Tag Archives: Focus stacking

Fossography

I never understood why waterfalls grab the hearts and minds of so many photographers. Go to any location that advertises a waterfall and it is guaranteed that there will be a large parking space, lots of cars, and buses with their engines idling. Masses of people, often out of shape, hike along a trail. The first action when the lookout point is reached is to pull out a camera and photograph the falls. In post-processing the images are cropped just above the pool, around which the fellow visitors had their picnic.

Gullfoss, Iceland. Nikon D810, Nikkor 28 f/1.4, at f/11, 4 s, ISO 50. Composite image with focus stack on foreground. 6-stop ND filter.

More recently, a popular thing seems to be “dying for a selfie”; people standing extremely close with their back on the brink of a fall, trying to get the best perspective of themselves leaning over the gorge.

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Posted in Photoessays, Travel photography Also tagged , , |

Focus Stacking, Part 1: Introduction

Focus stacking, also known as z stacking or depth of field blending, is a technique that combines multiple images focused at different planes, to obtain a greater depth of field. This is particularly useful in situations where the scene has a large range of depths in the subject space compared to the shallow depth of field obtained for a given sensor size, focal length, and aperture combination. This is often so in macro, landscape, and architectural work.

Toscana

Toscana, Italy: Three stack composite along the horizontal lines of the fields. 85 mm, f/9.

It is important to recall that for every single, non-stacked, image there is one (and only one) plane in the subject space at which the image points on the sensor are exactly sharp, that is, point like. Any point of a subject in another plane will be imaged as a disk, know as the blur spot. If this disk is sufficiently small for a given magnification and viewing distance, it will be indistinguishable from a point. The diameter of a sufficiently small blur spot is known as the acceptable circle of confusion. The acceptable sharpness between two planes on either side of the focal plane is known as the depth of field (DoF). These planes are always at right angles to the sensor plane unless we explore view cameras or use tilt/shift lenses on DSLRs.

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Posted in Image quality, Software Also tagged , , |