DIY lens adjustment

[rapids41]

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Last week I got my 3 lenses and my M9 back from Wetzlar.

Before that one lens has backfocus, one frontfocus and one was spot on.

After Wetzlar all 3 lenses had frontfocus on all distances so I just fixed the rangfinder of the M9 by myself and all 3 lenses are spot on now.

Its a joy to use and I am amazed again how good these lenses are.

So thank you Wetzlar for adjusting the lenses to one standard.

[jrh68uk]

Bit strange, since they had your camera as well, that they didn't adjust it for the lenses. I know they're meant to adjust both lenses and cameras to a standard but you'd think they'd match them within tolerance.

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[rapids41]

I think either I am not looking the same way through the rangefinder than the person in wetzlar, or they simply didnt make enough effort with the rangefinder calibration.

[alex7075]

Hello,

After three trips to Solms and five months wait my Noctilux 1.0 still back-focuses.

 

I could measure the problem: the rear ring of the lens should push the rangefinder cam exactly 70 microns (0,07 mm) more than it does (camera rangefinder has been perfectly calibrated and is spot on with my other lenses, so I don't want to tweak it).

In fact, when I focus to infinity, the photograph is sharp but the split image in the rangefinder can't reach perfect coincidence, asking to focus further > hence the back-focus at all focusing distances.

 

When I got the lens back the last time I noticed that it could be unscrewed, so I ended up with the optical part in my left hand and the focusing part in my right hand. I tried placing a 70 microns shim between the two parts: the result is that back focus disappear but the two parts are not aligned anymore (not very nice to see) and of course the lens can't reach sharpness at infinity because the optical part is now 70 microns too far from the sensor.

 

So I thought that I could add a 70 microns shim on the rear ring of the lens, where it touches the rangefinder cam; the problem of course is how to fix it on the ring but it shouldn't be impossible.

 

So here is my question: is there another place inside the focusing mechanism where I can put a shim? And how to disassemble the focusing mechanism?

 

Thanks for reading and for your answers.

[thighslapper]

I think either I am not looking the same way through the rangefinder than the person in wetzlar, or they simply didnt make enough effort with the rangefinder calibration.

 

They have adjusted and calibrated the lenses more carefully ....... to a fixed standard that this time with closer tolerances ...... which is what moaning about things usually produces......

 

They have adjusted the rangefinder to a fixed standard ..... they used to do this with a set 50/2 lens .... although I believe the method has changed with the M240.

 

If both lenses and camera are at the mid point of the accepted calibration range then all is ok..... if lenses are at one end and camera at the other ....... there will be a noticeable mis-match .......

 

...... which is why I always do my own RF adjustment ....... and have enough bodies and lenses to work out where the problem lies ...... which is why my 75/2 is back at Wetzlar for them to 'try again, please'......

 

Some lenses just seem to be like homing pigeons......

 

...... which is why it is often better to buy 'mint' used lenses....... as most of this frustrating and painful work has usually been done by the previous owner...... and I think the repair technicians are better at the job than the assembly ones ......

Edited June 22, 2014 by thighslapper

[Fgcm]

Alex, the job should be: 1) to correct the focusing sub assembly, than 2) to add the shim in between the focusing and the optical sub assembly. This is not a job you cans DIY with some written instructions. Also because you need tools specific to the lens.

 

The correction you need is very little.

Maybe you can send your lens to a trusted shop closer to your home so that you can talk with the technician and explain exactly what you want. And maybe you can follow the job while done.

 

Three trips to Solms are quite a lot.

I sent my stuff to Solms only a few times in many years, as Leica gear is very reliable and dependable.

Leica customer service always did a perfect job in a few days.

But I'm in Italy, so the trip to and back from Germany requires just a day or two.

 

Ciao

Franco

[alex7075]

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Franco, thanks for your clear explanation.

I understand it's better not to try to dismantle the focusing mechanism.

I had a shim made with the exact thickness and diameter that I will place on the rear of the mechanism.

I first tried with some scotch tape which is also 0,07 mm thick and believe me or not, I would have never thought a Noctilux could be so sharp!

Unfortunately I don't know any technician in town (Torino) who could do the job.

