ISO is one of the most critical options for people who want to take good pictures. This setting has just as important an effect on your images. If you're just starting on your photography journey and want to learn more about ISO camera meaning, you can further explore the article on the Skylum website. In this guide, we've compiled the most important things you need to know about it. After studying our tutorial, you will be able to significantly improve your skills and get one step closer to professional photography.
Let's explore the meaning
This is an extremely important parameter that determines how bright the picture will be. ISO is very useful because it gives you extra control over your exposure. It's an international standard that was established back in 1988. It`s functions differently in film and digital photos, now we will look at the second option.
Unlike shutter speed and aperture, it does not change the quantity of light that enters the camera, brightening or darkening the picture.If you look deeper, it is not one part of the exposition. The reason is that this parameter shows exactly the sensitivity of a sensor.
After the light has passed through the aperture and been filtered by the shutter speed, it reaches the sensor. By increasing it you increase the brightness. But at the same time, the image quality decreases, and there is more digital noise. That's why you need to prioritize your exposure and grain ratio. ITo make the picture clearer is the main task. In this case you can increase the values, which will decrease the quality of the picture.
So why do we use this setting?
We generally use it because the two main exposure metrics, shutter speed, and aperture, do not give us enough latitude to create the right exposure in all situations. Both shutter speed and aperture can be used to change exposure, but they also have some drawbacks. For example, the shutter speed controls motion blur, aperture controls the depth of field and sharpness.
With these two parameters only you cannot easily combine any shutter speed with any aperture value. The image will be overexposed, and this is unlikely to be the right decision. That's why an ISO value was brought in to control brightness independently of the other two, setting the sensitivity to incoming light and the amount of graining in the image.
Understanding ISO Stops
It is measured in stops of exposure value. The scale in a camera is similar to the shutter speed in the sense that doubling it also doubles the exposure. Stopping in ISO means doubling or halving the light (when compared to the previous stop). Let's understand step by step, with examples:
- The parameters are proportional to each other. A low ISO value gives a darker exposure, and a high one gives the lightest possible exposure. This is much easier than the aperture.
- Generally, the lowest value will be ISO 100. This is the darkest value, also called base ISO. The next full stop, ISO 200, is twice as light, and ISO 400 is even lighter. So there are two stops between ISO 100 and 400, four stops between 100 and 1600, and so on.
- This series can be continued, but it has some practical limits. Where exactly that limit depends on the individual camera. However, we can use ISO up to ISO 6400 to 25600. That means 6-8 stops of extra lighting. To put it more simply, you can properly expose 64-256 times darker surroundings than at the basic settings.
In newer digital cameras, there are even higher settings, but they degrade the picture quality so much that they are almost unusable. When adjusting ISO, most cameras offer more precise values than just full stops. It is most likely that all exposure settings are changed in 1/3 stop increments.
The biggest problem with high ISO – noise
A higher ISO is insanely useful. But there is a serious price to pay. The higher the ISO, the more noise or grain appears in your photos, which looks like specks of color and light randomly scattered over the image.
A higher ISO, while good for you, is a compromise. Yes, you get a brighter image, but the noise increases. For this reason, you can't shoot at high ISO all the time. Instead, you have to lower the ISO when you can and raise it when you need to. Just a few years ago, ISO 800 could lead to a huge amount of noise in photos. But now, you can shoot at ISO 1600 or 3200 and get noise-free photos, as long as you use a full-frame camera with the latest sensor technologies, and that you've used good exposure control techniques.
How do I adjust the ISO setting to get great photos?
It depends on the occasion and circumstances. A good guideline for novice photographers is to leave the baseline value for ISO except in the following three situations:
- The lighting is very low and you need to take a well-exposed photo.
- You need to freeze the picture in motion or take a sharper shot.
- It is very important to get an image with sufficient depth of field.
If you increase the ISO setting, the dark picture will be as bright as possible, but the noise level will also increase. When the ISO sensitivity is lower, the original quality of the picture will be maintained, but the picture will be blurry or underexposed. If you want to learn more about what is ISO in photography and the peculiarities of setting it up, we recommend reading the Skylum blog page.