What is this bit on the front of the lens for?

beercan

beercan

Suspended / Banned
Messages
582
Name
Steve
Edit My Images
Yes
Hi all,

Apoliogies if this is a really stupid question but someone gave me a Nikkor AF 28-105 1:3.5-4.5D lens and on the front (just behind the hoya filter) it has a small section which rotates about a quarter turn with a bit of effort. It has two white dots on opposite sides and the dot you can see rotates upwards from its position here to the top.



What does it do please? :shrug:

Thanks :thumbs:
 
can't really see the pic but is it where the hood is supposed to screw in?

do the elements move inside the lens when you turn it? (i.e are you just pulling the zoom mech by twisting it :) )
 
It's where the lens hood attaches on to the end. I'm not sure what you mean about it rotating though.
 
Hi,

Basically if I grab it, and twist it, it rotates a quarter turn. It doesn't appear to affect the zoom mechanism in any way though. I just couldn't figure out why the white dots are there but I guess in that case they're alignment marks for the hood.

Cheers for the replies. :thumbs:
 
beercan said:
Hi,

Basically if I grab it, and twist it, it rotates a quarter turn. It doesn't appear to affect the zoom mechanism in any way though. I just couldn't figure out why the white dots are there but I guess in that case they're alignment marks for the hood.

Cheers for the replies. :thumbs:
Click to expand...

I think you may have just broken your lens...:eek:
 
Nah it's not broken, its always been that way and it works fine.
 
Hmmm...OK
A general rule to observe is that anything that is meant to rotate on a lens usually has a rubber or knurled grip attached to it.

If it hasn't, then don't...
 
OK cheers, I'll keep that in mind to ensure I don't manage to break it! :)
 
beercan said:
Hi all,

Apoliogies if this is a really stupid question but someone gave me a Nikkor AF 28-105 1:3.5-4.5D lens and on the front (just behind the hoya filter) it has a small section which rotates about a quarter turn with a bit of effort. It has two white dots on opposite sides and the dot you can see rotates upwards from its position here to the top.

What does it do please? :shrug:

Thanks :thumbs:
Click to expand...

Hi Steve, I'm not familiar with that particular lens but I suspect that by twisting it you are manually moving the focus mechanism, which is not a good thing to do if the lens is in AF mode. Is there a M-A switch on the lens? If so, switch it to M and see if it then moves freely - but don't force it - and if the ribbed ring next to it turns at the same time.

If there's no M-A switch then watch the end of the lens as it focuses and see if that part is turning.

HTH :)
 
Bristolian said:
Hi Steve, I'm not familiar with that particular lens but I suspect that by twisting it you are manually moving the focus mechanism, which is not a good thing to do if the lens is in AF mode. Is there a M-A switch on the lens? If so, switch it to M and see if it then moves freely - but don't force it - and if the ribbed ring next to it turns at the same time.

If there's no M-A switch then watch the end of the lens as it focuses and see if that part is turning.

HTH :)
Click to expand...

As I see it, he's circled the lens-barrel in front of the MF-focus ring...the bit with the lens-hood bayonet-lugs...
 
The lens barrel extends, but doesn't rotate - or at least it's not meant to - otherwise your lens hood would also rotate - and that's no good at all if you use a petal-shaped one.

This lens has bayonet-lugs for the lens hood - the typical fitting for petal-style hoods, which are not the sort that you'd want to rotate - if it was a screw-on hood - attached to the filter-thread, then it wouldn't matter.
 
Rob,

I know what you mean about the bayonet lugs normally suggesting a petal type hood which shouldn't (ideally) rotate but my Sigma 28-70 has lugs and still rotates ... I use a circular, screw-in hood :)
 
Bristolian said:
Rob,

I know what you mean about the bayonet lugs normally suggesting a petal type hood which shouldn't (ideally) rotate but my Sigma 28-70 has lugs and still rotates ... I use a circular, screw-in hood :)
Click to expand...

Ahhh... Sigma... :cuckoo: :shrug:











I'm sorry - couldn't resist...
 
My old Nikon 28-80mm f/3.5-5.6 AF-D lens has similar attachment on the end to this, it rotates when you focus, but the lens hood that comes with it (a Nikon one, not a 3rd party one) is a regular "flat" edged lens hood, not petal.
 
You must log in or register to reply here.
Back
Top