The Bokeh Polka

I've chosen aperture for this weeks basic, basic photography post for a variety of reasons.  First off, I think this is the main thing amateur photographers want to know (or, at least it is for me), how do I achieve the "blurry background (aka, bokeh- how fun is that to say)?". Secondly, I think if I make myself type it all out with examples, I'll understand it better.

So here's how I see it...

Aperture is how big the "pupil" of your camera lens is. Each lens has an "f-stop" number.  This number represents the diameter of your camera's "pupil" in relation to the focal length (how much zoom zoom you've got).  More light is let in with a larger pupil. This also means your depth of field is shallower.  A large aperture is represented by a smaller number and vice-versa. This is because the number is actually a fraction (1/16 is smaller than 1/8, even though 16 is a larger number).

In the photo below my aperture is wide open, so the camera is only focused on the nearest plane. This is why with group shots it is so important to have all your subjects on the same plane. Otherwise, the person closest to the camera will be more in focus than the rest.



Here I have made the aperture smaller (a larger number).  This makes for a larger depth of field (the background is clearer) but, because of the smaller aperture (pupil) less light was let in. When less light was let in my shutter moved slower to compensate (shooting in A mode. The camera picks the shutter to jive with the aperture I've picked).  Since the shutter was slow, J moved, and the movement is blurry.



These photos were taken with a 55-200mm f/4-5.6, this means the largest the aperture gets is f/4.  Because this is more of a zoom zoom than the kit lens I have (18-55mm f/3.5-5.6) it produces more of a blurry background than the kit lens. This is because aperture is in relation to the focal length.  Your maximum aperture decreases the more zoomed in you are, but the zoom can increases the blur in some cases (telephoto lens talk is out of my comfort zone).

Here J is doing the only thing he does outside- chase leaves. His movement is clear because I have the aperture wide open allowing a faster shutter. I am only zoomed in at 55mm, this allows the lens to open up to f/4...



Little more zoomed in here as J is about to eat the leaf. So, although my max aperture decreases, because I am more zoomed in, the background is getting blurrier...



and blurrier...



and then I had to take the leaf out of my child's mouth.

This brings us to bokeh. Bokeh is how the parts of your photo that are not focused look.  Bad bokeh has sharp edges. Good bokeh has soft, blurry edges with the light in the center.  This is largely determined by your lens.  In fact, the lens determines a lot.  Which is why they are expensive.  Which is why as a complete amateur I have 2 and my examples are limited.  But what each lens does is off topic and way out of my realm of knowledge. Back to bokeh.  After sending very long e-mails to Ashley full of questions, I have decided that it depends on how large your lens aperture gets, and how much of a zoom zoom you have.

I don't think this is great bokeh. It is more of a mass of blur. And that circle at the top has pretty hard edges.



Perhaps a bit better (and everyone relax, I think he only actually ate like, one leaf. Wait- is that bark?). Moving on...



So while you may want the background to be blurry- it does matter what's back there. The lighting, lens and what's in your background will all determine the bokeh.  I wish I could post an awesome example of bokeh, but in the interest of only posting my photos, click here for the closest I think I've gotten to "half-way decent J bokeh".

Still things are a little easier, but I'm gonna need to keep practicing- a lot.



Well, this was long! I'm more confused, are you?

Pass along your tips and knowledge, I'd love to know! And, BIG thanks to Ashley for answering all my lengthy questions. And, as always, if you want to see the gold standard of photography in layman's terms- look here.

I also think I need a new place to take photos. Photos on the back and front porch? Check.