I’m continuing to clarify information on mirrorless cameras and lenses based on reader questions. There is a lot of new technology involved with mirrorless, and some new terms getting tossed around in daily conversations that may be confusing. One aspect of the new Nikon S lenses for the Z camera system is focus by wire. What exactly is that?
With Nikon F mount lenses, and other brand SLR lenses, most manually focus by twisting the focus ring on the lens and directly moving the lens elements. With the new S lenses, manual focus is achieved by focus by wire. What this means is that when you twist the focus ring on the lens, you don’t actually move the elements. Instead you send a signal to a motor in the lens which then physically moves the elements for focus. In essence you have added a ‘middle person’ to the process. Using focus by wire allows the new mirrorless S lenses to be lighter and cheaper, all good things. But you might get inconsistent results while manually focusing. If you twist the ring faster you might get a slightly different focus point than if you move it slower. If you are video shooter who relies on consistent manual focus, this may be an issue for you. I honestly can’t comment on this since I don’t shoot video, but I have many pro video photographer friends who absolutely swear by the Z6 as the best mirrorless video camera out there. Focus by wire doesn’t affect my still shooting, and I rarely use manual focus. When I do I just focus like I always have, no problems.
Another focusing aspect that I am really excited about is the new window on the 24-70mm F2.8 S lens. This window allows you to toggle through different settings including focal length, aperture setting and distance scale. What is really cool about the distance scale is as you change your aperture setting, the lens shows you your in-focus range and hyperlocal distance setting. Look at the image above. At 24mm at F13, one meter to infinity is in focus. If I choose a more open aperture setting like F8, the in-focus range would adjust to reflect F8. Very cool!