Why do Nikon Lenses Screw on Backwards?

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Twenty years using OM's and M42, I am quite used to swapping lenses by turning them like a bolt. Clockwise to screw 'on', anti-clockwise to screw 'off'.

I had forgotten that Nikon F-Mount goes the other way; and have been having some of those 'Doh!' moments, switching between cameras. And it got me wondering....

There HAS to be some quirky historical reason for this.... so I got googling, and as yet haven't turned up an answer.

I mean; in days of yore, cameras didn't have interchangeable lenses, so it wasn't an issue. But designers attached lenses by making a mount and used a conventional, convenient 'plumbers' means of attachment, either a flange with a few screws or a thread; which would conventionally screw 'in' clockwise.

Then came system lenses; the earliest of them using simple threaded screw in mounts, that used conventional 'right handed' threads, that would screw 'in' clockwise, and 'off' anti-clockwise. So when 'quick-fit' bayonet mounts came along, they tended to follow the same convention; clockwise on, anti-clockwise 'off'... makes sense.

Except for Nikon.

And I had the notion, that MAYBE the left-handedness of their design was a dint of legacy; something to do with the external coupling 'hitch' between the aperture ring and pentaprism meter... only the F-Mount pre-dates 'lens-coupled' meters. So that cant be it.

So what is it? any-one know?
 
It could be due to the fact that Nikon consider that when you hold your camera, you turn the zoom and focusing ring clockwise to increase distance, and that you turn the aperature ring clockwise to close (increase the depth of field). So turning clockwise to increase as in turning volume knobs clockwise to increase. Because of the designs of aperatures, for it to work, you would need to have the lens turn anti-clockwise to put on.

If lens were put on clockwise, then aperature ring, focusing ring, and such, would have to be turned anti-clockwise when viewed from behind (as in when holding the camera).
 
PS: Come to think of it, when you use binoculars, don't you normally turn the focusing ring clockwise (when holding to your eyes and viewing) to increase the focusing? So Nikon may be thinking the same thing with focusing ring on the lens, but when using camera (viewing from behind) in order to turn clockwise to increase focusing, lens must be designed to put on anti-clockwise.
 
I believe the Nikon S-mount (the rangefinder bayonet mount), which came before the Nikon SLR F-mount, mounted in the same direction. And that was basically a copy of the Zeiss Contax mount - the history of which is explained here.

So Zeiss make the Contax mount, Nikon copy it for the S-mount, and then to keep the transition simple between rangefinder and SLR, they used the same direction to develop their new SLR mount. And here, 60 years later, is probably why it mounts in that direction.
 
I believe the Nikon S-mount (the rangefinder bayonet mount), which came before the Nikon SLR F-mount, mounted in the same direction. And that was basically a copy of the Zeiss Contax mount - the history of which is explained here.

So Zeiss make the Contax mount, Nikon copy it for the S-mount, and then to keep the transition simple between rangefinder and SLR, they used the same direction to develop their new SLR mount. And here, 60 years later, is probably why it mounts in that direction.

Err... OK... so the Nikon F screws in anti-clockwise, because the rangefinder S-Mount screwed in anti-clockwise... so we have a legacy convention that explains why the Nikon lenses mount that way.... takes us part way back..

BUT....Nikon S-Mount lenses were a 'copy' of the Contax mount..... so why did THEY mount anti-clockwise?
 
Err... OK... so the Nikon F screws in anti-clockwise, because the rangefinder S-Mount screwed in anti-clockwise... so we have a legacy convention that explains why the Nikon lenses mount that way.... takes us part way back..

BUT....Nikon S-Mount lenses were a 'copy' of the Contax mount..... so why did THEY mount anti-clockwise?

I can only take you back to 1932...!
 
