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Leica 28mm Summicron ASPH 2016 #11672-- Owners Thread


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I have just tested: M240 on fixed position, magnification, focus on a thin near subject with aperture 2. This subject stays perfectly in focus when I close aperture step by step. I have tried at nearest possible distance and at a distance of 2m. And I have controlled the results on my computer, not only on the camera display.

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I do not see any posted results about focus shift in post #27 and I do not see yours posted here.  That's all.  I'd like to get to the bottom of it and be objective.  Some lenses have been reported to exhibit focus, glad yours is fine.

 

The reason for my statement is from post #9 which was not a rumor.  Lloyd Chambers has posted results (photos).  None here, just hearsay.  

 

This is from post #9:

 

"I tested the new Leica M 28mm f/2 Summicron in a Leica Store using their Lens Align.  The two copies I tested showed the 28mm Summicron had focus shift.  I also reported my findings to Stefan Daniels at Leica.   Lloyd Chambers (website) also tested both new 28mm M lenses and found the M 28mm f/2 Summicron had severe focus shift.  Which you could clearly see from his test shot comparisons."

 

Rick

Thanks for being more specific. It's always good to shoot before one buys. I do that with every lens no matter who or how the Internet yells about it, positive or negative. 

I have been  clear enough here about my copy, with examples, this is about what I am prepared to give qua time spent in it

Edited by otto.f
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Don, thanks for that.

 

Otto, thanks for your comments, as well.

 

I don't put much belief in Lloyd, he seems to be a sharp guy but, I haven't always agreed with his assessments in the past.  

 

I am interested in what changes were made with the 28 Summicron as I own the old one and it is my favorite and most used lens.  I am not defending what I own.  My real interest is that the sensor on the new M may make my old 28 Summicron look something like the images I got when I used it on my Sony A7r.  My suspicion is that Leica has changed the exit pupil location?

 

Rick

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Thanks Rick, this is much clearer. What I heard from my dealer is that production rules and tolerances are tighter for the new one, I am almost certain that if something optically signicant had changed he would have known and have told me. 

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[...] What I heard from my dealer is that production rules and tolerances are tighter for the new one, I am almost certain that if something optically signicant had changed he would have known and have told me. 

 

Wetzlar told my dealer that little changes have been made in the position of lens elements so that detail and contrast rendition are better, especially in the corners, for M, SL and Sony (sic) cameras.

Edited by lct
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Optical formulas are the same guys, check your sources... Only coatings a different... If the lens was of a really new design Leica would have boasted around with it...

 

They are simply the same, they just have updated housings and possibly coatings.

Edited by jip
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Optical formulas are the same guys, check your sources... Only coatings a different... If the lens was of a really new design Leica would have boasted around with it...

 

And your source is ?

 

The 28/2.8 asph has been proven to be sharper at the corners, therefore the optical formula is different.

 

Leica has not boasted around with it, because otherwise people would stop buying other lenses until they are also revised to work properly with the SL.

Edited by CheshireCat
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[...] check your sources. [...]

 

May i ask who are yours? Mine is my Leica dealer, a very serious guy whose father and grandfather were Leica dealers as well. As i wrote above, Wetzlar told him that « for 28/2 and 28/2.8 lenses, little changes have been made to the optical formula (changes in the position of lens elements) so that contrast and resolution are enhanced when these lenses are used on digital bodies. When comparing the new lenses to the previous one on M, SL or Sony bodies, detail and contrast rendition are better, especially in the corners ».

Edited by lct
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Wetzlar told my dealer that little changes have been made in the position of lens elements so that detail and contrast rendition are better, especially in the corners, for M, SL and Sony (sic) cameras.

 

Sounds like a general update similar to the Summarit series

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... little changes have been made in the position of lens elements so that detail and contrast rendition are better, especially in the corners...

 

That is what I had read; can't recall the source, though.  Assuming this information is accurate, we have lenses that have been improved upon, not just given a cosmetic makeover. 

 

 

The fact that each lens has a new Leica product number indicates that more than a facelift has happened.

Edited by Carlos Danger
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I don't know about the new cron, but focus shift is not obvious real world with the old one, and landscapes are not a problem. At f/8 you have hoge DOF :)

 

The old ones are down to just over 2K now :) Mine focuses well WO also:

 

25821865476_f6a61a84f4_b.jpg

Headgear by unoh7, on Flickr

 

And you can zone focus really well:

25752785291_5898e17dc1_b.jpg

Cloud Layer by unoh7, on Flickr

 

Photographers have been dealing with focus shift using rangefinders for 60 years with various lenses, most famous being the 50 sonnars. If it really starts to effect your results, you learn the lens and compensate. At 28 this would be very easy.

