Get maximum depth of field with focus stacking
Find the right subject 1
Not every image will benefit from focus stacking. Compositions with extreme foreground interest, such as a rocky coastline or detailed mud textures that lead into the scene, will certainly benefit from this technique, however. If the foreground isn’t interesting or is more than about three metres from your lens, then focus stacking is probably not necessary and you can get the detail you need with a medium or narrow aperture.
Focus three times 2
Once you have framed your composition, take the same image three times – each time focusing on a different point in the frame. For image one, focus to infinity or the furthest object in the frame; for image two, focus halfway into the frame; and for image three, focus on the extreme foreground close to the bottom of your frame. Be sure to shoot in manual mode, work fast in case things in your frame change, and avoid knocking your camera.
Stack your images 3 in Photoshop
P rocess your first image, then apply the settings to the other two images to ensure they are all the same. Open the three images in Photoshop as separate layers, with the distantfocused image on the top layer, mid-focus image as the middle layer, and the foregroundfocused image on the bottom layer. Select all three layers, then go to Edit > Auto Align Layers and select Auto to line everything up.
Reveal the sharpest 4 parts of your photo
Add a Layer Mask to both of the two top layers. On each of these layers in turn, simply brush away on the Layer Mask the parts of the layer that are not sharp, revealing the sharper layer beneath. Use a brush with a soft edge of around 50%. Take care while you’re brushing away areas of the image that may contain hard edges such as rocks or cracks in the ground: it’s important that any lines match up.
Crop and save 5
Once you have brushed away the soft areas of each layer, zoom in to 100% and check for any anomalies where the layers meet. This shouldn’t be a problem unless there was movement during your shots. Finally, check the edges of your image. When Photoshop aligns the layers, it will shift them slightly; as a result, you will need to crop your image by a few pixels. Save your image, and you should now have a pin-sharp picture from front to back.