How can a 50 mm be so long? It seems Nikon is using F mount optical scheme adding just room and some optics to correct for mirrorless shorter distance.

How can a 50 mm be so long? It seems Nikon is using F mount optical scheme adding just room and some optics to correct for mirrorless shorter distance.

An outstanding lens no doubt - but an absurd size! Can't see many carrying anything like that for a 50mm.

An outstanding lens no doubt - but an absurd size! Can't see many carrying anything like that for a 50mm.

[quote]How can a 50 mm be so long? It seems Nikon is using F mount optical scheme adding just room and some optics to correct for mirrorless shorter distance.[/quote] Then you don't understand lens design. The diameter of the flange as awell as the flange to sensor distance can make a large difference in the end performance. If you look at the design of the lens here: https://imaging.nikon.com/lineup/lens/z-mount/z_50mmf12s/spec.htm you can see that the rear element goes right to the back of the lens as close as possible to the sensor without protruding past the mount. Not only that, but the width of the last element is almost as wide as the mount throat which would not be possible with the old F mount. So, the new mount has allowed Nikon to design the lens to take full advantage of the extra room this new mount allows. An AF 50mm f1.2 was NOT possible with the F mount as there was not enough room for the electrical contacts as well as the wider throat required for wider rear element. Added to that, to keep CA and other distortions at bay, this required a wider mount and closer rear element which has been achieved with the new mount. Edge to edge sharpness, wide open sharpness, virtually non existent CA, low distortion, excellent bokeh and decent bokeh balls would be basically un-achievable in the old F mount. Even if they could have achieved some of these benefits, it would have been even larger and heavier and much more expensive than this Z mount design due to the use of much more glass, and more importantly more exotic glass, to correct for aberrations even if they could have been corrected in an F mount design. This is obviously not a lens for the average punter. This is a lens for specialist use for pros and advanced amateurs that want to get wide open sharpness and shallow DOF for that special look. I see it as another benchmark lens for Nikon. If you want a 50mm lens that does mostly what the 50 f1.2S lens can do but only a half stop slower, look at the sensatioonal 50mm f1.8S that has been compared to some of the best exotics out there. Small, light and a relative bargain.

Quote:How can a 50 mm be so long? It seems Nikon is using F mount optical scheme adding just room and some optics to correct for mirrorless shorter distance.


Then you don't understand lens design. The diameter of the flange as awell as the flange to sensor distance can make a large difference in the end performance. If you look at the design of the lens here:
https://imaging.nikon.com/lineup/lens/z-mount/z_50mmf12s/spec.htm
you can see that the rear element goes right to the back of the lens as close as possible to the sensor without protruding past the mount. Not only that, but the width of the last element is almost as wide as the mount throat which would not be possible with the old F mount. So, the new mount has allowed Nikon to design the lens to take full advantage of the extra room this new mount allows.

An AF 50mm f1.2 was NOT possible with the F mount as there was not enough room for the electrical contacts as well as the wider throat required for wider rear element. Added to that, to keep CA and other distortions at bay, this required a wider mount and closer rear element which has been achieved with the new mount. Edge to edge sharpness, wide open sharpness, virtually non existent CA, low distortion, excellent bokeh and decent bokeh balls would be basically un-achievable in the old F mount. Even if they could have achieved some of these benefits, it would have been even larger and heavier and much more expensive than this Z mount design due to the use of much more glass, and more importantly more exotic glass, to correct for aberrations even if they could have been corrected in an F mount design.

This is obviously not a lens for the average punter. This is a lens for specialist use for pros and advanced amateurs that want to get wide open sharpness and shallow DOF for that special look. I see it as another benchmark lens for Nikon. If you want a 50mm lens that does mostly what the 50 f1.2S lens can do but only a half stop slower, look at the sensatioonal 50mm f1.8S that has been compared to some of the best exotics out there. Small, light and a relative bargain.

As the owner of a fine copy of this lens, I can certainly attest to its optical prowess, and even how the autofocus can be used for some sports (youth basketball). Sure, for sports I relied on a Z9 which took this Z 50mm f/1.2 S to its autofocus limits, and though not meant for sports, still managed quite a good rate of keepers even at f/1.2. As far as closeups are concerned, I got a set of Kenko Z extension tubes, which gave me a combined 26mm extension, and increased the lens’ magnification from 0.15x to 0.65x, making it nearly a macro lens. Of course you have to stop down to f/4 or more otherwise the depth of field becomes so thin it’s unusable. Autofocus is not completely silent, but it’s quite fast, so for video purposes I recommend an external sound recording mic, or to manual focus. On the Z9 I was able to set the lens’ focus ring rotation to linear or non linear, as well as limit the amount of turns to rack focus end to end. Also another bonus, specific to the Z9 is the ability to set the L-fn button on the lens to switch between FX and DX, while keeping the DX resolution setting separate from FX resolution. So I can shoot medium size images in FX, then click the L-fn button to get a 50% instant zoom, and shoot at large size images in DX. This essentially gave me two lenses in one for shooting my son’s games. I really love this lens, but for full disclosure I am a Nikon employee. However I am a photographer and designer too, and I will take any tools that help elevate my photography. This lens does that perfectly.

As the owner of a fine copy of this lens, I can certainly attest to its optical prowess, and even how the autofocus can be used for some sports (youth basketball). Sure, for sports I relied on a Z9 which took this Z 50mm f/1.2 S to its autofocus limits, and though not meant for sports, still managed quite a good rate of keepers even at f/1.2. As far as closeups are concerned, I got a set of Kenko Z extension tubes, which gave me a combined 26mm extension, and increased the lens’ magnification from 0.15x to 0.65x, making it nearly a macro lens. Of course you have to stop down to f/4 or more otherwise the depth of field becomes so thin it’s unusable. Autofocus is not completely silent, but it’s quite fast, so for video purposes I recommend an external sound recording mic, or to manual focus. On the Z9 I was able to set the lens’ focus ring rotation to linear or non linear, as well as limit the amount of turns to rack focus end to end. Also another bonus, specific to the Z9 is the ability to set the L-fn button on the lens to switch between FX and DX, while keeping the DX resolution setting separate from FX resolution. So I can shoot medium size images in FX, then click the L-fn button to get a 50% instant zoom, and shoot at large size images in DX. This essentially gave me two lenses in one for shooting my son’s games. I really love this lens, but for full disclosure I am a Nikon employee. However I am a photographer and designer too, and I will take any tools that help elevate my photography. This lens does that perfectly.