Merge Macro Images to Improve Sharpness
Some photo-editing programs (like Photoshop version CS4 and later) enable you to capture multiple images of one subject, each with a separate point of focus, and merge the images to create one image with an expanded depth of field. You need to ensure that your subject can’t move when you use this technique; photographing still subjects in the studio, where there’s no wind, is ideal.
Set your camera on a tripod and choose a camera angle and composition that suits your subject and message.
In macro and close-up situations positioning your camera on a tripod is a good idea.
Lock the camera in place ensuring it won’t move during or between shots.
If you have a focusing rail, then I recommend using it for accurate and easy focusing.
Choose an aperture setting based on the sweet spot of your lens — neither wide open nor closed down, but somewhere in the middle of the lens’s aperture range.
Most lenses produce their sharpest results when the aperture is not set to be extremely large or small. Because you’ll be merging multiple images in this technique to produce one completely sharp image, there’s no need to maximize depth of field.
Position your focal point on the part of the subject that’s nearest to your camera, and take a photograph.
This is your starting point.
Shift the focal point farther into your scene (achieving sharp focus on a part of the subject that’s slightly farther from your camera).
I recommend that you use a focusing rail to shift your focus, but if you don’t own one then simply rotate the focusing ring on your lens to shift the focal point.
Take a photograph with your new focal point.
Repeat this step until you’ve taken enough images to cover the entire subject in sharp focus.
The size of your subject and your level of magnification determine how many photos you need to achieve focus throughout. Making smaller focusing shifts and taking more photographs ensures that you don’t miss any areas, providing proper results when you process the images in the photo-merge.
Open the images in Photoshop (or your preferred photo-editing software).
The photographs show you an example of the process; note the varying focal points.
Select a base image, and drag the others into it.
Hold down the shift key to ensure the images are aligned when you drag them in. You end up with a single file containing each image on a separate layer.
Select the bottom layer and then shift click on the top layer.
Doing so selects all of the layers.
Go to Edit→Auto-Blend Layers, and choose the Stack Images method.
You will now have one image.
Click OK and wait for the software to do the rest.
You end up with an image that’s sharp and crisp from end to end. This photograph shows the final image, with all focal points combined.