mawz wrote:
There's no ED glass in the non-ED labeled 300/4.5. Nikon sold an ED version and a non-ED version for essentially the entire life of the lens. The non-ED is very good considering its age, the ED is better, but not significantly so IMHO.
Comparing the 1971 300mm f/4.5 Nikkor-H and the first 300mm f/4.5 Nikkor*ED (the non-IF version) I'd say there's quite a big difference.
OK, 2 pages of talk about APO lenses and no one has given the definition of APO? There are no telescope makers in the crowd? Anyone know the definition of a "super" APO lens?
I understand the marketing hype of things, but this is all about longitudinal CA. And black and white photos is most certainly effected by this aberration.
We all have our own "near APO" favorites and mine is a EOS converted Leica M 135 /4 Tele-Elmar.
I wasn't reffering to the early versions. I have a late AI model and it performs very surprising well. Maybe it's just a good copy
Anyway the facts on the Nikorr 300/4.5's:
First version was introduced pre 1964. Last AI version (non ED) introduced in 1981. In between there were nine modifications (not necessarily optical mods) . The ED version was introduced in 1977.
telyt wrote:
Comparing the 1971 300mm f/4.5 Nikkor-H and the first 300mm f/4.5 Nikkor*ED (the non-IF version) I'd say there's quite a big difference.
Apochromatic: "In 1886 Ernst Abbe, the scientific genius of Carl Zeiss, found out that calcium fluoride crystals of extreme purity, if used for lens elements in a well balanced combination with at least two other thoughtfully chosen types of optical glass, allow to design lenses that an even focus 3 different colors in the same plane at the same time . He called his invention the “Apochromat”. Zeiss apochromatic lenses marked Zeiss’s clear superiority in design and manufacture of microscopes. They enabled quantum leaps in medical science and related fields, where powerful microscopes were crucial for success."
jcolwell wrote:
Apochromatic: "In 1886 Ernst Abbe, the scientific genius of Carl Zeiss, found out that calcium fluoride crystals of extreme purity, if used for lens elements in a well balanced combination with at least two other thoughtfully chosen types of optical glass, allow to design lenses that an even focus 3 different colors in the same plane at the same time . He called his invention the “Apochromat”. Zeiss apochromatic lenses marked Zeiss’s clear superiority in design and manufacture of microscopes. They enabled quantum leaps in medical science and related fields, where powerful microscopes were crucial for success."
This is a gross simplification which would allow a designer to trade other fundamental aberrations to mitigate chromatic aberration alone. This is NOT a good thing, and it's why "Semi APO" telescopes are decidedly stuck in the "Semi" category. And yet they still blow away most camera lenses.
Abbe's actual definition was closer to the following: a system able to correct for chromatic aberration at three widely spaced frequencies, plus spherical aberration at two widely spaced frequencies, plus coma at two widely spaced frequencies. That is, all these aberrations are brought to levels at which they're no longer apparent because they're hidden within the airy disk.
As the system becomes faster, the airy disk becomes smaller. This makes achieving Apochromatic correction progressively more difficult. It's why none of the lenses listed so far are anything close to Apochromatic wide open.
Abbe could not have predicted what modern marketing would do with the definition, but it's safe to say that when he said an optic was Apochromatic, he meant you could look through it and find that it was indeed so. He did not intend any hidden caveat about having to stop down the optic before the definition would be reached.
I think Olyacme does make a good point that there needs to be some objective criteria and stated measurements used by manufactureers in their designation of APO. Zeiss does do this with regard to their Super APO lenses. Here is what they say about the Hasselblad Sonnar Superachromat 250mm lens:
"The secondary spectrum which is the dominating aberration of lenses of long focal length, is corrected for the entire spectral range between approx. 400 and 1000 nm." That would seem sufficient for me.
olyacme wrote:
Unless a reviewer had access to a 135 sensor with no AA filter and 160MP (or more likely a smaller sensor they can move about on the focus plane), they won't have been able to tell whether it was Apochromatic at f/4.0 or not. I didn't pull that number of MP out of thin air, either, which should put the Apo at f/2.5 (try 300MP) thing into better perspective.
Even on an attainable sensor, and at a reasonable f-stop, the lack of CA does not alone make a lens Apochromatic. The lens must also be multiply corrected for Spherical Aberration, and, by most definitions, Coma. Even with all that, we're only getting started making a nice lens.
Too busy ranting and speaking down to others with the assumption you know more about optics than they do to read posts properly?
