Focus stacking is a technique in digital photography that captures a set of images at multiple different focal points then stacked portions of these images onto a single frame to create a resulting image that is fully in focus.
Focus stacking is most common in Macro Photography (see article macro jewelry photography explained) – shooting still life subjects like jewelry, diamonds, insects, flowers and other small subjects however can also be used in other types of photography such as landscape photography. In this article we’ll be discussing Focus Stacking specifically in still and 360 product photography and the new Focus Stacking Plugin for Shutter Stream and Shutter Stream 360 Product Photography Software.
Focus Stacking in Product Photography:
Sometimes there is a need for a product image that is fully in focus from front to back. This is often the case in eCommerce Product Photography where sellers are trying to visually communicate products being sold. Now in the case of most types of product photography, users are able to capture enough depth of field due to ample distance between lens and subject. When shooting with a Macro Lens, these are often much closer to the subject which creates a significantly shallower depth of field. Now for those unfamiliar the term depth of field, this is defined as the distance between the nearest and farthest points that are in acceptably sharp focus. Typically, users can decrease Aperture size (increase Aperture Value) to create a longer depth of field however this can cause issues with image quality and clarity – this is known as ‘Lens Diffraction’. Lets take a look at these examples to better communicate Lens Diffraction and the result of a jewelry photograph shot at different apertures:
As you can see on the left, the image shot with an Aperture value of 10 has a much shallower depth of field with only the front ring facet really in focus (depth of field in this case would be ~3mm. The image on the right was shot with an Aperture value of 29 – allowing a much longer depth of field and some would argue a better quality image. However upon closer inspection, you will see we have lost a lot of sharpness when shooting at an Aperture of 29, this is caused by lens diffraction:
As you can see, although using the exact same focal point in both images, the image shot at Aperture 10 is much sharper than the image shot at Aperture 29. An aperture of 10 is the Lens Sweet spot for the 100mm f 2.8 Macro Lens used to photograph this jewelry photography example (sweet spot being where you will be able to create the sharpest image).
Now that we have discussed why users typically want to shoot at lower aperture values when shooting Macro photography, we can transition into discussing the need for Focus Stacking.
The Need for Focus Stacking in Macro Product Photography
There is two parts to focus stacking:
- Image Capture: For the image capture portion of the focus stacking workflow, users are going to be required to shoot a series of images at different focal points. The focal point adjustment needs to be consistent from shot to shot. In addition, both the camera and subject will need to remain in the exact same position during the image capture sequence.
- Image Rendering: The rendering portion of focus stacking composes the image set into a single image. Ideally what happens here is a portion of each image (portion being the part with the acceptable level of sharpness) is cut out and then used in the final image to create a fully in focus image. It is often up to the user to define how many frames will be required to be captured to create the stack. Rendering also includes options of:
- Rendering Method: Weighted Average, Depth Map or Pyramid
The end result would look something like this Jewelry Focus Stacking example we shot using Shutter Stream Product Photography Software.
Focus Stacking can be a tedious and time consuming task. Many who require focus stacking opt for a software that can automate the image capture and image rendering workflows. Shutter Stream Product Photography Software has an optional Focus Stacking plugin that can automate the Focus Stacking workflow.
How it Works Video: Focus Stacking in Shutter Stream Software
Focus Stacking in 360 Product Photography
Iconasys is a leading provider of 360 Product Photography Software and Equipment that automate 360 image capture, editing, processing and output. The Focus Stacking plugin also works with Shutter Stream 360 Product Photography Software’s and an Iconasys 360 Product Photography Turntable to automate 360 Product Photography Focus Stacking.