Lesson plan

Focus stacking

of a Tachinid fly. First two images illustrate typical DOF of a single image at f/10 while the third image is the composite of six images. light microscopy. This example is of a diatom microfossil in diatomaceous earth. Three source images at different focus distances (top left) are combined with masks (top right) to obtain the contributions of their respective images to the final focus stacked image (bottom). Black is no contribution; white is full. Focus stacking also called focal plane merging, z-stacking, focus bracketing or focus blending is a digital image processing technique which combines multiple images taken at different focus distances to give a resulting image with a greater depth of field (DOF) than any of the individual source images. Focus stacking can be used in any situation where individual images have a very shallow depth of field; macro photography and optical microscopy are two typical examples. Focus stacking can also be useful in landscape photography. Focus stacking offers flexibility: since it is a computational technique, images with several different depths of field can be generated in post-processing and compared for best artistic merit or scientific clarity. Focus stacking also allows generation of images physically impossible with normal imaging equipment; images with nonplanar focus regions can be generated.…

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Article summary

of a Tachinid fly. First two images illustrate typical DOF of a single image at f/10 while the third image is the composite of six images. light microscopy. This example is of a diatom microfossil in diatomaceous earth. Three source images at different focus distances (top left) are combined with masks (top right) to obtain the contributions of their respective images to the final focus stacked image (bottom). Black is no contribution; white is full. Focus stacking also called focal plane merging, z-stacking, focus bracketing or focus blending is a digital image processing technique which combines multiple images taken at different focus distances to give a resulting image with a greater depth of field (DOF) than any of the individual source images. Focus stacking can be used in any situation where individual images have a very shallow depth of field; macro photography and optical microscopy are two typical examples. Focus stacking can also be useful in landscape photography. Focus stacking offers flexibility: since it is a computational technique, images with several different depths of field can be generated in post-processing and compared for best artistic merit or scientific clarity. Focus stacking also allows generation of images physically impossible with normal imaging equipment; images with nonplanar focus regions can be generated.…

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Discussion questions

  1. Summarise the article in your own words. Which single claim would you verify first, and why?
  2. Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
  3. If two sources disagreed about one of these facts, what would you need in order to trust one over the other?

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Key claims and bibliography are generated from the same tracked claims and sources as the article page.