If you're shooting macro or landscape images and are looking for maximum sharpness across your entire image, focus stacking is one of the most useful techniques you can learn. This helpful video will show you how it's done using Photoshop.
Coming to you from Mike Perea Photography, this great video will show you how to create focus-stacked images using Photoshop. Focus stacking is the technique of blending multiple shots of the same subject taken at varying focal distances to create a greater depth of field and thus, increased sharpness across the image. The problem is that after a certain point, increasing the aperture introduces more and more diffraction into the image, which robs it of the sharpness you're looking for. For landscape photographers, another option might be to use the hyperfocal distance to achieve maximum depth of field. This can be a good compromise a lot of the time, but it can fall short if you have a prominent foreground element you'd like to show off or if you simply want maximum sharpness across the entire frame, in which case, focus stacking is the best solution. Check out the video above for the full rundown of the technique.