Conndomat
United States of Europe
fully broadband multi-coating?
I do believe that the key people at SR speak fluent English.
Andreas
-
Welcome to BirdForum, the internet's largest birding community with thousands of members from all over the world. The forums are dedicated to wild birds, birding, binoculars and equipment and all that goes with it.
Please register for an account to take part in the discussions in the forum, post your pictures in the gallery and more.
New low power SRBC x32's announced... (1 Viewer)
- Thread starter Bentley03
- Start date
Andreas
Very interesting! I was earlier interested in Kowa 6x32 10° TFOV but hesitated when I understood it will not be good enough for me with eyeglasses.
But with 12,2° TFOV it's less necessary to take away the binocular from the eyes in order to locate. This new 6x32 will be close to Visionking 5x25 ~14° TFOV but with higher optical quality and much larger sweet spot.
But with 12,2° TFOV it's less necessary to take away the binocular from the eyes in order to locate. This new 6x32 will be close to Visionking 5x25 ~14° TFOV but with higher optical quality and much larger sweet spot.
Last edited:
pat mitchel
Well-known member
Full broadband multicoating. my guess
Hermann
Well-known member
Zeiss advertised their 10x50 Porro (1957-1969) as "semi-apochromatic".
Just saying.
Hermann
yarrellii
Well-known member
Interesting! I wonder why choose 7.5x32 and not simply 8x32 to complement the 6x32. Maybe because 7.5 sounds more "unique"? After all, I wonder how many people would: a) tell the difference between 7.5 and 8x, and then actually NOT choose an 8x if there is a 7.5 and viceversa... After all, there are many 6, 6.5, 7 and 8x with slight discrepancies in magnification.
Conndomat
United States of Europe
Last edited:
tenex
reality-based
Oh dear, more "whataboutism"! We are incorrigible. (I see I was too subtle above regarding nonsense so will now insert
)
Hermann
Well-known member
Not really. In Zeiss' case the term "semi-apochromatic" was AFAIK well justified and backed up by the technical details of that binocular. Zeiss obviously thought correcting CA by using special glass types made sense in a binocular with fast air-spaced objectives. And they mentioned it in their literature, even though some people here deem the use of the term "apo" makes no sense in relation to binoculars.Oh dear, more "whataboutism"! We are incorrigible. (I see I was too subtle above regarding nonsense so will now insert
Hermann
Conndomat
United States of Europe
Yep, today they're called ED binoculars, and because the advertising lyric is not enough, the ED will become an APO label.
"It should be noted that with APOs the residual color is only visible when the maximum magnification is reached and the resolution penetrates into the area of the Airy disk. With binoculars you are worlds away from that. So it makes no sense at all to aim for such an APO criterion for binoculars, since chromatic aberration only becomes visible if it can be resolved with the eye." H. Merlitz
Andreas
I have never found CA being a problem with binoculars at normal magnifications. Especially at 6x it's hardly an issue at all.
tenex
reality-based
There is also a long history of designating some camera lenses APO by Leica and other "German" makers like "Voigtländer", where one often can hardly even distinguish an objective in the optical design; presumably terms like APO or semi-APO simply predated the designation "ED". The two seem fairly equivalent to me, one referring to the effect, the other to the cause. So I find Sky Rover's use of the term more quaint than inaccurate, at least if their CA actually is that well controlled. Has this been substantiated by reviews?
has530
Well-known member
I think the problem with using apo in binoculars is that the defenition doesn't really make sense for afocal instruments. Apochromatic typically means three wavelengths are brought into focus in the same plane and spherical abberation is corrected at two wavelengths. Since binoculars do not produce net convergence of light there is not a plane at which to define these properties. I suppose a binocular could have an apochromatic objective lens but given that the eyepieces will then still introduce chromatic abberation the designation is still somewhat meaningless.
james holdsworth
Consulting Biologist
“We may be creating….””
