Get super sharp macro images using the focus stacking technique.
This is the third video in the series covering Macro Photography. Focus stacking is about as complex and difficult as macro photography can get but the results of this dedication can be truly stunning. The first video covers shooting macro photography with budget gear and the second with more advanced gear. This video will assume you are familiar with the techniques described in the previous episodes.
Focus stacking can be used in various areas of photography but is most naturally suited to macro photography. Essentially focus stacking is when we combine a number of images into a 'stack' to ensure sharp focus across the image where it would not normally be possible. In macro photography when we get in close to our subject the depth of field will be extremely small even when using small apertures such as f/16 or f/22. This means that many of our images will have large parts of it that are out of focus. This can be a desirable effect in many situations but for many shots a bigger depth of field is required such as taking portraits of insects. The only way to achieve this is through focus stacking.
Shooting the Image
Focus stacking is shot by taking a series of images with the same composition and gradually changing area of sharp focus. Depending on your aperture setting and the image you are shooting this could be anywhere from a few shots, up to 30+ frames. These images are then stacked in post-processing and the computer extracts the sharp area from each image and combines them to create one image with sharpness across the frame.
It is vital to keep the composition as still as possible between frames so a tripod is virtually essential. There are then a few ways to adjust your area of focus between frames:
- Adjust the lens focus ring.
- Move the object.
- Move the camera.
Only one of these options is truly accurate and effective and will produce good results every time. With many parts of macro photography you will want to get as close as possible to your subject to maximise the magnification. We therefore want to have the lens focused to it's minimum focus distance. If we then achieve focus stacking by adjusting the focus it means we have to initially focus on the furthest part of the subject away from the lens, then, bring the focus further out as we start taking our stacking images. The downsides of this are that accurate micro adjustments of your focus ring can be extremely difficult. Also, changing the focus causes small adjustments to the focal length even when using a prime lens; this will cause problems when stacking in post.
Secondly moving the subject is unlikely to work unless you have it on something that can make precision movements. Let us discount this method for today. This leaves moving the camera and this is the method featured in this focus stacking video tutorial.
The best and easiest way to do macro focus stacking is to move the camera using a macro slider. The camera sits on top of the macro slider that is mounted on the tripod. The slider then lets us make fine adjustments moving the camera gradually closer to the subject. We start our stack by focusing just in front of the subject, at the minimum focus distance, and then gradually move the camera forward taking the focus across our subject as we shoot each image. Most macro sliders have scales on them to allow fine and accurate adjustments. There are also automated systems available that will move the slider and fire the camera for you. Once the images have been captured it is time to move into post processing.
All the processing is done using Adobe Photoshop and Lightroom. To get a 30 day FREE trial Click here.
1. Normal Image Adjustment
Assuming the stacking images have been shot in RAW the first thing to do is make your normal image adjustments to each image eg, exposure, contrast, white balance etc in Lightroom. Copy the settings and paste them to all your stacking images.
2. Export JPEGs
Create a suitable folder and export your images as JPEG’s. This will save you a massive amount of time when Photoshop processes the images than if you tried to use RAW. If you have edited the images in Lightroom prior to exporting then you will have already reaped all the benefits of working with RAW.
3. Merge the images
Open Photoshop then go File > Automate > Photomerge. Hit the ‘Browse’ button and select your stacking images. Leave on Auto and uncheck all the boxes at the bottom including Blend Images Together. Click Ok and let Photoshop run the images. It will the load the Merged images into layers in a new document.
4. Create the Stack
Next move down to the layers panel and select all the new layers Photoshop has created. Go to Edit > Auto-Blend Layer and then ensure ‘Stack Images’ is selected under the ‘Blend Method’. Select ‘Seamless Tone and Colours’ and then hit ‘Ok’. Photoshop will then do it’s thing and spit out something close to your final image.
5. Final Adjustments
It’s now time to make the final adjustments to your image as you see fit. You may need to clone out any imperfections you had not noticed or crop the edges of the image as Photoshop may have created some transparent areas of the image where it has pulled the stack together.
Your image should now be a well stacked image with sharpness from front to back. If there are areas of the image that are blurred then it is likely that the adjustments you made during shooting were too large. You can rescue this by cloning bits out.
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