Depth of Field

Last week someone said to me, "you always take photos with the background all out of focus."  I never really thought about someone seeing it that way -- I like to think of it as my subject is in sharp focus.  But by doing it that way -- making sure the subject is sharp -- most of the time the background is not.  He wanted to know how I do it.

I shoot in aperture priority most of the time.  This is what I choose because -- for me -- the depth of field is important.  The depth of field choice gives me that out of focus background.  Isolating your subject via focus really puts the eye of the viewer where you want it to go.  

Here you have no choice but to look at the daisy.  There is nothing in the background except extremely out of focus objects.  The background was not interesting and consisted of gravel and even a couple weeds.  Who needs that in a photo?  My aperture for this photo was 6.3, I was about 20-24 inches from the flower, I zoomed in with my Tamron 18-250mm lens all the way, and made sure my auto focus point was on that daisy.  You will notice that the daisy is in pretty sharp focus from front to back.  

In this photo (above) I used my 50mm lens and an fstop of 2.5.  Again the background was unappealing.  I wanted to isolate the roots of the poison ivy vine and by creating such a shallow depth of field -- it worked.  By choice, when I am creating a very shallow depth of field I like to use this lens.

In the photo above, I wanted to have sharpness throughout the frame.  Not so much in the reflection -- but along the shoreline.  I chose f18 as my aperture here to achieve that.  Selecting a higher aperture number decreases the opening that lets light in for the photo.  A higher aperture number will decrease the shutter speed -- less light, the shutter needs to stay open longer to let enough in to expose the photo correctly.  

Usually if you work in low light conditions and wish to hand hold the camera -- you will need to use a lower aperture (create a larger opening to let more light in).  When I am shooting at a high fstop -- I will use a tripod.  There is nothing worse than wanting sharpness throughout and getting blur all over!