larger numbers (eg f/22) which represent a smaller hole (and therefore let in less light).
Aperture also has a huge impact on “depth of field” which refers to how much of your image is in “acceptably sharp” focus. When using the small f-stop numbers (larger hole) you will get a shallower depth of field, less of your image will be in focus, objects in front of and behind your focus point will be increasingly blurry the farther they are from the focus point. With the larger f-stop numbers (smaller hole) you will get a larger depth of field, that is more of your image in-front and behind the focus point will be in focus or sharp.
The shutter speed refers to the amount of time that the shutter remains open when you press the shutter button. The faster the shutter speed is the less light you will get into the camera, but you will be able to “freeze the action” or stop moving objects in your scene. Moving objects will be sharper with a faster shutter speed. Slower shutter speeds can be used when you want to see some of the movement in the scene, such as traffic light trails, or blurring water going over a waterfall, or perhaps artistically you want to see the blur of a bird flapping it’s wings.
When referring to the digital cameras that most of us use these days, ISO is basically an electronic amplification of the light signal by the camera. So at the “base ISO” for your camera (often ISO 100) there is no signal amplification. As you increase the ISO, the amplification of the light signal by the camera increases, so that you get enough light for a correct exposure. Unfortunately, with all electronic circuits there is an element of electrical interference present, and this can cause noise (grainy images) and loss of detail and dynamic range. When you have enough light coming into your camera this noise is hidden and hard to see, but as you raise the ISO the noise also gets amplified and becomes more visible.
Fortunately, the performance of modern camera sensors is always improving, as is the performance of the many different noise-removal software products that are available, so shooting with higher ISOs is not something you should be too worried about.
Of the three settings, aperture and shutter speed are the ones that as a photographer you should want to be fully in charge of, as they are the two things that give you creative control of your photograph. Depending on the style of photography you are shooting, you should be the one that decides the depth of field, and the amount of motion captured, you don’t want to leave these creative decisions up to the camera. If you use one of the semi-automatic modes in your camera like aperture priority or shutter priority you are letting your camera determine the other setting (ie in aperture priority mode the camera is choosing the shutter speed, and in shutter priority mode the camera is choosing the aperture). So, you are not in full “creative control”.
The ISO becomes the third “balancing” part of the equation and can be modified to give you the exposure you need, once the aperture and shutter speed are chosen.
Many purists will encourage you to shoot in full manual mode where you manually choose the aperture, shutter speed and ISO for each shot, and I can understand this recommendation as it puts you fully in charge, but in some situations many of us (certainly myself) are not quick enough to adjust.
In any situation where things are moving fast (wildlife, sports, children) full manual mode is very tough. This is especially true if light conditions are changing too. I spend a lot of time photographing birds in a woodland environment, where the bird could be sitting out in the sun one moment, then quickly move into a shaded position – there just isn’t enough time to get it right, and you miss a lot of shots, or you get the exposure drastically wrong and get blown highlights or deep, dark shadows.
Manual Mode + Auto ISO is the perfect solution.
Setting your camera to Manual Mode means you get to choose the aperture and shutter speed, and then setting your camera to Auto ISO means you are letting the camera choose the ISO to get a “correct” exposure. When shooting the bird on the branch sitting in the sun the camera will lower the ISO, when shooting the bird in the dark shady position it will choose a higher ISO.
I am not going to try and cover the specifics of how to set up Auto ISO because it will vary from camera to camera, but Googling should put you on the right track and turn up plenty of videos or articles specifically for your camera.
Most cameras will allow you to set a limit on what range of ISOs your camera can choose should you wish to do so.
You can also continue to use other features like Exposure Compensation and different metering methods (Spot metering or Evaluative metering for example) in order to get exactly the exposure you want.
As you are shooting you can also monitor the ISOs your camera is giving you in various situations, your camera should show you this in the viewfinder as you half-press the shutter button. Then, if the ISO values are getting too high, you can modify your other settings as required.
As you are shooting you can also monitor the ISOs your camera is giving you in various situations, your camera should show you this in the viewfinder as you half-press the shutter button. Then, if the ISO values are getting too high, you can modify your other settings as required.
For example, my usual starting settings for a birding session are f-stop f/7.1 and a shutter speed of 1/1000 sec. If the light drops a bit and I see the ISOs are getting too high, I might choose to open the aperture a bit more to f/6.3 and/or drop the shutter speed to 1/800 sec, then the ISOs chosen by the camera would be a little lower as both of those adjustments let in more light.
So, take charge of the important “creative” elements of the Exposure Triangle and let the camera do some work in those challenging, fast changing situations by using Manual Mode + Auto ISO.
And finally, Figure 2 is a photo taken recently, just to show that you don’t have to be afraid of a high ISO, this is an Asian Small-clawed Otter at Melbourne Zoo. Taken on my Canon 7D MkII, a camera model that is nearly 10 years old, at ISO 16,000.
Fig 2 - Asian Small-clawed Otter shot at ISO 16,000
After publication of this article, a reader Kye Thompson asked the following question, “Would Aperture Priority mode and Auto ISO work much the same?”.
So, I thought rather than just answering Kye privately I would add my answer here.
Again, let me preface my answer with the same disclaimer as I had above, my answer is directly relatable to the Canon cameras I use, but I think will be similar for others, but you might need some specific research if not using a Canon DSLR/mirrorless camera.
Yes, Auto ISO will work with Aperture Priority mode, but as we are now allowing the camera to change two settings (shutter speed and ISO) we will want to understand what the camera is going to do. Will it change the shutter speed first, or the ISO?
With my Canon R5, I have two options, firstly I can manually set a “Minimum Shutter Speed”. Let’s assume I set this to 1/250 second, as it needs more light the camera will adjust the shutter speed but only until it gets to 1/250 sec, if it needs more light it will not choose a slower shutter speed than 1/250 sec, rather it will start to raise the ISO.
The second option is Auto, where the camera will choose a shutter speed relative to the focal length in use, using the old rule that it is safe to handhold a shutter speed that is the inverse of your focal length, so if you are using a focal length of 100mm, the shutter speed might be 1/100 sec, then the camera will vary the ISO to get a proper exposure. In this Auto mode I also have a slider where I can make the camera bias towards a faster or slower shutter speed.
But – there’s always a but isn’t there – just remember that by letting the camera choose the shutter speed, you are not in full “creative control” of your image.
That’s not to say there isn’t a place for Aperture Priority. I use Aperture Priority a lot of the time. Whenever I don’t really care about the shutter speed I will generally use Aperture Priority. For me this is when I’m shooting all my street art photos, and many times when doing landscapes. Usually in these situations I am using a tripod, so the shutter speed is largely irrelevant to me, so I will be on Aperture Priority, with ISO set to 100, and the camera can choose whatever shutter speed it likes.
Obviously if I’m hand-holding I will be checking the shutter speeds and raising the ISO appropriately, and if there is any reason where I need “creative control” of the shutter speed (eg water motion for the ocean or a waterfall) I will move to full manual. Usually in these situations I am not rushing, or the light is not changing often, so I’m usually not going to choose Auto ISO.
But for the times where speed is of the essence, and light is changing like the woodlands wildlife or sports scenarios mentioned in the original article, Manual + Auto ISO is my “go to” setting.
This article was first published in the July 2024 issue of Artists Down Under magazine.