How Can You Tell They’re A Photographer

Hollyhocks photographed against the wall of a Public House.

How can you tell they’re a photographer? It’s a joke but the way you can tell is the way they look at the background behind what they want to shoot.

They don’t look at the object. Well yes they do of course, but they look at the background to see how the object will stand out..

If the background is confusing then the camera will present a confusing image.

Sometimes the scene presents a plain background. But if not, then photographers have ways to limit the confusion caused by messy backgrounds.

Limiting The Confusion

Every lens at every subject-to-object distance has a depth of field. That is, there is a distance ‘front to back’ that is in focus. Everything further in front and further behind that ‘front to back’ didstance is out of focus.

With a small aperture – say f11 for example – the lens has a great depth of field.

With a wide aperture – say f1.8 – the lens has a shallow depth of field. That enables the photographer to throw the background out of focus.

Here is a list of apertures. The widest in this list are not common. A lens with a maximum aperture of f1.4 is already an expensive lens.

f/0.95
f/1.0
f/1.2
f/1.4
f/1.8
f/2.0
f/2.8
f/3.5
f/4.0
f/5.6
f/8.0
f/11
f/16
f/22
f/32

For example, a Canon 50mm f1.8 lens costs £199 new, whereas a Canon 50mm f1.2 lens costs £2,449.

Why are lenses with large maximum apertures more expensive?

They are more expensive to produce. The front lens element has to be larger in diameter to cover the wider aperture, and that requires more glass.

And wide-aperture lenses are more prone to optical aberrations because more is being asked of them. For example, actually getting all the wavelengths of light to converge at the same focal point at wide apertures requires more lens elements and more complex designs.

And that’s why photographers look for plain backgrounds. And preferably further back than the object they are shooting because then the background will be even more out of focus (unlike with the pub wall that is just behind the hollyhocks).

And after all this talk about apertures I photographed the hollyhocks at f5.6 when the lens goes to f2.8.

I shot it a f5.6 partly because I just wasn’t thinking about throwing the background out of focus because I was overjoyed that it was plain already. And partly because in the wonderful world of compromises that is photography, I knew that with the 28mm focal length on the camera, with the depth of field at such a close distance I was as likely to miss focus on the flowers as I was to successfully blur the background.

And I was on my way to meet someone, so it was all a blur.