Arrgh, traumatic flashback of my first assisting at a wedding, circa 1981...........I was used to Pentax and Olympus, the wedding photographer used a couple of Nikons. The panic when I thought I'd jammed the lens when he tossed one to me for a quick film and lens change :D
 
Err... OK... so the Nikon F screws in anti-clockwise, because the rangefinder S-Mount screwed in anti-clockwise... so we have a legacy convention that explains why the Nikon lenses mount that way.... takes us part way back..

BUT....Nikon S-Mount lenses were a 'copy' of the Contax mount..... so why did THEY mount anti-clockwise?

Nikon's F-mount screws in anti-clockwise, as I mention above, is becuase when you are using the camera, you turn the focusing ring and aperature ring clockwise (as viewed from the rear) to increase distance or depth of field, so lens have to be mount on the camera the other way round. I have no idea why would Contax do that anti-clockwise in the first place (if you point out that Nikon's S-Mount was a copy of Contax's so maybe Contax started it first). I would guess either Contax had a similar idea, that to increase, you turn clockwise, but as viewed at the back of the camera or maybe Contax figure you would change your lenses while holding your camera pointing forwards.

I mean, you could waste time turning your camera around to you would be looking at the front of the camera, and change the lens by anti-clockwise for taking lens off, and clockwise for putting on a different one, but then you would turn the camera around to use it, when you consider that sometimes a photographer would keep the camera pointing forwards and change lens by turning anti-clockwise to take off (but anyone else standing in the front of you and looking at your camera would notice you turn clockwise to take off), you put on another lens clockwise (again from another person's point of view, it looked like anti-clockwise), while keeping your camera pointing forwards.

I don't know, but from limited imformation, I would have to guess they made them that way expecting photograhers to view clockwise/anti-clockwise from the back of the camera not from the front of the camera.

It could be clockwise if you view a camera by looking at its front, but when you use it to take photos, you have to turn the aperature ring anti-clockwise to maximise depth of field or focusing distance. It would be bit like turning the volume knob anti-clockwise to increase the vol.

Who knows, maybe Nikon and Contax were supposed to be right in thinking you turn clockwise from the back of the camera to increase depth of field, so that would meant if you turn anti-clockwise, you open up and let in more light, in a similar way as you would turn a tap anti-clockwise to get more water flowing??

Well, that's how I see it from limited info.
 
Arrgh, traumatic flashback of my first assisting at a wedding, circa 1981...........I was used to Pentax and Olympus, the wedding photographer used a couple of Nikons. The panic when I thought I'd jammed the lens when he tossed one to me for a quick film and lens change :D

I've used Minolta X-700 and later SR-1 for years, then when I switch to digital, I decided on Nikon, and had ended up getting them mixed up. Sometimes I tried to turn the wrong way on Nikon, like you, thought I jammed it and broken it, but after a while, I got used to it. Mind you, although I do get used to it, sometimes when I'm tried or under pressure, the mistakes slips in and I turn them the wrong way! Even thought I had the X-700 for like about 30 years and the Nikon for hardly 5 years, I sometimes tried putting lens on my X-700 the Nikon way!! (As well as trying to put lens on Nikon the Minolta way!!)
 
I've used Minolta X-700 and later SR-1 for years, then when I switch to digital, I decided on Nikon, and had ended up getting them mixed up. Sometimes I tried to turn the wrong way on Nikon, like you, thought I jammed it and broken it, but after a while, I got used to it. Mind you, although I do get used to it, sometimes when I'm tried or under pressure, the mistakes slips in and I turn them the wrong way! Even thought I had the X-700 for like about 30 years and the Nikon for hardly 5 years, I sometimes tried putting lens on my X-700 the Nikon way!! (As well as trying to put lens on Nikon the Minolta way!!)

Think how I feel when using my Minolta MC lenses on a Nikon adapter!
 
A few things with Nikon are back to front. In the menu, there are even options to reverse things. I find that with these settings I have then set to "reverse" so they now operate correctly. But yes, the lens mount gets me every time.
 
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