New Leica 90mm Lenses Article at overgaard.dk

[Overgaard]

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My new article on the Leica 90mm lenses.

 

Summicron, Elmarit, Macro-Elmarit, Summarit and the rare 90mm Thambar from 1935.

 

It also includes a list of all 90mm lenses ever lade by Leitz and Leica.

 

leica.overgaard.dk - Thorsten Overgaard's Leica Pages - Leica 90mm lenses - The Summarit, Thambar, Summicron, Tele-Elmarit and other Leitz 90mm lenses

 

Fell free to read, comment, suggest.

 

Enjoy!

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[Peter Branch]

Not sure where the idea that APO equates with Aspheric came from but I am certain that this is not correct.

 

Leica state quite clearly that the use of aspheric lens surfaces primarily helps with the control of the mono-chromatic aberrations.

 

What exactly APO means varies from manufacturer to manufacturer but it essentially relates to control of the secondary spectrum. At its simplest three wavelengths focused in the same plane. However this is a simplification as factors such as magnification and distortion have to be taken into account.

 

Perhaps best to actually ask one of the Leica people what they mean - but please note that the 135mm APO lens has no aspheric surfaces.

[Overgaard]

There is a definition of APO in the button of the article.

 

APO

stands for "apochromatically corrected" lenses. In most lenses, optical design concentrates the focus of blue light and green light into a single plane, but red light falls slightly into another plane of focus. Red subjects, therefore, would be ever so slightly out of focus compared to blue and green subjects in the same frame. In APO lenses, the design and expense has been put in to making red light focus on the same plane as blue and green. Under a microscope you would see that all light subject is now in focus, creating a sharper image overall. 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.

 

There is also a definition of ASPH just below that.

 

And a discussion on the forum a few years ago about what it means and does:

http://www.l-camera-forum.com/leica-forum/customer-forum/124785-what-does-apo-really-mean.html

[Jeff S]

Erwin Puts (in his Leica Chronicle) disagrees with your assessment of top 90 lens. He rates the Macro-Elmar (which you barely note) as "simply the best general purpose 90 lens in the current M range." He even goes further to say that "it's among the best performing lenses ever made for the 135 format", including on his list the 50 APO Summicron.

 

He writes that the 90 APO Summicron ''is second best in the class of 90 M lenses." He specifically notes "some softness and loss of contrast at closer distances (0.7-2)" and writes that "for optimum quality, one has to stop down to 1:4".

 

I really don't like ranking lenses, as much depends on the requirements of the particular shot, and the preferences of the user. But, be that as it may, you and Mr. Puts have different notions. I suspect the difference in speed enters more prominently in your thought process.

 

Jeff

[Overgaard]

I suspect the difference in speed enters more prominently in your thought process.

 

Jeff

 

Yes. The f/4.0 is outstanding good. But in my perspective useless for what I want to do due to the f/4.0.

 

A lens is not just a lens, it's a tool. And in many cases also a love affair.

[erudolph]

Fantastic article, Thorsten. Thank you.

[Overgaard]

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Not sure where the idea that APO equates with Aspheric came from but I am certain that this is not correct.

 

Leica state quite clearly that the use of aspheric lens surfaces primarily helps with the control of the mono-chromatic aberrations.

 

What exactly APO means varies from manufacturer to manufacturer but it essentially relates to control of the secondary spectrum. At its simplest three wavelengths focused in the same plane. However this is a simplification as factors such as magnification and distortion have to be taken into account.

 

Perhaps best to actually ask one of the Leica people what they mean - but please note that the 135mm APO lens has no aspheric surfaces.

 

Ok, I read through it again and see how the it may have been a little confused. So I have updated the article and added some illustrations to the Definitions section.

 

Thanks for noticing.

[hossegor]

it was a very nice read but i had the feeling it was focusing mainly on the newest lens, the APO. i would have loved to read a bit more about the Mandler lenses.

[ldhrads]

I have a very late pre- ASPH 90/2.0 APO lens. I rarely see this summicron mentioned. I use it a bit, it's a wonderful portrait lens, but it's a heavy beast so I often use my "thin" TEM 90. What is it about the pre -ASPH but APO lens that rarely gets it mentioned?

[gpwhite]

 

A lens is not just a lens, it's a tool. And in many cases also a love affair.

 

Thorsten, this sooo true! And now I understand why I hear whimpering all of the time coming from your Summilux-R 80mm as it sobs in the corner.

 

Peter

[Paul J]

Nice read as always Mr T. That APO is just something else.

[250swb]

An interesting read, well done. But I can't find any reference to the 90mm Elmarit M except in a passing comparison with other lenses, it gets no mention or a heading of its own. I would have though this lens in particular crossed over the classic to modern boundary at a price size and quality that made it an ideal 90mm for more people than a Thambar or a Summicron might.

 

Steve

[Jeff S]

I have a very late pre- ASPH 90/2.0 APO lens.

 

I'm not aware of a pre-asph 90 that is considered APO. Are you talking about the 90 Summicron produced from 1980-1998? If so, I don't know about an APO qualification.

 

Jeff

[Jeff S]

….it gets no mention or a heading of its own….

 

Except under the heading "The difference between the Elmarit, Summicron and Summarit look", under which he likens its 3-D look to that of the APO Summicron (that he doesn't find with the Summarit). I agree, though, that this is scant mention compared to the praise it receives on the forum.

 

The Macro-Elmar is the one without heading or discussion (due to its speed limitation, which Thorsten notes above).

 

Jeff

[ldhrads]

I'm not aware of a pre-asph 90 that is considered APO. Are you talking about the 90 Summicron produced from 1980-1998? If so, I don't know about an APO qualification.

 

Jeff

 

Jeff, My mistake, for some reason I was convinced that the Summicron 90 V3 was APO. Perhaps I had read it somewhere, but it apparently is not. Still love the lens though!

[jbl]

Great article, Thorsten, thanks for writing it! Now I want a Thambar.

[DigitalHeMan]

Thorsten, nice article, it would be good if you could fix the links at the bottom of the article. The second Steve Huff link doesn't work, and both Erwin Puts links are dead.

[CheshireCat]

I have an Elmarit. Great lens with just one defect: dull colors.

Are the APO-Summicron and Summarit better in this regard ?

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Hallo,

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[alan.y]

"The real interesting part is that when Peter Karbe designed the Leica 50mm Summilux-M ASPH f/1.4 he actually applied APO technology to it. But, as he said, they found it a little childish to write APO. traditionally APO has only been for tele lenses from 75mm and up. Not standard lenses."

 

Learnt a lot from this article. I was intrigued by the above passage. Do you mean apochromatic design has traditionally been reserved for 75mm and up, or simply an explicit APO designation? And why is that?

 

[JohnJWhite]

"The real interesting part is that when Peter Karbe designed the Leica 50mm Summilux-M ASPH f/1.4 he actually applied APO technology to it. But, as he said, they found it a little childish to write APO. traditionally APO has only been for tele lenses from 75mm and up. Not standard lenses."

 

Learnt a lot from this article. I was intrigued by the above passage. Do you mean apochromatic design has traditionally been reserved for 75mm and up, or simply an explicit APO designation? And why is that?

 

 

I suspect it's because diffraction is more of a problem with long focal length lenses.