Author Topic: Nikkor AF-S 28-70mm f2.8D IF  (Read 795 times)

Chris Betson

  • NG Member
  • *
  • Posts: 66
  • General Mr fixit and grumpy old bugger
    • Octarine Services
Nikkor AF-S 28-70mm f2.8D IF
« on: September 27, 2021, 10:25:44 »
Anyone know why the filter ring on this lens is sprung? 9 little springs around the three post screws that secure it to the front lens assembly....

Erik Lund

  • Global Moderator
  • **
  • Posts: 6053
  • Copenhagen
    • ErikLund.com
Re: Nikkor AF-S 28-70mm f2.8D IF
« Reply #1 on: October 07, 2021, 12:00:59 »
Good question, I have never noticed this, since I never took off the front bezel/filter ring,,, 
The 0.8mm of travel is indicated in the sectional drawing here with a text in Japanese.
Erik Lund

Akira

  • Homo jezoensis
  • NG Supporter
  • **
  • Posts: 11056
  • Tokyo, Japan
Re: Nikkor AF-S 28-70mm f2.8D IF
« Reply #2 on: October 07, 2021, 12:54:19 »
The Japanese word means "designed value".

Is the spring-loaded retaining ring there to avoid any possible warpage of the front-most element caused by the pressure of this ring?  I realize that some high-end filters has the spongy insertion between the filter glass and its retaining ring for this very purpose.
"The eye is blind if the mind is absent." - Confucius

"Limitation is inspiration." - Akira

longzoom

  • NG Member
  • *
  • Posts: 741
  • You ARE NikonGear
Re: Nikkor AF-S 28-70mm f2.8D IF
« Reply #3 on: October 07, 2021, 13:46:20 »
.

Erik Lund

  • Global Moderator
  • **
  • Posts: 6053
  • Copenhagen
    • ErikLund.com
Re: Nikkor AF-S 28-70mm f2.8D IF
« Reply #4 on: October 07, 2021, 13:47:35 »
Thank you for the translation!

I will check my lens when I can get to it, but according to the drawings the filter ring is not part of anything regarding retaining the front element assembly directly.
Looks like it's sort of a front decoupler function for when your not using the lens hood as protection,,, Bump protection.
Erik Lund

Akira

  • Homo jezoensis
  • NG Supporter
  • **
  • Posts: 11056
  • Tokyo, Japan
Re: Nikkor AF-S 28-70mm f2.8D IF
« Reply #5 on: October 07, 2021, 15:33:31 »
Thank you for the translation!

I will check my lens when I can get to it, but according to the drawings the filter ring is not part of anything regarding retaining the front element assembly directly.
Looks like it's sort of a front decoupler function for when your not using the lens hood as protection,,, Bump protection.

You are welcome, Erik.  And you seem to be right.  I Think I didn't read the drawing correctly.
"The eye is blind if the mind is absent." - Confucius

"Limitation is inspiration." - Akira

longzoom

  • NG Member
  • *
  • Posts: 741
  • You ARE NikonGear
Re: Nikkor AF-S 28-70mm f2.8D IF
« Reply #6 on: October 09, 2021, 19:03:44 »
Thank you for the translation!

I will check my lens when I can get to it, but according to the drawings the filter ring is not part of anything regarding retaining the front element assembly directly.
Looks like it's sort of a front decoupler function for when your not using the lens hood as protection,,, Bump protection.
     As to me, after drawing posted, it may serve for one purpose only - to "click" the hood to its place correctly!  LZ

Chris Betson

  • NG Member
  • *
  • Posts: 66
  • General Mr fixit and grumpy old bugger
    • Octarine Services
Re: Nikkor AF-S 28-70mm f2.8D IF
« Reply #7 on: October 09, 2021, 22:17:20 »
     As to me, after drawing posted, it may serve for one purpose only - to "click" the hood to its place correctly!  LZ

The hood clicks onto the widest part of the front case - not the filter ring.

Shock protection is the only sensible reason but I doubt how effective it would be.

longzoom

  • NG Member
  • *
  • Posts: 741
  • You ARE NikonGear
Re: Nikkor AF-S 28-70mm f2.8D IF
« Reply #8 on: October 09, 2021, 23:48:39 »
The hood clicks onto the widest part of the front case - not the filter ring.

Shock protection is the only sensible reason but I doubt how effective it would be.
   Read the drawing one more time, please. There is no filter ring on the outer part of the main tube. Shock protection isn't the correct explanation. 0.8 mm?? LZ

Chris Betson

  • NG Member
  • *
  • Posts: 66
  • General Mr fixit and grumpy old bugger
    • Octarine Services
Re: Nikkor AF-S 28-70mm f2.8D IF
« Reply #9 on: October 10, 2021, 01:03:25 »
I don't need to read the diagram - I have the lens and I have disassembled the front to replace a broken filter ring.

To clarify I have marked the section drawing to show where the hood fits, etc.



Erik Lund

  • Global Moderator
  • **
  • Posts: 6053
  • Copenhagen
    • ErikLund.com
Re: Nikkor AF-S 28-70mm f2.8D IF
« Reply #10 on: October 22, 2021, 12:25:47 »
I had a quick look at my lens yesterday - And I can confirm that indeed the lens filtering can slide into the lens housing as the drawing clearly indicate as well, very strange!I tested it as a bumper function and it doesn't work very well, the ring is only able to slide in along the lens axis because of the screws/studs fit tightly inside the holes, so I have literately no clue why it was designed like this.
Erik Lund