I said "perceivable chromatic aberration". For colour photographs longitudinal and transverse CA as well as coma are the aberrations most likely reduced with a so-called APO lens, which is the whole point for us. Provided the majority of the airy disks are below the nyquist frequency of the chosen medium then what is the problem? The AA filter argument is moot with any reasonable photographer, it's suitably weak enough on modern cameras.
Have you used either of the lenses I mentioned? I'm shooting on a 5D Mark II, for 35mm only the D3x and Sony A900 (at low ISO's) is more demanding. Maybe there's a 25 speed film with more extractable detail but for the purposes of measuring CA and coma digital tends to be very unforgiving to most lenses. With a film scanner you can introduce your own aberrations at that kind of (130mp) magnification with their optics.
I never said these lenses were apochromatic across the entire visible and near visible spectrum. Even the coastal optics 60/4 isn't quite that well corrected although it comes very close, I assume you use that one since you consider the Voigtlander 180/4 and Leica 100/2.8 not nice lenses?
pdmphoto wrote:
I wasn't reffering to the early versions. I have a late AI model and it performs very surprising well. Maybe it's just a good copy
Anyway the facts on the Nikorr 300/4.5's:
First version was introduced pre 1964. Last AI version (non ED) introduced in 1981. In between there were nine modifications (not necessarily optical mods) . The ED version was introduced in 1977.
I stand corrected, for some reason I was misremembering the ED version as being introduced with the H.C
thrice wrote:
Too busy ranting and speaking down to others with the assumption you know more about optics than they do to read posts properly?
I said "perceivable chromatic aberration". For colour photographs longitudinal and transverse CA as well as coma are the aberrations most likely reduced with a so-called APO lens, which is the whole point for us. Provided the majority of the airy disks are below the nyquist frequency of the chosen medium then what is the problem? The AA filter argument is moot with any reasonable photographer, it's suitably weak enough on modern cameras.
And that "definition" remains wrong. There are at least two reasons that lack of "perceivable chromatic aberration" does not make a lens Apochromatic.
Reason one - limited measurement.
If the sensor is coarse enough, it will not be able to see the aberrations that are nevertheless present. A lens that someone described as Apo on a sensor with X MP, is suddenly no longer Apo on a sensor with 2X MP? This is an absolutely absurd "definition". Use the term "no visible colour on such-and-such sensor" instead.
Reason two - hung up on CA.
Despite the inclusion "chromatic" in Apochromatic, the term is concerned with much more than spurious colour. In particular, it demands that the lens be as well corrected for spherical aberration as it is for CA. In photographic terms, this correction buys you the microcontrast and sharp focus transition so sought for a "3d" look. Correction of CA alone makes for a lens that images like a pot of mashed potatoes.
At any rate, I've been hammering away at these two points in various ways in nearly every post, and everyone who was going to "get it" has probably "gotten it" by now. If you're determined to be wrong I'll leave you be.
It is clear that various people are discussing APO lenses while they have different definitions of apochromatism in mind. Such discussions are wearisome.
Toothwalker wrote:
It is clear that various people are discussing APO lenses while they have different definitions of apochromatism in mind. Such discussions are wearisome.
There is a big difference between tweaking Abbe's definition, as TMB did, and inventing a completely different definition. The lenses being marketed to photographers as Apochromatic may indeed meet the credible definition in some circumstances, but by failing to describe those circumstances the manufacturers have fundamentally confused their consumers.
With an information vacuum, many people have invented a new meaning for the term. One which no longer bears any relation to the original, and is also much less useful.
I agree that trying to convert a mind that has already established its definition is wearisome. This effort is really not for those minds. It's here to provide enough information and debate to allow those who would learn the correct definition to do so.
Toothwalker wrote:
It is clear that various people are discussing APO lenses while they have different definitions of apochromatism in mind. Such discussions are wearisome.
jcolwell wrote:
Apochromatic: "In 1886 Ernst Abbe, the scientific genius of Carl Zeiss, found out that calcium fluoride crystals of extreme purity, if used for lens elements in a well balanced combination with at least two other thoughtfully chosen types of optical glass, allow to design lenses that an even focus 3 different colors in the same plane at the same time . He called his invention the “Apochromat”. Zeiss apochromatic lenses marked Zeiss’s clear superiority in design and manufacture of microscopes. They enabled quantum leaps in medical science and related fields, where powerful microscopes were crucial for success."
olyacme--I'm a big fan of non-sliding conventions. Carry on the good work. Don't get me started about "low contrast lenses being better for digital"... ugh.
olyacme wrote:
And that "definition" remains wrong. There are at least two reasons that lack of "perceivable chromatic aberration" does not make a lens Apochromatic.
