ISO and Exposure Review – Photography Lessons 3 and 4


We’re learning how to use a DSLR camera by following lessons on This month’s assignments were about ISO and Exposure Review.

In my second month with The Photo Ladies, we’re focused on ISO and tying it together with what we learned in last month’s lessons on aperture and shutter speed.

The Photo Ladies

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Being part of The Photo Ladies has been a great way to learn how to actually use the  Nikon D3200 DSLR camera I got for my birthday a few months ago. With two busy little boys at home, it would be easy just to put the camera on auto-mode all the time. Being part of the group is holding me accountable to actually figure out how to use the camera to take better photos.

About The Photo Ladies

If you’re just joining us now, The Photo Ladies is a group started by Teresa at Crafty Wife. “The Photo Ladies” is a group for people who want to learn and grow in our photography endeavors together. Together, the Photo Ladies are following free photography lessons for DSLR cameras on (As of March 16, 2019 this site is no longer available). Each month, we go through one or more lessons. At the end of each lesson, we get an assignment and post our results on Flickr. The members of the group can comment and give each other feedback so we learn from one another.

Our April Lessons: ISO and Exposure Review

In our latest lessons on, we’ve been learning about ISO to help us understand exposure. ISO indicates how sensitive a film or digital sensor is to light. For more specifics about ISO and how it relates to aperture and shutter speed for proper photo exposure, you can read the lessons on

  • What is ISO?
  • Tying Everything Together

Assignment 3: ISO

In this lesson, we learned how ISO sensitivity is measured in numbers, similarly to aperture and shutter speed. The lower the ISO number, the lower the sensitivity of the digital sensor or film is to light. This means to get proper exposure of a photograph, you need more light to hit the digital sensor or film. Thankfully with today’s digital cameras it’s incredibly easy to change ISO settings. With film cameras, the ISO rating was built into the roll of film so you had to use the whole roll before you could change your ISO. What a pain!

Generally speaking, this is the rule of thumb for which ISO rating to use:

  • ISO 100-200: Outside on a sunny day
  • ISO 400: Outside on an overcast/cloudy day or in the shade; Inside with lots of light
  • ISO 800 and above: Inside with minimal light; Other low light conditions, sports or action shots and night shots

Our assignment was to set our cameras to Program mode and take three photos: one outside in sunny weather, one outside in the shade and one inside with low light conditions. With the camera in Program mode, we’d be responsible for setting the ISO, but the camera would automatically set the aperture and shutter speed to get the proper exposure.

My first photo was taken outside in the sun using ISO 100. The camera set the aperture to f/10 and the shutter speed to 1/400.

ISO and Exposure Review - Photography Lessons 3 and 4 -

The second photo was taken outside in the shade using ISO 400. The camera set the aperture to f/8 and shutter speed to 1/250. Shade or overcast really seems to be ideal for photos as you get great photo exposure without all the shadows.

ISO and Exposure Review - Photography Lessons 3 and 4 -

The third photo was taken inside using ISO 3200. The camera set the aperture to f/5 and the shutter speed to 1/100. With the higher ISO, you have more “digital noise”, which lowers the clarity of the photo and gives it a slightly grainy appearance. If you look back at the first photo taken outside in the sun at ISO 100, you’ll see it looks much smoother than this one.

ISO and Exposure Review - Photography Lessons 3 and 4 -

Assignment 4: Tying It All Together

Our second lesson this month took what we just learned about ISO and tied it into our previous lessons on aperture and shutter speed. ISO, aperture and shutter speed can be combined in different ways to have creative effects in photography. However, for a photo to have proper exposure, all three elements must be in balance. We learned about the “Sunny 16 Rule” which states that “when using f/16 on a sunny day, you can use a shutter speed that is roughly equivalent to the ISO setting to get proper exposure of your scene. So, if we use ISO 100, we can set the aperture to f/16 and set shutter speed to 1/125 sec which is roughly equivalent to ISO.” (Source:

If you want a tighter photo with a more blurred background, you need to decrease your aperture or f-stop number. As a general rule of thumb, for each full f-stop you decrease, you need to double your shutter speed to get proper exposure. Likewise, if you’re trying to take a photo of a quickly moving subject (like a toddler!), you need to increase your shutter speed. The general rule of thumb there is to halve your f-stop for each full-stop increase in shutter speed to maintain proper exposure. 

Our assignment was to set our cameras to Manual mode and practice, practice, practice! Having the camera in manual mode means we’re responsible for setting the ISO, the aperture and the shutter speed for each photo. Thankfully, the camera has a built in light meter to show when the photo has proper exposure. We could set up the shot we want and then make adjustments to the settings until the exposure was correct.

My first photo was taken outside using ISO 100. I wanted to test out a new lens we just got to take photos at very low apertures (Nikon 35mm f/1.8G AF-S DX Lens). It was my goal for the toy in my photo to be super clear, but the background to be very blurry, so I set the aperture or f-stop to f/3.2. To maintain the proper exposure, I had to significantly increase my shutter speed to 1/2,000.

ISO and Exposure Review - Photography Lessons 3 and 4 -

For my second photo, I took a picture of the same subject at ISO 100, but wanted the background to be more recognizable so I set the aperture or f-stop to f/20. With the increase in f-stop, I needed to lower my shutter speed to 1/50 to keep the photo properly exposed. Now if only I could remember all these rules of thumb! I guess that’s why we’re supposed to practice, practice, practice.

ISO and Exposure Review - Photography Lessons 3 and 4 -

Join the Photo Ladies

It’s not too late to join the Photo Ladies. The lessons and assignments with the Photo Ladies are easy and don’t take much time. It’s also been a great way of holding me accountable to learn how to take better photos with my camera. You can see all the photos from our assignments in the Photo Ladies group on Flickr. If you’d like to join the Photo Ladies, visit Crafty Wife for more details.


This blog post contains affiliate links. All opinions expressed are our own, derived from our personal experience.


While you’re here, be sure to check out these great ways to take and display your photos on Ideas for the Home by Kenarry® –

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  1. Okay, I seriously do not understand the Sunny 16 rule! I don’t know why I’m having such a hard time grasping it. I think I’ve read that page at least ten times and it’s still over my head.

    But…your photos are awesome! I actually looked into the 35mm lens the other week at Best Buy but opted for my wide-angle (20mm) instead. I think, once we have kids, that 35mm will be great! But since I do mostly landscapes the 20mm ended up being more practical. However…I love the 35mm and the low f/stop it provides. It’s a great lens!

    Keep up the awesome work! I really love the group and I love looking at the progress everyone is making. 🙂

    1. I don’t understand the Sunny 16 rule either! It needs a clever phrase to remember or something. Maybe we can make one up? Thanks for stopping by to give your feedback, Teresa. I appreciate your encouragement!

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