Handheld focus stacking is a brilliant solution for many scenarios. It saves you all the troubles of using a focusing rail in the field and provides a maximum of flexibility.
Whenever you need more depth of field than you can get with trading off image quality, this is the way to work around it.
Have a look at the following slideshow; the stack was shot handheld. Although it shows some minor shifts in perspective, you wouldn’t know by the final image. The first image in the sequence is the stacked result, followed by the single photos of the stack.
Of course it is ambitious to compete with an actual focusing rail, but with a bit of practice and the right technique, creating a good focus stack becomes a simple task that works well, even at extreme magnification ratios.
1. The Equipment
A typical set I use for stacking in the field. A camera in highspeed continuous mode (\ and an on-camera speedlight with a slim modifier. The flash ensures proper lighting and helps to eliminate motion blur. All ambient light should be cancelled out as we will move the camera back and forth; take a test shot without flash and make sure it is black. Ideally the flash power is set to 1/16th or even lower, to keep its recharging times short; an external battery pack that holds eight additional batteries helps with this. The camera should be set to the sync-speed of your camera, typically 1/200th or 1/250th Second.
If you dislike black backgrounds, you can use a larger light modifier to shine some light on the background and try to find a composition with a background that is either close to your subject or has a lot of natural light, such as the sky or sun-lit foliage.
2. The technique
Performing a handheld focus stack is all about a physically stable body position. In order to create a stack that is easy to merge we need to align the single frames as perfectly as possible. Ideally the camera moves on only one axis – back and forth.
And as we slowly move the camera on through the zone of focus we hold the shutter button down and take as many shots as possible. If the buffer fills up or the flash needs to recharge, hold your breath and try not to move the camera or your body until your gear is ready again. Shifting the perspective to much within a stack will ruin it.
To ensure this doesn’t happen, use your body as a tripod.
I typically kneel down or lean against a tree, if possible, and hold my elbows close to the body or rest them on my knees. If the subject is low and the ground is dry I will lie down and rest my arms on the ground. Then I hold the camera firmly against my face with both hands to hold it steady. I only my neck to push the camera through the zone of focus, only on that one axis.
Most subjects in nature are subject to motion blur, unless you are lucky and it is windless. Although we made sure this won’t affect the image quality, it can still interfere with our focus stack. If the subject moves between frames you will have to start over. A good technique to avoid this is to hold on to your subject with the hand that’s not holding the camera.
To stabilise both, camera and subject, I will hold the stem of a plant between my fingers and rest the lens on either my wrist or the gap between index finger an thumb.
Now there is only one last thing to mention before you get started, and that is: Overshoot. You can never be sure that you have every slice of DOF that you will need to complete your stack. And the only way to eliminate this risk is to take 100 shots instead of ten. Of course the amount of images you’ll need to get it right depends on the magnification ratio and the aperture you’re using, but you will get a feel for that as you review your stacks.
And even if you just get two images in sequence before your subject flies off, that is still going to double the depth of field in your image:
3. Post Processing
Before you start the actual stacking, I recommend to develop your *.RAW files in Camera Raw and save them as *.jpeg files. This way you are sure to get the best image quality and it will speed up the process.
Load Files into Stack
In the next step we are going to load all the files of our stack as layers into one new document. To do so go into the “files”-tab of PS and select “scripts” → “Load Files into Stack…”.
Unless you have a completely black or blurry background, leave both boxes in the dialogue window unchecked. Sometimes PhotoShop gets cunfused by structures in the background and gets the alignment wrong.
Once all the layers are loaded we are going to put all of them into a new group. Then we duplicate the folder (ctrl + j) to create a back-up, just in case we need to fix something later in the process.
Before we use PhotoShop to align our layers for us we’re going to make sure, that the background won’t confuse the software.
Create a rough selection around your subject and make sure that it contains the whole subject in all layers. Then invert the selection (“ctrl”+”shift”+”I”) and delete it in all layers of the group.
Once finished you should have to groups; the original “Group 1” on the bottom and its duplicate “Group 1 Copy” with the isolated subject.
Select the group that we just worked on and go into the “Edit”-menu. Select Auto-Align Layers and choose the Auto-mode in the following dialogue window..
PhotoShop is going to move the freshly aligned layers into the top left corner of your document, to move them back select the whole group and press “ctrl”+”t”. Then turn down the layer opacity to 50% and move the group back where it came from.
Turn the opacity up again and look through all layers to ensure they are aligned well enough. Some slight shifts are acceptable, but the cleaner your stack, the easier the next step will be.
Duplicate the group once again; deactivate the new copy and select the group named “group 1 copy”.
Then go into the “Edit”-menu and cllick on “Auto-Blend Layers…” In the following dialogue window select “Stack” and tick “Seamless Tones and Colors”.
Once PhotoShop is done, merge the group into one layer and zoom in to inspect the result. There is a good chance that the PhotoShop got some things wrong and they’re not always obvious, so be thorough.
If everything looks good you can skip the next step, but if there are glitches or artefacts we will need to touch them up manually.
Now it’s time to touch up the image; to do so we will paint in bits and pieces from our back-up group vby using layer-masks.
Select “Group 1 copy 2” and deactivate all layers in it except for the very bottom layer. Add a black layer-mask to this layer by holding the “alt”-key while clicking on the layer mask symbol.
Use “ctrl”+”i” to switch between a black and white layer-mask and determine the parts of the layer that should be in the final image. Then set the layer mask back to black and use a the eraser tool at about 50% hardness to paint in the missing pieces. Move on to the next layer and repeat the process until your satisfied with the result.
Once you are done with this, all there’s left to do is to get rid of the hard edges around your subject. To blend it in create a white layer-mask for the entire group and paint over its edges with a soft black paint brush.
Before exporting the image, I typically delete unwanted layers, such as “Group 1”, in this case. Then I duplicate all layers and merge them into one layer, that I convert into a smart object. Last I will finish the image off by applying the Camera Raw filter in PhotoShop and perform some slight adjustments.
And here you see the final image. This would have been tricky to shoot with a focusing rail; the long set up time, wind in the environment and the limitations of using a tripod make it challenging to use rails in the field. In terms of flexibility and required gear handheld stacking is a lot more practical.
The only downside to this technique is some extra-work in post processing. A fair trade, as I find.
And with a bit of practice manual focus stacking is an easy technique that will open up new possibilities for your photography.
About the Author
Maximilian Simson is a macro photographer based in London, Ontario. You can find more of his work and creative ideas on his website and YouTube channel, and follow him on Instagram and Facebook. This article was also published here and shared with permission.