Creating a deep depth of field when you’re shooting macro photography is nearly impossible, even when using small apertures such as f/22 (find out when to use a small and when to use wide apertures). This can be frustrating if you want your subject to appear completely sharp from front to back. There is, however, a cunning solution to this problem: focus stacking. By using a combination of camera technique and careful photo editing you can expand the depth of field and get super-sharp results every time (learn more about depth of field with our guide Depth of Field: what you need to know for successful images).
The basic idea is to shoot a number of images using different focal points and then harness the power of Photoshop to merge them together. The result is one image that appears to be sharply focused from front to back.
The best way to think of this process is that it’s a little like merging different exposures together to get an image with a full range of tones. However, in this case you are actually using a sequence of differently focused images to get a final image that’s sharp throughout.
This technique is not nearly as complicated as it sounds, so let’s take a look at how it’s done, by following the three easy steps on the right. All you need is an SLR and Photoshop…
How to increase depth of field in macro photography
01 Keep it steady
A sturdy tripod is essential. Switch to Manual mode and set the focus to MF (for more, see our guide to Manual Focus: what you need to know to get sharp images). Now focus on the point closest to the camera that you want sharp. Take multiple shots, each time moving the focus ring a little until you have well-focused shots of each point.
02 Open your shots
Open Adobe Bridge and browse to your images – we’ve taken 15 in total. Select all the images and go to Tools>Photoshop>Load Files into Photoshop Layers. It’s a good idea to process your raw files and save them as JPEGs, otherwise your computer may struggle.
03 Try Auto Blend
When your file is open in Photoshop, you’ll see all the images are loaded as individual layers. To blend the sharp bits, go to Edit>Auto Blend. In the new window that appears, select Stack Images and ensure Seamless Tones and Colours is checked.