I'm not sure, but is this the M Cron 35 APO?

[rpsawin]

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4 hours ago, farnz said:

Yes - that was my perhaps poorly put point - it would be a tautology to call it the "Superfast-Noctilux-M 1:0.95/50 ASPH" just for marketing 'eye candy'.

With respect to calling a lens "APO" if it is apochromatically corrected (and if it needs to be) is quite right.  But adding apochromatic correction if a lens doesn't need it, as in the case of wide angle lenses, because the competition is doing it is quite another thing.

Pete.

Pete,

What focal length(s) benefit from being APO?

 

Thanks in advance,

[Dennis]

1 hour ago, fotomas said:

Always was hoping for a better 35 mm Summicron to come.

FWIS, except for the older versions, some people who has the last ASPH version are not so happy, like the people having the FLE for example.

My point is, nowadays, if one wants a 35/2, does it worth the price of $3.7k for a brand new Leica? Does the high price justify the price?

Because I know that a 50 Lux E46 is perfectly justified. Does it make sense what I'm trying to say? Forgive my bad saturday english 

Edited February 20, 2021 by Dennis

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[sebben]

Longer ones. The thing is though you still get chromatic aberrations just not as many in the plane of focus. So if you have a thin DOF it isn’t of much use depending on subject matter.  I think overall it’s overrated for anything less than 90mm.
 

The other likely benefits of the lens like having high MTF across the the frame are more appealing and useful and if they need to brand it APO to signify this then so be it. 

[padam]

I love the post towards the end saying 'it's not the lens, it's the sensor'

The 28/1.4 Otus does not have these problems, and I guess neither does the 28/2 Summicron SL.
So I guess whether it is strictly accurate or not, there is still some merit to the 'APO-Distagon' or 'APO-Summicron-SL' designations and there is indeed a need for correcting those aberrations, but it comes with the penalty having a lens that is way bigger and heavier. That's what Peter Karbe said to the question whether they can make a better corrected 50mm 0.95 Noctilux-M lens (yes, but...)
 

[Dennis]

Question. APO resolves/helps the chromatic aberrations. Besides that, is there something else that helps to get a slightly better IQ? Because if not, why the considerable size difference between Ultron and APO?
 
If the CV Ultron, for example, does pretty much almost everything that an APO could do, I stay with the tiny Ultron. If construction, overall IQ is better in the APO, if one wants to use a 35/2 as the primary and workhorse lens, maybe the APO worth the price difference.
 

[padam]

5 minutes ago, Dennis said:

Question. APO resolves/helps the chromatic aberrations. Besides that, is there something else that helps to get a slightly better IQ? Because if not, why the considerable size difference between Ultron and APO?
 
If the CV Ultron, for example, does pretty much almost everything that an APO could do, I stay with the tiny Ultron. If construction, overall IQ is better in the APO, if one wants to use a 35/2 as the primary and workhorse lens, maybe the APO worth the price difference.
 

It is a much simpler design, no floating elements that help maintain the performance at all distances.
Does it mean that you can tell a big difference between them?
If you shoot at f/2 all the time at closer distance, or in backlit situations, night scenes where coma may appear etc. then maybe.

Other times, the difference may be insignificant in practise.

They will also draw differently, there may be differences in distortion, colour, bokeh, vignetting, etc.
We are talking about higher-end lenses that haven't actually been released yet to the public, so it's all speculative.

[Pixeleater]

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2 hours ago, farnz said:

I suspect that the "default cast of, "folks we are taking quality as seriously as we can on this one!" " equally applies to all lenses from the perspective that no lens manufacturer would want to give the impression that they'd released a lens with the subtext "we only tried half-heartedly with this one"?  

Are you suggesting that by association "APO" now implies to a significant proportion of buyers ("a default cast") that the lens is also corrected for all of coma, spherical aberration, pincushion distortion, barrel distortion, moustache distortion, astigmatism, curvature of field?  If so, I think they might be disappointed with their presumed 'one size fits all' assumption.

Pete.

PS, I'm not convinced by: "Nobody has yet to release an apochromatic M lens that was not also extremely well-corrected across the board" unless somone has confirmed this on all the APO-marked lenses that have been released because there appear to be new lenses released by lesser known companies that are lacking in the appropriate design and manufacturing resource to support this.

Franz, well said.

As Thorsten Overgaard notes in his website under the definition of APO, “Many manufacturers offer APO designs, but in most of these only the very center of the lens is APO corrected. Leica prides itself on making most of the frame APO corrected.”  

In the Peter Karbe interview about the APO 50 mm (also on his website about halfway down) Karbe said “The concept behind the 50 APO is to realize the best performance in small size.” The interview is familiar to many but worth a visit.

 I think that design principal will apply to the APO 35 mm.

Edited February 20, 2021 by Pixeleater

[farnz]

2 hours ago, rpsawin said:

Pete,

What focal length(s) benefit from being APO?

