Hi again, This week let's take a look at how to control light in Photography. As you may know Photography in itself is capturing light and reproducing it digitally or on print. Photography is nothing but light. So what do we do when there is not enough light to photograph a scene? Almost every mode or equipment used in photography helps us manipulate light in some way or the other.First, we will need to understand how the different modes interact with light and then we will see how to use that knowledge to help us photograph in low light situations.
ISO in traditional film photography refers to the sensitivity of the film to light. Higher the ISO number, higher the sensitivity to light. But higher sensitivity also leads to higher noise levels in the photographs. It is the same principle in digital photography. Every photographer tries to use the lowest possible ISO to achieve pleasing shots with little noise/grain, but it isn't always possible. Sometimes the light is less to achieve a proper exposure with the lowest ISO, So we need to tweak it up a bit. Fortunately, modern cameras are getting better all the time in terms of their ISO capabilities. Certain cameras have acceptable photos even at ISO 3200, but some may not be usable at more than ISO 400. It's very important to know the range of the cameras you are using to be able to exploit its full potential.
Aperture is the opening of the Lens’s diaphragm through which light passes to the sensor. So the wider the opening, there is a chance for more light to pass through. Aperture is measured in f-stops. The numbers are usually in the format of f/x. Since ‘x’ is the denominator, lower numbers mean a larger aperture. For instance, f/2.8 is wider than f/22. So when the aperture opening is set to its widest, it allows more light to pass through and also we can achieve a shallow depth of field. Which means that when all other settings are the same, a wider aperture will get you a brighter picture and a smaller focus area.
Shutter speed is the duration of the time the camera’s shutter is open when taking a photograph. It is also the time the film or the sensor is exposed to light while photographing. The longer the shutter is open, it lets more light through but also induces motion blur when shooting objects which aren't still. Shorter durations usually lead to less light but tend to give sharper results without blur.
Since we have a clear idea about the working of the three modes, we will see how to manipulate them to get our desired results in working conditions. We have seen that all three modes can be used to control the amount of light reaching the sensor. But each one has its own side-effects. Higher ISO creates noise, Aperture affects the depth of field and shutter speed can cause motion blur. I am going to take a few scenarios, photographers face regularly and how to overcome low light in that situation.
Photographing people outdoors in natural light has a lot of Pros and cons. The Pictures are usually natural and pleasant. But what do we do when there isn't enough light and we don't have flash strobes to add more light? In general, the best option is to open your aperture to its widest setting ( the lowest F-number ) and the shutter speed to not less than 1/125. Though some of you might have steady hands to hold the camera still for more than that, the subject is most certainly bound to move their body. It's always good to keep the shutter speed of at least 1/125 when taking portraits. We can then adjust the ISO settings accordingly. Higher ISO could induce noise and grains, but remember that it's easier to fix noise in post-processing than fixing blur.
It's usually a good idea to use Tv(Shutter Priority) when there is low light during your portrait sessions.
In most scenarios of Landscape photography, the subject is usually not moving. Unless its running water, clouds or perhaps you are photographing the stars. But in general, the landscapes don't move. Which makes the shutter speed irrelevant in most cases. So we find the aperture setting we want and then choose the lowest ISO. It's always best to have a tripod when photographing landscapes so as to reduce the camera shake. As we know, Longer shutter speeds create motion blur. This can be used effectively in certain ways like showing the flow of a waterfall, river, oceans or to photograph star trails etc. When we know how our camera works, there are plenty of creative options to be explored.
Thanks for reading. Let us know in the comments if you need more in-depth guides.
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- Al Judge
- Subtle Visions Media
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- Bryan Peterson
- Amphoto Books
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