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jaeger

focus at infinity

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I had my camera and all lenses calibrated for back focus issue by Leica NJ 2 months ago.  I thought everything was good until now I just realized the patch at infinity isn't completely aligned on my 35mm Summilux.  Thanks to a newly acquired 1.4x diopter.  I see double lines with tiny space in between when I point at construction grids at infinity.  My 90mm APO doesn't have that.  It is sort of minute, am I being too picky? 

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My guess is you paid Leica NJ a pretty penny for the calibration.  Why are you being too picky if you insist that the work you paid for be done correctly.   Personally, it would make me angry and probably drive me crazy since the money we pay for Leica's and the prices Leica wants for their service should result in mechanical perfection (oh wait, isn't that the name of one of their cameras?)

I see nothing wrong with wanting things perfect but only you can decide if returning the for correction is worth your time and effort.

Edited by ktmrider2
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How does your 35 actually perform - are you getting out-of-focus pictures, especially at longer distances?

Which 35mm Summilux? Non-ASPH? Original ASPH? Newer v.2 ASPH FLE?

The original (1994) ASPH is known for occasional focus shift with stopping down (due to spherical aberration), so some people get theirs adjusted to be correct at f/1.4, and others for f/2.8, depending on where they most need correct focus. And than means one can be "correct" for the "aligned" aperture (and smaller apertures - DoF), but perhaps not aligning exactly at infinity. While another one is aligned at infinity.

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I think that the OP means something else. Ideally the RF patch lines up perfectly on an "infinite" object when the lens is at its hard stop. Some lenses don't, and I normally ignore it, as it has no impact on the photograph. But when everything has been adjusted recently, it is simply annoying. I would return the lens on guaranty.

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vor 5 Stunden schrieb jaeger:

I see double lines with tiny space in between when I point at construction grids at infinity. 

You may know that already, but for others it is worth noting that what the rangefinder patch indicates at infinity (with the attached lens in its infinity position) has nothing to do with whether your shots are properly in focus or not. If your lens has been properly adjusted optically, then your shots will be in focus at infinity when the lens is set to its infinity position, no matter what the rangefinder patch indicates. The only thing you need to check with your Summilux is whether your shots, when focusing to other distances, are also in focus at that distance. If they are, I would not touch the lens, since the results you obtain are perfectly in order. The more lenses you have, the more likely it is that some of them show what you have described, the more so if a magnifying diopter is used. If it is minute as you say it is, this does not affect focusing accuracy in any noticeable way.

Just to put things into proportion, I have an older LTM Elmar 3.5/50 lens which due its age has developed a tiny little bit of play in the focusing helicoid. If I hold the lens barrel and move it up and down when the lens is attached to an M camera, I can see that the rangefinder patch reacts. Nevertheless, that lens produces perfectly sharp shots, which means that what you see in the rangefinder patch is still well within focusing tolerances.

Cheers, Andy

Edited by wizard

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6 hours ago, adan said:

How does your 35 actually perform - are you getting out-of-focus pictures, especially at longer distances?

Which 35mm Summilux? Non-ASPH? Original ASPH? Newer v.2 ASPH FLE?

The original (1994) ASPH is known for occasional focus shift with stopping down (due to spherical aberration), so some people get theirs adjusted to be correct at f/1.4, and others for f/2.8, depending on where they most need correct focus. And than means one can be "correct" for the "aligned" aperture (and smaller apertures - DoF), but perhaps not aligning exactly at infinity. While another one is aligned at infinity.

the model I have is 11859 titan.  I am traveling actually on my way to airport now and will do more test on my next stop.  I can't see the true IQ until I get back home for another week. 

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Thank you everyone for the input. 

I'd like to upload a high resolution image as soon as I got home.  but I think my account has a limitation of 0.49MB, how can I increase that limit?

Edited by jaeger

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15 minutes ago, jaeger said:

Thank you everyone for the input. 

I'd like to upload a high resolution image as soon as I got home.  but I think my account has a limitation of 0.49MB, how can I increase that limit?

Simple. To double it send some money to the site admin.

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Or - one can adjust the .jpg compression used. No significant effect on screen resolution unless extreme "low" quality.

Or - crop for the significant part of the picture. We don't need to see a whole 35mm frame to tell if it is focused at infinity, just a center crop.

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quick question -- will the infinity problem create back focus on close distant?  I mean are these 2 issues related?  Thanks.

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If you have multiple lenses it becomes highly unlikely that all of them are exactly calibrated for near, infinity and intermediate distances when used with a rangefinder. You are dealing with mechanical adjustments that have a finite tolerance. 1.4X magnifying dioptres will show up all sorts of inconsistencies .... but it's the consequences that are important. 

