The term ISO sounds for the most people too technical and maybe that is the reason why the most beginners in photography hesitate to deal with it more detailed. But I can reassure you that this topic is much easier to understand as assumed. Let me explain it with a different example than photography.
I assume, the most of you guys possess or have had a CD player or a MP3-Player. And here is the deal: when you turn up the speakers, the music gets louder. But there is a point where the speakers begin to make some weird noises when you crank the loudness too much up. You will still hear the music, but it is not clear anymore. You will hear a kind of tone overlapping, and the sound gets confused.
The same is about the ISO, with the difference that it is about pixels and not about sound waves. Every digital camera has a light sensitive sensor which collects the light and transforms it into pixels, so you can see the photo.
And every sensor can be „adjusted“. This adjustment is expressed in the so-called ISO. The higher you turn up the ISO, the more do you tell to your sensor, how bright you want the picture to be. Hence, the more you give, the brighter will be your Image. This feature is usually helpful when you don´t have enough natural light, for example in the afternoon, a cloudy day or in night photography.
Hence, this is the positive aspect of the ISO. The negative one is that your pictures become noisy when you add too much of it. As a result you would get pixelated pictures which are looking grainy. Therefore, you should keep in mind that brightening a picture with ISO could be a balancing act.
Which ISO is the best?
If you are wondering about the best ISO, I can tell you that there is no best value. Actually, it depends on the situation. There are situations you should use a low ISO and there will be moments, you need to crank the ISO up. Let’s take a closer look on it.
Low ISO: Use the lowest value of ISO as possible when there is enough environment light. This is typically a value between 100 or 200. Some digital cameras have an extra feature which allows to minimize it to 50. But even in dark environments you can keep the ISO low to avoid digital noise in your photos. But in this case you should mount your camera on a tripod.
High ISO: Use a high ISO in situations of low light and absence of a tripod. For example, when you want to shoot motifs in motion, you should crank it up to avoid motion blurs. The next situation when you could use the high ISO is at night photography. For at night there is too little light (even with a full moon). But remember to not exaggerate with this. The most modern digital cameras allow to increase the values to 25000. But these values are not expedient and would cause a lot of grain and noise. Hence, when we are speaking about high ISO, we mean values between 800 and 3200. But remember, this is not a rule carved in stone and you should make your own experiences with that.
Interplay of three components
The ISO, shutter speed and the aperture don´t work separately from each other but always together. This interaction can be summarized in one generic term: the exposure.
For a beginner it might be a little bit tricky to deal with these actors of the game. But there is a key to success: practice, practice and again, practice. Thanks to digital cameras you can practice a lot without expenses. Before this time, when analog cameras have been up to date, you would have spent a lot of money for the films. But now you have the best conditions to become a good photographer, whether a pro or a passionate hobbyist.
Here I need to give you some extra information. As you can see, I consider ISO as a part of an exposure. Over time you will find out that there are a lot of photographers who say: ISO is NOT a part of an exposure.
But let me tell you this: the topic about ISO is an „eternal dispute“ and you can consider it like you want. For me, this is a part of an exposure. If you don’t agree, it is also okay and actually does not matter. If someone speaks to me and says I am wrong about ISO, I usually answer: „So what? Does it really matter? I don’t think so. What really matters, is to do outstanding pictures and not to waste time on discussing what is what.“ Now take your camera and start to practice, guys.
Concluding a final information for all of you, who are interested to learn photography seriously and to improve their skills: I can recommend the book from Jim Miotke “BetterPhoto Basics”. It is a good book for beginners and with its help you will learn a lot of photography basics.
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