Leica 50mm Summicron APO vs 50mm Summilux (unmarked, but also APO) - is there a drastic difference at f/2?

[BerndReini]

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 I own both. It took me a long time to be able to justify buying the 50Apo, but I absolutely love this lens. It is flawless. The 50lux aspherical has a lot of focus curvature. This means that what is in focus in the middle of the picture is on a different plane from what is in focus at the edges. The main difference however is that the fall-off from what is in focus to what is out of focus is absolutely immediate with the 50Apo, which imho gives a very three-dimensional appearance to the images it produces.

 This is the 50lux with the MM1.

 

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[BerndReini]

50Apo with MM1.

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[Jared]

What strikes me is that it can be marked APO or not, you would never know, nor see, the difference.

 

 

The definition of APO is a little unclear.  It was first proposed by Ernst Abbe (of Zeiss) in, I believe, the late 1800's and said that an apochromatic lens was one that corrected par focally (longitudinal chromatic aberration) at three widely varying wavelengths of light and corrected for spherical aberration and coma at two widely separated wavelengths of light.    That's all it says.  Nothing about overall correction, nothing about flatness of field, not even anything about lateral chromatic aberration, astigmatism, or spherochromatism.  It doesn't even specify how widely spaced the crossings must be.  

 

As a result, different companies have adopted different rules for when to designate a lens as an apochromat (if ever).  You have to take them all with a grain of salt since the Abbe definition is not comprehensive.  Frankly, I suspect Leica chose to designate the 50mm Summicron APO primarily to distinguish it from other models of 50mm Summicron, not because it crossed some particular threshold of color correction that made it an apochromat.  There are likely quite a few lenses in the Leica lineup that a manufacturer could call apochromatic if they chose to without getting in much trouble.  As long as longitudinal chromatic aberration has been successfully addressed through the use of SD/ED glass and the appropriate mating elements, I doubt anyone would be able to tell Leica, "No, that's not an apochromat since your color crossings weren't separated widely enough!"  Plenty of manufacturers avoid the problem entirely by not using the term--just specifying that a given lens uses special dispersion elements and leaving it at that.  Nikon and Canon are examples of companies that don't use the APO label, but they certainly have lenses that are as well corrected as, for example, the Voigtlander 90mm APO.  

 

I don't find it at all surprising that some lenses that aren't marked as APO have very good color correction.  Heck, certain lens focal lengths and focal ratios are much less prone to color error than others making this result almost inevitable.    Again, I think the APO label for the Summicron 50mm APO was more about correctly identifying the lens in a sea of Summicrons than anything else.

 

- Jared

[Peter Kilmister]

Good input, Jared, however I learnt about APO when looking at spotting scopes. I tried loads until I happened across the Leica APO Televid. As soon as I looked through the scope it was obvious that it had no vignetting, no purple fringing, no aberrations. Other makes are good but Leica's APO knocked them into a cocked hat (Sorry, that's a very English expression), in other words the APO Televid was way ahead of the field.

 

I have used the APO Televid via a T mount adapter and a tube on my M-P240 to photograph the moon with a shot that was as good as it gets.

 

The 50mm APO Summicron is also a beautiful lens. The Summilux is bigger, heavier, better in poor light, cheaper and a good lens. The APO Summicron knocks it into a cocked hat ... now you have learn that expression.

[NB23]

The 90 apo shows a lot of purple fringing wide open. The apo designation is a marketing tool snd yes, I agree, it probably simply serves for differenciating a new version lens from its older predecessors.

 

The APO designation really gains its importance with enlarging lenses.

[gotium]

The lux is a great lens and I generally prefer a lux to a cron if weight is not an issue. But I swear I see something special in most pictures I see taken with the APO Cron. A certain sharpness and micro contrast in the subject that seems sharp and detailed without being too clinical, and a nice out-of-focus, or bokeh if you prefer, that provides good subject separation but isn't too painterly or distracting. I don't know how to effectively describe it, but I swear I can see it. Maybe I'm just fooling myself. I don't own the APO. I'm just looking at other people's pictures.

I see the same

[helged]

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Would you say that with the increased ISO capabilities of the M10 or the (not ISO) MM246 the APO is on pair with low light performance compared with the Lux?

 

With the generally fine high-ISO performance of todays bodies, I would not chose the Lux before the APO based on f1.4 vs f2. I would rather look at the optical charateristics between wide open and, say, f5.6. For a (slightly) more artistic rendring, chose the Lux. For close to optical perfection, chose APO.

 

I ended up with the 75 Lux as companion to the 50 APO. The 75 Lux is a very interesting lens; dreamy and with a particular colour palette wide open; bitingly sharp and modern stopped down.

 

Many possibilities...

[tom0511]

The lux is a great lens and I generally prefer a lux to a cron if weight is not an issue. But I swear I see something special in most pictures I see taken with the APO Cron. A certain sharpness and micro contrast in the subject that seems sharp and detailed without being too clinical, and a nice out-of-focus, or bokeh if you prefer, that provides good subject separation but isn't too painterly or distracting. I don't know how to effectively describe it, but I swear I can see it. Maybe I'm just fooling myself. I don't own the APO. I'm just looking at other people's pictures.

