Bad LTM adapter?

[01maciel]

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Due to lack of a 35mm LTM adapter, I have been using an adapter for my 'new' Summaron 35mm 3.5 that shows a 50mm frame in the OVF. Now I have ordered the same adapter with 35mm frame and find that the rangefinder coupling does not work properly at close range. For about the entire first third of the close-up range, nothing happens at all in the OVF. Another adapter from a different manufacturer behaves exactly the same. What could be the cause?

[UliWer]

Usually the adapter does not interfere with the mechanism for focussing. Though if the adapter is too thick - way too thick! - it might prevent the rear of your lens touching the little wheel inside the camera which activates the rangefinder. The adapter should never be thicker than 1mm.

Are you sure that your Summaron is a proper LTM version? If it is an original version for M and the adapter fixed at the factory was removed I can‘t rule out that this causes problems with focussing - though even then it would be not very probable that the adapter was much thicker than the original rear part which was removed. 

[UliWer]

Did you look at your lens from the rear?

That's what you should see when your Summaron is focussed at infinity:

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The lenses interior protrudes most, so no risk that the focussing mechanism is not activated.

Now focussed at closest distance:

Now the interior almost disappears. If it recesses too much or if there is too much distance to the little wheel, the rangefinder mechanism won't be activated.

Did you try whether your lens works on an LTM-body?

[Ecar]

There could be many lens/adapter match issues. It's also possible that the adapter doesn't have enough thread length (or starts screwing in at a different point) and therefore doesn't screw in all the way, essentially leaving more space than it should before contact is made with the RF cam roller on the body. How's infinity?

Two options: try another good-quality adapter or keep your 50mm one that seems to work and slightly file the flange to bring up the 35mm framelines (of course, that's not reversible).

 

Edited September 26, 2023 by Ecar

[01maciel]

Am 26.9.2023 um 20:50 schrieb UliWer:

Did you look at your lens from the rear?

That's what you should see when your Summaron is focussed at infinity:

This looks the same on my lens.

 

Am 26.9.2023 um 20:50 schrieb UliWer:

Did you try whether your lens works on an LTM-body?

Unfortunately I do not have a LTM body for a test available.

Am 26.9.2023 um 21:50 schrieb Ecar:

It's also possible that the adapter doesn't have enough thread length (or starts screwing in at a different point)

I suspect this is the case. The 35mm frames take up almost all of the OVF anyway. Using a 50 frame to arrange the subject properly isn't too difficult. As a user of a RF camera, you are prepared to make a few compromises;)

[jgeenen]

From your description it seems possible that the roller in the camera that is taking the flange depth from the lens might be partly blocked by the adapter. The roller cam should travel freely when the adapter is attached to the body. It could be that the bajonet cutout in the adapter is not perfectly shaped. You can compare the adapter shape with a M-lens and look for differences or attach the adapter to the camera without lens and check the roller travel path. I do not think it has anything to do with threading or adapter thickness. A thick adapter or a not fully screwed in lens would create infinity problems and backfocus.
 

Johannes

[Huss]

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On 9/26/2023 at 10:54 AM, 01maciel said:

Due to lack of a 35mm LTM adapter, I have been using an adapter for my 'new' Summaron 35mm 3.5 that shows a 50mm frame in the OVF. Now I have ordered the same adapter with 35mm frame and find that the rangefinder coupling does not work properly at close range. For about the entire first third of the close-up range, nothing happens at all in the OVF. Another adapter from a different manufacturer behaves exactly the same. What could be the cause?

Does it focus correctly over the entire range with the 50mm adapter?  The only difference between a 35mm and a 50mm adapter is the frame line set they trigger.

Edited September 29, 2023 by Huss

[01maciel]

vor 1 Minute schrieb Huss:

Does it focus correctly over the entire range with the 50mm adapter?

yes, it does.

[Huss]

When you mount the lens w the 35mm adapter, is there any rotational play after it clicks on your camera? So you can perhaps turn it a little further after it clicks/locks?

Does it click/lock on your camera w the 35mm adapter?

