Onion Ring Bokeh ball 50mm Lux ASPH?

[adan]

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Please! This is pure Leica victim nonsense.

 

It costs 4800$ because it is pressed?

Then why do entry level dslr zoom lenses with multiple pressed aspheric elements cost only 100$?

Let's face it, pressing an asph element costs 12.38$. Or even 7.29$.

 

The high Leica prices are based on other factors with a huge premium for the name alone.

 

You missed the point.

 

It costs ONLY $4800 because it has pressed ASPHs - it would have cost much more in the era before pressed ASPHs, when grinding aspheric surfaces by hand was time-consuming (high labor cost) and had a high failure rate (time and money Leica spent on glass that ultimately didn't meet specs and had to be thrown away).

 

Indeed, being able to press-mold ASPH elements has reduced the cost of such elements across the industry by a huge amount. But more so if you can spread the setup costs across 500000 $100 zooms per year, vs. 4000 Summiluxes.

 

If you are going to make emotionally-immature remarks like "This is pure Leica victim nonsense"  - at least make sure your reading comprehension skills are at an adult level, boyo.

 

 

Depends what glass it is pressed from for a start and the level of failures (out of tolerance, etc.). Difficult for anyone here to be definitive on costs unless they are 'in the know' about actual costs to Leica. But I suspect that in the overall scheme of things the fact that a lens uses aspheric elements isn't a huge factor in its actual cost.

 

You might check into the history of the 35-70 Vario-Elmarit-R and the original "Aspherical" 35mm Summilux-M - both of which had to be withdrawn from production after the first batch because Leica was losing money on every lens. Due to production costs exceeding what they could rationally sell them for.

 

http://www.overgaard.dk/leica_35-70_Vario-Elmarit-R_28.html

 

http://www.reddotforum.com/content/2012/08/the-leica-35mm-f-1-4-summilux-aspherical-vs-asph-fle/

[NB23]

Compare the image taken wih the 50 Lux with same image taken with a 100$ zoom.

 

You will easily see the difference at any aperture. Not to mention how difficult it will be to find a 100$ zoom with an aperture of 1.4

What are you talking about?

 

To see what an aspherical element brings it would be wise to compare two zooms with and qithout aspherical glass.

 

You have to understand that there's nothing magical in aspherical glass and the age where it was difficult to manufacture are long gone. 5-10$ ia my bet.

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[NB23]

You missed the point.

 

It costs ONLY $4800 because it has pressed ASPHs - it would have cost much more in the era before pressed ASPHs, when grinding aspheric surfaces by hand was time-consuming (high labor cost) and had a high failure rate (time and money Leica spent on glass that ultimately didn't meet specs and had to be thrown away).

 

Indeed, being able to press-mold ASPH elements has reduced the cost of such elements across the industry by a huge amount. But more so if you can spread the setup costs across 500000 $100 zooms per year, vs. 4000 Summiluxes.

 

If you are going to make emotionally-immature remarks like "This is pure Leica victim nonsense" - at least make sure your reading comprehension skills are at an adult level, boyo.

 

 

 

You might check into the history of the 35-70 Vario-Elmarit-R and the original "Aspherical" 35mm Summilux-M - both of which had to be withdrawn from production after the first batch because Leica was losing money on every lens. Due to production costs exceeding what they could rationally sell them for.

 

http://www.overgaard.dk/leica_35-70_Vario-Elmarit-R_28.html

 

http://www.reddotforum.com/content/2012/08/the-leica-35mm-f-1-4-summilux-aspherical-vs-asph-fle/

Emotional? Hardly.

 

They withdrew the production of those lenses because, back then, the technology to create aspherical elements was expensive and difficult, and by hand was the only option. Just as it was very hard to create a Boeing airplane in 1743, thus why the production of exactly Zero units.

 

There would be no point fir Leica to produce these elements by hand today since it's so easy to manufacture by pressing.

 

Yes, they could offer a pointless a la carte lens with hand ground aspherical elements but that would, again, be a marked-up product not because of the dufficulty in making a few of them but because of Leica's marketing. Such a lens element made by hand would cost anywhere from 100 to 200$. The 4800$ markup would be sheer marketing.

Back then that was the only way of manufacturing those lenses abd they weren't proposed as exotic items. They were priced as regular production items. It os today's economy which permits the offering of such products as being exotic and exhobitantly priced.

 

Emotional? Not at all.

[jdlaing]

Hogwash.

[NB23]

Hogwash.

What's hogwash?

 

The summilux aspherical 35mm was meant as a regular replacement to the 35mm pre-asph summilux. It wasn't meant as a special limited edition deluxe. It has become a luxury item because it's rare, not because of the legendary unicorn farts that are present in between the noctilux elements (do a forum search, it is well explained).

 

When finally the manufacturing of pressed aspherical elements became a Good quality and cheap alternative, the summilux "asph." replaced the "aspherical" summilux at the same price point (or very close).

 

All the rest, including the hogwash, is pure Leica marketing and Leica magic that we want to believe in. Because you know, there's a little bit of HCB's soul trapped in between lens elemebts of all the Leica lenses ever produced.

