FAQ Fridays: Aperture settings explained

Hi Everyone! Happy St. Patrick’s day! Hope everyone is wearing green! In honor of the holiday, we’re releasing this post one day early! It’s an FAQ Friday post released on a Thursday ;p. Anyhow, to show our St. Patty’s day spirit, we went out to an especially green location to shoot a special VIDEO episode of Pretty Geeky’s FAQ Fridays (where you ask your photography questions and we try to answer them in plain english). This week, we’ll try to tackle a question that we probably get asked more often than any other question:


What camera settings do you use when you are out on location?


There is no magic setting that will work for every situation. This might not be the answer you want to hear, but really is the truth. Getting the correct exposure for your photos is about understanding the light (or lack of) that you are faced with at any given location. One setting that will work for one location, might not work for another.

To really get an “answer” for “what settings to use”, you must try to understand the three important settings that all combine together to create (properly expose) your photograph. These three settings are the same three things we have mentioned before: Aperture, Shutterspeed, and ISO. Don’t worry though, we have a special video below to better explain this. It is the first of three videos we will post to help you better understand the principles of photography.

Aperture Settings Explained:

What aperture settings should you use when you are on location? When should you use a particular aperture setting? Hopefully the video will answer all these questions. But before we start the video, you must first understand the basics of what “aperture” is, what it does, and how it affects your photos.

1. The “aperture” itself is the physical hole or opening on your lens through which light travels.
The “aperture setting” then is a measurement of how big the opening is. Think of the “aperture setting” as a drinking straw stuck through a cup. The bigger your straw, the more water can get through (or in this case, the more light can pass through). As mentioned before, aperture is one of three settings that controls the exposure of your photograph. Too much light and your picture is super bright and over exposed. Too little and everything is dark.

Need another example? Ok, you have a new house and your living room has a brand new black carpet. Now you’ve decided that you want to throw a house warming party, so you invite all your friends over. On the day of the party, your idiot sometimes absent minded husband decides to paint the whole front porch white. Now all your friends are outside stepping all over the wet white paint, waiting for you to open the door so they can all come in and step all over your brand new black carpet.

If you open your door nice and wide, they will all rush in and put the white paint wherever they step. The wider your door opens, the more friends you allow in; the more friends that are in, and the longer they stay, the more your carpet will be covered in paint. But, if you kick them out right away, you will see just some paint on your carpet. And if you let them walk around the carpet long enough you will have a completely white carpet and a black and blue husband ;p.

I hope I didn’t lose some of you with this example lol. Get the idea though? In the example, the black carpet = your camera sensor. The light = your friends with the wet paint. Your camera sensor picks up all the light it sees and automagically creates an image file out of it. Yays for technology! Now let’s talk about the camera settings in relation to this example. Your aperture setting = how wide your door opens. Your shutter speed = how long you let your friends walk all over. Your ISO = how sensitive your carpet is to stains.

In photography, your aperture setting controls how much light is passed through to the camera sensor, your shutter speed controls how long the light can “paint” on the sensor and finally, your ISO setting controls how sensitive your sensor is to all this light. Can you start to picture how all three things work together now?

2. Aperture is measured in f/stops.
F/stop is sometimes referred to as: f-stop, f-number, f-ratio, or lens speed. Basically it is the size of the opening of the lens. Numerically, it is the focal length of the lens (f) divided by the diameter(how wide) of the opening. So yes, it is a fraction: f/number. And if you recall 5th grade math, with fractions… the larger your bottom number, the smaller the total value is. Just like 1/100 is a smaller value than 1/2. And because f/stop is a fraction it behaves exactly the same way: f/22 is smaller than f/1.8. What does this mean? At f/22 the hole that light passes through your lens is super tiny… while at f/1.8 the hole is huge. Take a look at the photo below for a visual representation:

aperture sizes

BTW, my sincere apologies for bringing back nightmares of grade school math lol. And yes after much tv game-show footage, I for one, am definitely not smarter than a 5th grader! =/.

