Disassembly - MS-Optics Sonnetar 73mm F1.5 (Part I and Part II)

Fred Miranda
Offline
Admin
Upload & Sell: On

p.1 #1 · p.1 #1 · Disassembly - MS-Optics Sonnetar 73mm F1.5 (Part I and Part II)

@yukosteel has published a disassembly and repair article for the MS-Optics Sonnetar 73mm F1.5 Leica M mount lens.

One excerpt from the article's is as follows:

"What is shockingly-impressive about MS-Optics - these lenses are extremely compact, I mean, unbelievably small and lightweight for their focal length and aperture combo! They are also very beautifully crafted and have unique image rendering too. And yes, lenses are made for Leica M mount with full support of rangefinder coupling, though remain at relatively affordable price level for M mount shooters."

"Article to be continued with more details about fine tuning of RF precision and helicoid movements..."

To access Part I of the article, please click here.

Aug 07, 2023 at 02:08 PM

Fred Miranda
Offline
Admin
Upload & Sell: On

p.1 #2 · p.1 #2 · Disassembly - MS-Optics Sonnetar 73mm F1.5 (Part I and Part II)

In the upcoming section of this article, Yuri will show the process of achieving accuracy with the Sonnetar 75/1.3 lens using meticulous grinding and extensive experimentation. He will demonstrate that the rangefinder can accurately capture shots at all distances even when the lens is fully open.

I'm looking forward to receiving the lens by the end of this week and testing it out myself!

Aug 07, 2023 at 04:52 PM

Fred Miranda
Offline
Admin
Upload & Sell: On

p.1 #3 · p.1 #3 · Disassembly - MS-Optics Sonnetar 73mm F1.5 (Part I and Part II)

Part II of the article was posted.

Here is an excerpt:

During continuous exploration of MS-Optics Sonnetar 73mmm F1.5 lens model, I had chance to work on two copies - first one provided by Fred, and second one with SN:125 purchased used from FredMiranda forum. That second Sonnetar copy is much earlier production batch and has few minor cosmetic and mechanical differences:

Gray plastic ring of RF couple cylinder has much higher edge elevation, allowing to grind it for RF precision
Focusing distance scale is including "1m" indicator, and sign "Mtr." indicating meters
Mount ring shell does not have DOF scale, instead there is engraved red dot
Leica OVF framelines are showing correct 50/75 without need of grinding mount leaf

Observing only two copies of Sonnetar does not provide representative enough statistical information, though this second copy also exposed few similar problems which first and newer copy had:

short but noticeable lag of RF patch when changing focusing direction
Sticky focus rotation at infinity point
RF couple cylinder is jumping up slightly when reaching infinity point
RF indication is not showing correct focusing, leading to front/back focused resulting images.

NOTE: thanks to the lens manual provided by Mr. Miyazaki, and additional Fred's detailed observations when experimenting with Spherical Aberrations settings of Sonnetar, I've set it to optimal setting "3" when working with further mechanical improvements and tuning RF precision.

To read more, scroll down to the section labeled:

UPDATE: part two of the article
Fine tuning RF precision
https://www.yukosteel.com/2023/08/disassembly-and-repair-ms-optics.html

Aug 20, 2023 at 02:04 PM

Fred Miranda
Offline
Admin
Upload & Sell: On

p.1 #4 · p.1 #4 · Disassembly - MS-Optics Sonnetar 73mm F1.5 (Part I and Part II)

I just got my MS Optics 73/1.5 lens from Yuri, and I'm really impressed with it.

Here's what he did to it:

1) He smoothed out the rough RF cylinder, finely adjusting it with precise grinding to ensure the rangefinder is accurate at all distances. Now, I can use it with my M10-R at the minimum focusing distance, hard stop infinity, or anywhere in between, and it's always 100% accurate!

2) Yuri discovered that the lens was slightly off-center, but it wasn't an easy fix by adjusting the mount. It was actually one of the lens groups that wasn't perfectly centered. He made precise adjustments, and now the lens is perfectly centered. It was already good using decentering tests, but now it's at an exceptionally high level of precision.

