Summarits vs. Summicrons

[MichaelM7]

Well, there has been a lot said about the quality difference between Summicron and Summarit lenses without anybody here (I assume) having used a Summarit lens.

Let's have a more technical approach to it, based on the technical data which is already available:
Generally, as Mr. Puts reports, there is a difference of about 1000 to 1500 € per lens between Summicron and Summarit. Now, where could this difference come from?

1) The difference in max. aperture
The half stop difference between f2 and f2.5 might not seem to be much. But what is the difference for the lensmaker? Well if you look at the 35mm lenses: both have the same width (about 53mm) and share the same filter size (E39). This means, both have to have about the same size of entrance lens. But the difference between f2 and f2.5 means, that more of the summicron lens will be used than of the summarit lens. Also, the theoretical resolution of a f2 lens is higher than that of a f2.5 lens.
This results in more effort for polishing the summicron lenses, especially up to the border. It is much easier (and cost effective) to reach high quality polishing in the centre of a lens than at its border.
This also leads to a higher yield of the polishing process, as little scratches or inclusions in the glass have a higher probability of not being in the optical path. Also, straylight reduction is much easier, since straylight occurs mostly due to reflexes on the outer diameter of the lenses. A smaller aperture might simply block some of the straylight. Guess why Leica advertises the Summarits with the improved straylight reduction capabilities?

2) The lack of an asphere lens
Asphere lenses are normally made one after another: either by blank pressing a near-liquid glass bubble and final fine polishing or by dedicated computer controlled polishing of a spherical surface. Spherical lenses -- as are being used in the summarits -- can be manufactured in the classical way, i.e. by putting many lenses on one big carrier and polishing them altogether.

3) There is -- supposedly -- no chrome version
Leica M lenses use different materials for chrome (brass) and black versions (aluminium). This makes their parts very expensive since lower volumes can be produced, different mechanical designs are needed to accomodate the different material properties, etc.

4) More common parts
There are supposedly very little common parts used for the traditional Leica lenses. If one can use the same part on more lenses, the part gets much cheaper, i.e. the lens can get cheaper as well

5) Less exotic glass types
Glass manufacturers do offer quite a number of different glass type. For a lensmaker, one should have glasses with very high and very low refractive index in one lens, in order to make for a compact and elegant design. The more extreme the lens design, the more likely an exotic glass type will be used.
However, not all glass types are equally available. Some are made only every couple of years, Some are even discontinued, if the demand is too little. This happens quite often. In fact, the number of glass types at Schott (a major glass manufacturer) was significantly higher 10 or 20 years ago. Such a discontinuation will mean the end for specific lens designs or -- as most likely is the case for the Noctilux lens -- lead to an enormous price increase if the manufacturer needs to store the glass for future demand.

6) Less add ons
Well currently this is mostly speculation, but I would guess one needs to buy the lens hood separately for the Summarits. Already the lens pouch (velours) is less expensive than for the Summicrons (leather bag).

7) Less profit per lens
Well, I think it is evident that Leica wants to sell more and make the profit from the higher number of lenses sold.


OK. That was a long list. I tried to assess the technical reasons for the price difference between Summarit and Summicron lenses on the data which is already available and on my knowledge on how lenses are being made. I do not want to sound like another "I-know-it-all" but what are your comments on to this?

Greetings,

MichaelM7

 

[Gabriel M.A.]

I should point out that the difference between f/2.0 and f/2.5 is roughly 2/3, not 1/2 of a stop.

So for 1/3 stop difference between a 50mm "Summarit-M" and a 50mm Elmar (f/2.8), I would much rather go with the Elmar, since there are only four glass elements in the design, and an already proven, great lens, which can be had for about USD $900.00 new.

I don't understand their strategy there, at all.

 

[richard_l]

I should point out that the difference between f/2.0 and f/2.5 is roughly 2/3, not 1/2 of a stop.

Actually, it is roughly 1/2 stop, as well as roughly 2/3 stop. It depends on the degree of roughness of the approximation, right? 😎

So for 1/3 stop difference between a 50mm "Summarit-M" and a 50mm Elmar (f/2.8), I would much rather go with the Elmar, since there are only four glass elements in the design, and an already proven, great lens, which can be had for about USD $900.00 new.

I don't understand their strategy there, at all.

Good observation. However, there may be differences other than speed to consider. For some people, the Elmar's images are 'crisp' to the point of 'brittleness.' I would expect the Summarit's images to be more 'mellow,' if they are anything like those of the Minilux's 40mm Summarit. If this is indeed the case, the Summarit may be a better portrait lens, for example.

Richard

 

[ferider]

List of 1/6th f stops 🙂

Cheers,

Roland.

 

[Nemo]

Well, there has been a lot said about the quality difference between Summicron and Summarit lenses without anybody here (I assume) having used a Summarit lens.

