Light Lens Lab 35mm F2 replica: Back focus and/or focus shift?

[Greenhilltony]

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I just received a pre-owned LLL 35/2 from Japan, with a deal price of just around 600 USD. The previous owner claimed that it focused well on his/her 3 digital M-bodies. However, I think on my M10-P, it does not focus that well. I first noticed the possible focus shift problem when I was shooting the items on my desk, at a distance around 1.5 m. As I stopped down the aperture, the rangefinder patches no longer provide accurate focus results. E.g., I have to turn the focus ring to a closer distance to make the subject I want really "in-focus". It performs better at F2 and F2.8 but at F4 it seems to drift away quite a bit... The in-focus images are produced when the patches separate from each other quite noticeably in the viewfinder. For infinity, it seems the actual focus position is "over" while the rangefinder patches do not align perfectly when pointing at very distant subject. I once tried shooting a tall building from about 20 meters away, I turned the focus ring just before it locked on infinity, and got a sharper image than being locked on infinity.

For your information, my M10-P was bought from the official Leica store in Hong Kong. They claimed that this pre-owned M10-P has been sent to Germany for CLA and everything is fine. My everyday lens is a Minolta M-Rokkor-QF 40/2. It does not show any focus problem on my M10-P, even though its focusing cam is slope and some says it will lead to focus accuracy issue. Either focus with patches or guessing distance, it produced razor sharp images when the patches are aligned (I sometimes guess first and then confirm in viewfinder, when it tells me my guess is correct, the image is also in-focus perfectly). My Voigtlander 35/2 Ultron II works fine, though sometimes a bit suspicious. Interestingly, I bought the LLL Elcan replica and experienced a more serious focus problem, and similarly it back focus strongly.

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[Huss]

I just checked my 10r w my LLL 35/2 at 1.5m (indicated on the lens) at f2 and f4 and no change in focus.  Can't check infinity at the moment (working..) but never had an issue.

[Greenhilltony]

3 hours ago, Huss said:

I just checked my 10r w my LLL 35/2 at 1.5m (indicated on the lens) at f2 and f4 and no change in focus.  Can't check infinity at the moment (working..) but never had an issue.

It's nice to hear there is no focus shift on the other copy. I believe it's not a common issue for this lens. There are some scratches on the notches of the rear spanner ring. I doubt it had undergone an immature CLA and was not properly assembled back.

Edited June 27, 2023 by Greenhilltony

[Greenhilltony]

P.S.: My LLL 35/2 is the V6LC batch.

[pippy]

My LLL (#519/998 / V6 batch) has no more focus-shift than is commonly encountered on any non- APO / ASPH / FLE lens and, IMX, has less shift than found on most others.

Philip.

[Greenhilltony]

I brought the lens and my M10-P to a local repair master in Hong Kong. He checked the infinity focus of the LLL 35/2 and confirmed it is focusing way too much to the back. It seemed the whole groups of elements were assembled improperly, sinking backward to the designated position. As I said, the lens showed traces of CLA before, maybe it was adjusted foolishly to just adapt to the pre-owner's Ms, but not calibrated to the standard infinity focus.

[Al Brown]

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It’s an easy fix. Just let somebody qualified look at it and you’re good.

[tsleica]

LLL has a 50% defect rate when arriving at dealer

Dealer hopefully tests and then...sends lenses back that need fixing..

 

[Huss]

2 hours ago, tsleica said:

LLL has a 50% defect rate when arriving at dealer

Dealer hopefully tests and then...sends lenses back that need fixing..

 

My 35 Cron Asph v1 front focussed.  My LLL has been fine.  If the dealer sends back the ones that need fixin before the customer gets them - that's a good thing.

Better than relying on meaningless signed quality control cards.

[tsleica]

Both my LLL lenses came in just fine..

But the 1st one was an RFF 8E preorder..took forever ..and was bad out of the gate so the dealer sent me another good one instead..as he pretested it..

The LLL Elcan I got last year the dealer tested and sent it only when it got his stamp of approval.

But he was appalled with the 50% defect rate as it was a pita for him to send stuff back and forth and wait months for good lenses which should have been good from the start.

I would imgine your brass has a lot of patina by now!

[Greenhilltony]

9 hours ago, tsleica said:

Both my LLL lenses came in just fine..

But the 1st one was an RFF 8E preorder..took forever ..and was bad out of the gate so the dealer sent me another good one instead..as he pretested it..

The LLL Elcan I got last year the dealer tested and sent it only when it got his stamp of approval.

But he was appalled with the 50% defect rate as it was a pita for him to send stuff back and forth and wait months for good lenses which should have been good from the start.

I would imgine your brass has a lot of patina by now!

As my brand new Elcan and the pre-owned 8E both show back focus in different extent, this is a 50% * 50% = 25% thing, bad luck I have.

