Stumped

[andalus]

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With the M9 I have two lenses. The 50 Lux Asph and the 24 Elmar.

 

With the Lux mounted, I point the camera a half mile away at a tower and set focus to the infinity stop. The rangefinder is in perfect alignment. So far, so good.

 

But with the Elmar mounted, pointed at the same tower far away, and with the focus ring all the way to the stop at infinity, the image is NOT apparently in exact focus. If I back off just a slight tad from the stop, THEN the split image of the distant tower comes together.

 

What does this mean? Is the Elmar in need of repair? Anyone else experienced this with different lenses?

 

I would really appreciate any comment on this seeming irregularity.

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[SJP]

Are the elmar pictures sharp at infinity upon coincidence of the rangefinder? I would not be surpsised if some lenses are designed to be slightly rotated past infinity. Of course with 24mm elmar it should not affect the IQ much as it should all be well inside the DoF.

[cbretteville]

Short answer is 'yes' I have seen this, with two lenses that came back from coding by Leica CS in Solms. Lots on this here: http://www.l-camera-forum.com/leica-forum/leica-m9-forum/122176-m9-coincidence-infinity.html

 

Carl

[SJP]

I thought that thread was about adjusting the cam etc. of the rangfinder?

 

Here the question seems to be that for one lens "infinite on lens = "infinite on camera" and the other lens overrotates to some extent i.e. beyond infinity. Adjusting the rangefinder should reverse the problem, and then the 50 Lux Asph would appear not to able to reach infinity. So that is not the question as far as I can see.

 

Similar question was discussed here: http://www.l-camera-forum.com/leica-forum/leica-m8-forum/66348-focus-infinite.html#post686835

[andalus]

I was by the Leica shop in West Palm Beach Florida Saturday and showed one of the guys there this focus issue. He said it was NOT a problem. The 50 Lux is my main lens and that seems to be okay. The Elmar does seem sharp. So maybe this is just one small anomaly not worth questioning further, but it still does seem a bit odd.

[cbretteville]

Strange that you're mentioning 50s. My two with this problem were both 50s. A tabbed Summicron and an Elmar-M. The Summicron had to go back twice. I coudn't detect any focusing issues, but the fact that the two images of RF patch wouldn't line up really annoyed me. As the problem wasn't there when the lenses were sent to Leica they had to fix it.

Carl

[Jamie Roberts]

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I have a similar problem with my Nocti vs every other lens I have... it won't achieve infinity focus on the RF, though everything else does. It doesn't seem to affect anything but infinity though, so off it goes when I get time.

 

I checked on my M3 and M6 and they're the same. As is the M8... so this is odd. .

[Guest mc_k]

...The Elmar does seem sharp. So maybe this is just one small anomaly not worth questioning further...

 

I think you have it about right. T.A. started a thread on this topic, and there is another long thread also. It's quite common.

[JWW]

Make sure you check to see if infinity is still sharp at wide open. I had to send my a 35 summicron to DAG since at infinity it wouldn't align in the rangefinder correctly and compared to other lenses the focus at infinity wide open was noticibly softer. DAG fixed it correctly.

[Guest imported_torben]

I So maybe this is just one small anomaly not worth questioning further, but it still does seem a bit odd.

 

Yeah, the body was 7000 only, so you/we have to bear with it!

[erl]

Yeah, the body was 7000 only, so you/we have to bear with it!

 

It was not proposed as "have to" but rather a question regarding an alternative attitude. Frankly, the price is irrelevant. If you need to worry about the value you probably made a wrong decision about buying.

[Guest imported_torben]

It was not proposed as "have to" but rather a question regarding an alternative attitude. Frankly, the price is irrelevant. If you need to worry about the value you probably made a wrong decision about buying.

 

If you want to interfere and "teach", you should learn to distinguish btw. price and value!

 

Pls inform about the mandate of moderators; does it include "Besserwissen"? at the individual moderator's discretion

[thrice]

torben, I don't understand the second line at all.

 

However, judging from the first line of your response to erl, which sounds quite aggressive, I think you misinterpret him and andalus; both are implying that if it isn't causing a problem and is merely a quirk/observation that will never affect shooting in any way then it probably doesn't make sense to be without the camera/lens for trip(s) to Leica it may take for the lens to be shimmed and calibrated to be at infinity when it hits the infinity stop.

[Guest imported_torben]

Frankly, the price is irrelevant.

 

Yeah, it's ok to charge 7000 (USD) for a camera that doesn't focus properly!

 

Hallelujah!

[starwatcher]

Pls inform about the mandate of moderators; does it include "Besserwissen"? at the individual moderator's discretion

 

at least it allows a personal opinion - there is no need to get agressive.

[SJP]

Yeah, it's ok to charge 7000 (USD) for a camera that doesn't focus properly!

The point rased by the OP had to do with a M9 and a 50 lux lens that focussed perfectly, and an elmarit that also focussed perfectly using the rangefinder but where the lens can be overrotated i.e. slightly beyond infinite. This apparantly is not unusual, e.g. to make sure that you can always focus at infinite regardless of temperature etc.

 

Conclusion: this particular M9 is fine and not part of the question at hand.

[erl]

Stephen, I don't know where you got that "quote". It is definitely not mine. You may enquire of Torben, but duck your head afterwards.

[erl]

If you want to interfere and "teach", you should learn to distinguish btw. price and value!

 

Pls inform about the mandate of moderators; does it include "Besserwissen"? at the individual moderator's discretion

 

Interference is not a desire of mine, it is my duty. As for "teaching" I do have a few lessons for you. You are requested to mind your manners and substantially lower the agression in your posts. Feel free to disagree with any other poster, that is a universal privilege, but you are required to remain respectful of other posters. Do not temp the alternative consequences.

