This article is dedicated for quite unique and very interesting lens - Light Lens Lab 50mm F2 Elcan - a modern re-designed copy of extremely rare Leica 50mm F2 lens from military grade KE-7A kit.
The LLL 50mm F2 lens copy is provided by Fred Miranda (thank you!).
First impressions
Numerous reviews of LLL 50mm F2 Elcan lens are stating that it is a "smallest Leica M mount 50mm F2 lens", which is partially true. I own a copy of Voigtlander 50mm F2 Heliar collapsible, which in fact is 1mm shorter comparing to Elcan (picture shows custom 1mm filter on Heliar). Of course during shooting you must extract 50mm Heliar core making it larger, but for carry in the bag technically it is still a smaller lens : )
LLL 50mm F2 is very solidly built. You feel that right away from its condensed weight, similar to high-end brass framed Leica lenses (or 50mm Heliar collapsible). All details look very accurate and precisely machined to perfection. This lens feels very premium in hand and while operating on camera, and IMO that worths every $ paid. You can read a lot in reviews about optical performance, though personally what is highly appealing is - very compact size combined with strong and precise build.
Though the main reason I got this LLL 50mm copy - is a minor yet annoying focus rotation lag. It's when you turn focus direction, there is a minor sense of a "click" and "delay" indicating something internally has a fraction of millimeter gap. Typically it's easy-to-moderate complexity fix in most Leica M lenses (by tuning helicoid pin geometry or adding extra grease). I decided to take a closer look inside of LLL Elcan to see what can be done and .... it was a shocking discovery, and one of the hardest disassembly experience I had so far : )
NOTE: Just like many previous disassembly I explained, this one is performed without knowing the internals, only assuming and trying in a experimental way. It took me couple of weeks to safely open this lens mechanics.
Lens Disassembly - rear area
Even though externally LLL 50mm F2 Elcan lens geometry looks like original Leica, there are some tweaks to mechanical design, specifically the retention rings are different. I can say that from a picture shared on one of FM listings (which I can't repost here yet without permission, so just believe my words). That, and one more thing are making this disassembly EXTREMELY DIFFICULT (sorry for this exclamation, but has the reason).
To start the disassembly, you need to first unscrew CCW the outer black retention ring. The ring itself has two detent areas marked on picture below. Though it would be a huge mistake to try using the wrench on that lens for opening, and will most likely lead to damaging the ring.
WARNING: Do NOT use standard wrenches on LLL 50mm Elcan!
The reason is - there is a huge amount of quite strong sealing glue in the retention ring thread. It holds the ring rock solid. You need to apply lots of acetone to soften and remove the glue, then repeat process numerous times. After glue is removed, you still can't use the wrench, because ring walls are relatively thin (original Leica Elcan has few times thicker retention ring, similar to Leica 50mm F2 rigid).
I tried various approaches with custom shaped brass plates secured in a low profile vise - nothing worked. Eventually I came with idea of creating a custom 3D-printed composite wrench cylinder.
The final version of the custom Elcan opening wrench is shown on picture below. It consists of printable frame with socket to insert 1mm thick shaped brass plate. Additionally there is an outer groove to add very strong 3M adhesive foam. This combo is allowing to securely "grab" the retention ring over its all accessible surface enforced with strong brass plate (don't use steel to prevent serious damage to the brass made retention ring).
Once you attach the custom wrench, press it firm toward the lens and hold the pressure. Use the rubber belt to firmly grab the lens mount area. NOTE: Do NOT grab the aperture ring or front area, otherwise it may break another internal thread. You have to apply tremendous instant CCW torque power to break the retention ring form its position. I'd recommend to do a series of high torque movements, the ring may not move from the first try (I made a dozen of attempts until the ring finally rotated). After shifting ring from initial position it is relatively easy to unscrew it. (clean the glue from the threads to prevent issues with future disassembly)
Optical core assembly can be detached from the focusing mechanics frame at this point. NOTE: there are no any limiters of radial position for the optical core, during assembly simply align aperture dot with the central DOF mark of the focus frame.