From a practical point of view wide angles have the greatest leeway ...... if the image is in focus when the lens is wide open and set at infinity (or as near as you can get) then I would ignore it. I have had several where 'infinity' as far as the RF mechanism was concerned was unachievable, but due to the DOF infinity was sharp on the images. 

All the lenses with floating elements are difficult to calibrate for all distances. 

Edited by thighslapper

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On 12/8/2018 at 12:23 AM, thighslapper said:

If you have multiple lenses it becomes highly unlikely that all of them are exactly calibrated for near, infinity and intermediate distances when used with a rangefinder. You are dealing with mechanical adjustments that have a finite tolerance. 1.4X magnifying dioptres will show up all sorts of inconsistencies .... but it's the consequences that are important. 

From a practical point of view wide angles have the greatest leeway ...... if the image is in focus when the lens is wide open and set at infinity (or as near as you can get) then I would ignore it. I have had several where 'infinity' as far as the RF mechanism was concerned was unachievable, but due to the DOF infinity was sharp on the images. 

All the lenses with floating elements are difficult to calibrate for all distances. 

you are right, but it also brought me a bad new.... Leica New Jersey has calibrated all my lenses based on an un-calibrated M240 body.  My system used to have back focus and the I sent them in for service.  The focus patch were both vertical and horizontal misaligned but had never been addressed.  How come they didn't calibrate the body first really baffles me...

After the so called "calibration" I've notice my M system can quit accurately focus at minimal distant but as soon as distant increases the focus started to shift forward now.  Also the focus patch was blurry that I have no confidence to say I nail it but the system still has problem.  The latest development is that I use a 2mm hex key to correct both V and H alignments, and now the focus patch is perfect and most importantly I can use the rangefinder now.  The followings are the new result.

1) 24mm summilux is not sharp at all distant and is bias to back at any distant.  

2) 35mm summilux ASPH, minimal d is ok but focus is forward-bias* as d increases

3) 50mm summilux V3, minimal d is ok but focus is forward-bias as d increases

4) 90mm APO summicron seems to be centered.

*forward-bias is like... seeing the ruler on the calibration board is clear between 0 and -5 inch where -2.5 is the center, which supposed to be between -2.5 to +2.5 and 0 is clearest. 

My question is can Leica lens be adjusted to bias front, back or center.  A more proper way to describe it... can lenses be altered the MTF forward or backward?

Thank you for sharing.

 

 

 

 

 

 

 

 

 

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I have never understood the 'calibrating lenses to a body' business ..... calibrating lenses using a collimator (and other gear to ensure the floating elements work correctly) to a FIXED STANDARD (ie. the flange to sensor distance) as accurately is possible is what should be done.

They should THEN be checked against the body to make sure they work as expected. If they are confident the lenses are ok and there are errors with the RF that are consistent then the RF mechanism should then be adjusted. This is all dependent on the care taken with the lens adjustment ..... and Leica work to a TOLERANCE ..... not 100% accuracy. As these are mechanical adjustments, often just the act of tightening/locking elements will shift the adjustment. You are at the mercy of the technicians diligence and skill. Lenses with floating elements add another complication as there are intermediate focus points to get right as well. Noctilux assembly used to take 2 days and they only used a half a dozen of the best technicians who only worked on this lens. As a result you will find very few miscalibrated 50/0.95's compared to other lenses. You will generally find that independent technicians who specialise in Leica gear will do a much better job than the Leica Service Dept. 

The RF mechanism is extremely crude and precise adjustments on the M240 and older M's is an art rather than a science. Any alteration of the infinity point alters the near point and vice versa. The hex key distance adjustment is easy .... but for perfect alignment you need tiny adjustments which is difficult. The near point adjustment is a real pain and involves loosening a cam and nudging it a bit clockwise or anticlockwise, re-tightening, attaching a lens and seeing what the result is. Re-tightening often moves the cam. Any adjustment puts the far point out so this has to be re-done. This then alters the near point again.... and so it goes on.  The whole process is fiddly, repetitive and frustrating. You either keep see-sawing between near and far adjustments till the adjustments get smaller and smaller till nothing more is needed..... or when you get the hang of it over-adjust deliberately to compensate for the expected changes in the near/far points and shorten the process. Of course you must use a lens that is perfectly calibrated to start with. Leica used to use a single 50/2 on a gantry and check against targets in the factory. Infinity was NOT infinity .... just 20m or so which was far enough for most purposes. I suspect the move to Wetzlar means they now use some other method. On the M240 the near point cam now has Loctite on it to stop the unwary fiddling with it. It loosens with nail varnish remover. I have not looked at an M10, but Leica have apparently managed to automate/semi-automate  the adjustment process somehow and the whole mechanism is meant to be more accurate. 

