your aperture and changing your focus point

Remember aperture? If not, check out my definitions page. It’s the opening in your lens that allows you to do two things. One, it allows more light in and two, it controls your depth of field (how much is going to be sharply in focus in the background.

These two pictures below are taken at the aperture (also known as f stop) of 2.2. That means the hole in my lens is open up really wide, the hole is big. So, my depth of field behind my subject is shallow, creating a blurry background. The background is not sharply in focus. Right? So that’s a shallow depth of field. Make sense? These two pictures were taken with the same settings but a different focus point. When taking the picture on the left I focused on my little boy’s eyes. In the picture on the right I didn’t change any of my settings, but instead I focused on the donut. :)

My manual settings for this shot were:
ISO – 800 (inside the donut shop)
aperture – 2.2 (open pretty wide open for light and for a very shallow depth of field)
shutter speed – 1/250 second

aperture and focus


  1. Chrissy on September 1, 2010 at 11:56 am

    I just moved to Fresno from LA, and while google’ing local photography, I found you, and I LOVE YOU!! It feels like your blog was written just for moi!
    If you ever offer a class for intermediate folks, let me know! I know just enough to be dangerous. Sometimes I take a pictures and I am in love with the results, and even MORE often, I take a picture and it is crazy over/under exposed and by the time I’m done tweaking ISO, Fstop and Shutter speed, my 15 month old is hanging from the rafters naked.
    So- more on shooting in sunlight, getting shots with a high ISO that aren’t super grainy, and that kind of stuff.

  2. Cori Derksen on September 7, 2010 at 1:36 pm

    thanks for your sweet comment. i love hearing that this blog might just be helping some people! awesomeness! :) i have some things in the works for some intermediate people, but for now you should check out our facebook page and take on some of our photography challenges! :)

  3. Vicky on May 26, 2011 at 8:32 am

    Hi Cori, Looking at this website has REALLY helped me. I about to do a newborn shoot and feeling a little nervous. But, thanks to you i have some great knowledge! Thanks so much!