Okay, skill testing question. Who knows what ISO means in photography!?
IS IT?:
- Image Sensor Options
- International Standards Organization
- In-Side Out
Yeah, the last one was my husband being funny…
But if you guessed International Standards Organization, you are correct! I just looked this up, so until now I had no idea this is what it meant, nor would I have guessed International Standards Organization. It sure didn’t sound very photography-like to me!
Here’s a summary of what I found on Bright Hub:
ISO (a standard industry scale) measures how sensitive your camera sensor is to light. ISO is measured in numbers, and the lower the number, the less sensitive your camera will be to light.
CHOOSING THE RIGHT ISO SETTINGS
My Canon 70D for example goes from ISO 100 all the way to ISO 12,800. 100 is considered a low ISO. I can use this in brighter surroundings because at ISO 100, my sensor is less sensitive to light. At ISO 12,800, my camera will be very sensitive to light.
I’ll usually try to keep the ISO as low as I can, like somewhere between 100 & 400 during the day. The reason why is because the higher you go, the more grainy your photo becomes.
So, although my camera has the capability to go quite high, I’ll try not to go any higher than ISO 1600, even in dark surroundings, because of how grainy my photo will look.
I took two shots here with the exact same Shutter Speed and Aperture. The only thing I changed was the ISO to show how ISO affects the sensors sensitivity to light:
I did the exact same thing for these photos, except in the left photo, the dining room light is on and in the right photo, the light is off. I didn’t want the image with the higher ISO to be overexposed because I wanted to show how increasing the ISO will result in a grainier image.
HOW TO REMEMBER ISO:
Bright surroundings – low ISO (like 100 to produce nice clean image)
Dark surroundings – higher ISO (but not higher than ISO 1600 to avoid a grainy image)
But what if at ISO 1600 the photo still looks too dark? Then, try to adjust the other two elements of exposure (Aperture & Shutter Speed) to allow the desired amount of light through the sensor.
LITTLE TIDBIT:
My notes above on recommended ISO numbers to use relate to my experience with a crop sensor camera (Canon 70D). With a full sensor camera like the Canon 6D Mark II, you can go as high as ISO 6400 or even higher and the resulting photo won’t be nearly as grainy as ISO 6400 on a crop sensor. Great for future endeavours with astrophotography!