lens ring for sigma not fitting

[diax]

Have a sigma 8mm / 3.5 and a lens ring for R1 for it.

type: LRP45X
outer metal ring: LR2

However when i mount it and tighten it up very sturdy the sigma can still rotate. Especially when using the camera the lens ring turns easily.

Now i noticed there is some space between the sigma and the lens ring, light is shining through. I made a picture. It is not fitting well and i can not tighten the knob more without damaging the lens. I am almost sure i did the mounting according to your specification.

I have another lens ring for nikon 10.5 and that one fits perfect. Very sturdy.

In the lens ring component matrix the dimension of the outer metal ring LR2 should be : 83mm. When i measure the inside of the ring it is 76 mm. That is the dimension of the LR3.

So... someone knows what to do. Can i have by accident a LR3 outer ring instead of LR2??

[hindenhaag]

Diax,

http://www.nodalninja.com/qr/r1-r10/...-pano-head/17/

Check this tutorial, specially point 3. You have to replace the gap of the inner ring to the place of the gap of outer ring. The diameter of my Sigma 8mm lens ring for Nikon is 83mm, but you have to measure the outside of the ring. The gap of the fixing screw is 2,5mm and the lens is fixed. Against light I can see a tiny little gap between the two ring in the area of the fixing screw. This is similar to my 10.5 and 16mm nikon lens rings. To be sure check the inscription inside the plastic that you got the right inner ring.



The front of inner and outer has to be plane.- to front of lens - at the back of the metal ring the inner ring stand out a little bit. Be sure the inner ring is in it's place inside metal ring.

When you check the outside of the plastic ring near it's gap, you will realize that thickness is reduce to the gap for better adaptation of the whole system. This is the gap you realize formed of the reduced thickness of the inner plastic ring.



When you compare lens specifications of Sigma 8mm/f3.5 = 73.5mm + inner plastic ring 2,x mm for LR2 with 83mm. I'll check my Samyang 8mm/f3.5 lens tomorrow because I don't have it at home right now. That should be LR3.

Feel free to ask.
Heinz

[hindenhaag]

The lens ring in place:

Hope it helps a it.


Heinz

[diax]

Thanks for your explanation. Indeed the outer diameter of the metal ring is 83 mm, so it is really a LR2. I did all the things you mention, I readjusted the inner ring and that did not solve it.
After some experimenting with the lens ring i noticed that it can't be tightened fast enough.
It is a kind of construction problem, i think someone had a bad day in the factory. It is hard to explain buy it is constructed in a way that it is impossible to tighten it enough. When i tighten it at maximum the metal end stop of the brass inner tube prohibits the further tightening of screw. So the outer metal ring can still expand, and move outwards and that is probably why is not pressed hard enough to the lens and can still rotate the lens even when i tighten it at max.

There is a small metal brass tube inside which is 1 or 2 mm too big.
For the time (tomorrow a photoshoot) i fixed it with a small nylon ring so there is more pressure on the metal ring. That fixed it for now.
When i not use the additional nylon ring i can still expand the metal LR2 ring even when tightened at maximum.

Here a photo of the solution.
Thank you for your kind help and suggestions. Hope this problem i have is not in a big batch LR2 rings....

Harry

[DennisS]

The position of the gap in the plastic insert has nothing to do with the clamping force. I cut a window out of the ring so I can see the focus scale. I then cut the plastic insert so the gap is wide enough so I can see the focus scale. The gap in the plastic insert is rotated to show the focus scale.



I have no issues with clamping force. I modifiy all my ring clamps this way.

The issue is that the ring clamp has not been assembled correctly. There is a small brass part that is bottoming out on the ring. Here is a close up of one of my ring clamps:



Notice the highlighted area. The small brass part is not up against the clamp body. The clamp that Diax has shows the brass part bottoming out against the clamp body. Since this part is threaded, it moves with the clamping bolt. The function of the brass part is to help open up the clamp when you back out the clamping bolt.

