A little lesson in ISO:

Ok so, you may be wondering,

“What’s this setting marked ‘ISO’ on my DSLR, and why do I need it? It’s set to auto anyway.”

Well young photographer, your ISO setting is more important than you think. I personally never used to take much notice of it, until a friend set me straight.

ISO stands for “International Organisation for Standardisation” (IOS? Hah.)

As per their website:

ISO is an independent, non-governmental international organization with a membership of 162 national standards bodies.

Through its members, it brings together experts to share knowledge and develop voluntary, consensus-based, market relevant International Standards that support innovation and provide solutions to global challenges.


So basically, what the ISO do, is decide the standards to which lots of things adhere. This includes the afore mentioned camera settings.

They’ve decided that a certain level of camera sensor sensitivity shall be called ISO 100, and another level ISO 200, and so on.

Back in the day, these standards were applied to film cameras, and were used to designate film sensitivity. But luckily now that we are in the digital age, we don’t have to use film, and can switch our ISO settings on the fly.

There’s actually a few aspects of the picture that ISO can contribute to.

How much grain is in the photo, and how bright or dark it is.

Generally speaking, the higher your ISO setting, the brighter the picture will be, but the amount of grain will also be prominent.

And of course, the opposite is also true. The lower the ISO, the darker the picture will be, and the less grain you’ll see.

Luckily Wrench has allowed me to take some photos to demonstrate.

wrench ISO difference

These two photos were taken with exactly the same settings, except for the ones listed in the picture.

You can see that the ISO 6400 photo on the left is definitely grainier than the one on the right. However, you’d need a tripod to take a photo of the same brightness on ISO 100, because you’d need to expose the sensor for 5 seconds instead of 1/13th.

Why? Because ISO 100 lets a lot less light in, and as a result, if I took both photos at 1/13th of a second shutter speed, the ISO 100 picture would basically be black.

So there is an advantage to shooting at a higher ISO setting. If you can deal with the grain, you can take very quick photos with a lot less light.

Here’s another closer picture:

wrench ISO difference close


Again, look at the amount of detail you lose in the ISO 6400 shot. But also look at how long the sensor was exposed compared to the bottom picture. Quite a difference.

You’d need a very very steady hand to take the bottom picture unless you were carrying a tripod around.


And that about covers my current knowledge of ISO and the like. It is a super important and occasionally powerful setting.

Until next post~!

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