How To Shoot Manual – Understanding ISO
Last week I did an overview on all three of the settings that directly affect the exposure of an image: ISO, aperture (also known as f-stop) and shutter speed. I gave a few fun exercises and I hope you enjoyed them! Today, I want to dive more into ISO and why it’s so important to understand it more than just letting light in.
Back in the film days (which is still today for me and some of my friends!!), ISO was that number you looked for on the film box. Remember that 200, 400, or 800 film speed you used to commonly see? That was ISO! Today in the digital realm of photography, ISO is simply a way to measure the camera sensor’s sensitivity to light.
As the ISO number gets higher (800, 1600, 6400…) it lets more light in. For example, if you’re outside on a sunny day, you’ll set your ISO as low as possible (somewhere around 100-200). If you’re inside a room and you’re far away from the windows, you might be between 800-1600 or even higher (let’s hope not)! So why is is a higher ISO number not preferable? There is a secondary effect.
See, grain is a style that can be super pretty to some, and not preferred to others. I personally find grain pretty in some cases! Do you see the amount of grain in depicted in the photo directly above as opposed to the first image in this post with less grain? This is a direct effect of a higher ISO setting! Now, it’s not bad to have camera grain if this is something you find artistic or intriguing, but you must understand the cause/effect of ISO settings to better achieve your vision while photographing in different settings.
Below, I’ve included three SOOC (straight out of camera) images to compare what the ISO setting does to the same image.
ISO 25600, Aperture (f-stop) 2.0/f, Shutter 1/250.
This image above has the most grain of the three, because the ISO is higher here than the other two.
ISO 4000, Aperture (f-stop) 1.4/f, Shutter 1/50.
This image has less grain than above. Notice my shutter and aperture were higher above as well. This is because I had to balance the other settings when I let less light in with the ISO setting. I lowered my ISO to let less light in, but I compensated by slowing down my shutter speed and opening up my aperture to allow more light in. By doing this, I eliminated some of the grain while keeping the exposure almost the same!
This image is with flash, just for comparison. The other two above are ambient light (available light) with no flash.
Settings: ISO 800, Aperture (f-stop) 2.0/f, Shutter 1/50.
See how much sharper this image is when I used the flash to add more light and was then able to lower the ISO even more? The lower my ISO setting is, the more crisp the image appears.
I always set my ISO first, because it is one of the settings I change the least. Shutter is my last setting to think about, because I change it so frequently. What I like to do is choose my ISO based on the lighting conditions, and then I choose my aperture and shutter next based on other variables we will get to later!
Here are some starting points you can work with when setting your ISO. Keep in mind this is very rough, and it won’t always work! Use it as a starting point. Adjust your aperture and shutter, and if it’s not working go back and start over with an ISO to let more or less light in.
Outside on a sunny day:
– Shade – 100 ISO (or the lowest your camera allows)
– Full Sun – 100 ISO (or the lowest your camera allows)
– After the sun hits the horizon – 400 ISO (and keep going up as it gets darker! Once you hit 1600 you may need to go home or get a flash!!)
– By a window – 400-640
– Far from a window – 800-1600+
Tip for inside photos! If you can, turn off all of the lights in the room and bring your subject close to the window for nicer photos! This eliminates that sometimes ugly yellow light mixing with blue light.
I hope you’ve enjoyed this post on ISO and feel like you understand it a little better! If you have questions be sure to pot them below! Want to set up a one-on-one coaching session with me to walk you through this in person? Email me! email@example.com