3) The focusing ring had a tiny bit of play and lag when rotating, but he fixed that too. There's no play anymore, and the infinity hard stop now has a solid metal feel instead of a softer one like before. The focusing ring turns very smoothly now because he also replaced the grease. I believe he used extra soft helicoid grease, Polar grade "00."

4) He also cleaned out any dust from the internal components.

__________

It's important to mention that there's a solid explanation for why this level of precision isn't achieved in the factory. The mechanics of this lens are custom-machined with exceptional precision. However, fine-tuning it to this degree would demand many additional hours of work, which would significantly increase labor costs and likely double the lens's price compared to its current cost.

MS-Optics delivers a finely crafted piece of optical lens art right from the start. Yuri had reservations about making any adjustments, fearing that he might inadvertently affect the optics or mechanics. However, this process also emphasized that custom-crafted lenses with a significant manual labor factor are considerably more expensive to produce when compared to mass-produced Leica lenses.

I have also tried it on my Sony A9 with the TAP EA9 autofocus adapter, and it performs admirably, even for subject tracking. The focusing point stays locked on, even when it's away from the center area. It's an excellent lens for portrait photography, and it works seamlessly with features like Eye AF.

Here is a sample using EyeAF for animals:

ILCE-9 MS Optics 73mm f/1.5 Sonnetar lens 73mm f/2.0 1/10000s 100 ISO 0.0 EV

Sep 01, 2023 at 04:29 PM

helimat
Online
• • • • •
Upload & Sell: On

p.1 #5 · p.1 #5 · Disassembly - MS-Optics Sonnetar 73mm F1.5 (Part I and Part II)

Fred Miranda wrote:
I just got my MS Optics 73/1.5 lens from Yuri, and I'm really impressed with it.

Here's what he did to it:

1) He smoothed out the rough RF cylinder, finely adjusting it with precise grinding to ensure the rangefinder is accurate at all distances. Now, I can use it with my M10-R at the minimum focusing distance, hard stop infinity, or anywhere in between, and it's always 100% accurate!

2) Yuri discovered that the lens was slightly off-center, but it wasn't an easy fix by adjusting the mount. It was actually one of the lens groups that wasn't perfectly centered. He...Show more →

Thanks for the update Fred. I've reached out to Yuri, if he can get my copy fixed up to the same level as yours, I'd be excited to hang onto it, as I had such high hopes for it seeing what others like BJ could do with it. I just need it to work with a RF, not interested in adapting to mirrorless.

Sep 02, 2023 at 09:15 AM

Fred Miranda
Offline
Admin
Upload & Sell: On

p.1 #6 · p.1 #6 · Disassembly - MS-Optics Sonnetar 73mm F1.5 (Part I and Part II)

helimat wrote:
Thanks for the update Fred. I've reached out to Yuri, if he can get my copy fixed up to the same level as yours, I'd be excited to hang onto it, as I had such high hopes for it seeing what others like BJ could do with it. I just need it to work with a RF, not interested in adapting to mirrorless.

I noticed you were selling your copy. After his modification, I'll never sell mine! I hope everything goes well for you.

Sep 06, 2023 at 06:40 PM

helimat
Online
• • • • •
Upload & Sell: On

p.1 #7 · p.1 #7 · Disassembly - MS-Optics Sonnetar 73mm F1.5 (Part I and Part II)

Fred Miranda wrote:
I noticed you were selling your copy. After his modification, I'll never sell mine! I hope everything goes well for you.

Thanks Fred, but unfortunately Yuri has retired from Sonnetar repairs, onto bigger & better things I suppose.

I would really like to get mine up to the same standard as yours as far as RF calibration.... It's quite the lens and would likely stay in my kit for a long time if I could.

Sep 06, 2023 at 08:23 PM


FM Forums \| Leica & Alternative Gear \| Join Upload & Sell

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.