AF-S on a NIKON body with AF motor

[iskoos]

If an AF-S lens (the ones that have AF motor in the lens body) used on Nikon body with AF motor in it (like D90) which motor is used to autofocus? The one in the camera or the one in the lens?

 

[PhotoXopher]

AF-S lenses don't have the mechanism to be driven by the internal (body) AF motor. AF-S and similar lenses are always driven by the internal (lens) motor.

 

[Derrel]

The motor in the lens will be used if the lens is AF-i or AF-S. AF-i is the first in-lens motor protocol that came before AF-S.

 

[iskoos]

Pretty clear. Thanks to both of you...

One more... If an AF-S mounts on a D40, in-lens motor will be used for AF. If an AF lens mounts on a D40, then AF will not be achieved since no AF motor is present thus the only option is MF. Correct?

 

[ghache]

Pretty clear. Thanks to both of you...

One more... If an AF-S mounts on a D40, in-lens motor will be used for AF. If an AF lens mounts on a D40, then AF will not be achieved since no AF motor is present thus the only option is MF. Correct?

you are correct.

lens without the internal focus motor will not auto-focus on d40/x, d60/x, d3000 and possibly the d5000, i am not sure.

 

[PhotoXopher]

Pretty clear. Thanks to both of you...

One more... If an AF-S mounts on a D40, in-lens motor will be used for AF. If an AF lens mounts on a D40, then AF will not be achieved since no AF motor is present thus the only option is MF. Correct?

Correct for all 'baby Nikons'.

D40, D60, D3000 and D5000.

 

[Garbz]

In case you're interested in how this works, in the bottom right of the lens mount is a mechanical AF coupling.

On AF-S lenses and old manual focus lenses the flat screw coupling in the bottom right of the above lens mount is absent, even if the camera tried it wouldn't be able to focus an AF-S lens using the body motor.

 

[iskoos]

Hey Garbz, thank you for that picture. I really wanted to see the back of Nikon lens.
I looked at the picture you posted and I see that flat screw coupling.
I will ask another question now, it may sound a bit too detailed but bear with me please...)
If you mount an AF-S lens (which will not have that flat screw coupling as you mentioned) on D90, the AF will get done thru the in-lens motor since no mechanical connection can be made between the camera and the lens. But in this case would the AF motor (inside the camera body) still spin during the autofocus process? Or would the camera know that it is using lens's AF motor and not power the AF motor inside the camera body?

Just my curiosity

 

[PhotoXopher]

Camera knows all.

It won't do anything if a lens not requiring it is used.

 

[Garbz]

If you look at your camera with the lens off you'll find the screw mechanism is recessed. It won't (shouldn't?) even extend the coupling if you have a non-AF lens mounted. These things are clever indeed. The camera has historically known everything about the lens. Even these days what is done with electronics was in the past done with cleverly placed notches in the mount mechanism. For instance the notch on the 9:30 position of that lens indicates the lens is post AI, and the post sticking out at the bottom indicates it's not a pre-AI lens.
That's a simplistic example anyway.

 

[PatrickHMS]

Correct for all 'baby Nikons'.

D40, D60, D3000 and D5000.

Don't forget D40X.

Even if AF lens will not autofocus on the "baby Nikons' " there is a green light inside viewfinder that will come on when camera sees an in focus condition.

You will have to manually focus the shot, but the camera will tell you when you have done that.

I believe that to be correct for all of the "baby Nikons' "

 

[iskoos]

If you look at your camera with the lens off you'll find the screw mechanism is recessed. It won't (shouldn't?) even extend the coupling if you have a non-AF lens mounted.

If I had a Nikon, I doubt I would ask any of these questions. I have an extreme curiosity and passion for electromechanical gizmos. That's why I ask all these anal questions...:lmao:

If had an opportunity to play with a Nikon DSLR camera one day, you bet I will look at all these things...

 

[iskoos]

Even if AF lens will not autofocus on the "baby Nikons' " there is a green light inside viewfinder that will come on when camera sees an in focus condition.

You will have to manually focus the shot, but the camera will tell you when you have done that.

I believe that to be correct for all of the "baby Nikons' "

That's true for other DSLR's as well. It is same on my Canon, I can turn off the AF and when I focus manually, the camera will tell me if I achieved the focus by turning on the focus confirmation light. Even if we manually focus on the objects, light rays are still passing thru the focus sensor inside the camera and that's how the camera lets you know if the focus is achieved.
But if we go back to pre AF era, I am sure those camera bodies will not let you know if your focus is done or not...

 

[KmH]

Correct for all 'baby Nikons'.

D40, D60, D3000 and D5000.

Don't forget D40X.

Even if AF lens will not autofocus on the "baby Nikons' " there is a green light inside viewfinder that will come on when camera sees an in focus condition.

You will have to manually focus the shot, but the camera will tell you when you have done that.

I believe that to be correct for all of the "baby Nikons' "

Only if the AF lens has the "D" (distance) designation, which means it can convey distance info to the CPU in the body. (AF 50 mm f/1.8D) (AF 24-85 mm f/2.8-4D)

Not all AF lenses have the D designation.

 

[Garbz]

Really? Didn't know about that one. I would have thought that it would behave more like the D200 does with pre-AF lenses, or lenses used via adapters. The focus detection works constantly even with AI Nikkors and MF Zeiss lenses. Would seem strange that the focus detection would be related to lens distance information.