[Susie]

Hi,

Does the adaptor have the cut-away to accomodate the infinity lock?  If not, the lens might not screw fully home, and therefore not focus properly.

Edited September 29, 2023 by Susie

[01maciel]

vor 12 Minuten schrieb Huss:

is there any rotational play after it clicks on your camera?

No play, it fits tight and correct. I tried to turn it a bit further but it doesn't work. Yes, it clicks as it supposed to do.

vor 7 Minuten schrieb Susie:

Does the adaptor have the cut-away to accomodate the infinity lock?

How can I see this?

[Pyrogallol]

There have been other discussions about adaptors and their cutouts.

 

[Huss]

I do not see how an infinity cut out would affect close focusing.  It just effects whether the lens locks at infinity.

Edited September 29, 2023 by Huss

[01maciel]

I just tried the Elmar 50mm LTM on the 35mm adapter. It works flawlessly from close focus to infinity. Very strange. It seems like there is something wrong with the Summaron 35mm.

Am 28.9.2023 um 08:00 schrieb jgeenen:

The roller cam should travel freely when the adapter is attached to the body. It could be that the bajonet cutout in the adapter is not perfectly shaped.

I checked it just now. The roller cam works perfect with the adapter only.

 

[UliWer]

vor 16 Stunden schrieb 01maciel:

I just tried the Elmar 50mm LTM on the 35mm adapter. It works flawlessly from close focus to infinity. Very strange. It seems like there is something wrong with the Summaron 35mm.

 

I also think it is the lens. When you look at your lens from the rear side and turn the focus towards minimal distance, the helical mount should never recess but stick out at least a fraction of a millimeter.

[plaidshirts]

On 9/26/2023 at 10:54 AM, 01maciel said:

Due to lack of a 35mm LTM adapter, I have been using an adapter for my 'new' Summaron 35mm 3.5 that shows a 50mm frame in the OVF. Now I have ordered the same adapter with 35mm frame and find that the rangefinder coupling does not work properly at close range. For about the entire first third of the close-up range, nothing happens at all in the OVF. Another adapter from a different manufacturer behaves exactly the same. What could be the cause?

My problem was solved when I replaced the cheap Chinese brand with a brass Voigtlander. I posted about it a couple years back. 

[jankap]

Do you know if the lens has been cleaned ("cla"-ed)?  If that is the case, the lens could be set together in a wrong way. The thread for the rangefinder is a multi thread. That means, that there are several ways to put it together after the cleaning. 

On a mirrorless camera, the rangefinder is obsolete. Users with these kinds of cameras would not complain.

 

Edited September 30, 2023 by jankap

[jankap]

Am 26.9.2023 um 19:54 schrieb 01maciel:

Due to lack of a 35mm LTM adapter, I have been using an adapter for my 'new' Summaron 35mm 3.5 that shows a 50mm frame in the OVF. Now I have ordered the same adapter with 35mm frame and find that the rangefinder coupling does not work properly at close range. For about the entire first third of the close-up range, nothing happens at all in the OVF. Another adapter from a different manufacturer behaves exactly the same. What could be the cause?

Do you know if the lens has been cleaned ("cla"-ed)?  If that is the case, the lens could be set together in a wrong way. The thread for the rangefinder is a multi thread. That means, that there are several ways to put it together after the cleaning. 

On a mirrorless camera, the rangefinder is obsolete. Users with these kinds of cameras would not complain.

[01maciel]

vor 1 Stunde schrieb jankap:

Do you know if the lens has been cleaned ("cla"-ed)?

Unfortunately, no. But I send the lens yesterday to my favourite lens-service-station for a clean-up inside the lens. He is quite good and would restore the lens to its proper condition if necessary.

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[01maciel]

vor 4 Stunden schrieb plaidshirts:

My problem was solved when I replaced the cheap Chinese brand with a brass Voigtlander.

My first 35mm adapter was a cheap 中国人 brand. My second one is an Urth adapter from Amazon. I have only had good experiences with them so far.