Tight focus ring

[evikne]

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The focus ring on my 75mm Summilux is pretty tight, a bit more than I prefer. Is this something I can fix myself without taking it apart?

[jdlaing]

Repeated use may loosen up and move the lubricant around but it’s not a self fix. You may try turning it back and forth repeatedly to see if it loosens up with use.

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[evikne]

Thanks. I hope it will loosen up a bit with some more use. I just got the lens back from service for focusing adjustments, but I regret that I forgot to mention the focus ring. Now I won't live without it for another three months!

[evikne]

I had to deliver my lens back for service (Leica Germany) once more, and this time I asked if they could also loosen the focus ring a bit. When I got it back, they answered in an attached letter that this unfortunately wasn't possible. 

 

Is there anyone with some technical insight who knows why this isn't possible?

[Jeff S]

If in the US, send it to DAG (Don Goldberg in Wisconsin). He fixed the sticky focus on my 50 Summilux ASPH when Leica NJ could not. Fast return (1 week) and inexpensive ($90, incl shipping). He can also adjust aperture rings. In Europe, I’ve read similar comments about Will Van Manen.

 

I always recommend contacting in advance to discuss.

 

Jeff

[250swb]

 

Is there anyone with some technical insight who knows why this isn't possible?

 

I wouldn't say I had any technical insight but if the lens was designed to have a tighter action then they probably can't reverse it.

 

Why a tighter action? Well a lot of tele lenses have a tighter action to stop them going too far out of focus if nudged. When a theatre photographer I'd often use a Nikon 135mm that was very lose, and if I slung it to the side to use the other body when I picked it up again the lens may have gone from medium focus to infinity just by rubbing a bit. The other consideration is a lose focus ring is prone to 'back and forth' focusing, going too far each way with the lightest touch, a tighter ring slows it down and gets you spot on quicker. The third consideration is how many internal elements the focus ring has to move, and how far, and how much gearing is required from the helicoid to achieve it. I would imagine the Summilux shifts a lot of internal components around when you focus it. I would perm any two from three answers as being the reason, probably a bit of tightness for efficiency, and a bit from the mechanical side.

 

I would add that there is a distinction between 'sticky focus' and the 'heavy focus' which is what the OP is presumably talking about. Sticky focus is 'notchy' in feel and often a result of dead grease or the flange being misaligned, not an intrinsic design decision.

Edited August 23, 2018 by 250swb

[jaapv]

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The assembly of the focus thread is done by hand and involves tolerance-matching. I expect this hasn't changed with the move to Wetzlar.

The stiffness of focussing is thus dependent on the judgement of the person doing the parts choice and testing the assembly by hand. It will vary from lens to lens for tis reason.

It cannot be adjusted, as Leica does not depend on grease to dampen the focussing action.

[evikne]

Thanks a lot for your answers! Yes, the focus ring isn't "sticky", it's only a bit tighter than my other lenses. But it moves very nice and smoothly. So this isn't a big problem. Just have to get used to it. 

Edited August 23, 2018 by evikne

[TomB_tx]

The choice of helical grease viscosity also affects focus stiffness, and I’ve used a lighter weight lube to get lighter action on some tight lenses. As mentioned above the thread fit can vary, and ideally you select a lube to give the right action for the thread fit, but that can mean trial, disassembly, and try again, so I’m sure Leica doesn’t bother now. I’ve heard DAG had a stash of a lighter lube that Leica used to use, which is how he has adjusted some lenses.

Sometimes a tech may also use a lapping paste to loosed tight threads, especially if there has been damage.

[Jeff S]

The assembly of the focus thread is done by hand and involves tolerance-matching. I expect this hasn't changed with the move to Wetzlar.

The stiffness of focussing is thus dependent on the judgement of the person doing the parts choice and testing the assembly by hand. It will vary from lens to lens for tis reason.

It cannot be adjusted, as Leica does not depend on grease to dampen the focussing action.

The ‘sticky’ focus action on my 50 Summilux ASPH could not be fixed by NJ. DAG fixed it... perfectly smooth...with his supply of the old formula Leitz grease. The explanation from the NJ tech turned out to be nonsense.

 

Jeff

[RSS]

The ‘sticky’ focus action on my 50 Summilux ASPH could not be fixed by NJ. DAG fixed it... perfectly smooth...with his supply of the old formula Leitz grease. The explanation from the NJ tech turned out to be nonsense.

 

Jeff

 

I will second the motion. I have a 50 Summilux from the 1960s.  Leica will not 6 bit code this vintage lens and the focus was stiff.  I sent it to DAG, it was 6 bit coded, overhauled and returned with smooth focussing just right.   Access his website and follow his instructions for inquiries and sending your lens in.  

[low325]

Send it to DAG. The thought of every lens is perfect the way it is as it leaves Leica factory is nonsense.

[jaeger]

try sunbathing, few hours a day for few days and let use know?