 

 

 

The problem with this theory is that focus shift doesn't turn up on film as much as it does on digital.  Film is a three dimensional sensor:  There are layers and depth to the emulsion.  Digital chips are truly a flat plane that the light gets focused on.  There is no wiggle room for focus like there is for film. 

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Are you talking about focus shift here, or about back- or frontfocus? Because focusshift can only be judged on several captures from tripod with different apertures, to see if the focus point is shifting. 

 

Apart from that I don't know what people are splitting hairs over in this topic; we're talking about quite a wide angle here. In practice, focusshift on a 28 is of extremely relative importance. On a 75 or 90 it becomes a real problem

Edited by otto.f
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Apart from that I don't know what people are splitting hairs over in this topic; we're talking about quite a wide angle here. In practice, focusshift on a 28 is of extremely relative importance. On a 75 or 90 it becomes a real problem

 

 

Depens on sensor resolution.

 

Proper check for focus shift is taking different photos of a portrait-distance subject at different apertures without refocusing.

It is as simple as that. Anything else is inconclusive.

Edited by CheshireCat
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I have already done a proper check. Read post 61. But you could see focus shift in a normal single shot if you focus by rangefinder, not by EVF, and take pictures stopped down. You will then get backfocus because focus shifts as soon as you stop down. If maximum aperture is 2.0, you will see focus shift when you use 2.8 or 4, if you stop down to 5.6, depth of field will get big enough to hide focus shift. In the photograph above I focussed on the head of the chameleon and used aperture 2.8. If the lens suffered from focus shift, the head of the chameleon would not be focussed properly. I do not get focus shift with this lens, not in test images and not in real life images. And I have no idea why this is discussed here. 

 

I have owned the former Summicron 28 asph. and liked it very much. This new version keeps all the good stuff we already know and adds some sharpness and contrast to the corners. Would I change to the new one if I had the former version? No. I bought the new one because I had sold the former to buy the Summilux. The Summilux was to heavy and bulky for my taste and I wanted a Summicron 28mm back. So I went for the new one. It does not make me miss the Summilux.

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Well I decided to test the hypothesis that there is significant focus shift for the pre-2016 Summicron 28 ASPH. Having used this lens for several years on my M8 and now M240 & 246, without having any real world focus shift problems, I was ready to call bull s***. on it. I did confirm that at close focus there is a tiny amount of focus shift. At f/2.8 it's perhaps 4-5 mm at close focus (0.7 m). At no point is the original focus point out of focus, but the central focus point moves backwards a centimeter or two going from f/2 to f/16. Measurebators, like Lloyd Chambers, make a big deal about this, but at anything other than closest focus it's hard to believe it makes much of a difference. Indeed, field curvature and focus-recompose errors are probably more likely to cause real-world problems. Below is a link to a composite image showing the images. Sorry, it was quick, forgot  to take out about a stop of minus exposure compensation, so they're a bit dark. Tripod mounted, self-timer, fixed ISO. Apertures from f/2 to f/16 in one stop increments.

 

https://flic.kr/p/FE9mVY

Edited by JeffWright
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[...] I did confirm that at close focus there is a tiny amount of focus shift. At f/2.8 it's perhaps 4-5 mm at close focus (0.7 m). At no point is the original focus point out of focus, but the central focus point moves backwards a centimeter or two going from f/2 to f/16 [...]

 

Not sure what you mean by original and central focus point but if your focus point did stay in focus what you've measured is not focus shift but field curvature i suspect. 

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Not sure what you mean by original and central focus point but if your focus point did stay in focus what you've measured is not focus shift but field curvature i suspect. 

 

 

I'm sorry, I should have been more precise in my language,  By original focus point I meant the original plane of (sharpest) focus at f/2 (recognizing that the 'plane' is an idealized one that is actually curved due to field curvature). By central focus point, I mean the plane of sharpest focus in subseqeunt images, which shifts subtly farther away with decreasing aperture size. However, the depth of field at each subseqeuent smaller aperture, including f/2.8 (just barely) encompasses the original focus target as "in focus". Obviously this becomes more challenging to delineate as aperture size decreases, but is fairly obvious at f/2, 2.8, and 4.  Although not apparent from my magnified crops, the distance scale shown is very close to optically centered, as well as the lens and focus remaining in fixed position between exposures, so the tiny differences seen certainly do not represent field curvature.

 

P.S. Trained research scientist with physics experience....

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No techie here i'm afraid but may i ask if you can view those differences to the naked eyes?

I can't personally. M240, 28/2 # 39465**, f/2, f/2.8, f/4, f/5.6, 100% crops. Focus nailed at f/2 with the EVF. Sorry for the boring snaps.

 

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