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Noctivid must be ASPH! (1 Viewer)

tenex

tenex

reality-based
I just noticed this sentence about Noctivids on the Leica (US) website:
"Thanks to the modification of the radii at the lens surfaces, the sharpness towards the periphery of the field of view has been improved significantly."

This really has to mean an aspheric element, doesn't it? They label their camera lenses ASPH all the time, and boast about it. Why don't they for binoculars? And is this the first time a Leica bino has had it? How many others now do? I really don't see the word used in marketing. Instead we get... "plasticity".

(Not even contemplating a Noctivid myself, just curious about optical technology...)
 
Actually, I don't think that sentence means that they use any aspherical surfaces in the Noctivid. I take it to mean they changed the overall optical design so that they achieved better sharpness towards the edge of the field.

If they did use aspherical surfaces, they'd most certainly say so in no uncertain terms in their advertising. Leica isn't exactly shy when it comes to advertising ... 3:)

Hermann
 
tenex said:
I just noticed this sentence about Noctivids on the Leica (US) website:
"Thanks to the modification of the radii at the lens surfaces, the sharpness towards the periphery of the field of view has been improved significantly."

This really has to mean an aspheric element, doesn't it? They label their camera lenses ASPH all the time, and boast about it. Why don't they for binoculars? And is this the first time a Leica bino has had it? How many others now do? I really don't see the word used in marketing. Instead we get... "plasticity".

(Not even contemplating a Noctivid myself, just curious about optical technology...)
Click to expand...

I am thankful Leica had the good sense NOT to use an aspheric lens element.
 
tenex said:
I just noticed this sentence about Noctivids on the Leica (US) website:
"Thanks to the modification of the radii at the lens surfaces, the sharpness towards the periphery of the field of view has been improved significantly."

This really has to mean an aspheric element, doesn't it? They label their camera lenses ASPH all the time, and boast about it. Why don't they for binoculars? And is this the first time a Leica bino has had it? How many others now do? I really don't see the word used in marketing. Instead we get... "plasticity".

(Not even contemplating a Noctivid myself, just curious about optical technology...)
Click to expand...

The Nikon Diplomat 8 x 23 AS available from the late 1990s has an aspherical element. Some of the current Nikon Aculons do in the eyepiece. Being cheap and cheerful these are likely all plastic. The low element count of the EDG binoculars suggest a glass moulded aspheric to me. A single aspheric element can do the job of a doublet spherical with lower comatic flare and higher contrast
The fact that Leica doesn't say 'changing radii' at the lens surface suggests it does not... ;)
 
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45northmt said:
I am thankful Leica had the good sense NOT to use an aspheric lens element.
Click to expand...

Why is this? I figured aspheric lenses would've solved the biggest issue I have always had with Leica binoculars, their poor control of Chromatic Aberration relative to their similarly priced brethren. That complaint was still my biggest issue when I looked through the Noctivid, they haven't seemed to improve on CA control since the Trinovid BA/BN series, at least to my eyes.
 
jremmons said:
Why is this? I figured aspheric lenses would've solved the biggest issue I have always had with Leica binoculars, their poor control of Chromatic Aberration relative to their similarly priced brethren. That complaint was still my biggest issue when I looked through the Noctivid, they haven't seemed to improve on CA control since the Trinovid BA/BN series, at least to my eyes.
Click to expand...

Same for me. While i love the design element of Leica, and to some extent the colour rendition, the CA has always been a deal-breaker.
 
I would argue that the most discussed subject on the Binocular forum over the years has been Chromatic Aberration and I have come to the conclusion that it will always be a problem for some binocular users and never be a problem for others.

Bob
 
Aspherical elements mostly correct spherical aberration I think, not chromatic aberration.

I think Horace Dall mentioned aspherising the rear surface of doublet objectives, but I am not sure.
If so, easily measuring the curve on the front of a Noctivid won't help.

There are many possible curves with aspherising.
 
jremmons said:
Why is this? I figured aspheric lenses would've solved the biggest issue I have always had with Leica binoculars, their poor control of Chromatic Aberration relative to their similarly priced brethren. That complaint was still my biggest issue when I looked through the Noctivid, they haven't seemed to improve on CA control since the Trinovid BA/BN series, at least to my eyes.
Click to expand...

