In praise of the 35mm Summilux aspheric pre-FLE at f/2.8 - focus shift?

[pgk]

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My copy was secondhand some years ago. I use it at all apertures and find it very usable. If I try hard I can just about detect focus shift at closer distances but I've never found it to be a problem. I post the two following shots simply as 'real world' examples of its viability at middle distance shots at around f/2.8 for anyone interested in seeing its actual, in the field performance. Focus was on the cab door.

 

First, the uncropped image:

 

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And an 'overblown' detail (more than sufficient to illustrate "sharpness"):

 

[rijve044]

Just my experience, love it and is from 1973. Not so flare resistance as the newer lenses. So hood is always on.

Which camera did you use?

Thanks Dre

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[pgk]

Just my experience, love it and is from 1973. Not so flare resistance as the newer lenses. So hood is always on.

Which camera did you use?

Thanks Dre

 

Different lens - the pre-aspheric Summilux is the older version - the one above is the previous model to the current one - an aspheric lens. That said it is confusing as there have been pre-aspheric (original) lenses (in a variety of variants), the original short-lived, rare and collectable aspheric, the pre-FLE aspheric and the current FLE aspheric - some available in different guises too. The joy/frustration of Leica identification . Oh yes, and shot on a rather battered M9  .

[lct]

On Summilux 35/1.4 asph pre-FLE (11874), focus shift is noticeable around f/4 AFAIK. I have no experience with this lens though. Focus shift is more obvious at short distance due to shallower DoF anyway. 

[adli]

You should take some test photos at all apertures from 1.4 to 8.0 to identify at which aperture the lens is calibrated for. If it is calibrated at 1.4 you will have noticeably focus shift at 4.0. If it is calibrated at 2.8, the focus shift will be less noticable, as the shift will swing on both sides of your focus plane.

[pgk]

You should take some test photos at all apertures from 1.4 to 8.0 to identify at which aperture the lens is calibrated for. If it is calibrated at 1.4 you will have noticeably focus shift at 4.0. If it is calibrated at 2.8, the focus shift will be less noticable, as the shift will swing on both sides of your focus plane.

 

In practice I've never really had much of a problem with this lens to be honest. I suspect that it is correct wide open andI don't use the apertures close up where  focus shift is likely to be most obvious. Depends on what you do (as it always does) as to whether its a big deal for you. I rarely test except in the situations I'm likely to use a lens (makes sense to me) and depending on what you use the lens for decides whether or not the focus shift is a problem. Hence my post which may be of use to others doing the same.

[a.noctilux]

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May I suggest that focus shifts of Summilux-M 35mm Asph. Pre-FLE are only on some lenses, not all.

Internet is very helpful to broadcast things , fast and people repeat that things as "rule" .

 

I have two of this 35mm Summilux-M asph. (plus one Pre-asph. also lovely lens with flaw I must admit), and never bother with focus shifts with them in my practical (normal) use.

 

And now with M + LV (or Visoflex/EVF), it's very easy to check that if there is or not focus shifts at particular apertures.

[Ecar]

Same here: no more focus shift than any of my modern lenses - or at least none that I can detect in practical use.

Also, LV/EVF on M240 and M10 do not show a noticeable change in focus point as the aperture changes.

Perhaps I have a particularly good copy. The good news is that I (slightly) prefer its overall rendering to that of the FLE, which I let go.

[adli]

I suspect that the variation in focus shift on the same lens model is rather limited, but some perceive little or no focus shift as it hard to notice in practical use, while others find the lens to have focus shift as the test the lens specifically for this.

[michaelwj]

May I suggest that focus shifts of Summilux-M 35mm Asph. Pre-FLE are only on some lenses, not all.

Internet is very helpful to broadcast things , fast and people repeat that things as "rule" .

 

I have two of this 35mm Summilux-M asph. (plus one Pre-asph. also lovely lens with flaw I must admit), and never bother with focus shifts with them in my practical (normal) use.

 

And now with M + LV (or Visoflex/EVF), it's very easy to check that if there is or not focus shifts at particular apertures.

 

 

Not exactly. Focus shift is inherent to the lens design, so it's not a calibration or manufacture issue.