Let's have a more technical approach to it, based on the technical data which is already available:
Generally, as Mr. Puts reports, there is a difference of about 1000 to 1500 € per lens between Summicron and Summarit. Now, where could this difference come from?

1) The difference in max. aperture
The half stop difference between f2 and f2.5 might not seem to be much. But what is the difference for the lensmaker? Well if you look at the 35mm lenses: both have the same width (about 53mm) and share the same filter size (E39). This means, both have to have about the same size of entrance lens. But the difference between f2 and f2.5 means, that more of the summicron lens will be used than of the summarit lens. Also, the theoretical resolution of a f2 lens is higher than that of a f2.5 lens.
This results in more effort for polishing the summicron lenses, especially up to the border. It is much easier (and cost effective) to reach high quality polishing in the centre of a lens than at its border.
This also leads to a higher yield of the polishing process, as little scratches or inclusions in the glass have a higher probability of not being in the optical path. Also, straylight reduction is much easier, since straylight occurs mostly due to reflexes on the outer diameter of the lenses. A smaller aperture might simply block some of the straylight. Guess why Leica advertises the Summarits with the improved straylight reduction capabilities?

2) The lack of an asphere lens
Asphere lenses are normally made one after another: either by blank pressing a near-liquid glass bubble and final fine polishing or by dedicated computer controlled polishing of a spherical surface. Spherical lenses -- as are being used in the summarits -- can be manufactured in the classical way, i.e. by putting many lenses on one big carrier and polishing them altogether.

3) There is -- supposedly -- no chrome version
Leica M lenses use different materials for chrome (brass) and black versions (aluminium). This makes their parts very expensive since lower volumes can be produced, different mechanical designs are needed to accomodate the different material properties, etc.

4) More common parts
There are supposedly very little common parts used for the traditional Leica lenses. If one can use the same part on more lenses, the part gets much cheaper, i.e. the lens can get cheaper as well

5) Less exotic glass types
Glass manufacturers do offer quite a number of different glass type. For a lensmaker, one should have glasses with very high and very low refractive index in one lens, in order to make for a compact and elegant design. The more extreme the lens design, the more likely an exotic glass type will be used.
However, not all glass types are equally available. Some are made only every couple of years, Some are even discontinued, if the demand is too little. This happens quite often. In fact, the number of glass types at Schott (a major glass manufacturer) was significantly higher 10 or 20 years ago. Such a discontinuation will mean the end for specific lens designs or -- as most likely is the case for the Noctilux lens -- lead to an enormous price increase if the manufacturer needs to store the glass for future demand.

6) Less add ons
Well currently this is mostly speculation, but I would guess one needs to buy the lens hood separately for the Summarits. Already the lens pouch (velours) is less expensive than for the Summicrons (leather bag).

7) Less profit per lens
Well, I think it is evident that Leica wants to sell more and make the profit from the higher number of lenses sold.


OK. That was a long list. I tried to assess the technical reasons for the price difference between Summarit and Summicron lenses on the data which is already available and on my knowledge on how lenses are being made. I do not want to sound like another "I-know-it-all" but what are your comments on to this?

Greetings,

MichaelM7

Michael, you are 100% right.

 

[richard_l]

List of 1/6th f stops 🙂

Cheers,

Roland.

That's handy. Or one could use a scientific calculator: The difference in stops between two apertures (f-stops) a and b is
log((a^2)/(b^2))/log(2). One could also use ln (base e) instead of log (base 10). Applying this to the f-stops 2.5 and 2 gives 0.6438.... or approximately 2/3.

Richard

 

[Gabriel M.A.]

That's handy. Or one could use a scientific calculator: The difference in stops between two apertures (f-stops) a and b is
log((a^2)/(b^2))/log(2). One could also use ln (base e) instead of log (base 10). Applying this to the f-stops 2.5 and 2 gives 0.6438.... or approximately 2/3.

Which you've stated is roughly 1/2 😉

 

[peter_n]

While I respect the technical discussion, I'd like to see pictures from the Summarit lenses (not the ones on the German Leica forum) and maybe try one out for myself. I think I'll have to wait post-November for that.

 

[jjovin]

I wonder how one justifies the price difference between 90/2.5 and 90/2.8?
The 2.8 is 1/3 or 1/2 😀 of a stop slower with fewer lens elements and
no exotic glass or aspherical elements.
Zoran

 

[Ororaro]

That's handy. Or one could use a scientific calculator: The difference in stops between two apertures (f-stops) a and b is
log((a^2)/(b^2))/log(2). One could also use ln (base e) instead of log (base 10). Applying this to the f-stops 2.5 and 2 gives 0.6438.... or approximately 2/3.

Richard

Do you realize you just lost many folks with this mathematic talk?

 

[richard_l]

Do you realize you just lost many folks with this mathematic talk?

