The Dreaded Backfocus

[washy21]

After saving for ages and finally receiving my mint E60 Noctilux I discover that it has backfocus issues across the whole range of focus. None of my other lenses have this problem and so I suspect that the Noctilux is out of calibration - or is it?

I have already learnt to compensate by focusing in front, but of course this is no consolation when infinity focus is required and everything is off.

I have tried reading as many threads as possible, but a lot of them end up as an argument as to quality control or simply do not provide the answers.

Can anyone tell me:

• Is it most likely that only the lens needs adjusting
• What exactly can they, or do they do when adjusting the lens
• Is Solms the only place that this work can be done

I really don't want to be without my Noctilux for 3 months - it will kill me to part with it. Are there any lens experts in the UK that can help ?

 

[washy21]

ErikFive:
LOL - No, I love the Noctilux, but not the Backfocus.

 

[RichC]

Are there any lens experts in the UK that can help ?

Yes: Malcolm Taylor, a Leica specialist in Hereford - usually has a small yellow ad in the back of Amateur Photographer.

He rebuilt my well-worn and misfocusing 35 Summilux Pre-asph for just over £100 in less than a week!

He did a very thorough job, and kept me totally informed. I have nothing but praise for him...

Google search: "Malcolm Taylor" Leica

PS: I've heard that Leica use him to restore their cameras!

 

[washy21]

Rich C

Thanks, I'll contact him

 

[summilux]

my noctilux back focus on my M8, until I used a hex key to adjust it myself, adjusting focus on M8 should be much easier, because now you have instant feedback, it is a good idea learning it as the rangefinder will be out of syn sooner or later, my practise is to tune your most demanding lens, like noctilux or 90 summicron.


one more thing about the noctilux, the focus starts to shift at about f2, all the way to until f5.6, where the increased dof compensates for the shift. so i use noctilux at f1 or f1.2 only, smaller than these, you will have to learn compensation yourself.

now, when will solms rock the world by releasing a noctilux with asph and floating elements? presently i much prefer the canon 85/1.2L, it is sharp wide open.

 

[washy21]

Actually, I have just decided that it is front focus not back focus. Not being terribly technically minded I jus didn't test corretly.

So, can anyone confirm that it is indeed front focus.

If i focus on eyes and the nose comes into focus then that is front focus - right !!

Anyway, it is very dissapointing and especially seeing as the infinity lines up but nothing is in focused at infinity.

UPDATE:

I have also just noticed that the lens actually focuses slightly closer than 1m, or at least where you would expect the lens to stop when the 1m mark lines up with the DOF scale it travels slightly past by what I believe is the distance of front focus.

Anyone shed any light on this ?

 

[Richard Marks]

I dont think the focus scales are all that accurate for distances less than 1m.
I suspect the new lens has so little depth of fieled that any errors in the system become critical. Its not necessarilly the lens. Worth checking all the steps in the syetm.
You can always stop it down a bit (He He).
best wishes
Richard

 

[jaapv]

At what f-stop does it misfocus? at f-1 it should be spot-on, at 2.0-5.6 the focus shifts and you must compensate.

 

[usccharles]

i think once you take it in the shop and get it adjusted, you will be fine.

i've had to have all my lenses calibrated at one time or another. i think it is just inevitable for fast lenses, and you have there the fastestest of them all. i would be more surprised if the lens was spot on right out of the box.

🙂

 

[zeitz]

You use the word "mint" rather than "new". I assume that means it is "used". You could return it to the seller, or, as others recommend, take it to a Leica repairman and have it adjusted.

 

[washy21]

zeitz:

Good point. It is in mint condition which to me indicates that it has had minimal use. That said, it could have been used a lot, but I very much doubt it as I believe my source.

I will probably have someone look at the lens only. I'm sure that the camera is fine.

 

[Gabriel M.A.]

At what f-stop does it misfocus? at f-1 it should be spot-on, at 2.0-5.6 the focus shifts and you must compensate.

I tend to see threads where they blame the M8 and not the lens for this "dreaded backfocusing". They always involve a very fast lens (50 f/1.5 Sonnar-C, Noctilux, etc.) which tends to have focus shift, or a very long focal length, like the 135mm Elmarit.

Erik's suggestion for using a better magnification viewfinder is dead-on. I have a 1.25x magnifier for my M8, and I hardly ever miss proper focusing (the times I've missed, I didn't focus through the viewfinder). Without it, my 50 Summilux and Canon 50mm f/1.2 can become very annoying in low light, wide open.

 

[Gabriel M.A.]

::groan:: I just realized Erik meant the 50mm f/0.95. You are as much a "smart alec" as I tend to be (on this side of the pond, "smart" does not tend to be a compliment)

 

[washy21]

Thanks Gabriel

I've got a magnifier on order, but I doubt very much that I am not focusing correctly. I can focus a Summilux dead on most of the time, plus with compensation for the front focus issue on the Noctilux I can nail most of them as well.

I took my M8 and all my lenses over to a friends house today. Hehas an M8 and a variety of lenses that I don't have. It turns out that the Noctilux is the only lens that does not focus correctly and exhibits the same front focus problems on his M8 body.

It must be the lens that needs sorting.

 

[newyorkone]

zeitz:

Good point. It is in mint condition which to me indicates that it has had minimal use. That said, it could have been used a lot, but I very much doubt it as I believe my source.

I will probably have someone look at the lens only. I'm sure that the camera is fine.

Sorry to hear that...

Some have gotten lucky and everything turned out spot on. For the rest of us, myself included, it appears that the M8 is a bit more sensitive to focusing discrepancies. I am waiting to personally drop off my M8/Noct combo at Leica NJ for a quick tweak.

For now, I have lurned to compensate. A little annoying maybe, buy the results make it worth the trouble.

I tried the hex key thing and it didn't really help me. Others have faired better. YMMV. Good luck...

 

[washy21]

I would still be interested to know what they actually do when calibrating a lens.

Does anyone know ????