Spent the night re-grinding the cam of an early Amadeo adapter, now fiocuses great

[Vickko]

Spent the night re-grinding the cam of an early Amadeo adapter, now fiocuses great for my 5cm f1.4 Olympic, and my Zunow 5cm f1.1 focuses just a touch closer than the RF image on my Leica M9. But, key is I know how much.

I don't think I'm going to do any more filling, since it is good for the 5cm f1.4.

Oh I wish there was a digital Nikon RF option. I guess that is my M9 with adapters.

Too tired (and slightly buzzed on wine) to post resulting images, but, let say that I'm very happy with the results using my M9.

And, now I can use my Zunow on the M9 without having to compensate too much on the RF.... or translated, my Zunow is now fully compatible on my M9.

 

[pb908]

congrats .
did you find issue of adapter with other nikon/zeiss lenses

when i get my contax to ltm adapter in the past which i assume early generation, all my zeiss lenses were having focus issue, i forget if that was front focus or back focus but similar issue.at the end i add/reduce shimming on all lenses, it was easier and can be undone.

 

[Vickko]

Hmmm. Good question.

Ｔｈｉｓ was one of Amadeo's earlier efforts and I was using 2 lenses to test. Both were taking the photo about six inches closer than were my RF was indicating. I filed the focus cam surface down, at an angle and almost 0.5mm at the steep end.

The beauty is using an M9 for instant feedback.

I am thinking that this was a Contax / Zorki mount, attached to a Leica M mount base.

 

[raytoei@gmail.com]

i have the same issue with a recent nikon rf adapter
from amedeo. tested on two 50 f1.4,
same issue..... very vexing.

 

[Vickko]

Ray
Does it image closer than the RF indication?
Then the cam needs to be further out, meaning removal of metal.
I don't know if the newer Amadeo cams have an adjustment. Filing is pretty involved (i.e. lots of care and motivation needed) operation.
But I hear that he is very cooperative in adjusting his work.
If it is new, I'd discuss it with him first.

 

[raytoei@gmail.com]

my email to him:

"I find that the focusing isn't correct, ie. when I focus at 1.15m, the object is actually at sharp at 1.18m. I thought it was my Nikkor 50 f1.4 issue, I bought another Nikkor 50 f1.14 and I found that I have the same issue. "

his response:

" Let me explain something about. The rangefinder on the Leica body was calibrated
for a 50mm lens, but happen than a Nikon 50mm not is really 50mm, it is longest around 51mm.

For to have a spot-on adapter at infinite and close distance, the edge on the adapter than push the rangefinder cam must be machined in ramp in a kind of counter-helical, for to make the movement of the rangefinder cam faster than the pitch of the helical of the lens. In the case of Nikon, the lens move 3.75mm but the rangefinder cam 3.66..

This tipe of correction can be sight on Leica lenses because every one can have light variations of focal lenght and are calibrated individually.

I have optimized the adapter for the average 50mm lenses, any modification must be made in the edge than push the rangefinder cam, if you have backfocus of a few centimeters, add somewhat of nail paint "only in the segment than is pushing the rangefinder cam", the cam must be moved back 0.02mm to 0.05mm. The paint can be removed easily again. "


I have, in my limited way, failed to comprehend what he is talking about. any clue ?

raytoei

 

[Highway 61]

I have, in my limited way, failed to comprehend what he is talking about. any clue ?

He's saying that the adapter RF coupling cam must have a non-linear pitch as you turn the adapter focus helical, so that it doesn't push the RF arm in the camera following a linear route, but a non-linear one, and that this non-linearity has to be determined upon each lens actual focal length.

In other words : each adapter should be made for ONE lens only, once you know the exact focal length of this Nikon lens.

This is why those adapters suck IMO.

A friend of mine (and a RFFer, and living close to Amedeo) found that his Amedeo "Contax-Leica" adapter didn't work properly with a Sonnar 50/1.5, but was just perfect with the Nikkor-S 50/1.4 lens I had given to him. So Amedeo probably missed something out with the "Contax-Leica" adapter as well. But the same adapter may not work properly with another Nikon 50mm lens...

Given the price of those adapters, and of certain Nikon S-mount lenses, installing M or ZM lenses on M cameras and not fiddling with those adapters may be the best option.

 

[Vickko]

I ended up filing my cam into a ramp. It took a few iterations, and very little filing.

It is great for the 5cm Olympic, and I hope it works with my Zunow too.

I'll test with the Zunow soon. I just posted photos with the Olympic.

... the rangefinder cam must be machined in ramp .....