ISO, ISO, What is an ISO? | Atlanta Child Photographer

ISO, ISO, what is an ISO? When the title for this blog post came to me, it was in the form of a song. Do you remember the Limbo Song? Limbo, limbo everybody limbo. No? Anyway, I believe it’s a Calypso song that went with the party game, Limbo. ISO, much like Limbo, has been around for a long time. If you’re new to photography or a hobbyist, you may have heard about ISO but not sure where it came from. ISO said as one word or each letter, I-S-O stands for International Organization for Standardization, which was created in 1987. Yes, I know the order is not the same but I didn’t name it. It came about from the combination of ASA (American Standards Association) which uses an arithmetic scale to measure film speed and DIN, created by the German Institute for Standardization, which uses a logarithmic scale to measure film speed. 

Now you’re probably saying, “What the heck? Film speed?” Yes, back in the day, the film’s light sensitivity was measured in terms of film speed. Film speeds went from 50 up to 6400, I believe. The higher the number, the more sensitive, meaning the faster your shutter speed at higher f-stops. The main drawback of a very high ISO is graininess. If you want grain, fabulous. If not, not so much. Now if you’re still wondering about how to effectively use ISO, here’s a hint: it’s very good in low light situations. 

As you may or may not know, ISO is part of the exposure triangle (ISO, shutter speed and f-stop). They all work together to provide you with a properly exposed image. Let’s say you are shooting with off-camera flash. Most flashes don’t sync with shutter speeds higher than 1/200 or 1/250 of a second. So, to get around that you could either use high-speed sync if you have it or you could just bump up your ISO to increase the light sensitivity of your sensor. Another example is if you want to use a higher f-stop with a fast shutter speed so that you can capture more detail and freeze motion but there’s not enough available light, you can bump up your ISO to add more sensitivity. You may want to practice this to get more familiar with how ISO works and how it works with the other parts of the exposure triangle. 

It is important to remember that changing the ISO does not change your creative choices. What I mean by that is, if you want a shallow depth of field, changing the ISO will not change that aspect of the image. The same goes for the shutter speed. In sports photography, shutter speed is very important. You make decisions based on whether you want to stop motion completely or have a little bit of blur to imply motion. ISO does not change any of that. And if you’re thinking of photographing weddings, you definitely want to master using the ISO because some churches do not allow flash during the ceremony. If you’ve ever been to a church, then you already know that many are dimly lit. 

Welp, that’s it for this week. I hope you learned something that you didn’t know and that it was helpful. If you have any ideas as to what other subjects I can tackle for you, please don’t hesitate. I’m always looking for good content to provide. Thanks so much and remember, sharing is caring unless it’s a cold sore.