If you are serious about improving your landscape photography, then it's worth investing the time to learn how to focus stack your images. But what is focus stacking and why is it both important and necessary? Let's explore this in detail now!
Focus stacking is a photography technique where multiple images, each taken using different focus points, are combined to create a single image that has a much greater depth of field. This method will allow you to ensure sharpness from the nearest object in your foreground right through to a distant background in the scene. This is often impossible to achieve with just one shot, even when you choose to shoot at a narrow aperture like f/11 or above.
The longer the focal length you are using, the more likely you are to need to focus stack and more images will be required to achieve sharpness throughout the whole scene. In the scene below I was using a long zoom at 200mm to try and get the road leading up to the church. Without focus stacking there is no way I could have achieved sharpness through the entire scene. I used my camera's in-built focus stacking feature to decide how many images were needed, and successfully handheld this 9-image focus stack (this was because we were under time pressure with a lot of other people waiting for their turn to shoot the church so I didn't have time to set up a tripod).
You have the potential to achieve multiple benefits from focus stacking your images, so let's find out what these are.
This is the most obvious benefit and probably the main reason why you'd choose to focus stack your shots. Let's presume you have an interesting foreground like some rocks, grass or flowers in your scene, but you also have a mountain range way off in the distance. Focus stacking will allow you to produce images that are sharp throughout the scene no matter the lens, focal length or aperture you are shooting at.
Wider angle lenses naturally have a better depth of field, so you may find you only have to stack 2 or at most 3 images to get the entire scene sharp, whereas a longer telephoto zoom lens will require many images taken at different focus points from the front of the scene to the back to achieve the same result.
Focus stacking ensures that every part of your scene is as sharp as possible. When shooting a landscape, it’s easy for parts of the image to fall out of the camera’s depth of field, especially with your closest foreground elements. Let's assume you know how to shoot at the correct hyperfocal distance for your focal length and aperture combination. Hyperfocal distance is the exact distance into the scene that if you focus correctly, the image should be acceptably sharp from halfway in front of that point and all the way behind it. But even if you are able to focus on a point relatively close to the hyperfocal distance, you may still notice that the very front of your image is slightly soft (or the very back).
By taking multiple shots with different focus points, you can later blend these in post-processing, resulting in a final image where you can guarantee every part is perfectly in focus rather than relying on an approximate calculation from just one shot where it can be easy to miss the mark.
If you aren't using focus stacking or hyperfocal distance, you'd have to rely on a very narrow aperture, potentially around f/16 or higher to try and get as much as possible in focus in one shot. But because every lens has a sweet spot for aperture sharpness (normally f/8-f/11) you're going to end up trading off overall sharpness of the image and introducing elements of diffraction into your shot. What is diffraction? As your aperture gets smaller and smaller, light waves spread out and interfere with one another more and more. This will cause small details of your photographs to blur reducing overall sharpness.
Focus stacking will giver you far greater flexibility when choosing an interesting composition. If you don’t have to worry about keeping everything in focus in a single shot, you have more freedom to be more creative in your compositions. This means you can get closer to foreground subjects or shoot with a wider aperture than normal to achieve a specific look, knowing that focus stacking will allow you to maintain overall sharpness in the final result.
Focus stacking can significantly enhance the quality of large prints. While an image shown at a small size (e.g. on social media) wouldn't obviously show any issues with a lack of depth of field or overall sharpness throughout, the larger you print, the more obvious any soft focus areas will be. The technique of focus stacking ensures that even when your image is printed at a large scale, it will maintain crisp details throughout, making for a far more impressive viewing experience.
So now we know there are many benefits from focus stacking, are there any downsides or limitations? Unfortunately yes! Like most things in life, there are no perfect solutions, and sometimes compromises must be made, so it's important to understand what issues might arise when you try to focus stack your landscape photography images.
Focus stacking requires you to take multiple shots with different focus points, which can be time-consuming as you need to set up your tripod for your ideal composition, and then change the focus point for each shot, either with a button or joystick on your camera or by using a touch screen. Then there's the time it takes to process the images afterwards which is much longer than if you were just editing a single image.