[pgk]

You might check into the history of the 35-70 Vario-Elmarit-R and the original "Aspherical" 35mm Summilux-M - both of which had to be withdrawn from production after the first batch because Leica was losing money on every lens. Due to production costs exceeding what they could rationally sell them for.

 

 

Adan, you use the word 'history' and yes, then, aspheric elements were no doubt very costly. Things change. If you look up buying aspheric lenses today you will find that there are numerous suppliers and they are not too costly. Actual lens elements used by Leica may well be aspherical, and they may be expensive if they custom built from expensive glass types. Or they may be quite cheap, 'off the shelf' from readily available glass types. Only Leica are likely to know. But inclusion of aspherical elements in a lens is no real indicator of excessively high production costs these days - many cheap lenses contain them nowadays.

 

And today, custom lenses can be laser cut so again, I would assume that even short run custom lenses should be more accurately made and at lower cost than hand-ground aspheric elements (if anyone still makes them even).

Edited April 18, 2017 by pgk

[georg]

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There are various ways to manufacture aspherical lens elements:

 

a) Pressing it with a special mold tool into it's final aspheric shape is the most common way and was co-developed by Leica in the 1990s. It's commonly used and feasible mostly for certain geometries, glass types and lower precision requirements, it often causes defects visible as "onion rings". Prices may vary between 5x and 10x times the price of a regular, ground spherical element. A different glass type or a slightly different geometry can increase the production cost considerably.

 

Using a hybrid of a spheric glass with a plastic part creating the aspheric shape - rarely used nowadays.

 

c) Hand-polishing aspherical lenses - rarely used nowadays

 

d) CNC-polishing with a a quite small (much smaller than the lens) polishing tool - allows larger sizes, more exotic glass types, extreme geometries and the fulfillment of more demanding precision requirements. Production costs are much higher, grinding/polishing a single surface can take several hours - only a few companies (e.g. Leica and Zeiss) are capable of performing serial production on high level. A few M and S-lenses have aspherical elements made with this technology, it also is free of "onion rings".

 

The measurement technology is also essential and can be extremely expensive.

 

Not all aspherical elements are equal!

Edited April 18, 2017 by georg

[pgk]

There are various ways to manufacture aspherical lens elements:

 

a) Pressing it with a special mold tool into it's final aspheric shape is the most common way and was co-developed by Leica in the 1990s. It's commonly used and feasible mostly for certain geometries, glass types and lower precision requirements, it often causes defects visible as "onion rings". Prices may vary between 5x and 10x times the price of a regular, ground spherical element. A different glass type or a slightly different geometry can increase the production cost considerably.

 

d) CNC-polishing with a a quite small (much smaller than the lens) polishing tool - allows larger sizes, more exotic glass types, extreme geometries and the fulfillment of more demanding precision requirements. Production costs are much higher, grinding/polishing a single surface can take several hours - only a few companies (e.g. Leica and Zeiss) are capable of performing serial production on high level. A few M and S-lenses have aspherical elements made with this technology, it also is free of "onion rings".

 

The measurement technology is also essential and can be extremely expensive.

 

Not all aspherical elements are equal!

 

Forgive my bafflement, but I don't see why one of these options might give 'onion rings' and the other not. Are you saying that larger sized elements, exotic glass, extreme geometries or high precision prevent 'onion rings'? Or are the cheaper aspheric 'pressed' elements simply not precise enough (ie they are more often defective) and this is the cause? So its not aspheric elements per se that produce 'onion rings'?

[lct]

Excerpt of a Peter Karbe's interview in 2009:

 

« In former times Leitz Wetzlar tried to construct improved high-speed 50mm lenses by incorporating aspherical elements into the design (e.g., the Noctilux 50mm f/1.2). However, Leitz abandoned this concept due to the extreme difficulty and cost entailed in producing glass aspherical elements by traditional grinding methods at that time. The new Summilux 35mm f/1.4 ASPH was the first lens we produced using a molded aspherical lens element. And significantly it was also the first aspherical lens delivering the highest level of optical performance that we were able to produce economically at a profit. (…)

« The optical design of the Summilux 35mm f/1.4 ASPH showed that placing an aspherical element behind the aperture (iris diaphragm) enables an effective reduction of oblique spherical aberration. However, that means that you have to “flatten out” the resulting curvature of field by using high refractive index glass in the positive (convex) lenses. The drawback of these types of glass is that they tend to increase chromatic aberration significantly. I had to find a way to minimize the residual color aberration by choosing glass types with low dispersion and/or anomalous partial dispersion on the one side and glass types with high refractive indices for flattening the curvature on the other side.(…)

« For example, the glass I chose for lens element 3 is of crucial importance in minimizing the secondary color aberration. This glass, formerly made at the Leitz glass laboratory, was for a long time offered by another supplier who had taken over its production. But they had stopped making it, so I had to “encourage” another German glassmaker to literally reinvent this glass type. Today this glass is extremely expensive. Indeed, the material for this lens element alone costs as much as the glass used in all the other lens elements of the Summilux 50mm f/1.4 ASPH. »

 

(Source: http://tinyurl.com/kru24n5)

[georg]

@pgk

The "onion rings" are just a side effect of pressed aspherics - it's very unlikely that someone would choose much more expensive cnc-polishing processes just to prevent "onion rings".