 

Thanks in advance,

Hi Bob,

50 mm and longer.  The 50/1.4 Summilux asph is actually apochromatically corrected even though it's not labelled an APO lens.  (There are statements from Herr Karbe to support this but no explanation as far as I remember as to why APO was left off the name.)

If you look at the Leica lenses that have been around for a while that are apochromatically corrected you have:

• 50/2 APO-Summicron-M asph
• 75/2 APO-Summicron-M asph
• 90/2 APO-Summicron-M asph
• 135/3.4 APO-Telyt-M asph

• 90/2 APO-Summicron-R asph
• 100/2.8 APO-Macro-Elmarit-R
• 180/2.8 APO-Elmarit-R
• 180/3.4 APO-Telyt-R
• 280/2.8 APO-Telyt-R
• 280/4 APO-Telyt-R
• 280, 400, 560, 800/2.8 APO-Telyt-Modul-R
• 70-180/2.8 APO-Vario-Elmarit-R

Pete.

Edited February 20, 2021 by farnz

[lct]

Lenses like 50/2 apo and now 35/2 apo (i suppose) are aimed at showing the best performance the best lens maker can offer in a package as compact as possible. If the 35/2 apo behaves the same way as the 50/2 apo it will be a transparent lens with no other character than transparency so to speak. Straight wire with gain as audiophile say. Boring for some, awesome for others .

[adan]

(Hah! farnz posts as I write - but I do include some dates )

Longitudinal Chromatic Aberration tracks with increasing focal length (and aperture). Especially in proportion to format size (a 90mm lens for Barnack format needs APO correction more than a 90mm for a 4x5 camera (equivalent field of view about "30mm").

Since it is a problem of getting multiple colors to focus in the same plane, it also tracks with depth of field and magnification. Which is why it is less and less important with shorter and shorter focal lengths - their inherent DoF is larger at a given aperture and hides any LongCA.

One can note, from Leica's own 35mm-format lenses, the progression of when and where Leica decided LongCA was significant enough to bother addressing.

APO-Telyt-R 180mm f/3.4 - 1974 (special order for US Navy).
APO-Telyt-R 280mm f/2.8 - 1984
APO-Macro-Elmarit-R 100mm f/2.8 - 1987
APO-Telyt-R 400mm f/2.8 - 1992
APO-Telyt-R 280mm f/4.0 - 1993
APO-Summicron-R 180mm f/2.0 -1994
APO-Telyt-R modular system (280-800mm) - 1996
APO-Telyt-M 135mm - 1998
APO-Summicron-M 90mm - 1998 (R version 2002)
APO-Summicron-M 75mm - 2005
Summilux-M ASPH 50mm - 2006 (supposedly a "crypto-APO" lens not labelled (i.e "marketed") as such)
APO-Summicron-M 50mm - 2013

Historical note - better correction of LongCA only became really important around 1960, when 1) the small "35mm" format became an important professional format, 2) color film began to surpass B&W film as a preferred medium, and 3) demand increased for ever-longer/faster/better long lenses (200-1000mm).

The first method of addressing LongCA was the catadioptric mirror lens, borrowed from astronomical telescopes (reflective mirrors do not disperse the colors of light as do refractive lenses). Mirror-Nikkor 50cm f/5.0 - 1961, f/8.0 - 1968.

But by the mid-1970s the obvious defects of mirrors' aperture limits and "doughnut bokeh" (which just go to show that avoiding LongCA is in no way a guarantee that a lens is extra-good in other respects) pressed manufacturers to create (or acquire) lower-dispersion glass. Anomolous-dispersion, extra-low dispersion (Nikon ED), ultra-low-dispersion (Canon UD), fluorite crystals (Canon), etc. etc.

[Jeff S]

Then there are the SL 35 and SL28 APO-Summicrons.

Jeff

Edited February 20, 2021 by Jeff S

[Rick in CO]

Are compact wide angle lenses more subject to chromatic aberrations due to the extreme angle of transmitted light, especially in the corners?

From the previous list there is not a single wide angle APO lens, but now we have the 28 and 35 Summicron-L lenses which are massive in size compared to M lenses.

Would not a 35mm APO Summicron-M be significantly larger as well?  I have seen it discussed that the 35mm ZM Distagon is near-APO, but it is a retro-focus design, also larger in size.

The 50 Summilux-M ASPH is described as being near-APO (by Herr Karbe), as is the 90 Macro-Elmar-M (by Erwin Puts).  The suggestion is that Leica will not label a lens "APO" unless it meets all criteria of the definition.

Reminds me of discussions about the large format Kodak Wide Field Ektars which were essentially APO, but not labelled as such.

[padam]

An important design criteria for a Leica M lens is to use as few glass elements as possible. It will not have 11 elements like the 35/2 APO-Lanthar VM.

