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Macro shot of ruby
specimen with shallow depth of field
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Collecting rocks was a hobby I got into some time ago. I stopped collecting and had several drawers
of specimens hiding in the closet. I
decided to make photographs of the specimens and ran into a problem with depth
of field. The images were sufficient to
show off the rocks except portions of the rock were out of focus. The solution was to use a technique called
“focus stacking.”
I shoot the rocks in a light box on a tripod and used a Tamron 90 mm macro with a 2x converter. The converter allowed for auto
focusing. For the focus stacking project
I used extension tubes instead of the 2x converter and manually focused each slice. I used the focus ring to carefully move the focus point. A shutter release was attached to the camera to prevent shake.
Starting from focusing on the front of the specimen I shot a
frame, then moved the focus ring to focus on the next section of the specimen. This was repeated
for a total of seven frames. I shoot in RAW
then convert all the frames to PSD.
ON1 doesn’t utilize a convenient focus stacking method so I
used Photoshop CS5 to perform the task.
I understand that this method was available since CS2.
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Seven RAW frames
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Photomerge Dialog
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This will take a few moments for Photoshop to process. This process automatically aligns all the
photos in case the camera moved a bit.
For a large amount of frames it will take a longer time. Open up the Layers window to see all the
frames in separate layers. Select all of
these layers then from the “Edit” menu click on “Auto Blend Layers.” Then on the “Auto-Blend Layers” dialog select
the “Stack Images” selection. Then click
OK. Again Photoshop will take some time
to blend these images. When the process is complete, the resultant image is
displayed. The “Layers” window will show
the masks created for each of the layers.
Each layer masks out what is out of focus. This is why focus stacking software is
required.
The image is ready for enhancements, cropping, etc. if
desired.
The final image is completed and fully in focus. Note this specimen is 3/4” long and approx. ¼” diameter. There is a bit of care and work involved but in the long run it is worth it.
If you don’t have Photoshop available the following software is available for either free or purchase:
Affinity Photo $49.99 Raw editing, HDR merge, Panorama stitching, Focus stacking, Professional retouching, Batch processing, PSD editing, Digital painting, 360° image editing, Multi-layered compositions https://affinity.serif.com/en-us/photo/
Zerene Free for 30 Days. Personal license $89, Prosumer $189. https://www.zerenesystems.com/cms/stacker
Combine ZP is both free & reasonably capable. Originally written for use with microscopes but seems to work fine at lower magnifications too.
Picolay Free Focus stacking - slim and fast - stereo images from a single z-stack - image processing - slide shows - animated gif images etc. - portable freeware - easy installation - http://www.picolay.de/ (May be difficult to use, noted some users)
Gimp Free https://www.gimp.org/downloads requires to download separate plugins. Search the internet with “Gimp focus stacking plugin” for more information.
