
Nikon D700 | f/3.2 | 70mm | 1/60
Like your golf swing, Depth of Field is one of those things in photography that is easy to do until you start to think about it. Scroll the wheel to “Macro” on your point-and-shoot, walk right up to an object and focus on it and chances are that everything in the background will look all fuzzy.
There, you did it. That was easy.
Ok, so there is more to it than that. A point-and-shooter most likely wouldn’t be here reading my blog. Chances are, you thumb your nose at camera presets, pocket cameras, camera phones – and as any self-respecting shooter, will choose to only roll that dial to “M” for manly. I mean manual. Well, now we need to think about this a little more.
What’s in the Word?
OK, we need to define this whole DOF or DoF thing. What the heck is Depth of Field? Most people define it wrong in their head and think it refers to the fuzzy background. But not at all. Depth of Field refers to the part that is in sharp focus. In the example above, the tree is the DOF in that shot. Everything else is out of that field of focus.
A shallow DOF or shallow focus is when one area is sharp, and the rest is out of focus. This is used to emphasize one object over another. In my example, the tree is being emphasized. This creates what we call a bokeh background. Bokeh is the blur or out of focus area of a picture. And that’s the literal meaning from Japanese: boke which means “blur” or “haze” or the “blur quality.”

Deep Focus
The opposite of shallow DOF is Deep DOF or Deep Focus. This is when you want an entire image in focus. In this photo to the right, you can see that everything is in focus – there is no blur, no bokeh. I’ll get into more definitions soon, but this effect is achieved by slamming a bunch of light into a small aperture.
Aperture is your f-stop. Though the shot to the right is only at f/7.1 – the hyperfocal distance comes into play. From Wikipedia, the hyperfocal distance is the distance beyond which all objects are acceptably sharp, for a lens focused at infinity.
We need one more term. Circle of Confusion – a circle of confusion is an optical spot caused by a cone of light rays from a lens not coming to a perfect focus when imaging a point source. I’ll toss this at you in a bit – so expect it coming your way.
See? Gets more complicated.
But that’s enough on the definitions for now. I wanted to get those out of the way so I could just throw around the terms haphazardly and sound mind-bogglingly intelligent. Did it work?
Getting DOF – Manual Mode
If you like full control of your camera (and frankly, when dropping $3000 on a body and $1500 per lens, who doesn’t?) then you want to know how to control focus to achieve deep or shallow depths in your shots at will. You’ll become a snob and never use Auto or Program modes. Those modes were put on your camera for handing it off to a point-n-shootist to to take a snap - effectively turning your $5000 rig into a $100 pocket camera. At a minimum, use your Aperture Priority (AV on your Canon) or Shutter Priority (TV on your Canon) modes. If you really want to learn your camera, keep spinning that dial until you hit the Manual mode – and leave it there.
For the camera Gods’ sake, be a man.
That out of the way, you need to choose your lens. Doesn’t really matter what you use – but depends on how far away from your subject you want to be. If you are shooting a soccer player on a field, you’re going to need some long glass to get him in your DOF. If you are shooting the wings of a butterfly, you’ll need shorter glass – preferably macro glass.

Shallow Focus - 50mm f/2
There are a bazillion websites that explain how to calculate the depth, focus, field of confusion, etc. rather than reinventing the wheel here, follow this link to get the raw formulas. Grab a pencil and paper and start figuring out all your settings.
Or…
If you’re a lazy-ass like myself, just try this handy calculator. I have one on my iPhone as well.
What they all boil down to is how far away you can be to get a fuzzy background and a clear object in the same shot. The longer the glass, the further away you can be.
Playing with your aperture can give varying results. For example, standing 1m away from an object with my 50mm @ f/1.4 will giving an amazingly shallow DOF with an incredible bokeh background. Taking a few steps back will reduce the bokeh and going into the next room will reduce it more – and going into the next town will eliminate it. Putting on a 10mm lens at F/25 and standing in the same distances, everything will tend to be sharp. This is because you are moving in and out of your hyperfocal distance with the large aperture, moving your circle of confusion. In most cases, confusing you more as well.
Putting this into English
Your DOF is dependent on a few simple factors. Mastering these elements will give you greater control of your DOF.
- First is your Aperture – the smaller the number (the larger your aperture) the better your bokeh. Usually.
- Next, the focal length of your glass – wide-angle is a greater (deeper) DOF. Everything in focus. Zooms tend to give a much more shallow DOF.
- Distance to subject – the closer you are, the smaller the DOF (area in sharp focus). Simple as that.
It’s the combinations of these (which are infinite) that you now need to learn. Getting out there and shooting is what will really get you understanding this whole thing. You can go from having everything sharp and in perfect focus (large landscape, wide angle, small aperture) to having an object sharp and everything unrecognizable (wings of a butterfly, macro, large aperture) – and things in between (subject in sharp focus, everything around just barely out of focus).