 

Thats exactly my experience, and why I prefer the 50APO over the 50 cron over the 50/1.4asph. I would add I prefer the color I get with the 50APO.

The 50/1.4 was long time my favorite lens, but it has been sold after I use the cron and the APO so much.

[Alberti]

Both lenses depict the ATMOSphere very well! 

[B-A-C]

I shoot a lot of film and the Lux gives

me so much more capability in low light. I actually sold my Cron and kept APO Lux 1.4 asph. I much prefer the bokeh of this lense.

[BerndReini]

I shoot a lot of film and the Lux gives

me so much more capability in low light. I actually sold my Cron and kept APO Lux 1.4 asph. I much prefer the bokeh of this lense.

 

Are you talking about the regular cron or the 50Apo?

[B-A-C]

Are you talking about the regular cron or the 50Apo?

The 50apo

[Jared]

Good input, Jared, however I learnt about APO when looking at spotting scopes. I tried loads until I happened across the Leica APO Televid. As soon as I looked through the scope it was obvious that it had no vignetting, no purple fringing, no aberrations. Other makes are good but Leica's APO knocked them into a cocked hat (Sorry, that's a very English expression), in other words the APO Televid was way ahead of the field.

 

I have used the APO Televid via a T mount adapter and a tube on my M-P240 to photograph the moon with a shot that was as good as it gets.

 

The 50mm APO Summicron is also a beautiful lens. The Summilux is bigger, heavier, better in poor light, cheaper and a good lens. The APO Summicron knocks it into a cocked hat ... now you have learn that expression.

 

 

Yeah, I'm actually an astrophotographer more than I am a terrestrial photographer, and there is no question that there is a very wiiiiiiiiddee range of correction on telescopes that are marketed as APO, whether spotting scopes or astronomical telescopes.  The level of correction is much wider than in camera lenses.  In addition, the eyepiece is actually where most of the lateral chromatic aberration is introduced rather than the objective, so even if you have a nearly apochromatic telescope, differences in eyepieces can make a big difference in overall performance.  Frankly, though, quite a few telescope manufacturers and importers are choosing to list a scope as APO as long as it has at least one element of ED glass.  Most spotting scopes, in particular, are relatively fast telescopes, and a single ED element of Ohara FPL-51 or Hoya FCD1 and an appropriate mate are not enough by themselves to control chromatic aberration on a fast telescope.  Purple fringing, even on-axis, is the result.  

 

There is no question the Leica Televid line is among the best spotting scopes out there for optical quality.  However, a lot of the improved performance of the Televids vs. other premium brands I would attribute to Leica's zoom eyepieces which are head and shoulders above most of their competitors.  In order to compete on cost, a lot of makers of spotting scopes, even very good spotting scopes, make a good objective that could reasonably be advertised as apochromatic, then couple them to mediocre quality eyepieces.  Kind of dumb, but it does help control the cost, and a lot of people are not very sensitive to purple fringing and so may not perceive a difference.  The Leica zoom eyepieces are really nice.  Much bigger difference there than in the objectives themselves.  There are actually several brands making spotting scopes that are similar in performance to the Leica models, and a few astronomical telescopes of similar size that are better still (though unarmored, heavy, awkward to focus, fog-prone, etc. as you'd expect from an astronomical scope that only needs to work on clear nights at infinity focus).

 

I agree that the 50mm Summicron-M APO is a fantastic lens, and there is no question in my mind that at f/2 it has significantly better contrast and resolution than did my Summilux -M at the same aperture.  By f/2.8 the differences, in my experience, were slight, and at f/4 I could never tell them apart.  At f/1.4 the edge would have to go to the Summilux.  Personally, I'm glad I bought the Summicron-M APO and it is one of my favorite lenses, but the Summilux is no slouch in its own right, and for 95% of my photographs neither would offer any meaningful advantage over the other.  Certainly, the fact that the 50mm Summicron has an APO label I see as not very important.  

 

- Jared

[laowai_]

Achromat, Apochromat, Superachromat, I think the definition of these terms are very well defined. The degree of correction is another question. I could imagine that some manufactures might not label their apochromats as such. At the end of the day and from the end-user perspective, does it really matter how a manufacturer achieves good imaging quality of a lens. But do manufacturers label lenses as apochromats that don't have apochromatic correction? 

 

A good resource to answer all sort of optical questions from a scientific/engineering perspective  and that are easily accessible for us with no training in classical optics is in my opinion at Edmund Optics and of course the reference at the bottom of the app notes

(disclaimer: I am sure there are plenty of other similar places on the web, I have no affiliation with this manufacture/distributor of optical components, etc.)

