ISO in Photography: Important Concepts you Need to Know
Are you starting as a photographer, and have no idea how to make everything work?
Once you understand these terms and how you can apply them to your camera, you’re a step closer to taking exceptional photos.
One of the settings that can be confusing to a lot of people is ISO.
Fortunately, this comprehensive guide will help you better understand ISO in photography and ISO in a Camera.
The full form of ISO is “International Organization of Standardization“.
In the film days, ISO was referred to as ASA, which is the level of sensitivity of film to light. The scale of ISO sensitivity was measured from 100, 200, 400, and so on, with lower numbers indicating low sensitivity to light.
Selecting a roll of ISO 100, given its insensitivity to light, makes it useful for taking photos in bright lighting conditions. You would go for a roll of ISO 400 when taking pictures in low lighting conditions such as indoors.
In this age of digital photography, the way ISO is measured remains the same as the film era. The only difference is that while ISO referred to the physical quantities of film, it’s now about the process inside the camera.
Using ISO to Control Shutter Speed and Aperture
While the aperture controls the amount of light that reaches the sensor, the shutter speed controls the duration of time the sun reaches the sensor. However, it’s possible to affect the shutter speed and aperture for a particular shot using ISO.
For instance, if you’re shooting wildlife, you may need constant high shutter speeds.
When shooting during sunset and sunrise, or in shades, the light won’t provide enough exposure. If you slow down the shutter speed, you may introduce motion blur, which may spoil the shot.
By keeping the desired shutter speed and increasing ISO, you will hardly interfere with the picture quality.
The use of Camera ISO
While the basic of ISO is something photographers are conversant with, many of them aren’t sure of the best value to use in the field. There’s a reason why cameras feature more robust ISO settings.
Here’s an outline of some of the common scenarios you may encounter.
If you have to use a tripod to stabilize your camera, make sure you use slower shutter speeds as it gives clear, precise images. This, in turn, allows you to use lower ISO. For images that don’t require a large depth of field, you should raise the aperture (allow more light to the lens), which means that you’ll use a lower ISO.
Take note that different types of lenses have different high aperture values. So, not all of them allow the same amount of light. The ideal time to increase ISO is when there isn’t enough light to capture sharp, bright objects.
For instance, if you’re shooting handheld photos indoors without a flash, you may want to consider increasing your ISO to capture the image without a blur.
Maximizing Image Quality and Minimizing Noise
Most photographers believe that the only way one can capture high-quality images is by using the Base ISO. Understand that sometimes, you may be in a dark environment, and you’ll have no choice but settle for a higher ISO.
Only stick to using base ISO when there’s enough light. To maximize your image quality, there are a few things you’ve got to follow.
- Choose an aperture setting that can provide your desired depth of field
- Set your ISO to the base level then set your shutter to a setting that provides proper exposure
- If the subject is blurry, slowly raise your ISO, then use faster speeds until the blur disappears
- If the ISO is getting high and you can use a wider aperture, open up until the ISO gets to a manageable level.
ISO Myths and Misconception
There are a lot of myths and misconceptions surrounding ISO. Here are a few you need to know.
Is the ISO part of exposure?
ISO isn’t in any way related to exposure. Aperture and shutter speed can make a photo bright by capturing more light, but this isn’t the case with ISO. It brightens the picture you’ve already taken.
ISO “Sensor Sensitivity”?
Whether or not ISO is the same as sensor sensitivity is something that confuses new photographers. While many people believe that ISO “acts as” a camera sensor sensitivity, that’s not true. Many digital sensors feature a single sensitivity, regardless of ISO.
Is Raising ISO Just Like Brightening a Photo on a Computer?
Raising your ISO acts in many ways like brightening a photo on your computer since it makes an image more visible. However, the only difference is that you’ll get a better image quality by raising your ISO than brightening on your computer.
What’s the best ISO setting for Landscape Photography?
If you’re a landscape photography enthusiast, consider using a tripod when setting ISO to your cameras base ISO. This is usually 100.
How ISO affect a photo?
ISO doesn’t just decrease or increase the brightness of a photograph; it can have an impact on both the dynamic range as well as noise/grain level.
You’ll have the highest dynamic range and the least amount of noise reduction at the lowest (base) setting, which gives you more flexibility in post-processing. As the ISO increases, the dynamic range decreases, and noise level increase as well.
What’s the ideal ISO for low-light?
If you’re shooting in low light, the chances are that your shutter speed will decrease, causing motion blur or camera shake. If you’re to avoid such issues, you should raise the ISO setting to a higher value, like ISO 1600.
Depending on the light condition and aperture, you may want to increase the ISO even more.
Its time photographers understood that ISO isn’t part of the exposure triangle in digital photography. However, it can help control parameters (shutter speed and aperture) and control the overall brightness of an image.
Once you conceptualize these dynamic relationships, you can accurately match the vision you have of your final photo with the lighting conditions and last picture with the scene in front of you.