Polishing happens by chaotic movement of the polishing tool over the lens element to prevent regular structures occuring on the polished surfaces. Pressing the lens is doing just that, the tool is precision turned with fine turning marks which are transfered onto the glass surface. You can try to hand polish the tool but the surface will never achieve the quality of a polished lens element.

[pgk]

@pgk

The "onion rings" are just a side effect of pressed aspherics - it's very unlikely that someone would choose much more expensive cnc-polishing processes just to prevent "onion rings".

Polishing happens by chaotic movement of the polishing tool over the lens element to prevent regular structures occuring on the polished surfaces. Pressing the lens is doing just that, the tool is precision turned with fine turning marks which are transfered onto the glass surface. You can try to hand polish the tool but the surface will never achieve the quality of a polished lens element.

 

But I don't understand what is causing the 'onion rings' - is it because the pressed aspheric elements are, or can be, 'stepped' as a result of pressing. Or is it because of tolerance differences between different samples? I would have thought that whatever process was used the aim would be for a smoothly varying surface. I'm seeing a lens designer friend this weekend so I'll have a chat with him too.

[pgk]

Excerpt of a Peter Karbe's interview in 2009

Yes, I know that glass types can be expensive! Glass types come and go from catalogues too.

[Guest]

Marketing in all departments is important. Who speaks of Japanese or Zeiss lens designers of past decades? The were and are world champions, while they don't deserve to be as anonymous as the team, that needed almost ten years to design the M5.

 

Regarding early aspherical lens development:

at about the same time as the Noctilux 1.2/50 came out, Canon introduced the FD 1.2/55 Aspherical and FD 1.2/85 Aspherical.

Could someone explain, what all the fuss about polishing aspherical lenses in the seventies is about, other than maintaining hype for five digit prices? For some lenses, while for other lenses not.

(Wondering how many photo lenses containing aspherical glass came from Japan before 1991, when the M-1.4/35 AsphERICAL was introduced.)

Edited April 19, 2017 by tri

[laowai_]

More technical information on aspherical lenses, modern manufacturing of aspherical lenses, tolerances, metrology, design tradeoffs, etc. in an easy to understand format in the technical resource section of Edmund Optics (no affiliation, etc.)

[pgk]

Again no affiliation: https://www.electrooptics.com/white-paper/production-precision-optics-using-laser-micro-machining

 

The point is that technology moves on. Old, expensive systems are replaced by newer, better, more precise systems. Expensive at first but then they usually drop in cost. Exciting times.

Edited April 19, 2017 by pgk

[georg]

But I don't understand what is causing the 'onion rings' - is it because the pressed aspheric elements are, or can be, 'stepped' as a result of pressing. Or is it because of tolerance differences between different samples? I would have thought that whatever process was used the aim would be for a smoothly varying surface. I'm seeing a lens designer friend this weekend so I'll have a chat with him too.

Both, it's a surface defect on the pressing tool and it can be improved by using more advanced turning technology when manufacturing the tool or polishing the tool (both to reduce roughness/turning marks). These tools also wear quite quickly and have to be refurbished properly. So the "onion ring" can also vary depending on the quality of the pressing process/tooling.

[pgk]

Both, it's a surface defect on the pressing tool and it can be improved by using more advanced turning technology when manufacturing the tool or polishing the tool (both to reduce roughness/turning marks). These tools also wear quite quickly and have to be refurbished properly. So the "onion ring" can also vary depending on the quality of the pressing process/tooling.

 

So what you are saying is that a lens exhibiting 'onion rings' has not been made as well as it could have been? I have to admit that I do have a 50mm Summilux Aspheric which I don't recall ever exhibiting such characteristics. Given this I would suggest that any copy that does may need careful consideration?

[jdlaing]

Forgive my bafflement, but I don't see why one of these options might give 'onion rings' and the other not. Are you saying that larger sized elements, exotic glass, extreme geometries or high precision prevent 'onion rings'? Or are the cheaper aspheric 'pressed' elements simply not precise enough (ie they are more often defective) and this is the cause? So its not aspheric elements per se that produce 'onion rings'?

In the pressing method different areas of the lens element cool at different rates causing the glass to block the light rays at different rates causing the rings.

[harmen]

Might it not also be due to interference? If the light comes from point sources you should start to see it due to the enlargement that being out of focus provides. When I started searching for bokeh and diffraction, I came upon this interesting explanation: http://toothwalker.org/optics/bokeh.html

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Hallo,

Look here: Leica M

[Rus]

Might it not also be due to interference? If the light comes from point sources you should start to see it due to the enlargement that being out of focus provides. When I started searching for bokeh and diffraction, I came upon this interesting explanation: http://toothwalker.org/optics/bokeh.html

Thanks for this Harmen!