JCJ said:ZEISS, ZEISS, and ZEISS.
I think they all have good coatings, especially swaro and zeiss. For some reason zeiss on avg. always seem brighter than the others. I have owned about every bino made by these 3 for the last 10 years or so(except 12x) and zeiss is usually brighter. Not that I like them better, they are just brighter. Maybe its their a-k prisms. I don't really care for their fit as much as the other 2. But this is subjective, I like them all.AlanFrench said:Best fit, or best coatings <G>.
They are supposed to be good.
Clear skies, Alan
JCJ said:I think they all have good coatings, especially swaro and zeiss. For some reason zeiss on avg. always seem brighter than the others. I have owned about every bino made by these 3 for the last 10 years or so(except 12x) and zeiss is usually brighter. Not that I like them better, they are just brighter. Maybe its their a-k prisms. I don't really care for their fit as much as the other 2. But this is subjective, I like them all.
AlanFrench said:I've often wondered if apparent field has an influence on perceived brightness. Is comparing binoculars of the same power but different apparent (and true) fields bias the results?
One thing I look for is companies that say the coatings are carefully matched to the glass types. For best results you can not simply slap the same coatings on each lens.
Clear skies, Alan
AlanFrench said:I've often wondered if apparent field has an influence on perceived brightness. Is comparing binoculars of the same power but different apparent (and true) fields bias the results?
One thing I look for is companies that say the coatings are carefully matched to the glass types. For best results you can not simply slap the same coatings on each lens.
Clear skies, Alan
Wehr said:Hi Alan,
this was done years ago to compensate the yellow, red or green color of some glass types. Today coatings don't care about the glass types but are all optimized for the deep blue part of the spectrum, because all glass types still swallow up UV and with it a small amount of visible blue.
Different color reflections on the coated surface say nothing about the range of optimization, it depends only on which layer is the last on the entire package.
Walter
AlanFrench said:Walter,
That wasn't the issue I was writing about. For maxium transmission, the coating should be taylored to the particular glass it is being used on. For maximum transmission, a coating should be designed for the indices of the glass being coated.
For instance... "At Leica, high-performance broadband coatings are applied that are tailored specifically to the types of glass that are being used."
I am not sure what you mean by "optimized for the deep blue part of the spectrum." The general goal of glass and coating selection is to maximize transmission across the visual spectrum. It is probably a good thing - and no accident - that our eyes are less sensitive to blue and red light, which represent the portions of the spectrum less well controlled by refractive optics (including our eyes).
Clear skies, Alan
Wehr said:Hello Alan,
[SNIP]
And last but not least, stressing the dark blue and violet part of the spectrum compensates the light absorption within the glass, which leads to a colour-neutral performance.
[SNIP]
Walter
AlanFrench said:Walter,
I agree that coating technology has put even one on pretty much an even footing, so it is not much of an issue.
I still don't understand your point about the blue and violet. I looked at the transmission data for BAK 4 on the Schott glass map and it is still extremely high at the blue end of the spectrum. Our eye's loss of sensitivity in the blue is far, far greater than the slight difference in transmission. Also, if coatings have transmissions in the upper 90 percent range, how can you do much to emphasize the blue? I am sorry, it just makes no sense to me.
Do you know specific glass types used in binocular prisms?
Clear skies, Alan
Wehr said:Hello Alan,
you are right with BAK 4, but it is usually only for prisms. There are different materials used for the lenses (would lead to far to talk about), but all these glasses suffer from some loss at the visual blue end of the spectrum, because they absorb UV. Missing blue makes all colours yellowish. Our eye's loss of sensitivity in the blue is not the point. With that loss, our brain judges colours to be natural. Using binoculars shall lead to the same result. So there must not be an additional loss caused by the glass (brain is very sensitive regarding deviations from what it thinks is natural). Not to forget, light more and more becomes blue at dusk. With the mentioned measures low light performance is increased best. Good example is Zeiss with their new FLs. With the FLs they practice this kind of coating in a rather extreme way, and on my impression they lose a bit of contrast in daylight. In daylight I personnally prefer a slight yellowish characterization, because it increases contrast by blocking a portion of the blue straylight, when observing in the mountains or at the sea.
Walter
RobConnel said:Of the big three (four if you count Nikon's premier line) whose coatings best handle low light situations?
Leif said:I would include Nikon!
Somewhere on BF there is a list of % transmission for various binoculars. I think the best were Nikon SE and Zeiss Victory (FL?) which reached ~96%. Zeiss claim ~96% in their techie bumf. The 'worst' of the premium bins were Swarovski EL at about 84% IIRC. I seem to recall that Leica were closer to the Nikon/Zeiss than the Swarovski. However, those figures are probably peak measurements, rather than averages over the visible range, and manufacturers sometimes change and improve coatings on existing bins as the years go by, so the figures are not necessarily up to date.
Transmission is not everything though as the Nikon HG range do not transmit as much light as the best, but the contrast is very high which largely compensates. In my experience performance in low light depends on both transmission and contrast.
As someone else said, I'm not sure the differences between the best are that significant. Maybe someone with direct experience in low light can contradict me.
Leif