One good news to see is - there is a set of focus precision calibrating shims around the lens core. It allows easy tuning of infinity focus precision by adding/removing shims number.
Surprise! There is another noticeable amount of securing sealing glue applied to the next retention ring. Fortunately this one only requires acetone soaking and glue removal. The detents work well with standard lens wrench. Unscrew the ring in CCW direction.
This retention ring is securing outer focus ring to internal helicoid. During assembly you need to align infinity position before tightening the retention ring (first collapse helicoid to infinity stop).
Retention ring is removed and focus ring can be detached. It's made of solid brass with four ( ! ) bolts are securing the large and comfortable focus tab from the inside.
Next step is to unscrew another retention ring (use acetone and clean glue as well first). It is difficult to access the ring with the wrench I have, so it is recommended to disassemble the mount ring. However if you have long enough wrench blades, removing mount is not necessary.
Unscrew all tiny mount bolts using flat screwdriver.
Detach the mount ring.
Detach the outer shell ring.
Heres the main helicoid. All parts are heavy and made of brass with very high precision (minus tolerance for the grease). The RF cylinder is thick and has thick brass helicoid guider.
The opposite side is showing inner helicoid cylinder (that is holding the lens core assembly). I'm struggling to say if it's chromed brass or lighter aluminum-like alloy. There is much thinner spacing for the focusing helicoid guider due to it's located in a thinner thread area.
With retention ring removed helicoid can be opened by splitting rings apart. As you can see here - the thick brass guider (to the right) is mounted with two bolts. I didn't check if you can shift its radial positions.
Another most-right bolt on the picture is limiting lens focusing range (for a good reason, so don't remove it, the helicoid has limited thread length).
The point of interest for me is on the left picture area - focusing helicoid pin. It's relatively thin though wide and durable enough for normal lens focusing. It's a solid part of the outer helicoid ring, so be gentle with it when tuning its geometry. I applied gentle pressure on its right edge making it wider by a fraction of millimeter, then polished that edge. It eliminated focus lag and at that posint I assembled the lens back.
Now there is a time for a bonus picture, not related to the article : )
Meet my new hobby - assembling of 1/12 scale action figures. It's a nice relaxing activity (though may take averagely ~20h per model) and I like doing it more than some lenses tinkering : ) Building plastic kits also require precision and accuracy (especially with painting, which I didn't master yet). If you are experienced plastic model crafter - most likely your skill level is well fitting the lens disassembly territory.
Brief Summary
Light Lens Lab 50mm F2 Elcan is incredibly interesting lens for Leica M system. Even though it's a copy of Leica Elcan, but is an extremely good one. The mechanics is top grade - on a similar level with other Leica lenses I was tinkering with. Optically it behaves very pleasant and fits my shooting needs.
I personally ended up purchasing a black paint version of LLL 50mm F2 and just received it today. Once have some pictures will also post into this article later. If you also like ultra-compact lenses, LLL is definitely highly recommended and unique lens for a moderate price.
One more bonus content
If you read by here, I have a bit of extra info : ) During the disassembly I unintentionally discovered how the front area is opening (yes, by holding the lens front area while attempting to unscrew the stubborn retention ring). Though it was a stressful time, no pictures taken. I will post more details (and pictures) once I need to deal with opening my own lens copy later. Generally, there is a front nameplate unscrewing CCW, then you unglue and unscrew another outer retention ring (hidden under nameplate). It allows to extract the front optical core and get access to the aperture chamber for cleaning. Additionally you may be able to unscrew the front ring, though it has a bolt socket on the side and may be secured on factory.
Tinkering with photo equipment is my big hobby. It's often quite challenging to explore disassembly steps or designing new useful accessories, but also a joy to share them later with people. I keep these activities apart from primary work, though appreciating a small tips for a coffee if you find my shared results useful.
