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Summilux 50/1.4 focus problem


63strat

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I've had my M8.2 and Summilux 50/1.4 Asph for almost a year, and now I've finally confirmed that the focus with the Summilux 50 is off. If I'm say 2 meters from the subject (with the lens wide open) and take the shot, the photo will be slightly out of focus. Then, if I take the shot again but this time turn the focus ring about 1/32 of an inch counterclockwise (looking at the camera from in front of it), so that it looks a little out of focus in the viewfinder, the resultant shot will be perfectly in focus. I'm not sure if this is the definition of back focus or front focus. I'm turning the focus ring from say 2 meters to a hair under the 2 meter mark.

 

So, I guess this lens needs to go back for adjustment. Where is the best place for to send it? Solms or New Jersey? I don't have the problem with my other lens, a 28/2.8. Any other advice is greatly appreciated.

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Did you check for your range finder being properly alligned?

I had the same problem with a 90mm while other lenses seemed to work correctly.

In the end the problem was in the camera and I had to send it to Solms for a vertical re-allignement.

Just a hint.

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Maybe make sure first, that as it is most likely, the problem is in the lens?

Buying an M8.2 almost a year ago, you probably got it new. But still do not fix it if it works :), unless you want a dedicated body for your 50 Summi Asph. If you got it from a store nearby, or if you have a tele lens that focusses fine, testing that combination would exclude body focussing problems WITHOUT BODY ADJUSTMENTS.

 

The test is of cause only complete after finding the same problem with this lens on a different M body.

A viewfinder magnifier, preferably the 1.4, which I keep on at all times, with a diopter lens screwed on and additionally secured with black tape all around, gives more certain results.

I have no idea about New Jersey since I live an hour drive from Solms, but maybe you make accurate and meticulously recorded focussing notes down to 0.7m and all the way to infinity all at 1.4 with your 50mm Lux Asph, because it is a lens second to none, including the Zeiss SLR Macro 2.0/50 and Nikon 2.8/60. It is one apple that is better than pears by comparison and so it has to work well.

 

Focussing your 2.8/28 is no challenge and IMO no help for problem solving in the described context. (That is why this is no concern for me regarding the X1, but there are others ;) ).

Edited by Guest
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Did you check for your range finder being properly alligned?

I had the same problem with a 90mm while other lenses seemed to work correctly.

In the end the problem was in the camera and I had to send it to Solms for a vertical re-allignement.

Just a hint.

 

In my understanding the 90mm is the most critical lens in terms of focusing precision. In case a 90mm works fine on a specific body and a shorter focal length has a problem then the body can be excluded as a source of the issue.

 

Is this thought correct?

 

Ralph

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Ralph, I think you are right, I discovered my rangefinder vertical misallignement problem thanks to my Elmarit 90 the day I bought it. Before then, all my other lenses gave acceptable performances, but when using the 90mm I found impossible taking pictures with it. It was front focusing about 10 meters in front of the point I was focusing on. No way out of that.

I thought it was the lens and went to my dealer in Paris. He mounted the 90 on other two brand new cameras and it was spot on. Looking into my rangefinder he told me it was vertically misalligned. Sent the camera to Solms and when back with the RF properly alligned, my focus was much improved when not perfect with all my lenses.

Edited by epand56
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If you know someone who has had their M8 rangefinder calibrated at Solms recently - try the lens on that camera.

 

I had a 50lux asph that was back-focusing about 5cm at close range on my M8. When I tried other 50 lux's they also back-focused. however I couldn't notice any problem with my 28, 24 or 35mm lenses. After sending my camera to be repaired, most 50lux's that I try focus just fine.

 

In the end I sent the body and the lens back, as the body had many other issues to be fixed. When the lens and camera returned, the lens now focuses perfectly (and I still don't have a problem with the 24, 28 or 35 - although the 35 is now very slightly front-focused at 1.4 which is normal to compensate for focus shift).

 

Because of the fact that other 50's also now focus well - I'm convinced the camera was contributing to the problem.

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My experiences with three M8 bodies and countless lenses has been that you have to "optimize" the rangefinder alignment. You can do this yourself with an allen wrench, just be very subtle, a small turn with the wrench is a fairly big adjustment. Use a test chart or just a tape measure on a table extending away from you. Focus on one of the numbers several times taking a photo each time. If the plane of focus is slightly behind the number you focused on, your lens backfocuses (in relation to the rangefinder. Make a slight adjustment. Repeat this with several of your lenses until you find the sweet spot.

 

I realized that my 50 1.4 backfocused ever so slightly, while my 35 1.4 front focused ever so slightly. I adjusted the rangefinder right in the middle of these two lenses and for any real life situations both focus nicely now, and all the other lenses fell right into place.

 

Now, focus shift is another story. It is widely acknowledged that the 50 1.4 exhibits some focus shift, i.e. when the focus is dead on at 1.4, the lens backfocuses slightly at f2 and f2.8. There is not much that can be done about this except manually adjust for it in focusing.

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You can do this yourself with an allen wrench, just be very subtle, a small turn with the wrench is a fairly big adjustment. Use a test chart or just a tape measure on a table extending away from you. Focus on one of the numbers several times taking a photo each time. If the plane of focus is slightly behind the number you focused on, your lens backfocuses (in relation to the rangefinder. Make a slight adjustment. Repeat this with several of your lenses until you find the sweet spot.

