When it comes to achieving crystal clear focus, nothing is better than the human eye. Layer upon layer of sophisticated lenses and light reflectors work hard to deliver the sharpest possible image to the brain. With this in mind, could layering be the answer to perfect focus? And if so, how can you apply this to your photos? The answer is the focus stacking technique.
Here we explain how and when to use focus stacking to make your images as sharp as when you saw it with your own eyes.
What is Focus Stacking?
Focus stacking, sometimes referred to as photo stacking or image stacking, is a process of layering multiple versions of the same image, each taken with a different focal point or depth of field. The images are layered using photo editing software to create a single image that puts all of the image content into sharp focus from foreground to background.
This is one of the best ways to sharpen photos, especially with a lot of detail at various depths, such as landscapes or macro photography. By using the focus stacking technique, you can create images with more depth of field than would ever be possible with a single exposure.
How to Focus Stack: 5 Steps to Sharper Shots
While most of the hard work will be handled by your editing software, capturing the right quality of images to stack is down to you. Here are a few tips to help you get the best results from focus stacking:
- Use a very steady tripod: The art of photo stacking is to work with images that have small variance. This is only possible if you have a stable camera. It’s also important that your tripod can be lowered if you are trying macro photo stacking, as you’ll need to get down low to capture your subject’s best side.
- Use a good quality DSR camera: Though you are building up images of varying focal points, the result relies on these focal points being in the sharpest focus possible.
- Choose a still subject in stable light and weather: The only variance in the photos you stack should be the focal point. Any changes in the composition such as blowing leaves will distort the effect of photo stacking. You will need to take several shots over a few seconds, so your subject needs to be stable throughout that time.
- Once your camera is securely on your tripod, frame your subject and compose the image you want to capture.
- Determine the correct exposure and then set your camera to manual mode – this will make sure the exposure remains consistent across each image you take.
- Set your camera to live view and set your first focal point on the nearest object, using the camera’s zoom to preview. Then switch to manual focus to fine tune the sharpness. Once happy, take the first exposure.
- Here’s the most important step – without moving the camera or adjusting any settings, move your focal point to an object mid-way in the composition and refocus. Then take the second exposure.
- Repeat step 4, but this time refocus on an object at the furthest point of your image and take the third exposure.
For landscape photos, three images is usually enough, however there’s no limit to the number of images you can stack – just bear in mind that more images to process means more time sat at your computer! You may find that images with longer focal lengths may need a higher stack.
Just One Small Thing About Macro Photo Stacking…
With macro photos, simply repeat the process above, but keep in mind that when shooting such small subjects, you’ll be making very small adjustments to your focal points. Depth of focus in macro photography will be measured in fractions of an inch instead of feet as in landscape pieces. You’ll probably need more images too – a minimum of six to make sure your whole subject is covered.
Why and When to use Focus Stacking
Photo stacking can be used across multiple genres, but there are certain types of photography where the technique is particularly useful. Here are a few pointers on when to consider photo stacking.
Detailed Landscape Scenes
No matter how skilled you are with your DSLR, your landscape images won’t be sharp all the way through when there is such a big distance between your foreground and background. This is particularly the case when using a wide angled lens for an image that has plenty of elements to its composition, both near and far.
If you’re lucky enough to take a snap of the Great Wall of China or Golden Gate Bridge, there’s a lot of interesting detail to try and capture. By focus stacking, you can capture the whole structure in crystal clear detail, including the surrounding scenery, to transport you back there every time you look at it.
If a single flower or a bouquet is your subject, the zoom function on your camera will be tested to the limit. Getting the whole flower sharp is tricky! Photo stacking will make sure that every fibre of every petal is given the same status as the pollen filled centre, meaning you can confidently turn your photographs into a large canvas print.
Night Sky Photography
Want to give every star equal billing? Photo stacking is a big help. No other genre puts so much distance between lens and subject, which makes this the perfect time to use focus stacking. A blurred star can interrupt your perfect night time scene.
Instead, with focus stacking you can give every star the opportunity to shine, by focusing on them in clusters across the full composition and aligning them for the final image.
Read more night sky photography tips.
Creating large format images
Large format printing leaves no hiding place for any blurriness or soft focus in your image. So when you want to create some wall art, photo stacking is a great way to make sure your finished print is eye-catching from edge to edge.
Want to create a coffee table book too? Stacked panoramic images will look particularly striking in a photo book with layflat pages, as you won’t lose any of the details in the binding.