Edited June 29, 2023 by Greenhilltony

[Charles Morgan]

My first batch 8 element LLL 35mm f2 was perfect when it arrived with me, but the organiser of the Rangefinder forum group purchase had to send it back to LLL to sort the aperture ring. It's a great lens, but sadly it would appear the quality control needs quite an improvement. One reason why I won't buy another LLL (very taken with the Speed Panchro) unless from a reputable dealer.

[Pierre68]

4 minutes ago, Charles Morgan said:

My first batch 8 element LLL 35mm f2 was perfect when it arrived with me, but the organiser of the Rangefinder forum group purchase had to send it back to LLL to sort the aperture ring. It's a great lens, but sadly it would appear the quality control needs quite an improvement. One reason why I won't buy another LLL (very taken with the Speed Panchro) unless from a reputable dealer.

So who would you recommend as a reputable dealer?

[tsleica]

Quote

So who would you recommend as a reputable dealer?

SH Cameras in HK.

Wen-Li is a real good dude and knows his stuff and will test for you.

[Huss]

21 hours ago, tsleica said:

..and wait months for good lenses which should have been good from the start.

..

so they really are Leica replicas!

[tsleica]

Huss...

Leica as well as LLL...are eating their lunches..and yup..its TUNA!

Edited June 29, 2023 by tsleica

[Huss]

18 hours ago, tsleica said:

Huss...

Leica as well as LLL...are eating their lunches..and yup..its TUNA!

lol, it's been a while!

[Greenhilltony]

Okay now it's the latest update. I got the LLL 35/2 and my M10-P back. The repairman calibrated the infinity and back focus issue of the lens and also tested on my M10-P. I also used his focus testing board and tripod to test it briefly by myself.

There are indeed improvements, but also something the master cannot help me:

1. The rangefinder and peak focusing results are aligned, most obvious at wide-open.
2. The focus seems correct at F2, F2.8, F8 and down to F16. However the focus still shifts backward a bit at F4, and F5.6 I can't really tell.
3. The infinity of this lens seems to be aligned at objects at 50-100 meters away. I understand this is reasonable and it's a character of a lens...right? But at least it produces sharp image when I point it at distant objects and lock to infinity. Before it is CLAed, I have to turn the ring to just before the infinity lock clicks to produce the sharpest images for distant objects.
4. At F4, though the rangefinder and peak focusing shows the consistent results, I need to turn the focus nearer to get the sharpest image of the focused object. The peak focusing also shows the highest contrast point is shifted away from the target and gets nearer due to my operations. BUT the target object does get sharper and in-focus!

I also learned that every lens has its characteristic infinity positions. The master used the Elmarit-M 90mm as the reference base for its checking machine. Compared to it, the LLL 35's infinity is back to it and the M-Rokkor 40/2 is front to it. My LLL 35 shows a larger extent of deviation from the Elmarit-M 90 than the Rokkor 40/2. Probably that's why I always feel my M-Rokkor 40/2 beats the LLL 35 in terms of sharpness, when focus to the same position...?

I haven't tried the LLL 35 on films. According to the common speakings, as the focal plane of film has a considerable thickness, the focus shift is not as prominent as it is on digital sensors. I have rolls of 5219 and 5222 at hand, so I will test it in the future.

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[pippy]

3 hours ago, Greenhilltony said:

...The focus seems correct at F2, F2.8, F8 and down to F16. However the focus still shifts backward a bit at F4, and F5.6 I can't really tell...

IMX this is perfectly normal behaviour for 'older' (non APO/ASPH/FLE) lens designs.

A number of years ago I spent the majority of one day in the studio testing nine 35mm/40mm/50mm lenses (from Leitz; Voigtlander; 7Artisan; Canon) - and every single one of them exhibited, to varying degrees, this same trend towards back-focussing at certain (approx. 1.5m to 2.5m) distances from around f2.8 through f4. With the 35mm lenses by f5.6 focus-shift had either been eliminated or else depth-of-field had become sufficient to mask any focus issues. I even went so far as to plot the results - colour-coded by lens - on graph paper so I could compare results at a glance.

To be perfectly honest it was a bit of a PITA but the lesson I learned was that when snapping subject-matter at this sort of distance I should shoot either wide-open (or thereabouts) or else stop down fo f5.6 and beyond. Adopting this approach subsequently, I've found, works perfectly well for me and my kit.

Philip.

[Jeff S]

Focus shift results from uncorrected spherical aberrations.  Floating elements don’t address focus shift directly, but indirectly as a result of improving close focus performance and related aberrations.  My 35 Summicron ASPH v.1 still exhibits minor focus shift at f/2.8 -f/4 at closer distances, but this is easily accommodated by shooting technique and is not a problem in my prints. 
 

Jeff