Aperture Settings: The Video

Anyways.. enough talking huh? Let’s jump into the cool video we have to show you how your aperture settings affect your photos. BTW, this video was shot with the brand new iPad 2 video camera. iPad 2 still photos totally sucks… the video camera is acceptable. iPhone 4 definitely has a better video and still camera. =/



I hope our video above gives you a better understanding of Aperture settings and how they affect your photos. In summary:

  1. Aperture setting is the size of the opening of your lens.
  2. Aperture setting is part of three things (aperture, shutter speed, ISO) that defines the exposure of a photo.
  3. Aperture setting affects the depth of field (DOF) of your photos: what you see and don’t see in focus. An f/stop of f/22 = deep depth of field. With a deep depth of field, more of everything in the photo will be in focus. An f/stop of f/1.4 = shallow depth of field. With a small (narrow/shallow) depth of field, only a few things in the photo will be in focus. Technically, depth of field is the distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image. You can think of DOF in terms of 3D. DOF is more a distance measurement (how near and far from your camera) NOT a sideways measurement of what’s in focus (wide and narrow from your subject). More info on depth of field here.
  4. Ways to “cheat” to get the most background blur out of your lens is to: 1. zoom in 2. get your subject as far away from the background as possible. 3. open up your aperture as wide as it can get (set as low an f-stop number as you can go).
  5. Lens that have big apertures (f/2.8 to f/1.2) are considered “fast” lenses and will enhance your ability to take nice photos in dim light conditions without having to use flash.
  6. update:For you number junkies out there, you can use this online DOF calculator to understand how much room you have to work with before something gets de-focused (a loose definition of DOF) at different f/stops and distances.

Just in case you wanted to see, here are the photos that are in the video. Photos were taken under natural light with the Nikon D700 with the 50mm f/1.4 lens.

What is FAQ Fridays?
FAQ Fridays is an ongoing weekly feature on this site where WE answer questions submitted by you. We hope this new segment will help with many of your photography challenges. As always, you can ask questions in the comments section if it relates to that certain post.

Here is a list of: all previous FAQ Fridays posts

If you have specific questions that do not relate directly… then feel free to submit your questions by using the FAQ Fridays Submission Form page.

Alternatively, you can email your questions to: faq -at- prettygeeky.com (note: email broken up to prevent spam bots).

  • Fay said:

    Thank you guys for the easy explanation, plus the sample pictures, finally it makes sense to me :D

  • jenny said:

    thanks so much for this tutorial...it really helps me to understand aperture even more...can't wait to see the upcoming video...

  • Vaameng said:

    Great tutorial! Love the shots for side-by-side comparison.

    One question though. How did you get the DOF with the 1.4 aperture? Was this due to being further away from your subject?

    Often times when I shoot at such a wide aperture, there is such a thin slice of focus that the majority of my subject is out of focus.

    • tyger said:

      Aperture controls your depth of field (DOF)... which yes, can be affected by distance. The further your subject is from the camera, the larger the depth of field becomes even at the same given aperture setting. It is part of the reason you can "cheat" to get the most background blur as possible by moving your subject closer to camera. And contrastly, as you move in closer to the subject, your DOF becomes increasingly narrow... razor thin at times; this is how you can get just the eyes in focus and the rest of the body de-focused.

      DOF is also affected by focal length. Standing at the same distance from camera to subject and using the same f/stop, at wide focal lengths (10-35mm) the DOF gets larger (more in focus) than at long focal lengths (85mm +). The reason for this is that long focal lengths essentially brings your subject closer to you, which coicides with what was said early, bring your subject closer to you (either by zooming or them moving) to get more background blur.

      If you're a numbers junkie, you can visit this online DOF calculator to see how much room you have to work with (basically your DOF) before something gets defocused.

  • Naley Xiong said:

    Thanks! It's given me a better picture what the aperture can do! Thanks!

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  • James said:

    Awesome, yet simple idea - demonstrating f/stop through pictures. My biggest hangup is trying to remember what the low numbers mean vs. high numbers.