If you can open the slot wide enough to thread the brass part back onto the clamping bolt that should take care of your issue. Otherwise you should send it back for repair/replacement.

[hindenhaag]

Thx for the basic tip Dennis,

Diax, I believe the brass tube has a thread inside and has to be screwed towards the big knob outside. Have a look inside, you'll see the black screw with a hex fitting inside. This screw goes through the whole construction into the lens ring foot. Hold the black screw with the hex key and try to screw the brass tube towards the big knob. I tried this with mine, but it seems to be glued with lock bond, so I can not move my screw. In most cases these brass parts are glued with lock bond. You can reach it with a forceps with thin tips once you open the ring till the center screw comes loose in the foot part. In case you can not turn the brass easily, just let your ring being replaced. Otherwise you might loose your guaranty.

. This is how mine looks like. But close to be fixed I get a similar gap as shown by Dennis.

Heinz

[diax]

Hello Heinz and Denis,

Thanks for the reply. I am glad in a way that i now know what the problem is. The details photo's of you are clear and look identical to my NN 10.5 lensring and brass innertube which works fine with the 10.5.

Today i tried to release the brass inner tube from the knob with a hex key of the sigma 8mm lensring. Mission Impossible (for me). Is is probably glued as you mentioned. Best is to replace it. Tomorrow i use the nylon ring which seems to work and this week i will try to replace the lensring.

Hope for Nodal Ninja that not more photographers have this problem with the Sigma 8mm. The lens is used a lot now for the Google 360 business photo's.

Thanks a lot you for all the help.

[diax]

Hello Dennis,

What a useful window you have made in the lensring, very nice made, seems rather difficult.
How did you did it, can i make it myself that with a Dremel tool.

Is it maybe an idea for Nadal Ninja to make such a windows standard in the lensring?
Of course i taped the lens but sometime you want to know the distance.

Harry

[DennisS]

Diax,

I cut the window out using my milling machine. With the right tools and knowledge, just about anything is possible.

I see no reason why you could not do it with a dremel. The ring is aluminum. Lay out the lines and have a go. Your warranty will most likely be voided.

Nick will not do this modification due to the universal nature of the ring clamp. Can you imagine stocking all the variations of the opening due to the different lenses? People also mount the clamp in different orientations. Way too costly to do this as a custom option. I already asked Nick.

Dennis

[nick fan]

Thanks for your explanation. Indeed the outer diameter of the metal ring is 83 mm, so it is really a LR2. I did all the things you mention, I readjusted the inner ring and that did not solve it.
After some experimenting with the lens ring i noticed that it can't be tightened fast enough.
It is a kind of construction problem, i think someone had a bad day in the factory. It is hard to explain buy it is constructed in a way that it is impossible to tighten it enough. When i tighten it at maximum the metal end stop of the brass inner tube prohibits the further tightening of screw. So the outer metal ring can still expand, and move outwards and that is probably why is not pressed hard enough to the lens and can still rotate the lens even when i tighten it at max.

There is a small metal brass tube inside which is 1 or 2 mm too big.
For the time (tomorrow a photoshoot) i fixed it with a small nylon ring so there is more pressure on the metal ring. That fixed it for now.
When i not use the additional nylon ring i can still expand the metal LR2 ring even when tightened at maximum.

Here a photo of the solution.
Thank you for your kind help and suggestions. Hope this problem i have is not in a big batch LR2 rings....

Harry

Hi Harry,

Sorry to hear the problem. Please check that placement of lens ring insert is correct. check the new guide here. Starting with page 3.
http://www.nodalninja.com/Manuals/QR...%20Package.pdf

Your unit is defective if the minimum gap is bigger than 2.8mm. In that case, you need replacement. When you request a replacement, please include this link
http://www.nodalninja.com/forum/show...7865#post37865
Ask sender to check the gap width of the ring is <2.8mm before shipping. Please also cc the mail to nick at fanotec dot com.

Nick

Developer and Manufacturer of Nodal Ninja

PS we will be updating the manuals of R1/10 and lens rings.