DOUBLE-DISTANCE FOCUSING

Learn how to set the focus position of your lens for easy and quick front-to-back image sharpness

Learn how to set the focus position of your lens for quick and easy front-to-back image sharpness

For decades, the core technique for precision focusing was the hyperfocal method, especially in landscape images. This makes use of pre-calculated focus distances to quickly set a lens for an acceptable level of sharpness throughout. It is calculated using the formula H = f² / Nc + f, where H is hyperfocal distance, f is focal length, N is f-stop and c is circle of confusion. However, while generally suitable, hyperfocal focusing doesn’t always deliver optimal results. The values used are based on outdated parameters, namely the circle of confusion, which refers to the physical size of a blurred point of light, measured in milimetres.

The term “acceptable sharpness” is also objective, and was originally based on the quality of lenses and film available in the 19th century. In today’s world of ultra-precision optics and high-resolution sensors, the values produced won’t make the most of this quality. Plus, not all scenes are equally structured, resulting in detail loss in the foreground.

The double-distance focusing we’ve tried here is an effective technique for producing a better equality of sharpness from foreground to background, helping us to get more from our equipment. This technique is increasing in popularity among pros and is an easy, all-round solution. So let’s give it a go…

66 DOUBLE-DISTANCE FOCUSING

AFTER EQUAL DETAIL BY USING THE DOUBLEDISTANCE METHOD WE COULD PRODUCE A UNIFORM SHARPNESS THROUGHOUT THE FRAME. BACKGROUND DETAIL IS REDUCED BUT FOREGROUND AREAS APPEAR SHARPER Inset FOCUS FALL-OFF USING THE HYPERFOCAL METHOD, A GOOD LEVEL OF SHARPNESS IS ACHIEVED, BUT THE FOREGROUND ROCK STACK IS SOFTER THAN EXPECTED, WHEN COMPARED TO THE BACKGROUND

BEFORE 100%

1 COMPOSE THE SHOT Arrange the frame to your liking, taking note of the spatial separation of foreground and background elements. In our scene it was clear there would be focus challenges with the receding stacks.

2 SET F-STOP Select an aperture that provides a balance of depth of field and resolution. Here we stopped down from f/8 to f/11, as this produced minimal diffraction but deeper focus coverage, for better overall detail.

3 MEASURE FOREGROUND DISTANCE Using Live View, focus on the closest visible object, in this case a rock at the bottom of the frame. This will quickly set the lens at the initial focus distance, blurring the background.