“and, we may not…”
“and, we may not…”
Hermann
Well-known member
The term "apochromatisch" goes back to Ernst Abbe. According to Abbe apochromatic lenses are designed to bring three colors into focus in the same plane, rather than two like an achromat. CA is thus a lot less than in an achromat. Apochomats also need to be more highly corrected for spherical aberation, at two different wavelengths. So the definition of apochromatic is rather clear. BTW, the first apochromats on the market were as far as I recall microscope objectives, using pure fluorite to correct CA. Telescopes followed later. Nowadays I think the Astro Physics still make "true" Apos. I don't know of any binocular that was claimed to be truly apochromatic.
Where things got muddled, was when some companies started using "semi-apochromatic" for some of their products, meaning these products weren't true apochromats but more highly corrected for CA than a straightforward achromat. Other companies started using "ED" to mean the same thing, for instance Nikon in their Fieldscopes. And the ED Fieldscopes were indeed much better corrected than the "conventional" Fieldscopes. Other manufacturers used different designations, Kowa for instance just used the term "fluorite" for their scopes with superior CA correction simply because they used fluorite (not fluorite glass) in these scopes. The only big manufacturer I can think of that uses the term Apo is Leica. No idea if these scopes fulfill Abbe's criteria in full.
That was the 80s and 90s. Nowadays it's become a free-for all. Any company that manages to bung a few lenses and prisms together and sell their contraptions on the internet claims they (of course!) use "ED lenses" or "fluorite glass" or whatever. If one of the big manufacturers claims they use ED glass, fluorite, fluorite glass or whatever, you can usually trust them. Many of the other manufacturers ... No, not really.
What does that mean for me as a user/buyer of binoculars and scopes? Simple: I don't care what the manufacturers say their products do or don't do, whether they contain 2, 3 or 8 ED lenses or not. If I find the specifications interest me, I'll have a look at the product, and I either like it or I don't.
It's basically like eating out at a fancy restaurant: You look at the menu to decide what to get, but what counts in the end is the food they serve you. You don't eat the menu, do you. Not even if it's well-worded.
Hermann
Where things got muddled, was when some companies started using "semi-apochromatic" for some of their products, meaning these products weren't true apochromats but more highly corrected for CA than a straightforward achromat. Other companies started using "ED" to mean the same thing, for instance Nikon in their Fieldscopes. And the ED Fieldscopes were indeed much better corrected than the "conventional" Fieldscopes. Other manufacturers used different designations, Kowa for instance just used the term "fluorite" for their scopes with superior CA correction simply because they used fluorite (not fluorite glass) in these scopes. The only big manufacturer I can think of that uses the term Apo is Leica. No idea if these scopes fulfill Abbe's criteria in full.
That was the 80s and 90s. Nowadays it's become a free-for all. Any company that manages to bung a few lenses and prisms together and sell their contraptions on the internet claims they (of course!) use "ED lenses" or "fluorite glass" or whatever. If one of the big manufacturers claims they use ED glass, fluorite, fluorite glass or whatever, you can usually trust them. Many of the other manufacturers ... No, not really.
What does that mean for me as a user/buyer of binoculars and scopes? Simple: I don't care what the manufacturers say their products do or don't do, whether they contain 2, 3 or 8 ED lenses or not. If I find the specifications interest me, I'll have a look at the product, and I either like it or I don't.
It's basically like eating out at a fancy restaurant: You look at the menu to decide what to get, but what counts in the end is the food they serve you. You don't eat the menu, do you. Not even if it's well-worded.
Hermann
Last edited:
tenex
reality-based
I wonder how this term and its Teutonic origin play on the Chinese domestic market; surely SR don't think they're deceiving anyone here, especially since they're not even writing out the word "apochromatic" in descriptions, just using "APO" in the name. And speaking of names, I don't even understand what a brand is in China, when identical products from the same factory are sold under many different ones, as if there's no concept of building a brand's reputation, distinguishing higher or lower quality products.
Anyway what counts is the actual binocular, and a number of members here (who got good examples) have been pleased with Banner Clouds. I recall no complaints about CA in particular.
Anyway what counts is the actual binocular, and a number of members here (who got good examples) have been pleased with Banner Clouds. I recall no complaints about CA in particular.
Last edited:
To be fair, every product release or rumour by a well-known brand gets drawn into all sorts of speculation. If Leica releases (or even heavy hints emerge that they plan on releasing) a x32 Noctivid I can almost guarantee there'll be no shortage of opinions and "discussion" to be had.
