Focus shift shooting Also known as ‘focus stacking’
Focus stacking is a technique widely used by photographers who need to maximize depth of field in close-up shots such as this one. The problem is that even at minimum aperture, it’s not possible to keep the subject and the background sharp. As this is a limitation of physics and the optics in a typical DSLR, there’s no way of resolving it – even with the D850.
The solution, or rather workaround, is to take a series of shots at slightly different focus settings and then blend them later using specialist software. This is normally a tedious manual process prone to error during the shooting phase when it’s easy to lose track or miss a step, but the D850 can do it all automatically – you simply choose the number of shots and focus interval.
When you tap the Start option on the menu, the camera then takes all the shots in the stack, one after the other – you can see the focus adjusting slightly between each shot. The only thing it can’t do is blend the shots in-camera – you have to do that in software later, but because the shots should be perfectly focused and aligned, the process should be mostly painless.