[bjolester]

I recently purchased a SMC-A 35-105 1:3.5 zoom. Unfortunately the front lens elements are quite loose, and I am wondering how to tighten these lens elements properly?

I have taken some photos of my lens:

Picture 1. Pentax SMC-A 35-105 1:3.5 lens

Picture 2. On my lens this front metal tube covering the front (glass) lens element is loose (where I have my thumb). To tighten this metal tube you have to tighten anti-clockwise. When you turn it clockwise it moves into the focus ring until it is unscrewed completely from the front lens element.

Picture 3. The front (glass) lens element is about 8-10mm thick and is fitted onto the inner part of the lens by turning it clockwise. It can be removed completely by rotating it anti-clockwise.

Then back to my questions:

A. How tight should the front (glass) element be tightened (Picture 3) ? Should the zoom be in a special position when tightening? I am afraid of ruining my lens.

B. When tightening the front metal tube (Picture 2), how should I prevent ending up loosening the front (glass) element? How much should I tighten this metal tube?

These technicalities are very hard to describe. I hope somebody can understand my problem and give me some advice!

Regards
Bjørn

Attached Images

View Picture EXIF

File Date

 

View Picture EXIF

File Date

 

View Picture EXIF

File Date

 

---

Last edited by bjolester; 06-06-2010 at 06:02 PM.

[Adam]

Wouldn't you simply have to tighten it all the way? Normally, this lens doesn't have any protrusions, and the height of the center of the front element shouldn't be above the metal edge on the side of the barrel.

[bjolester]

Thank you for your response Adam!

Firstly, I agree with you that the front metal tube must be tightened all the way out, in such a way that there are 4-6 threads to fit filters, cap, etc. into. The lens in the first picture above is how the A35-105 looks fully assembled, as you all probably know...

I find it difficult to describe precisely what my problem is The two front lens elements were rather loose when I received the lens last week. For now I have tightened both these elements very very carefully, so that they are in place. But I am sure there is a way of tightening the front part of the lens so that it is rock solid. The lens is built like a tank, it seems non-logical that it should be possible to spin off the front parts of the lens (including the front lens glass element) with only mild hand-power. The front lens (glass) element has two positions for a wrench, and the two lens elements I describe are fitted together so that they seal off the lens. But how do I do it...

A. How tight should the front (glass) element be tightened (Picture 3) ? Should the zoom be in a special position when tightening? I am afraid of ruining my lens.

B. When tightening the front metal tube (Picture 2), how should I prevent ending up loosening the front (glass) element? How much should I tighten this metal tube

[bjolester]

I have come to the conclusion that attempting to repair this lens is not a DIY project - at least not for me. So today I sent it off to a highly regarded Pentax repairman here in Norway. I am very much looking forward to getting it fixed, it is such a brilliant lens!