This nonsense and the issues with lenses is why I use an SL and CL and have sold all my M bodies and most of the lenses. I have had 7 M bodies in total and only one had a perfectly adjusted RF mechanism out of factory. Out of 20 or so lenses nearly all the new ones were out by a bit and some by a lot .... and it was rather telling that the best were second hand lenses ..... most of which I suspect had been back to Solms for adjustment at some time in their life.  :rolleyes:

Edited by thighslapper

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On 12/15/2018 at 1:50 AM, thighslapper said:

This nonsense and the issues with lenses is why I use an SL and CL and have sold all my M bodies and most of the lenses. I have had 7 M bodies in total and only one had a perfectly adjusted RF mechanism out of factory. Out of 20 or so lenses nearly all the new ones were out by a bit and some by a lot .

I hear you.  I am exhausted, frustrated and helpless...

 

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On 12/15/2018 at 12:25 AM, jaeger said:

you are right, but it also brought me a bad new.... Leica New Jersey has calibrated all my lenses based on an un-calibrated M240 body.  My system used to have back focus and the I sent them in for service.  The focus patch were both vertical and horizontal misaligned but had never been addressed.  How come they didn't calibrate the body first really baffles me...

After the so called "calibration" I've notice my M system can quit accurately focus at minimal distant but as soon as distant increases the focus started to shift forward now.  Also the focus patch was blurry that I have no confidence to say I nail it but the system still has problem.  The latest development is that I use a 2mm hex key to correct both V and H alignments, and now the focus patch is perfect and most importantly I can use the rangefinder now.  The followings are the new result.

1) 24mm summilux is not sharp at all distant and is bias to back at any distant.  

2) 35mm summilux ASPH, minimal d is ok but focus is forward-bias* as d increases

3) 50mm summilux V3, minimal d is ok but focus is forward-bias as d increases

4) 90mm APO summicron seems to be centered.

*forward-bias is like... seeing the ruler on the calibration board is clear between 0 and -5 inch where -2.5 is the center, which supposed to be between -2.5 to +2.5 and 0 is clearest. 

My question is can Leica lens be adjusted to bias front, back or center.  A more proper way to describe it... can lenses be altered the MTF forward or backward?

Thank you for sharing.

Since when does Leica NJ violate Leica's service protocol by calibrating lenses on a body? Surely they will have been using the calibrating rig set up for the purpose? All lenses can be fully adjusted. Send to Wetzlar.

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1 hour ago, jaapv said:

Since when does Leica NJ violate Leica's service protocol by calibrating lenses on a body? Surely they will have been using the calibrating rig set up for the purpose? All lenses can be fully adjusted. Send to Wetzlar.

I thought we had discussed this enough times for it to stick.

Lenses and bodies are calibrated to a standard. Separately. 

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Of course; but I am reacting to this:

 

Quote

 

you are right, but it also brought me a bad new.... Leica New Jersey has calibrated all my lenses based on an un-calibrated M240 body

 

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3 hours ago, jaapv said:

Since when does Leica NJ violate Leica's service protocol by calibrating lenses on a body? Surely they will have been using the calibrating rig set up for the purpose? All lenses can be fully adjusted. Send to Wetzlar.

+1 or to good workshops like DAG in the USA. I have used several M bodies as well and most of my M lenses focussed accurately on them. I never expected perfection in this matter though. Any rangefinder has limited accuracy when using high magnifications (pixel peeping on 100% crops typically), especially with 75mm and higher focal lengths at wide aperture. Better use an EVF in zoom mode stop down when nailing focus is requested then. 

Edited by lct

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4 hours ago, lct said:

+1 or to good workshops like DAG in the USA. I have used several M bodies as well and most of my M lenses focussed accurately on them. I never expected perfection in this matter though. Any rangefinder has limited accuracy when using high magnifications (pixel peeping on 100% crops typically), especially with 75mm and higher focal lengths at wide aperture. Better use an EVF in zoom mode stop down when nailing focus is requested then. 

I did contact Doug from DAG before... not feeling safe or secured...  he seems to be too busy too yeah?

 

7 hours ago, jaapv said:

Since when does Leica NJ violate Leica's service protocol by calibrating lenses on a body? Surely they will have been using the calibrating rig set up for the purpose? All lenses can be fully adjusted. Send to Wetzlar.

the shipping + insurance is expensive yeah?  I heard about their long lead time and not guarantee able to fix.  Any advise?  

 

5 hours ago, jdlaing said:

I thought we had discussed this enough times for it to stick.

Lenses and bodies are calibrated to a standard. Separately. 

That make sense... if both are in factory specification and should work well together.

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