Focus Stacking in Photoshop
Sometimes you might want to shoot something and get it all in focus but stopping down doesn’t quite get you there, or maybe it does but you don’t want to take the loss in image quality that comes with shooting at f22.
Focus stacking comes in handy in these situations.
D850 focus shift settings
I’ve used the D850’s focus shift shooting fuction (often called focus bracketing) to capture the images. I’ve guessed the number of shots and the focus step width, the settings worked well, I have every part of the image in focus. Sometimes you might need to capture a few extra shots to cover the entire range or restart with a smaller step width.
I have the interval at 30 seconds so my speedlights have time to recycle. I’d normally use Silent Photography (electronic shutter) but it doesn’t work with the speedlights.
If your camera doesn’t have focus shift you can just shoot it manually, adjusting the focus ring between shots.
Image #1 - front focused image
Image #8 - back focused image
I’ve taken 8 images that cover the full range of focus. If you shot RAW format you’ll need to save them in another format, I’ve applied some minor corrections in ACR and saved them as JPGs.
Select all images (CTRL+A Windows or CMD+A Mac), go to tools>Photoshop>Load files into Photoshop layers
Once the images are loaded into Photoshop, select all layers (select top layer in stach then SHIFT+click bottom layer in stack), go to Edit>Auto align layers.
Select Auto, you can remove vignette and apply correction if needed, I used the Tamron 90mm macro which doesn’t need either.
Once that’s complete go to Edit Auto blend layers.
On the dialog box that pops up choose the Stack Images option, I always check seamless tones and colours, I don’t check the content aware fill box but if you end up with gaps in the final image you could go back and try again with that box checked.
When the process is complete you will see layer masks applied to the layers like the ones shown above. Depending on what you are shooting you might see errors in the image, this exaple came out ok as it’s not a very complex scene. If there are out of focus areas in the blended image I manually touch up the layer mask(s) using a black or white brush.
The final image, sharp focus front to back.
Time to drink that coffee.