 

App note on chromatic aberration:

https://www.edmundoptics.com/resources/application-notes/optics/chromatic-and-monochromatic-optical-aberrations/

 

General information on all kinds of optical aberrations (not only chromatic):

https://www.edmundoptics.com/resources/application-notes/optics/comparison-of-optical-aberrations/

 

Optical design and tolerancing (and associated cost considerations):

https://www.edmundoptics.com/resources/application-notes/lab-and-production/keys-to-cost-effective-optical-design-and-tolerancing/

 

Want do design a simple optical system by hand: here's an example of paraxial ray tracing:

https://www.edmundoptics.com/resources/application-notes/optics/geometrical-optics-101-paraxial-ray-tracing-calculations/

 

Enjoy!

[uhoh7]

Are you ever going to shoot low light or want some extra subject isolation? What is your body?

 

The 50 Lux is so gorgeous on M9. Less romantic on the 240, and I'm not sure about the M10 yet. Close up, even the v4 50 cron beats it at F/2, and as we see above the APO is great close up. But F/2 is half the light of F/1.4, and the bokeh is certainly not as good with the APO. 

 

As noted by F/4 hard to tell which is which. Price difference is 2-3 grand. 

 

I would certainly rather have the 50 Lux and 3 grand for another lens like FLE or whatever. But there is a reason why the APO costs so much.

Edited March 13, 2017 by uhoh7

[james.liam]

 

The 50 Lux is so gorgeous on M9.....Close up, even the v4 50 cron beats it at F/2, and as we see above the APO is great close up. But F/2 is half the light of F/1.4, and the bokeh is certainly not as good with the APO. 

 

As noted by F/4 hard to tell which is which. Price difference is 2-3 grand. 

 

But this is the point; if you absolutely cannot live without f/1.4, you have your answer. f/2 and its DOF is more interesting to me than the extra stop, though I miss the Summilux' bokeh. But this latter aspect of the APO is neither better or worse, just different and in its own unobtrusive way, isolates the subject even more so (again, to my taste).

 

 

I agree that the 50mm Summicron-M APO is a fantastic lens, and there is no question in my mind that at f/2 it has significantly better contrast and resolution than did my Summilux -M at the same aperture.  By f/2.8 the differences, in my experience, were slight, and at f/4 I could never tell them apart.  At f/1.4 the edge would have to go to the Summilux.  Personally, I'm glad I bought the Summicron-M APO and it is one of my favorite lenses, but the Summilux is no slouch in its own right, and for 95% of my photographs neither would offer any meaningful advantage over the other.  Certainly, the fact that the 50mm Summicron has an APO label I see as not very important.  

 

- Jared

 

If it were purely a matter of resolution, the real difference is WO, where it performs at the level of other great lenses at f4 or 5.6 and that alone would not merit the disparate cost. But there's a lot more to it than that. The fidelity of its color reproduction is dependent upon its APO capabilities.

 

I will also add that using it on a Monochrom against the 50 Summilux ASPH is where you really see a greater resolution & micro-contrast difference, even to f/4. This is the "money" sensor, where you can see what it's truly capable of. By f/5.6, however, I'd be hard-pressed to tell them apart.

 

Is it worth 3 grand?

Consider that second-hand, they can be had for far less now and well worth the try if you can afford it; sell it if it doesn't suit you and you're not likely to lose much in the transaction.. 

Edited March 14, 2017 by james.liam

[BerndReini]

The 50apo

 

I find the bokeh of the 50 Apo exceptional. The lux has more shallow depth of field, but the rendering of the out-of-focus areas, highlights in particular, is better with the Apo.

[NB23]

I find the bokeh of the 50 Apo exceptional. The lux has more shallow depth of field, but the rendering of the out-of-focus areas, highlights in particular, is better with the Apo.

 

Okay, boys and girls! We now have contradicting reports!

 

The 50 Lux asph was the clear Quality BOKEH winner. Now things have switched: the APO CRON is gaining ground.

 

Who will win in the end? Stay tuned...

[lct]

[...] The 50 Lux asph was the clear Quality BOKEH winner. [...]

 

Never been to me. This reputation comes perhaps from occasional (or professional?) reviewers comparing apples to oranges i.e. bokeh at f/1.4 for the 50/1.4 asph vs bokeh at f/2 or above for other lenses. Not to say that the 50/1.4 asph's OoF rendition is harsh but as much as i like it at f/1.4 i find it a bit too contrasty around f/2.8 to my taste. Subjective matter anyway. 

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[RayD28]

 I own both. It took me a long time to be able to justify buying the 50Apo, but I absolutely love this lens. It is flawless. The 50lux aspherical has a lot of focus curvature. This means that what is in focus in the middle of the picture is on a different plane from what is in focus at the edges. The main difference however is that the fall-off from what is in focus to what is out of focus is absolutely immediate with the 50Apo, which imho gives a very three-dimensional appearance to the images it produces.

 This is the 50lux with the MM1.

 

 

I test shot a 50 Lux several months ago so I'm not familiar with it's performance in detail.  But could the curvature you mention also apply to the 50 Cron?  I ask because I like to focus and then recompose and the subject ends up out of focus, or at least in soft focus.  This happens at medium distances, like 20 feet, and with aperture in the mid-range.