Back in the days when people were taking photos on film, the rolls of film came in various sensitivities. The more sensitive the film was, the less light was needed to obtain a good exposure. This meant that people could use faster shutter speeds or smaller apertures to get their desired results and allowed for more creative control. Who doesn’t want that? Sounds like a perfect invention to freeze the moment in photography! Well, there are both pros and cons about shooting with both low and high ISO numbers. We will explain further in this article why that is.
With digital sensors, ISO still refers to the sensitivity, but to that of the digital sensor. The great thing about a digital sensor, is that you can manipulate its sensitivity with every shot. As your sensor works electronically, the readout of each photo site on your sensor is amplified to an amount that matches and resembles the correct ISO sensitivity. Before, a roll of film had a set ISO. You were not able to adjust your desired ISO until your roll was finished, and you had to purchase a new roll. This made the decision to choose a particular ISO a whole lot more difficult.
Grain/Noise
As mentioned before, the great thing about shooting with a high ISO number, is that you could shoot with faster shutter speeds and smaller apertures. The major drawback to this was, and still is, that the photo would contain more grain/noise. Grain, or noise, are the speckles in a photo where the film or sensor has difficulties to process the light it captures/records. This would often lead to incorrect colors, loss of detail and sharpness, and/or generally a lesser quality photo. See, not everything is as good as it seems. In the end, it is important to know how to balance your aperture, shutter speed, and ISO to achieve the best quality photo.
As time progresses, and technology advances, digital sensors are able to handle high ISO settings better and better. For example, though with today’s cameras, you may be able to shoot with the same ISO value as with a camera of 5 years ago, the way that the sensors read light, and the way that the camera processes the data from the sensors to produce an image, are of significantly better quality.
Reading your ISO
Now you understand that both low and high ISO numbers have their pros and cons, it would actually be great to show you a table with ISO numbers, which will help you get a better overview of ISO in your exposure.
ISO number |
---|
100 |
200 |
400 |
800 |
1600 |
3200 |
6400 |
12800 |
25600 |
51200 |
102400 |
204800 |
Notice how each ISO number doubles the higher that you set your ISO? With each double increment, you are basically doubling the sensitivity of your sensor to the light that enters your camera. Each doubling of your ISO number represents one stop of light. For example, if you are in a situation where your camera indicates that your exposure is one stop underexposed, you could double your ISO value to achieve a perfectly exposed photo. Below you will find a clear example of how to adjust your camera settings to achieve perfect exposure.
1 stop underexposed | Perfect exposure | |
Aperture | f/4 | f/4 |
Shutter speed | 1/80 | 1/80 |
ISO | 800 | 1600 |
On the other hand, if you are one stop overexposed, you could half your ISO value to achieve perfect exposure, as can be seen below.
1 stop overexposed | Perfect exposure | |
Aperture | f/8 | f/8 |
Shutter speed | 1/200 | 1/200 |
ISO | 400 | 200 |
When you are just starting out, it is not the most important to have a camera that handles ISO like the latest and greatest. It is important to learn to understand how ISO affects your images and how this setting can assist you to create the desires results in your craft.
After reading this article, or the articles about aperture and/or shutter speed, you may not fully understand yet how each settings influences your exposure and your final image. That is OK. We are here to learn, and we are giving you all the information.. all the technical knowledge, that you could use to better understand the bigger picture (pun not intended). From here on, you should grab your camera, try to play with the different settings, and see how changes in each setting will influence your photos.
Everyone starts here. You will make a lot of mistakes, and that is perfectly fine. Actually, that’s perfect! Without making mistakes, we will not understand why something does not work. So, don’t be afraid! Just have fun! And I will promise you.. it will only get more fun along the way!
In case you haven’t read our articles on ‘aperture’ and/or ‘shutter speed’ yet, then you’re missing out on some serious essential knowledge. We highly recommend you to read both articles to get the most complete information that we can provide you. Don’t worry, just as in this article, we will provide you with all the tools to get you started!
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