Focus Stacking is the merging (stacking) of many frames, captured at a slightly different focal point. The capturing of multiple frames at a different focal point is focus bracketing. The focus bracketed images are merged in a focus stack by a photo editing software – focus stacker. Before the creation of designated focus stackers the images were manually added in photoshop as separate layers and only the sharpest areas were revealed by using layer masks.
When photographing a subject from very close you get a very shallow depth of field. Parts of your subject are in a different focal plane and are out of focus. Only a small area remains in focus.
When you digitally combine the images together, you get a lot more areas that are in focus. You get what seems to be a wider DOF and a lot more details. The captured subject must appear identical in each frame – any difference between the frames, no matter how minor it seems, could round the stack.
The number of images you will need will vary depending on the subject you photograph. Also the method may vary slightly. For flatter subjects / surfaces you won’t need as many shots.
What kind of equipment is needed for Focus Stacking Macro Photography ?
How is it possible to take so many sharp shots of a moving subject ?
As I mentioned above – the images captured in the frames must be matching exactly. I use anything between 100 and 300 frames. Focus stacking doesn’t work with a constantly moving subject.
Some people say that when photographing insects they freeze them to slow down their metabolism for few minutes and when done photographing, they set them free.
Others claim to be using hair spray ( I definitely do not recommend this). I have tried those options but never found them to work. For the time being I do not use live subjects for focus stacking. I pick up already dead insects and I photograph them.
No, you can use this method on many different subjects. Working with inanimate objects it is actually a lot easier. You are relieved from the moral dilemma of how to most adequately “prepare your subject for the photoshoot” since they do not move.
Insects are fascinating subjects and many photographers choose them because of the great amount of details they have.
But if you are not into that, don’t feel restricted – you can have a look at my gallery HEREfor examples of several different subjects that are also great for focus stacking.
Does Focus Stacking work only for Macro Photography ?
No, focus stacking can be done with any type of photography, it’s just more visible when working with shallow DOF. The closer you are when you are photographing your subject, the shallower the DOF becomes. This makes it most suitable for closeup, macro and micro photography.
But focus stacking can be done even when working with wider DOF and the difference in focus is very subtle.
How are the Frames Stacked ?
The frames are stacked by a photo editing software such as Affinity Photo, Zerene Stacker, Helicon Focus, Photoshop and other programs…
It takes a while – the more images you are stacking the longer it takes. 300+ images may take like an hour and a half to stack, in Zerene Stacker and much much longer in Photoshop so be patient. Of course time will vary depending on the machine that you are using too.
If you have further questions please let me know and I will do my best to include them in this post.
Is higher ISO ruining my focus stacks ?
In most cases – no, of course it depends on your camera but newer model cameras handle higher ISO just fine. When it comes to focus stacking macro – higher ISO is the least of your problems also because noise reduction stacking will happen during the processing. More common causes of bad quality final image are –
camera shake / motion blur / vibrations.
not enough frames – some details were simply not captured in certain areas.
uneven light – no details where the harsh shadows are.
I personally have never experienced any problems related to higher ISO when focus stacking.
I am not saying that you must increase the ISO every time – but just don’t be afraid to do it when it fits the situation.
Is There a Difference Between Focus Stacking and Noise Reduction Stacking ?
Yes, there is a difference in the way that the software determines which part of the image is going to be used. As explained focus stacking targets the parts of the image that are in focus and uses only them for the final result.
Noise reduction stacking works in slightly different way. Each photo has it’s own a unique noise pattern – no matter what the camera settings are, there will be some amount of noise. Since the noise is random and unique for each frame, noise reduction stacking works by combining the less noisy parts of the images into the final result.
The main factor that usually determines which type of stacking is more suitable is the DOF. It is very important to remember that the DOF is a guide not a rule. You can use each technique as you see fit.
You can focus stack even if you are working with wider depth of field and you can do noise reduction stack even if you are working with shallow DOF – in fact noise reduction stacking will happen during focus stacking anyways.
Here are few videos on Focus Stacking
About the Author
Esther White • Photographer • Photo Editor • Graphic Designer
7 years experience.