One of the most common requests I get before the start of a session are portraits ‘with blurry backgrounds’ (otherwise known as ‘bokeh’), like the two photos below of a brother and sister from my Fall Mini Sessions:

Bokeh (pronounced Boh-kay) refers to the blurred, out-of-focus (intentionally) points of light in the background of an image.  You can get a better idea of what bokeh looks like in the photo below (the circles on the right hand side of the image).

One way to produce an image with a blurry background, or bokeh, is to use a shallow depth of field.  Depth of field refers to the “the area of sharpness (from near to far”) within a photograph” (Understanding Exposure, Bryan Peterson, Page 42).  Peterson goes on to explain:

Optical law states that the smaller the opening of any given lens (large f-stop numbers – 16, 22, 32), the greater the area of sharpness or detail in the photo.  When using apertures at or near wide open (small f-stop numbers-2.8, 4, or 5.6) only the light that falls on the focused subject will be rendered as “sharp”; all the other light in the scene – the out-of-focus light-will “splatter” across the sensor or film (page 43)

Most kit lenses (the lenses that come with the camera) don’t have f-stops small enough to produce bokeh or blurry backgrounds.  If you have a Canon DSLR camera you can buy a ‘Portrait Lens’ with an f-stop as small as 1.8 ($139.99 at Henry’s).  There is also an equivalent lens for Nikon DSLR’s (50mm, 1.4).  These lens are great for taking portraits as well as taking photographs in low lighting conditions (without using a flash).

Although I shoot in Manual mode you can experiment with bokeh by changing your camera’s settings from Automatic to AV: this allows you to adjust your f-stop manually (making it smaller or bigger), while your camera will adjust the rest of your settings for you.

In this first image my f-stop is set at 1.4 (my lens is a 50mm, 1.4, which means that my f-stops can be set smaller than the Portrait lens I mentioned above).  Because the f-stop is set so small, the lens on the camera is wide open and letting in the maximum amount of light.  The shutter speed will be high (the camera will automatically set this for you) so your photo isn’t washed out (in this case the camera set it at 1/4000).  Each time I took a photo I made my f-stop larger, meaning that more of the image came into focus.  Notice that with each photo I took the shutter speed decreased to accommodate for the lesser amounts of light let in by the lens (the bigger the f-stop, the less light it lets in).

f-stop: 1.4, shutter speed: 1/4000

f-stop: 1.8, shutter speed: 1/2500

f-stop: 2.2, shutter speed: 1/1600

f-stop: 2.8, shutter speed: 1/1250

f-stop: 3.5, shutter speed: 1/800

f-stop: 4.5, shutter speed: 1/500

f-stop: 5.6, shutter speed: 1/320

f-stop: 7.1, shutter speed: 1/200

What do you notice with the progression through the different f-stops?  Other than the increasing irritation of my 5 year old model who was watching his brother play behind me 😉  As the f-stop number gets higher, the background comes more into focus and you lose the “blur” and “bokeh”

I encourage you to experiment with the AV mode on your camera to see if you can produce the blurred background effect that often makes such beautiful images.  If you have any questions feel free to ask them on my Facebook page!  I look forward to hearing from you

{Another article on achieving boken in your photographs}