Part 2 - Aperture

What exactly is the Aperture of the camera?

It's the opening in the lens that allows light to come through. It can be REALLY wide or really small. Both work, but give different resulting images. If you see f/2.8, then the aperture setting was 2.8.

Here's the KEY to this setting:

The smaller the number, the larger the opening.

The larger the number, the smaller the opening.

Notice...it's OPPOSITES! :)

So, when a lens says f/1.8 on it, that means the largest aperture setting it has is 1.8. If it says f/4.0-5.6 then the largest aperture setting is 4.0-5.6 (it's variable and that's for another day). Some will have an "ending" aperture of f/16 or f/22.

What is the difference? Why do we care?

The larger opening gives a shallower depth of field. It is what creates that lovely blurred background that so many people love.

(f/1.8 ss 1/2500 ISO 200 85mm lens Canon 5D)

The smaller opening, the f/16, means that the depth of field is much larger and more of the image will be in focus.

Hmmm, why is this important to you?

Well, when I'm photographing Katie, I like to shoot around f/2.8 so that I can get her singled out in an image. She can be the focal point of the image. I can draw your eyes to her LOVELY eyes. :)

(f/4.0 SS1/200 ISO400 Canon 5D 24-105mm lens at 99mm)

However, if I'm shooting all 3 kids, then most likely they are NOT in the same focal plane (meaning side by side) and if I'm at a wide open aperture with a shallow depth of field and I focus on Katie who is sitting in front of JM...well, JM is going to be blurry! That's not good. If I make the aperture smaller, then I can get all 3 kids in focus (I usually start around f/4.0 or f/5.6 depending on how far away I am).


(f/7.1 SS 1/320 ISO 640 Canon5D 24-105mm at 73mm)

AND


(f/5.0 SS 1/250 ISO200 Canon5D 24-105mm at 105mm)
Notice on this one above, JM and Samuel are almost side by side, and I probably could have gone "wider open" than I did.

So, our lesson today, is to set your camera to a specific ISO (I'm going to suggest 1600 if you are indoors). ;) I would suggest finding a group of object, like 5 glasses sitting on a table at different lengths from you (front to back), or 5 toys, or flowers.

Then, move the Aperture to the widest opening (remember the smallest number) that you can (for some this is f/1.8 and other it might be f/4.0). If you have the ability to change the focal length (turn your lens to get closer or farther away), move it so that you are in as close as you can. Then back your body up to be able to see all of the items in one photo. Focus on the object closest to you, take the photo (write down the SS please). Do you NOTICE that blurred background?

Now, move the Aperture ONE up from where you were. Take the photo of the SAME object, and write down the SS. Repeat again and again, writing down the SS.

Do you see what the shutter speeds are doing every time you increase your aperture? Each time you make the aperture opening smaller, the Shutter speed HAS to decrease to compensate and make a properly exposed image.

I'm guessing that some of you are following me, some are not. It takes a few times doing this exercise and reading about aperture for things to sink in about the relationships. Don't worry, I'm going to go over this with a visual (or mental visual) soon.

What I want for you to have gotten out of this post, is that when you hold the ISO the same and change the Aperture...the Shutter Speeds change as well.

I also hope that at this point you are comfortable with changing the ISO and the Aperture settings on your camera.

PLEASE post your images to your own blog and let me know! I would love to see what you've done and how this is helping you. If you have questions, please let me know as well. If you post a comment here directing me to your blog with the images, I will be more than happy to comment on your blog with whatever help I can give you.


*note: to change aperture there should be a dial near the shutter button or near your thumb that has ridges. In AV mode you should be able to turn this to change the aperture. Check with the manual if this does not work. You should see numbers like 1.8, 2.0, 2.8, 3.2, 4.0, 5.6, 7.1, 8.0 etc.