Taking time to shoot multiple images may not be ideal if you’re shooting in rapidly changing light conditions, such as during sunrise or sunset.
Focus stacking can be challenging if there are inconsistencies between the shots, such as changes in lighting or movement within the scene.
Landscapes often include elements that can move between shots, such as leaves, grass, clouds, or water. When these elements shift between the multiple exposures needed for focus stacking, they can cause blending issues in the final image. This makes focus stacking challenging and sometimes even impossible in scenes with significant movement, so it requires you to access the scene before you attempt any given composition.
The same is true for changes in lighting. During sunrise and sunset, lighting can change very quickly. Parts of your image may be lit up in one shot, but not in the next and this can again cause issues in blending the final result, again requiring you to assess the likelihood of success before attempting to focus stack a scene.
Focus stacking is best done in stable conditions where the camera can remain completely still between shots. Even the slightest movement can cause misalignment, leading to blurry or unusable images. This means that windy conditions or shaky surfaces, are generally unsuitable for this technique. That being said, handheld focus stacking is still possible at certain shutter speeds (and I have done it successfully on a number of occasions), but it does require you to use good handheld techniques and to accept that you may lose some pixels around the edges when the image is blended.
When you shoot images to create a focus stack, you will have taken multiple RAW images which will use up your memory card more quickly, not to mention taking up more space on your hard drive. Ultimately, you can delete your original RAW images once you have merged and blended your shots (in Adobe Photoshop this results in a large TIFF file) but the final file might be hundreds of MB or even 1-2 GB depending on the process, which is far larger than a RAW file from a single image shot.
While this is a not a technical limitation, you shouldn't underestimate the impact this might have on your results. Since focus stacking requires careful planning, setup, and execution, it can limit you from being more intuitive and creative in your landscape photography. This might result in missed opportunities, particularly if you are trying to capture fleeting moments of light or dynamic, rapidly-changing scenes.
So how do you set yourself up to focus stack an image in the field?
Some mirrorless cameras have in-built focus stacking like the Sony A7RV. This has been a GAME CHANGER for my photography and I use the feature all the time. Whilst it may have been created more with macro photography in mind, I find it SO useful for landscape photography. I have my settings set to Standard (1 is narrow and up to 10 is wide) and set to a number of shots that exceeds the number of images I think the camera will take, and then I just put my focus point in the bottom of the screen and push the shutter button to begin. The camera decides based on the aperture and focal length I'm using how many images it needs to take, which takes the guesswork out of it for me!
I also have my camera set so that it creates a new folder and groups the focus stacked images together. This makes it really easy for me to find my focus stacked images later in my image library as the file naming is different to my single shot images and makes it easy to identify the stack.
There are several different software tools you can use to complete the blending of your focus stack, the most common being Adobe Photoshop or Helicon Focus. Here I'll go over the process using Lightroom and Photoshop:
Here is an example of the individual layers of a 3-image stack that Photoshop has identified in creating the final result below.
There are times where I have found Photoshop making quite random selections in the layers, and therefore times where using this automatic process doesn't give the best result. If that happens, I normally use the above process to get a rough idea first of where the edges of the sharpest pixels are across each layer and then using my own layer masks I will manually blend the layers together - something I did in the image below since the automatic blend didn't work well.
While focus stacking is a valuable tool for achieving sharpness throughout an image, you can also see that it’s not without challenges. The time and effort required, along with potential difficulties in post-processing, mean that it’s not always the best choice for every landscape photography situation.
But when used correctly, focus stacking can produce stunning, sharp images that just wouldn’t be possible with a single exposure. So next time you’re out in the field, don’t be afraid to have a go and experiment with focus stacking. With a little practice, you’ll be able to create stunning landscapes that are pin sharp and look amazing viewed on a large scale. So get out there and give it a go!
If you would like to learn more about achieving pin sharp images every time in your photography as well as a practical, interactive tutorial on how to focus stack your images, check out my online course: Improve your Focus: Practical Tips for Sharp Shots.
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