Lifesavers focus stack
Jan 24, 2017
Lifesaver Focus Stack
The focus stack, a technique used largely in macro photography and when one needs to add greater depth of field than is allowable with the lens. Now certainly I could have raised the aperture and got the shot all in one take, but I wanted the bokeh of the lights at f/2. Focus stacking allows me to achieve this. All it means is combining different photos at different focus points.
Here's how I did it
As you can see, shooting at f/2 this close to the subject your DOF (depth of field) is going to be razor thin. Also, shooting this wide open it is going to require barely any power out of the strobe and your scene is going to be very sensitive to ambient light. So.... turn the lights out.
I turned on the modeling lamp on the strobe to give just enough light on the subject to be able to focus in live view. If your strobe doesn't have a lamp, or your using flashes, a flashlight will work as well.
Use live view to manually focus throughout the series of images, it will greatly help in making sure you have it all. I started at one end of the roll and kept moving the focus ring ever so slightly between each shot. In the end I had about 12 shots total.
Import your shots into Lightroom and remember the Auto-Sync button? Do global adjustments to your image and then > Open as layers in Photoshop
Once in PS, highlight all of your layers and Edit>Auto-align layers
Even pressing the shutter may cause a small shift from one picture to another and PS will line them all up nice and tight for ya.
Now its time have the magic happen, with your layers all still highlighted
Edit > Auto-blend layers
This isn't necessarily a quick process, so grab a snack, sit back and wait a minute.
Once done you will see that PS has masked each layer for you (as you can see in the screenshots above, they were taken after the fact) which then can be used to further refine if needed the focusing. After this run I didn't fine tune anything, saved it, and it then re-imported back into Lightroom.
Here are close-ups of 2 individual frames from the series. Note the razor thin DOF.
Now this technique may not work well on kids or pets:) It is however pretty handy for stilllife.
Questions, Comments, or rants (yup but em below).