Why are there no APO version of noctilux 50mm f0.95?

[Herman Zhang]

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Why are there no APO version of noctilux 50mm f0.95?

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The Leica Q3 is available for pre-order at B&H Photo Video and Adorama

[Gregm61]

I can see that.....breaking the $20,000 one lens barrier.

[scott kirkpatrick]

 APOs have all been f/2.0, where correction of three wavelengths is still possible.  In  the M series, the recently re-released 28/2.0 offers closer focusing, but is not called an APO, and in fact has the same optical formula as its predecessor.  The Super Elmar M21 and M24 lenses have what seems to be almost as good performance edge to edge, but are much slower.

Edited November 16, 2023 by scott kirkpatrick

[Stuart Richardson]

28 minutes ago, Herman Zhang said:

Why are there no APO version of noctilux 50mm f0.95?

Engineering challenges, cost and size would be the main culprits, I think. Your closest bet in a fast lens would be the 50mm 1.4 ASPH, which is pretty close to APO correction. Or the f2 versions. The other advantage of those lenses is that they are cheaper, sharper and more practical in basically every way.

[Herman Zhang]

but the whole point of APO is to avoid fringing, and the lens that creates the most fringing is the noctilux

[IkarusJohn]

As I recall, both the 50 Summilux ASPH and 0.95 Noctilux are APO lenses, just not marketed as such.

[BastianK]

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vor 5 Stunden schrieb IkarusJohn:

As I recall, both the 50 Summilux ASPH and 0.95 Noctilux are APO lenses, just not marketed as such.

As someone who has used both lenses I can only say: best joke I read today.

Leica 50mm 0.95 on Leica M10 (100% crop):

 

Leica 50mm 1.4 Asph on M10 (100% crop):


In the dimensions desirable for an M-mount lens it is hardly possible to include enough lens elements to correct all the aberrations that come with making a lens as fast as f/0.95.
Even the Nikon 58mm 0.95 is not a real Apo lens, but it is the f/0.95 lens that comes closest.
17 elements in a 2 kg lens where needed for that, whereas the Leica 50mm 0.95 only has 8 elements and in a (by comparison) lightweight 767g structure.

[pgk]

Quite simply, the faster a lens is, the more difficult it is to correct. So you can have speed or you can have extremely high correction but both are difficult to achieve together. Post #7 does not show aberration but purple fringing which has other causes and is not a result of aop or lack of app correction (app technically means that three wavelengths are corrected for rather than two). A search through the forum will show that this topic has recurred many times, 

[Crem]

15 hours ago, Herman Zhang said:

Why are there no APO version of noctilux 50mm f0.95?

I have no doubt it’s technically possible, but at what cost, size, weight, and viewfinder blockage. How much are you willing to pay? How big and heavy is too much? What if 75% of the viewfinder was blocked?

I also suspect Leica marketing has a good idea on what will sell. My guess: we see a 35 f1.2 noct (non apo) before we see them update the 50 noct. Only a guess since they didn’t update the optical formula of the 35 lux when they made it close focus.

It seems like they are going to eventually make an EVF only M with a virtualized rangefinder patch. This also means a lot more flexibility for the lens designers since they won’t have to worry about viewfinder blockage.

Edited November 16, 2023 by Crem

[IkarusJohn]

3 hours ago, BastianK said:

As someone who has used both lenses I can only say: best joke I read today.

Leica 50mm 0.95 on Leica M10 (100% crop):

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

 

Leica 50mm 1.4 Asph on M10 (100% crop):


In the dimensions desirable for an M-mount lens it is hardly possible to include enough lens elements to correct all the aberrations that come with making a lens as fast as f/0.95.
Even the Nikon 58mm 0.95 is not a real Apo lens, but it is the f/0.95 lens that comes closest.
17 elements in a 2 kg lens where needed for that, whereas the Leica 50mm 0.95 only has 8 elements and in a (by comparison) lightweight 767g structure.

As someone who owns and uses both, it wasn’t a joke (I’m sure the insult was unintentional).

As Paul comments immediatgely above, the issue is extremely fast lenses shot wide open with a sharp change from bright to dark.  Something the owners of all fast lenses are well aware of, and those of course who have been around the forum for a while and have read previous discusions.

Edited November 16, 2023 by IkarusJohn

[Al Brown]

16 hours ago, scott kirkpatrick said:

APOs have all been f/2.0,

Not true, the 50/1.4 lux ASPH is also APO. Confirmed by Karbe. They just didn’t write it on the barrel. Nobody understood the marketing potential that gets the ants to the honey jar back then.

[Al Brown]

4 hours ago, BastianK said:

As someone who has used both lenses I can only say: best joke I read today.

Leica 50mm 0.95 on Leica M10 (100% crop):

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

 

Leica 50mm 1.4 Asph on M10 (100% crop):


In the dimensions desirable for an M-mount lens it is hardly possible to include enough lens elements to correct all the aberrations that come with making a lens as fast as f/0.95.
Even the Nikon 58mm 0.95 is not a real Apo lens, but it is the f/0.95 lens that comes closest.
17 elements in a 2 kg lens where needed for that, whereas the Leica 50mm 0.95 only has 8 elements and in a (by comparison) lightweight 767g structure.