Thanks again,

Alex

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[pico]

They have adjusted and calibrated the lenses more carefully ....... to a fixed standard [...]

 

Fixed standard of what focal length? 50.1mm? 50.2mm? 51mm? Lenses have different, actual focal lengths.

.

[menos I M6]

I think you should communicate your findings with Leica and have them fix your Noctilux to perfection.

I know it can be frustrating with all the travel back and forth and being let down a few times already but this lens ought to be calibrated perfect when you have paid for it already.

 

With my experience with Leica Germany, I am certain they will do anything in their powers to right this one.

[jdlaing]

Fixed standard of what focal length? 50.1mm? 50.2mm? 51mm? Lenses have different, actual focal lengths.

.

 

Each lens, no matter what actual focal length, is bench adjusted to a tolerance..........per lens.

 

What happens after it falls down the stairs, is kicked across the runway, drop kicked across a loading dock is anybody's guess.

[alex7075]

I think you should communicate your findings with Leica and have them fix your Noctilux to perfection.

I know it can be frustrating with all the travel back and forth and being let down a few times already but this lens ought to be calibrated perfect when you have paid for it already.

 

With my experience with Leica Germany, I am certain they will do anything in their powers to right this one.

 

You're absolutely right. I had great communication with them and they have been extremely kind and willing to fix the problem. They really helped me in any possible way. They called on my phone many times, took care of the shippings, and so on.

 

But the fact is, in almost five months the lens could not be fixed and I am not disposed anymore to send it a fourth time (maybe once more together with the camera).

I consider my solution not a very elegant one, probably it's a matter of adapting the lens to my specific digital M, but I am happy because at least it works.

 

Of course if the lens was front-focusing I should have sent it in.

[pico]

Each lens, no matter what actual focal length, is bench adjusted to a tolerance..........per lens.

 

 

That issue has been represented in different ways. In one video a technician eyeballs lens focus on a machine projection, in others we are told that every lens is built on a standard jig, another claims both.

 

I used to work with various hideously expensive aerial lenses and every single one was inscribed on the film-side with the actual focal length which varied from lens to lens. Every one had very fine shims to make focus perfect. Leica does not do that.

[Fgcm]

Alex, I PM you

Franco

[menos I M6]

That issue has been represented in different ways. In one video a technician eyeballs lens focus on a machine projection, in others we are told that every lens is built on a standard jig, another claims both.

 

I used to work with various hideously expensive aerial lenses and every single one was inscribed on the film-side with the actual focal length which varied from lens to lens. Every one had very fine shims to make focus perfect. Leica does not do that.

 

This is not correct. On certain lenses Leica inscribes the actual focal length in a 2 digit code on the barrel in full sight.

 

As I understand this visible inscription is done on critical lenses and is a relatively recent addition for some, while a long practice for other lenses.

 

It is not necessary to do with all lenses as per handling of separate lenses with separate procedures during assembly/ calibration.

 

Some lenses as the Noctilux are even manufactured to such high tolerances that Leica takes pride to manufacture and adjust the optical cell to >0< indicated by a "00" inscribed on the distance ring of the v4 Noctilux f1. Earlier Noctilux lenses ay have this inscription as well, I don't remember.

I have not seen one Noctilux sample showing deviation from "00" while I have seen many other lenses, showing deviation (which in manufacturing and calibration is balanced by a specifically chosen focus mount and adjustment to the distance of the optical cell/ rangefinder coupling.

 

Leica is not a butcher shop, disregarding some most basic principles in lens manufacturing.

[jdlaing]

That issue has been represented in different ways. In one video a technician eyeballs lens focus on a machine projection, in others we are told that every lens is built on a standard jig, another claims both.

 

I used to work with various hideously expensive aerial lenses and every single one was inscribed on the film-side with the actual focal length which varied from lens to lens. Every one had very fine shims to make focus perfect. Leica does not do that.

 

Thusly:

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[pico]

This is not correct. On certain lenses Leica inscribes the actual focal length in a 2 digit code on the barrel in full sight.

 

Me gosh, I am embarrassed. I just plain forgot that, even though I participated in a thread of the subject a few years ago and even posted a picture of the "00" on my 75mm Summilux.