Why Focus Stack

focus stack of fordite

Cropped version of final Focus Stack. Olympus OM-D E-M1 Mark II, 60mm + 26mm extension tubes, ISO 400, f/4, 1/50 sec.

Not all macro subjects are captured sharp in a single image, that makes a great reason to focus stack. In preparing for a camera club presentation, I decided to focus stack a new object. I chose a piece of fordite from Cadillac Ranch. If you aren’t familiar with fordite, just think – layers of paint. The first image (image A) is a close-up image of the piece of fordite that measures 2” x 1”. I used my 12-100mm lens and got as close as I could to capture the image. Then, with my macro lens and extension tubes, I captured image B. A small sliver of the subject is sharp, but not the whole piece of fordite. In order to have sharpness throughout the entire frame, I would need to focus stack.

 

At first, I tried a stack of 50 images. My Olympus camera has a focus bracketing mode so all I do is focus on the closest part of the fordite and program the camera for 50 images at a small increment of focus bracketing. The camera then captures 50 raw images changing the focus with small increments from front to back. After looking at image 50, the farthest part of the fordite was still blurry, so I needed more photos in my stack. I tried again, this time with 125 focus bracketing images. When I reviewed the photos, at image 118, I had the sharpness I needed. Next step was to focus stack the 118 images in Helicon Focus. Helicon is amazingly easy to use. After selecting the images in Lightroom, I export to Helicon and press the render button. Helicon does the rest. The last image is the final image of 118 focus stacked images.

A few tips on focus stacking:

  • Mark the start of a focus stack by capturing a single image of your hand, or other random subject otherwise if you capture several stacks, it will be hard to identify the start and stop of the stack otherwise.
  • Use a tripod and shutter release to minimize camera shake. Photoshop CC offers focus stacking but it is more complicated than Helicon Focus.

2 thoughts on “Why Focus Stack

  1. Emma Benenati

    Thanks Amy!
    Wow- 118 image stack.
    I’m figuring Helicon Focus allows for saving of large images?
    Do you save it as a DNG ?

    Reply

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