Both lenses ARE APO. Not a joke.

The noctilux is just a very old design by today’s standards. 

Edited November 16, 2023 by Al Brown

[Al Brown]

16 hours ago, Stuart Richardson said:

Your closest bet in a fast lens would be the 50mm 1.4 ASPH, which is pretty close to APO correction.

It is not close. It is APO corrected. 

[BastianK]

Karbe may go for the lowest possible bar saying a lens is "Apo" (like Sigma did in the past, too).
Fact is, there are plenty of lenses out there that correct all longitudinal chromatic aberrations perfectly,
also the ones in the out of focus areas which do seem to be much harder to correct than the simple "purple fringing".
And most manufacturers only award their lenses an Apo tag if that is actually the case.
And only if that is the case I find an Apo tag is actually helpful to the customer.

And neither the 50mm 0.95 nor the 50mm 1.4 Asph are among those.

[Al Brown]

18 minutes ago, BastianK said:

Karbe may go for the lowest possible bar saying a lens is "Apo" (like Sigma did in the past, too).
Fact is, there are plenty of lenses out there that correct all longitudinal chromatic aberrations perfectly,
also the ones in the out of focus areas which do seem to be much harder to correct than the simple "purple fringing".
And most manufacturers only award their lenses an Apo tag if that is actually the case.
And only if that is the case I find an Apo tag is actually helpful to the customer.

And neither the 50mm 0.95 nor the 50mm 1.4 Asph are among those.

I will stick with what the chief optical designer at Leica claims. He sounds credible.

You do have a point though, but that does not change the APO fact of those two.

[RexGig0]

“APO” is a marketing term. Leica has not been the only manufacturer to use “APO.” An APO lens is presumed to have some amount of apochromatic correction. Some APO lenses, obviously, have more apochromatic correction than others. I suspect that one Cosina-made SLR lens, designed a number of years ago, has very little apochromatic correction, in spite of its “APO Lanthar” labeling, compared to newer, excellent Cosina Voiglander APO Lanthar lenses.

I am not an engineer, but my take-away is that designing a lens to have a “fast” aperture, and to also have apochromatic correction, is quite a challenge. The result, if successful, would be prohibitively expensive, and could not be compact, which would block more of the viewfinder, or light in weight, which affects portability and one’s physical endurance. Recognizing this, I bought a Cosina Voigtlander Nokton 50mm f/1.0 Aspheric VM in 2022, and a Cosina Voigtlander 50mm APO Lanthar VM in 2023*. Neither will replace my much-favored Summilux-M 50mm ASPH, which was my first M-mount lens acquisition, in 2018. Each has its best use cases.

Edited to add: A significant reason that I did not buy a Noctilux-M 50mm f/0.95 ASPH, last year, was its size and weight. A lens weighing 700 grams is something that I would rather affix to the front of a camera the size of a Nikon D5. Plus, the length of the Noctilux would block more of an M camera’s viewfinder, compared to the Voigtlander Nokton 50mm f/1,0 VM. An f/0.95 Nocti-something, with significant apochromatic correction, would be how large and heavy? 

 

Edited November 16, 2023 by RexGig0

[RexGig0]

Nikon has built a Nocti-something 58mm lens, with an f/0.95 maximum aperture. Aspherical. “ED” glass, to correct chromatic aberrations. 

https://www.nikonusa.com/en/nikon-products/product/mirrorless-lenses/nikkor-z-58mm-f%2f0.95-s-noct.html#tab-ProductDetail-ProductTabs-Overview

Weight: 2000 grams.

[jaapv]

3 hours ago, pgk said:

Quite simply, the faster a lens is, the more difficult it is to correct. So you can have speed or you can have extremely high correction but both are difficult to achieve together. Post #7 does not show aberration but purple fringing which has other causes and is not a result of aop or lack of app correction (app technically means that three wavelengths are corrected for rather than two). A search through the forum will show that this topic has recurred many times, 

This.  APO means simply that at least the light rays at three points of the spectrum (R,G and B ) will coincide in the plane of focus. Nothing more, nothing less. Longitudinal CA is outside the plane of focus by definition. Purple and blue fringinging are only rarely caused by CA but are a combined sensor/raw conversion artefact. 

See this Imatest tutorial

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Hallo,

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[Jan1985]

When you compare the optical construction of the 0.95 with the 75mm 1.25 you have nearly 13 years of improvement in the Karbe Design Lab. I work with both. The 0.95 is far from being an APO and I think it shouldn‘t because of its character.

But the 75mm in the regard of an APO is quite another leaque. It‘s very well corrected so that even at 1.25 I honestly never had any purple fringing or things I get with an 0.95. So it‘s very close to what you might expect of an APO. But all this APO discussion is misleading.

As the other wrote its a matter of costs and what kind of „tool“ you want to produce. And 1.25 or 0.95 lens in my eyes has a quite different purpose and use. More for artistic photographs and portraits. And APO is a documentary lens, a lens for the more perfect shot and photographs that should show more the scene and not be a representation of that signature of a particular lens.

[sinjun]

1 hour ago, jaapv said:

Purple and blue fringinging are only rarely caused by CA but are a combined sensor/raw conversion artefact. 

I've seen this stated before, but if it is the case why do some lenses seem to be more immune from it than others?