How smooth SHOULD a collapsible 'cron focus be?

[SteveM(PA)]

I just got my 1955 collapsible summicron back from a CLA by Youxin Ye, I don't have any other older tabbed lenses to compare this to. It was stiff before, now it seems just as stiff, if not moreso. Should I be able to focus with one finger? I need to grip the lens with two or three fingers to get it to turn, and when it does turn, it is jerky. Is this as good as it gets? I keep going back to my '80s Jupiter 8 which has the most lush, fluid one-finger focusing I've ever encountered, and I was hoping my 'cron would come back like that 🙁 Maybe it just has a "break in" period?

 

[sleepyhead]

Hi, I have a collapsible from 1957 (I believe). It's a bit more stiff to focus than some other lenses that I've used, but yours sounds a little too stiff. I can focus mine with one finger. ALso, the jerky-ness sounds worrying.

Any possibility of sending it back to Youxin Ye and see what he/she can do?

 

[SteveM(PA)]

ok...I take it off the camera, and...oh yeah...there we go...nice and smooth! That's what I'm talkin' about. My thought now is that maybe this is just the nature of this beast? I'll drop Youxin an email (I LOVE Youxin, what a great guy) and maybe wait a few days, see if it gets a little looser. It SMELLS cool though, I love that fresh-lubed smell (I got my iiif RDST done as well).

 

[sleepyhead]

Hmm... but don't you think that's a little strange - looser focus off the camera?

Still, doesn't sound right to me, and doesn't do you much good off the camera!

 

[back alley]

my canon lenses are a bit stiffer when i put the ltm>m adapter on and then mount on the m3.
not sure why.

 

[Gabriel M.A.]

That certainly sounds strange. Both my Summar and Summitar, which of course are no 'crons but have comparable, if not virtually identical focusing mechanisms, are very smooth, either mounted on a screwmount camera or with an LTM-to-M adapter.

Do you experience the "same" with other lenses on the same camera?

 

[SteveM(PA)]

That certainly sounds strange. Both my Summar and Summitar, which of course are no 'crons but have comparable, if not virtually identical focusing mechanisms, are very smooth, either mounted on a screwmount camera or with an LTM-to-M adapter.

Do you experience the "same" with other lenses on the same camera?

I only have a J9, j12, j8, and Canon 135, and none of those suffer from this dual personality. So, it's not a "tabbed" thing, huh? Alright, I'm prolly gonna send this guy back up to Boston *sigh*.

 

[aizan]

even with a cleaning and relubrication, focusing won't be smooth enough to push and pull with the tab. you have to focus with two fingers. same thing happened with my collapsible 'cron.

 

[Gabriel M.A.]

even with a cleaning and relubrication, focusing won't be smooth enough to push and pull with the tab. you have to focus with two fingers. same thing happened with my collapsible 'cron.

Really? I think there are variations out there, then. I don't need two fingers to focus these lenses, not even to lock/unlock to/from the infinity lock. I only need my index finger, sometimes --and rarely-- my thumb (depends on how I'm holding the camera at the moment)

 

[SteveM(PA)]

even with a cleaning and relubrication, focusing won't be smooth enough to push and pull with the tab. you have to focus with two fingers. same thing happened with my collapsible 'cron.

Oh is that right? The only other tab I can compare to is my Oly XA
🙂 and that is truly "fingertip."

 

[Ronald M]

Both Summitars and Coll `cron can be done with one finger. They require only slightly more effort than my 3.5 elmar 50mm or 2.8 elmar first version. None have sticky spots.

Lens is either damaged or not lubed properly.

 

[ffttklackdedeng]

ok...I take it off the camera, and...oh yeah...there we go...nice and smooth! That's what I'm talkin' about.

This sounds really strange to me. There's no difference between on the camera and off the camera.. Anyway, one finger does it on my Summitar, a bit more resistance than the Elmar, but: two fingers are simply more convenient, grabbing on both sides of the tab feels faster for me than one finger on the 'bubble'

Robert

 

[aizan]

is it buttery smooth, even in the close range? that's where they usually have trouble.

 

[Paul Connet]

ok...I take it off the camera, and...oh yeah...there we go...nice and smooth! That's what I'm talkin' about. My thought now is that maybe this is just the nature of this beast? I'll drop Youxin an email (I LOVE Youxin, what a great guy) and maybe wait a few days, see if it gets a little looser. It SMELLS cool though, I love that fresh-lubed smell (I got my iiif RDST done as well).

Langdon, in my experience some screw mount lenses just seem to bind up when mounted firmly onto some bodies. My own col. Cron is index finger smooth, but I have several other lenses that bind on some bodies if I screw them on too tightly.

Try just snugging the lens up on the body so that it will not loosen when you focus, and see if that will work for you. I don't think the problem is the lens. More probably it is the body/lens fit. Try the lens on another body before you send it back to Youxin.

Regards, Paul C.

 

[Stu W]

Langdon, my collapsible was cla'd by Sherry and you can easily focus it with 1 finger-it's like butter. My dual range was cla'd by someone else, and it seems the one done by Sherry has oil on the helical while the dual range has grease. I just finished dis-assembleing the dual ranged, washed out all the grease, and lubed it with ny-oil. It too is now smooth as silk. I guess it depends on who does it and your personal taste. Stu

 

[SteveM(PA)]

Langdon, in my experience some screw mount lenses just seem to bind up when mounted firmly onto some bodies. My own col. Cron is index finger smooth, but I have several other lenses that bind on some bodies if I screw them on too tightly.

Try just snugging the lens up on the body so that it will not loosen when you focus, and see if that will work for you. I don't think the problem is the lens. More probably it is the body/lens fit. Try the lens on another body before you send it back to Youxin.

Regards, Paul C.

This is a coincidence Paul, I just got an email back from Youxin, in which he says the problem is not the lens, but the camera flange, that it is not "perfectly level." He, too, suggests just not screwing the lens on too tightly. I don't think this is correct. Since I've gotten home, I've mounted the lens on my Fed 3b, and it has the same stiffness as on the iiif, and (yes, aizan) very very stiff in the close focus range. And concurrently, my buttery-smooth J8 is buttery smooth on both cameras, just as it's always been. I can not screw the lens on to a loose-but-tight-enough degree whereby it won't come unscrewed during focusing. So problem obviously is with the lens flange, although i don't know what adjustment could be made. Man, I so want this thing to turn as smooth ON the camera as it does here, twirling around in my hand.

 

[SteveM(PA)]

Langdon, my collapsible was cla'd by Sherry and you can easily focus it with 1 finger-it's like butter. My dual range was cla'd by someone else, and it seems the one done by Sherry has oil on the helical while the dual range has grease. I just finished dis-assembleing the dual ranged, washed out all the grease, and lubed it with ny-oil. It too is now smooth as silk. I guess it depends on who does it and your personal taste. Stu

hey Stu, thanks...mine is greased. Once it is mounted, it just feels like it's choking, it binds and scrapes...it sticks so bad that I actually have a cut on my face from the dial of the vc meter.... 😎