300mm Zoom Question

[chrisburke]

I have the Nikon AD Nikkor|70-300mm1:4-5 6 G lens.. it doesnt auto focus on my d40... i plugged it onto my friends d80 the other day and it does... I don't use auto focus, but I'm intrigued as to why it focuses on the 80 and not the 40

 

[TamiyaGuy]

All Nikon lenses with an AF-D mount do not contain their own focusing motors, and they rely on the camera's motor in order to autofocus. However, the D40 does not have its own motor in order to save on size and weight, so the D40 can only autofocus on AF-S lenses or equivalent (Sigma HSM, etc).

Edit: Hmm... it seems as though the Nikon 70-300 lenses are AF-S. Is your one AF-S or AF-D? You should be able to see on the lens' box or on the lens itself. Does the 18-55 kit lens autofocus well?

 

[djacobox372]

See the little plus shape thingy in the lower right of the lens mount? that turns the screw that focuses a AF lens. The D80 has one, the D40 doesn't.
The D40 will only focus with lenses that have a focusing motor in the lens. Lenses with this feature are labeled "AFS."

 

[chrisburke]

I'm not sure.. it just says AF no mention of a D or S...

 

[TamiyaGuy]

Hmm... Ah, of course, it's a "G" lens. After a bit of searching, I think I've found it. Does the lens look exactly like this one, except silver?

If yes, then it doesn't have an internal focusing motor, and won't autofocus with the D40 (or D40x/D60 for that matter). You can find more info about it on Ken Rockwell's page on the lens HERE.

Despite it not AFing on your D40, I still hope it satisfies your needs. Have fun!

 

[Village Idiot]

So they didn't tell you your d40 wouldn't AF with all of Nikon's lenses when you bought it?

 

[JimmyO]

And you didnt pick that up already from here on the forum, its like the most talked about thing here, lol

 

[chrisburke]

yea its the same lens.... i figured that was why it didnt focus, I just want to make sure, because when I slapped it on my friends d80 it dod auto focus... I don't even use auto focus, so I dont even care, I was just wondering that was all.

 

[Garbz]

Nikon Terminology:
AI - Auto indexing, uses a notch that mechanically couples to the camera to tell what the aperture is.
AF - Autofocus relies on the camera body
AF-S - Autofocus via an inlens silent wave motor
D - Lens contains a chip that transmits distance information to camera and controls the aperture etc.
G - As above except that these lenses do not contain an Aperture Ring and are not backwards compatible with manual cameras.

Lenses aren't either "AF-S" or "AF-D", they are either AF or AF-S, both AF-S D lenses (80-200), and AF G lenses (the above one) exist.

The D / G part has nothing to do with the autofocus.