Stacking Depth of Field

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Today’s Question: In response to a question about hyperfocal distance and depth of field, you said “…when it will be impossible to achieve the desired depth of field with a single capture.” How is it possible to achieve more depth of field with more than a single capture?

Tim’s Quick Answer: You can expand depth of field for a scene by essentially bracketing the focus with multiple captures set at different focal points. This is referred to as focus stacking, and it can be very effective at providing greater depth of field than you could otherwise achieve in a single exposure.

More Detail: In many cases it can be difficult (or impossible) to achieve as much depth of field as you’d like. An extreme example would be macro photography, where you are focusing so close to the subject that you will have depth of field measured in the fractions of an inch. However, even with landscape photography you can easily run into a situation where you’re not able to get as much depth of field as you’d like.

Focus stacking to achieve greater depth of field is similar in concept to creating an HDR image. The difference is that for HDR you bracket the exposures, while for focus stacking you bracket the focus point.

Some cameras actually include built-in focus stacking. During my recent Palouse Photo Workshop (http://www.timgreyphoto.com/palouse-2019) a couple of photographers were making use of this feature with a Nikon D850, and the results were quite impressive.

It is also possible to manually create focus-stacked images. You need to adjust the focus for each of a series of exposures, making sure that you overlap the depth of field for each exposure to cover the entire area you want in focus in the final image.

You can then use software to assemble the resulting photos into a final focus-stacked image. My personal preference is Helicon Focus (https://www.heliconsoft.com), which I’ve been using for focus stacking for quite a few years with excellent results. Another option is Zerene Stacker (http://www.zerenesystems.com). Both provide similar options for building a final image by blending the original captures to maximize depth of field.

And, of course, some photographers take an even more manual approach, capturing several images and then blending them through the use of layer masks in Photoshop.