So no, it will not be a large or heavy lens at all, but with the built-in hood, floating elements, etc. the size difference between the 35/2 Summicron-M ASPH and 35/2 APO-Summicron-M ASPH will likely be more noticeable than with the 50mm lenses.

[astrostl]

4 hours ago, farnz said:

I suspect that the "default cast of, "folks we are taking quality as seriously as we can on this one!" " equally applies to all lenses from the perspective that no lens manufacturer would want to give the impression that they'd released a lens with the subtext "we only tried half-heartedly with this one"?  

Fair. Something like, "went all-out" would be a better turn of phrase than, "taking quality as seriously as we can." Leica has the 50/2 Summicron in both regular and APO versions, with more than $6000 in price between them. One is presented as "A classic lens in its best form, powerful performance in a handy package" and the other " The sharpest of all standard lenses, sharpness from corner to corner". Surely Leica wouldn't say they half-assed the normal Summicron, but also do say the APO is much stronger.

Quote

Are you suggesting that by association "APO" now implies to a significant proportion of buyers ("a default cast") that the lens is also corrected for all of coma, spherical aberration, pincushion distortion, barrel distortion, moustache distortion, astigmatism, curvature of field?  If so, I think they might be disappointed with their presumed 'one size fits all' assumption.

PS, I'm not convinced by: "Nobody has yet to release an apochromatic M lens that was not also extremely well-corrected across the board" unless somone has confirmed this on all the APO-marked lenses that have been released because there appear to be new lenses released by lesser known companies that are lacking in the appropriate design and manufacturing resource to support this.

I would posit that most folks are taking APO to mean well-corrected across the board because they've been conditioned to associate the two things by manufacturers such as Leica and Voigtlander. And as far as I know, the only APO-designated non-Leica lens ever released is the Voigtlander APO-LANTHAR 50/2, soon to be joined by the 35/2.

Edited February 20, 2021 by astrostl

[UliWer]

Unfortunately I deleted the results when I tried to compare a Leitz 1:4/135mm Elmar to a Carl Zeiss 1:4/135 Sonnar.

The Elmar - with a lens design almost 30 years "younger" than the Sonnar - showed a little bit more resolution than the Sonnar. But it also clearly showed the results of longitudinal chromatic aberrations: purple and green shadows at the border of bright structures. The Sonnar showed none. So would you call the Sonnar an "apochromatically corrected" lens entitled to be called "Apo-Sonnar"?

I don't think so. The Elmar with a simpler lens design optimized for resolution obviously lacks apochromatical correction, the Sonnar with a more sophisticated design (later copied by the Leitz Tele-Elmar) didn't need it as it didn't resolve as much than the later Elmar.

One may try the 90mm Apo-Summicron against the Summarex: if you try hard you'll produce results with the Apo-Summicron which show some chromatic aberration, you won't succeed to see them with the Summarex. So one could argue that the Summarex deserves the prefix "Apo-" more than the Apo-Summicron, but this would be nonsense. The Summarex (45 years older) is just a "bad" lens, you cannot compare its ability to resolve fine details with the Apo-Summicron.

You need apochromatical correction if your lenses resolution is so high that the optical design reaches its limits. If a lens design goes farther in one direction (e.g. resolution) the more problems you'll get in other respects: distortion, chromatic aberration etc.

It is true that chromatic aberration is not such a big danger for short focal lenses. Though modern lens design pushes resolution extremely far: 80% resolution for 40 lines per millimeter over the whole frame was far beyond any 35mm lens could resolve. Now it's supposed to be the "standard".  Of course I havn't seen any 1:2/35mm  with extremely high resolution which was not especially corrected against chromatic aberration. Though i am almost sure you would notice longitudinal chromatic aberrations if the lens designer didn't take pains to cope with them. 

 

 

 

Edited February 20, 2021 by UliWer

[duoenboge]

It´s high time for the APO-Summicron-M 35. The APO Lanthar is finished by now as well.

[AZN]

11 hours ago, Stuart Richardson said:

the new high resolution bodies deserve a 35mm lens like the 50mm APO. A fairly compact kit of 35mm APO and another super sharp lens like the 75mm APO Summicron

Agree.  Am thinking more along the lines of sensibly-sized high-quality lenses for the SL (601, 2, 2-S), for those of us who have Sony's for proper AF 😃

 

[dkmoore]

10 hours ago, astrostl said:

Totally disagree. I personally backed off of the APO 50/2-M because of the imminent APO 50/2 VM which I now own.

The 50 APO has been out for years. You were not an APO 50 customer. I rest my case. 

[astrostl]

10 minutes ago, dkmoore said:

The 50 APO has been out for years. You were not an APO 50 customer. I rest my case. 

I am me, and know my intents. You are you, and don't. This is an asinine take. I can assure you that I'm not lying, and have no incentive to lie.

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Hallo,

Look here: Leica M

[Alistairm]

Do the M lenses rely as heavily on software “correction” as the SL lenses?