Home
SearchSearch MemberlistMemberlist RegisterRegister ProfileProfile Log in to check your private messagesLog in to check your private messages Log inLog in

Vivitar 70-150 f3.8
View previous topic :: View next topic  


PostPosted: Thu Sep 07, 2017 9:41 pm    Post subject: Vivitar 70-150 f3.8 Reply with quote

I recently acquired the above lens on a PK mount.Very Impressive!
However I have a question that I hope a Vivitar fan can help with.
The lens is the older type I believe with the Rotary zoom function as opposed to Slide or Pump zoom.
Just below the Zoom ring and above the Aperture ring is another 'knurled' grip ring.
I have found that this ring also rotates for some reason. It seems to be on a thread as it moves a couple millimetres up or down from end to end,about eight turns in all.
Does anyone have a clue what this is doing,if anything!
Thanks in advance.


PostPosted: Thu Sep 07, 2017 11:54 pm    Post subject: Reply with quote

I don't have the lens but this may help: http://www.boggys.co.uk/page24.html


PostPosted: Fri Sep 08, 2017 12:12 am    Post subject: Reply with quote

You mean the Close Focus mode actuation ring?


PostPosted: Fri Sep 08, 2017 12:17 am    Post subject: Reply with quote

visualopsins wrote:
You mean the Close Focus mode actuation ring?

I dont think so,close focus is by going past the 70mm stop on Focal length,moved a different element.


PostPosted: Fri Sep 08, 2017 12:20 am    Post subject: Reply with quote

NACEOD wrote:
I don't have the lens but this may help: http://www.boggys.co.uk/page24.html

Nice find,Bookmarked! Thanks.


PostPosted: Fri Sep 08, 2017 8:25 am    Post subject: Reply with quote

Is this ring the open/close aperture ring.
I can see that the aperture is set by the back aperture ring, but that may work together with the next ring like a pre-set lens does.
Just a thought
T


PostPosted: Fri Sep 08, 2017 8:30 am    Post subject: Reply with quote

I think a set screw has become loose allowing that adjustment ring to turn. I suspect the adjustment sets a focus, perhaps infinity, perhaps to adjust close-focus element repositioning.


PostPosted: Fri Sep 08, 2017 12:21 pm    Post subject: Reply with quote

Visualopsins is correct. It is the close focus/macro ring. Ye set the zoom at 70mm then use the 3rd. ring (close focus) for just that...close focus. It's probable as visualopsins said that a screw on that ring is loose or missing. Wink


PostPosted: Sat Sep 09, 2017 6:43 am    Post subject: Reply with quote

hi,
i had the same problem with this lens. this ring is just for holding the lens, there is no special function. it is screwable and i screwed it against the aperture ring until it was fixed. there is no little screw to fix it. now it looks and works like my other vivitar 70 -150mm lenses.


PostPosted: Sun Sep 10, 2017 7:12 pm    Post subject: Reply with quote

Planet.groove.thank you.That was my impression,it definitely screws and unscrews for something and I,m certain its part of the construction as opposed to a function.Confidence restored.