Still life and product photography often require that your entire subject be sharp.
This can be difficult to achieve in-camera because if you’re shooting up-close, you can’t always get a lot of your subject in focus.
Stopping down to a smaller aperture (higher F-stop number) will not necessarily help you get a sharper image.
Enter Photoshop and focus stacking.
Focus stacking is a post-production technique of blending several images with different focus points to create one image that is sharp and in focus throughout the entire subject.
It’s the ultimate way to get the sharpest images, and it’s a crucial technique to know for still life photography.
Why you can’t get razor sharp photos
Your aperture, focal length and the distance from your subject all impact the sharpness of your image.
Shooting at a higher F-stop number like f/22 won’t help you get sharper images in still life photography because of lens diffraction.
Lens diffraction in a phenomenon of optical physics that occurs in the lens and camera sensor.
When you shoot at f/2.8 or f/4, a lot of light hits your camera sensor directly. At apertures like f/16, the light hits the subject less precisely and causes a loss of sharpness.
It doesn’t matter how good your lens is – your images will be less sharp at apertures of f/16 and higher due to this law of physics.
The more you stop down, the finer details will blur out further.
Lens diffraction tends to be worse in zoom lenses than prime lenses because zooms have several moving parts.
The depth-of-field problem
In still life and product photography, you often need to get pretty close to your subject. This means a shallower depth-of-field.
If you’re shooting small objects like jewelry, or objects that need to fill the frame, you’re usually so close that its entire depth cannot be in focus.
Using a macro lens like a 100mm or 110mm will also give you a shallow depth-of-field.
This is great if you’re doing food photography and want that blurred out background that is sought after in that genre, but for other types of still life, it creates a problem.
Shooting for focus stacking
In order to focus stack in Photoshop, you need to shoot in a certain way with certain tools.
First of all, you need a sturdy tripod because your subject must be in exactly the same position from shot to shot in order to be successfully blended later in Photoshop.
If you accidentally bump your tripod, you’ll need to start all over again.
A shutter release is recommended to activate the shutter. Pressing the shutter by hand will introduce a small vibration that can introduce camera shake into the image and cause them to be misaligned in Photoshop.
That being said, Photoshop does a good job with aligning layers that are slightly off.
Personally, I like to tether my camera to Lightroom or Capture One and activate the shutter from within the program.
To shoot for focus stacking, start off by composing your shots and determining your exposure. You should use manual mode so that your exposure is the same from shot to shot.
- Choose a point on your subject to focus on and take a shot.
- Focus on a different point on your subject without moving the camera or adjusting any setting
- Choose the next point and take the final exposure.
Three images will often be enough to cover each area of depth-of-field but it will vary by image
Focus stacking in Photoshop
To blend the images together in Photoshop, start off by exporting PSD files into a folder or onto your desktop where you can easily find them.
- Open Photoshop.
- Go to File and choose Scripts.
- Select Load Files into Stack.
- Click Browse and select all the images from where you saved them initially.
- Check the Box for Attempt to Automatically Align Source Images.
- Click OK. Each of the images will open as a new layer in Photoshop.
- Hold down Shift and click on the top layer in the Layers panel to highlight all the layers.
- Under Edit, select Auto Blend-Layers.
- Check the box for Stack Images and also for Seamless Tones and Colors. DO NOT check ‘Content Aware.’ Click OK.
- Save the final image.
If you have uploaded a lot of images, flatten the final image by selecting Layer -> Flatten Image -> Save.
Conclusion
Focus stacking is necessary for product photography but also very useful for other types of still life photography – even food photography.
If you’re fairly new to Photoshop, don’t be intimidated.
Focus stacking is a lot easier than you might think and you will undoubtedly be pleased with your results.
Have you used photoshop focus stacking? If so, share with us your thoughts and images below.