You sound resentful. Are you? Every high school graduate should have been introduced to logarithms and scientific calculators in algebra. I mentioned a useful formula which can be used in place of a table for determining stop differences. It's probably in most photography handbooks. Sorry, I don't think it can be dumbed down any further.

Richard

 

[Chris101]

... Every high school graduate should have been introduced to logarithms and scientific calculators in algebra. ...

Taking the log of a fraction is beyond the ability of roughly two thirds of college freshman.

 

[richard_l]

Taking the log of a fraction is beyond the ability of roughly two thirds of college freshman.

Unfortunately, that's probably true. That's their problem, but it's not necessarily their fault. A lot of high school math teachers are unqualified.

Richard

 

[richard_l]

Adding to the list, Michael prepared, I'd also add a bullet reading, Where are the components coming from? That is to say, has Leica now tapped into a glass supplier that helps their business model better than doing everything inhouse (sort of in the similar fashion Zeiss and Cosina are partners)?

In a separate post, I theorized that perhaps, Hoya, Sigma, Tomioka or even Panasonic is helping Leica out on these new offerings...

I think they've been using Hoya glass for a long time. I've heard that they don't make their own glass anymore. What difference does it make?

Richard

 

[Chris101]

Unfortunately, that's probably true. That's their problem, but it's not necessarily their fault. A lot of high school math teachers are unqualified.

Maybe in your part of the world, but I doubt it. Sure there some examples, but that's just the latest excuse I'm hearing. Someone else to blame. I've been teaching college chemistry and tutoring high school math for twenty years, and student's work ethic has eroded beyond recognition. If something isn't easy, then they just won't do it. If you've got a solution that goes beyond blaming the teachers, I'd like to hear it.

 

[richard_l]

Maybe in your part of the world, but I doubt it. Sure there some examples, but that's just the latest excuse I'm hearing. Someone else to blame. I've been teaching college chemistry and tutoring high school math for twenty years, and student's work ethic has eroded beyond recognition. If something isn't easy, then they just won't do it. If you've got a solution that goes beyond blaming the teachers, I'd like to hear it.

I said it's 'not necessarily' their fault, but even that's not really an excuse. If they're supposed to learn something, they can learn it from their textbooks, if their teacher is incompetent. In my experience, most students use their (extremely expensive) textbooks only for the homework assignments. I certainly know where you're coming from, having taught in colleges all over the US for 25+ years. 🙁

Richard

 

[Chris101]

I said it's 'not necessarily' their fault, but even that's not really an excuse. If they're supposed to learn something, they can learn it from their textbooks, if their teacher is incompetent. In my experience, most students use their (extremely expensive) textbooks only for the homework assignments. I certainly know where you're coming from, having taught in colleges all over the US for 25+ years. 🙁

I can't tell you how often I've been asked "Do we need the book for this course?"


Hey! How about them summarits! (er, sorry about the hijack.)

 

[Mike Richards]

Do you realize you just lost many folks with this mathematic talk?

Perhaps, but you piqued my interest. Complicated math formulae are works of art. Math is fun and has been very lucrative for me.

My guess is that the Leica business model calls for dropping the Elmars and keeping the Summicron and Summilux lines at premium prices -- perhaps eventually just the latter. The Summitars will be the base models. They are small, light, and no need for expensive design and manufacturing. For example, no need for APO, asph, or floating elements. Although temporarily expanding their lens line, I'm sure the end result will be simplification.

 

[payasam]

I'd say that Mike is right and we'll need to wait some years or even a decade to see what happens.

 

[MichaelM7]

I think they've been using Hoya glass for a long time. I've heard that they don't make their own glass anymore. What difference does it make?

Richard

Well, there's a difference between the glass and the lens, i.e. the polished glass.
I am pretty sure that Leica does not make their own glass anymore (as doesn't Zeiss and probably all major lens manufacturers). I have not seen any indication of this during my visits to Solms and Oberkochen and it probably would make the Leica lenses even more expensive than they are now. It is much more economical to make glass in huge quantities. Normally it is made in swimming-pool size pans made of fireclay. Such an amount of a single glass would last virtually forever for a company of Leica's size, given that they would need several different sorts per lens. So most of the time their glass department would not do anything but wait for the lensmakers to use up all the glass they have on stock. Making glass in smaller pans will generally not give you the high quality you need for top notch optics.
So they are most probably buying the raw glass at Schott, Hoya, Coherent or somebody else. Whether they buy pre-polished lenses is another question, which I cannot answer for sure. While it could be realy true, I would say manual assembly of the lenses is more expensive than automatically polishing a lot of lenses at the same time, where only one or two people could operate such a machine.
So there would be more to be saved if they outsourced assembly of the lenses to a country with cheaper labor. This is how Zeiss does it by using Cosina as their partner. Leica does not, according to their statements. If -- on the other hand -- Leica did not have a machine for polishing many spherical lenses at once and needed to buy one extra, it could be cheaper to buy polished lenses elsewhere.

Just my two cents,

MichaelM7