But, sometimes a lens can be calibrated (shimmed) to focus accurately at wide apertures and suffer from shift where depth of field can mask the change in focus distance. The ZM 1.5/50 C-Sonnar is famous for this calibration, as it can be calibrated to focus accurately at 1.5 or 2.8. With a wider angle, the 35mm focus shift will be masked at more apertures so it will not be noticed as much.

Also, I don't think the internet is wholly to blame. Digital cameras also made it easy to run these tests, and the increased resolution made ever more slight errors more obvious. On the other hand, it takes a dedicated user to run the required tests with a high resolution film - I'd never remember my settings!

[pgk]

Not exactly. Focus shift is inherent to the lens design, so it's not a calibration or manufacture issue.

Indeed. My point in posting was to illustrate that this lens, which has the reputation of having a degree of focus shift which , depending on who is commenting about it, ranges from catastrophic to barely noticeable, is in fact a very competent performer and the shift is not a big deal in many situations. I have its cousin, the pre-aspheric 35mm Summilux. Both are somewhat 'flawed' in terms of their absolute performance, but at the same time both are perfectly useable lenses - and I do use both!

[adli]

The introduction of digital cameras meant that focus shift could be detected much more easily than before. I have a hard time seeing that LV/EVF is a game changer. The best way to detect focus shift is to keep the focus fixed and shoot a series of pictures, where you run through all the relevant apertures. Camera on tripod of course. Looking through the pictures will then show any focus shift. This can of course be done on the camera screen, but is more easily done on a computer screen where the picture will be larger and thus makes it easier to detect any shift.  The trick is to not touch the focus between each picture, only change the aperture.

[pgk]

The introduction of digital cameras meant that focus shift could be detected much more easily than before.

 

If you can't detect it then it really isn't that much of a problem. Depends what you do of course. Cameras are for taking photos when all said and done, although to some it appears that they are actually for obsessing over. There has been much discussion about focus shift with the pre-FLE though I do wonder just how many photographers genuinely find it problematic - undoubtedly a few but for most its probably less of an issue than many would make out.

[happymac]

This marvelous lens has been with me since 1996. I never realized focus shift, even since I've heard about. In practical use it doesn't matter at all.

 

Tom

[adli]

If you can't detect it then it really isn't that much of a problem. Depends what you do of course. Cameras are for taking photos when all said and done, although to some it appears that they are actually for obsessing over. There has been much discussion about focus shift with the pre-FLE though I do wonder just how many photographers genuinely find it problematic - undoubtedly a few but for most its probably less of an issue than many would make out.

 

I completely agree to that. But the question in this thread was not if focus shift is a problem, but if it exists in the specific lens model. Mine has focus shift, but not to the extent that is a real world problem. But the shift is there so denying that the lens has shift because it can’t be seen in your pictures is kind of nonsense. It is like arguing that the earht is flat. It looks like flat from a practical perspective, but it is not.

[pgk]

But the shift is there so denying that the lens has shift because it can’t be seen in your pictures is kind of nonsense.

 

Any shift is subject to two factors. Firstly, my lens is obviously adjusted so that infinity focus wide open is correct. But a lens could be adjusted differently to minimise focus shift closer (by adjusting the position of the rear group I assume. Secondly, whether the type of photography undertaken is going to show focus shift. Its not that focus shift isn't there, its whether its problematic.

[michaelwj]

You need to adjust the 'relative' position of one group to another (such as with a floating group), but I can't remember how it fixes the issue as focus and aperture are independent of each other. I used to know why...

[lct]

Focus shift is a fact indeed but was not the same on pre-asph and pre-FLE versions. The Summilux 35/1.4 pre-asph (at least my v2 from 1989) is calibrated at f/2.8 while the pre-FLE is calibrated at f/1.4 if i understand well. I have no experience with the latter though. Now focus shift of the pre-FLE version was the main if not the sole reason why the FLE was launched if memory serves. We've been discussing about this in 2010 or so on the LUF.

[michaelwj]

Only since 2010! We've got at least another 30 years of discussion...

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Hallo,

Look here: Leica M

[lct]

 Just retrieved this thread from 2010: https://www.l-camera-forum.com/topic/118947-new-summilux-35mm-merged/