Wind-blown grassesWind-blown grassesDry grass blowing in the wind near Canberra.

Controlled depth of field covers many an issue

December 31, 2015  •  Leave a Comment

Most serious photographers, whether they be professional of enthusiast, like to control depth of field.

For the uninitiated, depth of field is the area in front of the camera which is acceptably in focus. A large aperture (e.g.: f/2.8) will produce a shallow depth of Glencoe © Linda PearsonGlencoe © Linda PearsonGlencoe - overcast. field, whereas a small aperture (e.g.: f/16) will produce a deep depth of field.

Why (and more importantly: when) does this matter? Well, it allows the photographer to control what the viewer looks at in the image. Want someone to just look at the model in front of Notre Dame and not the cathedral? Use a shallow depth of field and the church will be out of focus. On the other hand, if you want people to be able to see the whole vista of Glencoe? Use a high f-number!

So, what's my point? Well, yesterday I visited the Perth Zoo for the first time in years - and naturally, I lugged along my D800. 

I got nothing earth-shattering - but I was quite pleased with this image of a numbat: Numbat at the Perth Zoo.NumbatNumbat at the Perth Zoo.

 

The image was made with my D800 and Nikkor 70 - 200 at 200mm and f/6.3. While that's not a particularly small aperture, when used with a long focal length, depth of field is quite shallow. (The opposite is also true: use a short lens like a 14mm and depth of field will be huge.)

The effect of this shallow DoF is two fold. Firstly, the numbat is sharp whereas virtually everything else is out of focus - so what does the viewer concentrate on? The numbat - where I want you to look. The second benefit is that with the background in nice soft bokeh, the little numbat could be anywhere. I wouldn't be so dishonest as to suggest the numbat was out in the wild, but the soft background gives the impression of being in the bush. 

And soft backgrounds are after all, how we perceive things we look at, isn't it? When we concentrate on something, our brains do a lot of processing, which seems to include (in my brain at least) a lot of soft focus around the object itself.

Win, win, win - and all it takes is control of the aperture on your camera!

So, if you're not doing it already, try shooting in either aperture priority or manual. In either mode, you control the depth of field of your images - and where your admirers look when they view your work. (Just don't do it for the first time when you're trying to capture your child's big concert, or your niece's wedding. It takes a little practice!)

Happy 2016 to you all - and good photography.

Shane Baker

 

 


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