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Hallo,

Look here: Leica M

[marknorton]

The OP has started two threads on the same subject - infinity setting of the 24mm Elmar, so I'll repeat here in more detail what I said in the other thread. Apologies for the length of the post.

 

If you look at this thread: http://http://www.l-camera-forum.com/leica-forum/leica-m9-forum/115034-rangefinderproblems-new-m9s.html#post1219445, Julian Thompson gives some very useful information on rangefinder alignment.

 

You can see the adjustment to suit a particular camera consists of changing the lever arm length and the roller eccentric and either of these will fractionally change the lateral position at which the roller makes contact with the focussing cam on the lens.

 

When Leica design a lens, they have to provide a cam which provides the 3 - 4 mm movement back and forwards which the rangefinder requires for 0.7m to infinity, irrespective of how much the lens barrel itself moves during in this range.

 

In a 50mm lens, that movement is about 3.8mm and the roller can pretty much follow the extension of the lens barrel - this is no coincidence given the age of the rangefinder design and the prevalence of the 50mm focal length at the time. In my experience, a 50mm Summicron is the best lens to work with when adjusting the rangefinder.

 

Come back to 24mm and the lens barrel extension is only 0.85mm so some other method has to be provided - remember that 24mm M lenses didn't exist when the rangefinder was designed. The "right" way to do it is to provide a second helicoid in the lens mount which is more steeply raked than the one used to move the lens barrel. As the focussing ring is turned, one helicoid moves the lens barrel through the range it requires, the second moves the rangefinder cam through the range it requires.That's what we have in, for example, the 21 and 24mm Elmarits and Summiluxes. By using a second helicoid, the rangefinder cam presented to the roller is flat, or very nearly so, so that it doesn't much matter where precisely the rangefinder roller makes contact.

 

Adding a second helicoid adds to the lens cost so instead, Leica opted in the 24mm Elmar and 18mm Super Elmar to provide a cam which is on the back of the focussing ring and profiled to provide the required roller movement as the lens is focussed. That means the cam is quite steeply raked in comparison and is not flat. The lateral position of where the roller now makes contact is now important and the infinity position presented by the lens is interpreted differently by the camera depending on where its roller, for its state of adjustment, makes contact with the cam.

 

Providing the lens itself does not focus past infinity, this rangefinder error is negligible since it is covered by the deep depth of field. This wriggle-room is there for a wide angle lens with modest maximum aperture and allows Leica to introduce these lenses at lower cost - just look at the difference in price between a 24mm Elmar and a 24mm Elmarit - quite a lot for 2/3 stop speed increase.

 

FWIW, the Elmar is my favourite 24 (I have all three) and I like its compactness and the infinity position is off on one of my 4 digital M bodies. It is, however, not a good lens to use to judge rangefinder alignment by.

[k-hawinkler]

The OP has started two threads on the same subject - infinity setting of the 24mm Elmar, so I'll repeat here in more detail what I said in the other thread. Apologies for the length of the post.

 

If you look at this thread: http://http://www.l-camera-forum.com/leica-forum/leica-m9-forum/115034-rangefinderproblems-new-m9s.html#post1219445, Julian Thompson gives some very useful information on rangefinder alignment.

 

You can see the adjustment to suit a particular camera consists of changing the lever arm length and the roller eccentric and either of these will fractionally change the lateral position at which the roller makes contact with the focussing cam on the lens.

 

When Leica design a lens, they have to provide a cam which provides the 3 - 4 mm movement back and forwards which the rangefinder requires for 0.7m to infinity, irrespective of how much the lens barrel itself moves during in this range.

 

In a 50mm lens, that movement is about 3.8mm and the roller can pretty much follow the extension of the lens barrel - this is no coincidence given the age of the rangefinder design and the prevalence of the 50mm focal length at the time. In my experience, a 50mm Summicron is the best lens to work with when adjusting the rangefinder.

 

Come back to 24mm and the lens barrel extension is only 0.85mm so some other method has to be provided - remember that 24mm M lenses didn't exist when the rangefinder was designed. The "right" way to do it is to provide a second helicoid in the lens mount which is more steeply raked than the one used to move the lens barrel. As the focussing ring is turned, one helicoid moves the lens barrel through the range it requires, the second moves the rangefinder cam through the range it requires.That's what we have in, for example, the 21 and 24mm Elmarits and Summiluxes. By using a second helicoid, the rangefinder cam presented to the roller is flat, or very nearly so, so that it doesn't much matter where precisely the rangefinder roller makes contact.

 

Adding a second helicoid adds to the lens cost so instead, Leica opted in the 24mm Elmar and 18mm Super Elmar to provide a cam which is on the back of the focussing ring and profiled to provide the required roller movement as the lens is focussed. That means the cam is quite steeply raked in comparison and is not flat. The lateral position of where the roller now makes contact is now important and the infinity position presented by the lens is interpreted differently by the camera depending on where its roller, for its state of adjustment, makes contact with the cam.

 

Providing the lens itself does not focus past infinity, this rangefinder error is negligible since it is covered by the deep depth of field. This wriggle-room is there for a wide angle lens with modest maximum aperture and allows Leica to introduce these lenses at lower cost - just look at the difference in price between a 24mm Elmar and a 24mm Elmarit - quite a lot for 2/3 stop speed increase.

 

FWIW, the Elmar is my favourite 24 (I have all three) and I like its compactness and the infinity position is off on one of my 4 digital M bodies. It is, however, not a good lens to use to judge rangefinder alignment by.

 

 

http://www.l-camera-forum.com/leica-forum/leica-m9-forum/115034-rangefinderproblems-new-m9s.html#post1219445