In this article we will look at a technique to increase depth of field, also known as depth of focus. The technique will “stack” several images of the subject taken at different focal points.
Methodology & Equipment:
- A camera & lens which allow for manual focus.
- A tripod.
- A software program which allows for alignment and stacking of images. Photoshop CS4 and above has these features.
Place the camera on the tripod so that it will not move during the exposures.
Position the subject to be photographed in front of the camera and compose the photograph. It is important that the subject not move during the sequence of photographs as this will throw off the alignment and create ghosting around the subject.
Meter the subject and set your shutter speed and f-stop accordingly. Note: it is important that you do not change the f-stop during the sequence of photographs.
Set the camera for manual focus, and focused on the first part of the subject you want to be sharp. Take the photograph.
Refocus a bit further into the subject and take another photograph.
Repeat this process until the entire subject will appear sharp from front to back. While three photographs is typical, this could take anywhere from two to six photographs. Note: the greater the number of photographs you take, the greater the chance of alignment errors. Less is more!
Open the sequence of photographs in your chosen stacking program. For this article Photoshop CS6 will be used. From Lightroom select the images you want to stack then hold down CTRL (CMD in MAC), right click on one of the selected images, “Edit In” > “Open As Layers in Photoshop…”
Select the layers in Photoshop by holding down CTRL (CMD in MAC), right click on each of the layers to select them.
“Edit” > “Auto-align Layers…” then click “Auto.”
“Edit” > “Auto-Blend Layers…” then select the “Stack Images” button.
Note: This can take some time to complete.
If you have enough light use an f stop around f8, f11, or f16. The photographs in this article were shot at 1/8sec., f4, ISO 200.
Conclusion: The technique of alignment and stacking can provide excellent results when you need increased depth of field.