Disassembly - Leica Summilux-M 35mm F1.4 Steel Rim reissue lens 11301

 In this article I'm performing exploratory disassembly of most interesting Leica M mount lens I ever had chance to deal with -  Leica Summilux-M 35mm F1.4 Steel Rim reissue 11301 . It is modern model (often called as version 2, or reissue) of legendary Leica Summilux-M 35mm F1.4 Steel Rim from 1961 that has same optical formula with unique classic rendering, though with redesigned mechanics.

I'm very grateful for this very rare and unique opportunity provided by Fred Miranda. He shipped his lens copy to me for performing this exploration and learn more about Leica 35mm F1.4 Steel Rim reissue internals. Thank you Fred!

 It's one of great example where human curiosity is driving the progress and new discoveries. The main purpose of upcoming disassembly is connected to the point that minimal focus distance (MFD) of both 1961 and modern reissue lens models is rather limiting at their 1m / 3ft distance. Numerous latest Leica M cameras have rangefinder couple supporting accurate focusing much closer - down to 0.7m.

In many situations that's not a big deal, though if you are actively shooting with other lenses allowing to focus closer, using lens with 3ft MFD in some cases may feel limiting.

Fred pointed my attention to very interesting details on modifying close focus in one of Leica Summilux-M 35mm F1.4 lens model performed by danielcai and shared on Leica Forum in article "Summilux 35mm f/1.4 Pre-ASPH V2 close focus mod". That is indeed a great encouraging attempt of useful lens mechanics modification allowing to focus much closer.

The next question appeared - is it possible to make Leica 35mm F1.4 Steel Rim reissue 11301 to focus any closer than 3ft?

To answer that I need to take a closer look inside, since there is almost no information available online. However if you are looking for details how to deal with earlier versions (they have external bolts on lens frame), check these two articles by Gigantoptik:

• Leitz Summilux 35mm F1.4 1st Steel Rim Balsam separation Repair & CLA
• Leitz Summilux 35mm F1.4 1st Steel Rim Disassembly & CLA

Lens disassembly steps

 Exploring steps of lens disassembly takes time, accuracy and patience. With lower equipment cost you typically have some flexibility with making small mistakes and there are options of more affordable repairs and parts replacements, or simply purchasing another new lens sample. Working with quite pricy lens that belongs to other person sets much higher level of responsibility and potential stress. I'd not recommend you to try to disassemble anything unless you first prepare yourself to any potential result, including the risk of completely ruining the object of disassembly.

Once you have some level of experience and knowledge, it is elevating confidence and sets of safer disassembly techniques that increasing chance of success when dealing with unknown lens. However there is always the risk of thing to go wrong, it's important to be very accurate and patient regardless to how confident you feel.

Leica 35mm F1.4 Steel Rim has 6 visible screws on the mount ring, so I'm starting with them. I've checked 7 different fitting precision screwdrivers to check which one fits best, and moved with Vessel JIS 0 screwdriver.

Mount ring can be pulled up and removed. Next step is to unscrew three bolts holding the textured mounting grip ring with red dot.

Then I'm unlocking focus ring and rotating it to MFD of 3ft.

Black frame with RF helicoid cylinder can be accurately pulled up, there is a silver plate that may be catching edges of infinity lock socket of DOF ring, you may rotate DOF ring a bit to one or other side to provide more space to extract silver plate.

I'm using rubber strap to grab black frame.

 Once black frame is extracted you can see it has two focus helicoid guiders on opposite side.

Next step is to hold focus ring or focus tab with one hand, and unscrew DOF ring in CCW direction, it will take 6.5x turns.

 Then slowly rotate focus ring in CW direction until "f" letter of "feet" word appears on top of aperture indicator. It is a point where helicoid focus threads are disconnecting. 

Now remove the focus ring.

There is very important point to note here - you can see tiny silver bolt on inner focus helicoid thread. That bolt is securing black optical frame from unscrewing it out of focus helicoid frame. It means that unlike the 1961 Steel Rim version, this modern lens optical core can not be unscrewed from focusing frame until you disassemble frame till this point.

Focusing ring has infinity lock mechanism. It can be also disassembled further by unscrewing three bolts on the inner side of focusing ring and disconnecting it to two parts. I'll explain that in my next article where I'll be discovering modification attempt of closer focusing.

There is protruding brass plate mounted on focus ring - it is serving as RF couple cylinder helicoid guider pin, and can be adjusted by releasing single bolt holding it. 

I've seen all I need to know to think more about potential close focus modification and there is no need to disassemble anything else in this perfectly operating lens. For now I'm assembling the Leica Summilux-M 35mm F1.4 Steel Rim reissue lens back in a reverse order. 

 

Conclusions

Leica engineers significantly redesigned mechanical design of Leica Summilux-M 35mm F1.4 Steel Rim reissue lens. It is very different comparing to 1961 Steel Rim model, and allows to hide all securing bolts inside the frame only exposing bolts at mount ring. All parts are machined from durable brass and lighter metal alloy with extremely high precision. I'm impressed by simplified access to focusing mechanics for CLA, though adjusting infinity focus is not a trivial task here - that requires shifting of brass helicoid slider mount position on focusing ring. 

There are two focus helicoid guiders which does not leave much space for closer focusing modification. Though with some fine grinding of few moving areas there is a potential to slightly extend MFD of this lens.

UPDATE: here's follow up article on close focus mod for Leica Summilux-M 35mm F1.4 Steel Rim reissue lens.