Friday, August 14, 2009

Friday's photo Tip - What Does the Aperture Do?

Friday's Photo Tip - What Does the Aperture Do?

macro of f-stops on an old lens

"Aperture" is a photography term that we have all heard about, but sometimes don't really understand what it is or how it works.

If anyone has taken the time to read the owner's manual for their camera, whether you have a point and shoot, or a DSLR, you have run across this term.

How well it is explained in those manuals is another topic.

Most times, you will have read something about your camera being automatic, shutter priority, aperture priority, or manual when it comes to taking photos.

The auto setting is the most popular so the other terms aren't usually given too much thought.

There is an aperture in every lens, and it is used by the camera to control the amount of light that reaches the film or digital sensor.

This aperture is adjustable - from large openings to very small openings, depending on the amount of light that is available.

The size of the aperture is controlled by a ring (on the old lens photo above) that is closest to the camera body.

This ring has numbers that usually range from 1.4 up to 22, and they are known as the f-stop numbers.

These numbers are a value that is given to the aperture opening, and in photography, the lower the number, the bigger the aperture or opening.

The larger the number, the smaller the opening, which usually means you have a lot of light available for the photo.

Think of it like the iris in your eye, because the aperture in a lens works just like one.

When it is really bright outside, the pupil is very tiny - only letting in a small amount of light.

When it is dark, the pupils are huge - they need to let in as much light as possible.

In most digital cameras of today, the aperture is controlled by a dial on the camera, not the lens, and it all still works the same way as the old lenses do when the photo is taken.

And the next question is, what do these f-stop numbers mean, and why does a photographer need to know about them when the camera can automatically figure the light available and pick all the correct settings itself?

Ah - but that's one of the fun parts of photography, and I will explain it the best I can in next week's Friday's Photo Tip.


  1. It's been a long time since I used the f-stop. I do so want a new digital camera. I have all these lens and no Digital camera to put them on and then I hear the new digital cameras might not be compatible do to the way the new lens are configured. Some day, maybe Christmas..New Camera.

  2. Excellent Kathy!! This is an area where I have encountered a great deal of confusion.

    My manual is very confusing and actually does not explain it very well at all.

    Now I understand where to go, mine controls are inside my camera for this action, and tomorrow while we are out for a drive I will play with different settings.

    I have promised Mimi that I would reserve a day this week to write about the Blogblast for peace. So that will be my post for tomorrow.

    But, I am going to try my best to remember to make my post next Thursday all about your Friday photo tips.

    I know there are a ton more out there other than myself that also need this help.

    Thanks for stopping by today. I knew many were going to be surprised. I was up almost 24 hrs. while she was working on it and still am not completely rested up.

    We are grilling out tonight and I am only making a few more visits today.

    I hope you have a great weekend!!

  3. We were out all day yesterday Kathy and I did try different lighting settings. But, I still get so frustrated with this camera.

    Walter was using our old Kodak Instamatic and it shoots a clearer, higher PXI, and truer colored image than what I can get.

    What happens if I hit the format button? Will it reset everything back to the way it was when I bought my camera or will I wipe out everything?

    I really need to start from scratch, keep working from your tips and also take that class online in October.

    Geez, I bet you could teach a class online. The people teaching at this place are just professional photographers. It's not an accredited class or anything.

    It's at if you want to check it out.

    Yesterday we found the most lovely spots while we were out and I was so disappointed in the quality of my images when I got home and downloaded them.

    The lighting is really off. But, the place is close so as I get better I can always go back and do a re-shoot.

    I hope you have a great week,

  4. Kathy you are the best. Your explanations are simple and to the point. I use aperture a lot, it is starting to be more fun playing with all the controls on the camera. Thanks for sharing as always, Anna :)

  5. I've been taking photos for about 2 years but I'm STILL trying to learn all of this. I will have to check back in for your next tip!

  6. Very nice blog. Good tips. But do you have also a tips with regards in printing? I'm also interested. Thanks for that post.

  7. Love your analogy with the iris, looks like you have a well used lens there,lol.

  8. Love your Friday tips.. Looking forward to your next one.. :)


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