Reason one - limited measurement.
If the sensor is coarse enough, it will not be able to see the aberrations that are nevertheless present. A lens that someone described as Apo on a sensor with X MP, is suddenly no longer Apo on a sensor with 2X MP? This is an absolutely absurd "definition". Use the term "no visible colour on such-and-such sensor" instead.
Reason two - hung up on CA.
Despite the inclusion "chromatic" in Apochromatic, the term is concerned with much more than spurious colour. In particular, it demands that the lens be as well corrected for spherical aberration as it is for CA. In photographic terms, this correction buys you the microcontrast and sharp focus transition so sought for a "3d" look. Correction of CA alone makes for a lens that images like a pot of mashed potatoes.
At any rate, I've been hammering away at these two points in various ways in nearly every post, and everyone who was going to "get it" has probably "gotten it" by now. If you're determined to be wrong I'll leave you be....Show more →
Wow... You still neglect to read my post...
I NEVER said these lenses were apochromatic, I said "so-called APO".
"no visible colour on such-and-such sensor" yeah I can really see lens manufacturers doing that instead of a little 3 letter designation.
What do you shoot with? Or better yet, link me to your photo gallery, I'd love to see how brilliant the images such a genius using such incredible equipment captures.
EDIT: I find your condescension and elitism tiring, what is your scientific qualification?
thrice wrote:
I said "perceivable chromatic aberration". For colour photographs longitudinal and transverse CA as well as coma are the aberrations most likely reduced with a so-called APO lens, which is the whole point for us. Provided the majority of the airy
An Apochromatic lens is corrected for spherical aberration as well, which is absolutely critical to us!
thrice wrote:
disks are below the nyquist frequency of the chosen medium then what is the problem? The AA filter argument is moot with any reasonable photographer, it's suitably weak enough on modern cameras.
This, second and lesser objection, is that it makes the term ambiguous. It's a given that these lenses are not Apochromatic wide open. Perhaps they only meet the bar at f/45 - the manufacturer isn't saying.
thrice wrote:
Wow... You still neglect to read my post...
I NEVER said these lenses were apochromatic, I said "so-called APO".
"no visible colour on such-and-such sensor" yeah I can really see lens manufacturers doing that instead of a little 3 letter designation.
I suggested you say that. I suggest manufacturers stick to MTF charts, spot diagrams, and, if they want to say Apo, they say at just what f-stop it applies.
thrice wrote:
What do you shoot with? Or better yet, link me to your photo gallery, I'd love to see how brilliant the images such a genius using such incredible equipment captures.
olyacme wrote:
There is a big difference between tweaking Abbe's definition, as TMB did, and inventing a completely different definition. The lenses being marketed to photographers as Apochromatic may indeed meet the credible definition in some circumstances, but by failing to describe those circumstances the manufacturers have fundamentally confused their consumers.
With an information vacuum, many people have invented a new meaning for the term. One which no longer bears any relation to the original, and is also much less useful.
I agree that the definitions which manufacturers seem to use are probably nowhere near Abbe's original definition or TMB's definition. But TMB's modern definition is also far from Abbe's definition. The last paragraph on the page that you referred to does not even mention the number of zero crossings as a prerequisite. Why do people (including TMB) try to change the meaning of something that has been defined in the past, instead of inventing a new word to suit their new description? Widespread confusion is a natural consequence.
I agree that trying to convert a mind that has already established its definition is wearisome. This effort is really not for those minds. It's here to provide enough information and debate to allow those who would learn the correct definition to do so.
From all definitions, why would yours be the correct one?
Toothwalker wrote:
I agree that the definitions which manufacturers seem to use are probably nowhere near Abbe's original definition or TMB's definition. But TMB's modern definition is also far from Abbe's definition. The last paragraph on the page that you referred to does not even mention the number of zero crossings as a prerequisite. Why do people (including TMB) try to change the meaning of something that has been defined in the past, instead of inventing a new word to suit their new description? Widespread confusion is a natural consequence.
Reality still precludes zeros. As TMB explained, crossings must be tight enough that the result is diffraction limited. That is, crossings must occur within the Airy disk. The minimum size of the Airy disk is capped by the f-number.
There really isn't much room for confusion here, even with just a lay understanding of the field, so long as one bothers to look up the definitions.
For what it's worth, I expect and hope that the manufacturers are using the commonly (non photo-forum) accepted definition of Apochromatism. They're just failing to reveal to consumers at which f-stop the term applies.