 

Thanks for all the replies so far. I've confirmed that it is back-focusing a little at 1.4, wide open. I'm tempted to try this allen wrench adjustment...

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Thanks for all the replies so far. I've confirmed that it is back-focusing a little at 1.4, wide open. I'm tempted to try this allen wrench adjustment...

 

I would not advise so. If you call Leica they will invite you to send all your lenses and camera to readjust. I would not hustle around with such an important problem, which is probably still under warranty

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Guest EarlBurrellPhoto

I never had any focus issues with that lens on half a dozen film bodies ranging from M42 to M7, noone of which where ever sent back to Leica for calibration. So there was nothing wrong with the lens. It back focused exactly the same on both my M8's. Yet both M8's focus my 90 APO-ASPH and 75/1.4 just fine, so I don't believe my bodies are out of kilter either. Bizarre. I ended up selling it and now just use a 50 Summicron on the rare occasions I actually use a 50 on the M8. That 67mm focal just isn't very useful to me.

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I'm glad you did it. I did it on my own camera and then on my friend's. It is such a simple adjustment that I wouldn't ship my M8 out for. Also, I don't trust anybody else to do this as precisely as I can do it myself. I'm not a wiz when it comes to these things and would never attempt the kind of repairs other people have done, but this really is a piece of cake.

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As the roller adjustment is an adjustment for infinity, it is not very wise to tamper with it yourself. The whole system is adjusted at three interdependent points, and tweaking one point will affect the two others. You may strike lucky with such an adjustment, but it is likely that other parts of the focussing range become incorrect. Best leave this to a qualified technician or Leica.

My new Summilux 50 asph showed exactly the same problem as the one of the OP, and it turned out that a part in the lens was out of tolerance and needed to be replaced.

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I recommend that you do not adjust the focus for yorself. You may introduce other problems. If you adjust that paticular point yourself you are altering the camera for every other lens as well. If the camera and lens are under guarantee, Leica will adjust them for you. However if you alter the factory settings you may be at risk of voiding your warranty.

I suggest that you speak to customer service rather than follow suggestions from people to do it yourself.

Solms has very specialised equipment that will adjust both the body and lens if required. My camera was checked (with an upgrade) and two lenses too. I can tell you that they are perfectly accurate now whenever I do my part ;-)

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Well, I decided to just try the tweak myself. Just a fraction of an inch counter-clockwise, and now the 50lux is focusing perfectly, matching the viewfinder. Time will tell if this has caused any other issues...

 

I did the same adjustment nearly two years ago on my M8 and the focus on all of my lenses have been spot on ever since.

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I did the same adjustment nearly two years ago on my M8 and the focus on all of my lenses have been spot on ever since.

 

 

Did the same adjustment on both my M8's becasue the 50 Lux, 75 Cron and 90 Elmarit didn't focus correctly at close focusing distances.

I worked on it with the 75 until I was satisfied with near focusing and they then focused correctly through out the range with all lenses.

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Some members on this forum and others report success using this method. Some of those later reported that they then later found problems.

I do suggest that you discuss this with Leica customer service first. Most especially if the camera and lens are under guarantee. Aternatively expert repairers such as DAG or Sherry Krauter (if you are in the USA) would certainly be able to advise you and perform any adjustments needed.

 

Remember too that however well meaning people's advice is, they will not be responsible if you create issues with YOUR camera.

You may like to search the forum for earlier discussions on this method.

 

It may well be possible to achieve an apparent improvement doing the adjustment yourself and any introduced errors at infinity for example may be masked by DoF. It MAY also deteriorate the camera's performance with other lenses.

 

There are a number of complications with apparent focus errors, including (but not only)

user eyesight (for example glasses correction)

Limtations of accuracy of rangefinder base length against focal lengths (magnification helps a lot)

test methodology (accuracy of your test method, repeatability, target distance, camera alignment, measurement accuracy etc)

Lens used for test (including any deviation from ideal adjustment that individual example may have) The Summilux 50 ASPH. and the APO Summicron 75 ASPH. are both lenses less susceptible to focus shift than those with other designs for example.

eye position when focusing

DoF (and sharpest point position within DoF and acceptable front/back focus/tolerance)

focus shift (when aperture changed)

Camera rangefinder adjustments (the one mentioned is not the only one)

Sensor positioning (Leica have their new sensor location measurement very probably due to the criticality of sensor vs. film focus)

 

If you have not seen the video on M9 assembly, it is well worth watching as it shows the precision jig that Solms use with targets from .7m out to 8m and much more sophisticated measurement systems. We were not allowed to photograph this in action in June but now you can see for yourself.

Also glimpsed is the sensor positioning arrangement.

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I never checked this before making the adjustment, but throwing the 50lux all the way to infinity on a bright star yields a very very slight double image. I have to back off throwing the lens all the way in that direction by the smallest amount possible. So I guess in practical terms this would be taken care of by depth of field, but fixing my close focus might have had some negatives on the other end. Same results with my Summarit 28/2.8. Although, I do seem to remember having to back off a fraction when taking distant outdoor shots, mountains, etc.

Edited by 63strat
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