Photography enthusiasts, especially those who are interested in macro photography, may have heard the term focus bracketing – but many will still be wondering what it is, how it’s done and what it’s used for. Read on to find out the answers to these questions and to discover why focus stacking is an important skill to learn for those who want to take their photography to the next level.
What is Focus Bracketing?
Focus bracketing is the process of shooting a single scene at a series of different focusing distances. The camera is kept static on a tripod while the shots are taken, and then the shots are combined on a computer in a process called focus stacking. This creates a single shot that is sharp from front to back, essentially providing a deeper depth-of-field than a single exposure can provide.
Owners of the new FUJIFILM GFX 50R and X-T3 cameras, or the GFX 50S, X-H1 and X-T2 with the latest firmware updates, will find that their cameras have a Focus Bracketing feature, which can help to automate this process. When this function is activated, the camera automatically takes a series of images, shifting the focusing distance between shots. The distance of each increment can be adjusted, and the camera can shoot up to 999 frames to ensure that every focus distance is covered.
When Can Focus Bracketing Help?
Focus bracketing can be a powerful tool in the following situations:
- When you want to achieve sharp detail from the foreground to the background in landscape photography, more than can be obtained from the depth-of-field of a single shot.
- Macro photography naturally creates very shallow depth-of-field. Focus bracketing gives you the ability to have as much of your subject in focus as desired.
- When you want more depth-of-field but do not want to increase your ISO in low light situations.
How is it Done?
You have found your scene and mounted your camera on a tripod – so what happens next? The Focus Bracketing menu has three parameters:
- Frames: the number of shots the camera takes
- Step: the distance the camera shifts the focus between shots
- Interval: the time delay between frames
The number of frames can be set between 1 and 999, and the total number needed per image will vary, depending on the factors below:
- When the step between frames decreases… # of frames required increases
- When the aperture gets smaller… # of frames required decreases
- When subject magnification increases… # of frames required increases
- When print/image size increases… # of frames required increases
As an example, here are two shots of a pinecone. The shot on the left was captured using a single frame, the shot on the right was captured using 50 frames.
What is a Step?
When using the Focus Bracketing feature on FUJIFILM cameras, users can set the Step value from 1 to 10. The Step is calculated using the distance between the near and far limit of the depth-of-field on the first image captured. Setting the Step to 1 moves the focus by approximately 20% of that distance. A Step of 5 moves the focus by around 100% of that distance. As an example, if the difference between the near and far limit of depth-of-field is four feet, a Step of 5 would move the focus point four feet for each shot.
What is an Interval?
The Focus Bracketing function offers photographers the opportunity to adjust the Interval, which is the time taken between shots. This value can be anything from 0 to 10 seconds. A longer interval can be useful in situations where the tripod is not completely steady, because shutter actuations can cause vibrations that negatively affect image sharpness. A longer interval between shots means that any vibration will have ended before the next shot is taken, which can help to keep shots sharp. On the other hand, when shooting landscapes, it’s a good idea to keep the interval as low as possible to ensure that the light doesn’t change between shots.
The following values can be used as a general guide for getting started.
- Landscape frames 20 / step 10 / interval 0
- Macro frames 100 / step 5 / interval 5
- Low Light frames 20 / step 5 / interval 10
Helpful tips and tricks
- When using the Focus Bracketing function, the camera will stop if the lens reaches infinity. This means that setting a higher frame number than necessary is not a problem.
- Use electronic shutter whenever possible. Electronic shutter eliminates vibrations caused by mechanical moving parts. It also allows you to set the interval to 0.
- When shooting macro shots, check that the lens is able to focus on the farthest point in the shot that should be sharp. When using the 8 R LM OIS WR Macro lens, this is unlikely to be a problem, but when using extension tubes and/or the GF120mmF4 R LM OIS WR Macro lens, it can save time to check that the lens can focus on the farthest point before shooting a bracket of, potentially, hundreds of frames.
What is Focus Stacking?
Once you’ve taken your shots, you then have to combine them. This is often called focus stacking, because doing it in Adobe Photoshop involves placing shots in separate Layers in a single Photoshop document – or “stacking” them on top of each other.
To do it in Photoshop, follow this simple, six-step process:
- Navigate to the File menu in the Menu Bar, choose Scripts, then choose Load Files into Stack.
- In the Load Layers dialog box, set Use to Files and then select Browse. Navigate to your images on your hard drive, select them, and click Open. Use JPEGs rather than RAW files to speed up the process.
- Still in the Load Layers dialog box, select Attempt to Automatically Align Source Images, then click OK.
- Your Layers will now be visible in the Layers panel. Select all the Layers by clicking on the top Layer, then Shift-clicking on the bottom Layer.
- Navigate to the Edit menu in the Menu Bar and select Auto-Blend Layers.
- Aligning the frames can cause the edges of the shot to look strange. Crop the image with the Crop Tool to tidy up those edges.
All that’s left is to navigate to File, then SaveAs, and save your shot with a new name. If you’ve created a focus bracketed image that you like, be sure to share it with us on social media. Post your images online and tag them with #fujifilmx_us and #fujifilmfocusstacking!
For more tips, tricks and techniques, visit the GFX Technique page.