Controlling spherical aberration with an aspherical lens, which curves outwards at the edge, helps sharpness by making sure the rays from the edge of the lens are focussing at the same point as the centre.

Chromatic aberration is reduced by using low dispersion/refraction glass types and fluorite which focus different wavelengths (colours) at the same point.

Some residual CA though can be useful in getting a 3D look. A perfectly corrected image can look like a cut and paste montage because of perfect edge sharpness and delineated colours.

With an expensive fluorite telephoto lens the thorough elimination of the secondary spectrum means red ,green and blue are brought together at the precise same focal point making the lens a true apochromatic. For some reason, I don't fully understand, Leica don't want to do that with binoculars but can and do with their APO telephoto lenses.
 
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ceasar said:
I would argue that the most discussed subject on the Binocular forum over the years has been Chromatic Aberration and I have come to the conclusion that it will always be a problem for some binocular users and never be a problem for others...
Click to expand...

I would argue that CA is bothersome to some and not to others but that it is a problem for everyone (or is at least a problem for anyone pushing their eyes and bins to their limits of seeing fine details), whether they are aware of CA or not.

--AP
 
Compared to the Ultravid there is an obvious change in the Noctivid eyepiece design: the addition of a negative field lens just behind the prism visible in the cutaway below. A negative element in that position ought to reduce off-axis aberrations compared to the 5 element/3 group Ultravid eyepiece.

There is a similar negative field lens (which Nikon refers to as a field flattener) in the Nikon HG, EDG and SEs along with a similar arrangement of six elements in four groups. The Zeiss SF also has a similar negative field lens combined with three cemented doublets.
 

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Hermann said:
Actually, I don't think that sentence means that they use any aspherical surfaces in the Noctivid. I take it to mean they changed the overall optical design so that they achieved better sharpness towards the edge of the field.
Click to expand...

I'll admit this is ambiguous, surprisingly so for advertising. The question is, why refer to modifying radii at all? It's bizarrely technical, and yet quite unclear. "We improved the optical design" would be much more sensible. This still makes me think of something aspheric. (Do ASPH elements improve the outer field especially?)

maico said:
...making the lens a true apochromatic. For some reason, I don't fully understand, Leica don't want to do that with binoculars but can and do with their APO telephoto lenses.
Click to expand...

Cost seems a likely possibility. As expensive as their binos are now, a Leica lens can cost 2-3x as much. And unlike a photograph, this image usually isn't available for pixel-peeping afterwards.


[Edit] Just saw Henry's post. OK, perhaps they're just being coy about introducing a field flattening lens since that would make the Noctivid sound like a slavish imitation of Swarovski. So they must also hope you won't notice the open-bridge design...
 
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henry link said:
Compared to the Ultravid there is an obvious change in the Noctivid eyepiece design: the addition of a negative field lens just behind the prism visible in the cutaway below. A negative element in that position ought to reduce off-axis aberrations compared to the 5 element/3 group Ultravid eyepiece. There is a similar field lens (which Nikon calls a field flattener) in the Nikon HG, EDG and SEs along with a similar arrangement of six elements in four groups.
Click to expand...

Henry:

Thanks for the cutaway and your evaluation.

It seems not much is new here. Here is what "Better View Desired", said
about the Nikon Venturer LX, HG, 1998, 20 years ago.

"When Nikon introduced the Venturer LX in 1998, they set a new standard
for brightness and resolution in birding binoculars."

From: Cloudy Nights, "Better View Desired".

Jerry
 
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Alexis Powell said:
I would argue that CA is bothersome to some and not to others but that it is a problem for everyone (or is at least a problem for anyone pushing their eyes and bins to their limits of seeing fine details), whether they are aware of CA or not.

--AP
Click to expand...

Is that an argument for trying to make yourself aware of it?;)

Bob
 
tenex said:
I'll admit this is ambiguous, surprisingly so for advertising.
Click to expand...

I find that it is not unusual to find this kind of ambiguity or plain-wrong statements on websites. My theory is that the text was originally written in the mother tongue (eg German) then translated by a web-page compiler who is fluent in everyday English but lacks technical competence in optical terms.

So at the moment we can see on the Zeiss Harpia pages that it has a 3-stage zoom. What is a 3-stage zoom? It is no such thing and just means a 3x zoom. These little twists in language can take you up mental cul-de-sacs trying to work out what new technology has been introduced.

Lee
 
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