revans
Carpal Tunnel
Reged: 09/26/05
Posts: 1514
Loc: Fitchburg, MA
|
|
I see that Leica and Zeiss make fluorite lens binoculars but I'm not sure if these are real fluorite or some sort of FPL low dispersion glass. The most interesting to me was the Zeiss Victory which is 8 x 56 mm. I assume that these high end and very expensive binoculars are intended to be apochromatic... but from what I know about telescopes it is impossible to make an apochromat with a real low f-ratio.... and what could have a lower F ratio than binoculars?
Is there any advantage to fluorite lens or ED lens binoculars for astronomic use? Is it worth the price premium?
--------------------
Rick Evans
http://www.freewebs.com/revans_01420/
"The universe is there for us to see, but it cannot be understood without learning its language -- mathematics." Galileo Galilei
|
Solar B
scholastic sledgehammer
Reged: 02/28/07
Posts: 911
Loc: By Edinburgh , Scotland
|
|
Im new to Binos not Refractors,but from my brief experience i would say that CaF2 objectives are worth it,im not sure that the Leica or Zeiss options (as much as i "Worship" these Manus) are CaF2,but be careful as once you try fluorites there is no going back,im already thinking about larger objectives 
Brian
PS i would love to hear about other CaF2 binos apart from the obvious Highlanders/Taks
--------------------
" Gentlemen only ever use Refractors "
Edited by Solar B (10/18/09 06:35 PM)
|
jkevn
sage
Reged: 03/02/06
Posts: 211
Loc: Tucson, Arizona
|
|
Except for the moon, Jupiter, Venus, possibly Mars at opposition, and very bright stars, chromatic aberration isn't very noticeable for me. It would seem that with apochromatic 3-element objectives or ED glass, more light would be concentrated from stellar point sources, so this might extend the limiting magnitude a little, but someone would have to test this to see by how much, if at all. I wouldn't think that it would make much of a difference for diffuse objects like nebula.
If you really like views of the moon without color fringing on the moon's edge, then maybe it would be worth it.
Chromatic aberration, for me, is far more distracting in daytime viewing (possibly because I know it is there and I look for it automatically). I can see how this would be important for birding.
Since I had cataract surgery in both eyes, I notice it more at night looking at the moon and bright stars with binoculars and through my 12" scope.
|
GaryS
super member
Reged: 10/30/06
Posts: 191
|
|
Quote:
Is there any advantage to fluorite lens or ED lens binoculars for astronomic use? Is it worth the price premium?
I carefully compared cosmetically identical 10x50s by Orion and William Optics for a S&T Test Report once. The W.O. binos claimed to use ED glass, the Orions did not. In performance, they appeared to be identical. That's not a definitive answer to your question, but it is a direct comparison with a minimum number of variables in the mix.
That said, I'd be surprised to discover any colour correction differences at binocular magnifications that could be traced to the objective lenses. Other factors (overall optical quality, mechanical build) are likely to be more important.
Regards,
Gary
--------------------
Sky & Telescope Contributing Editor
SkyNews Columnist & Blogger
www.GarySeronik.com
A place for stargazing enthusiasts.
|
charen
Pooh-Bah
Reged: 05/28/05
Posts: 1082
Loc: New Zealand
|
|
"The W.O. binos claimed to use ED glass, the Orions did not. In performance, they appeared to be identical"
Previous reviews on these W.O. binos appear to indicate that the ED glass is in the oculars not in the objectives ?
I have not been able to verify this.
This ED glass positioning would not have such a significant effect in image quality as if they were in the objectives.
I do have a excellent Minox 10x58 ED. The image - contrast, brightness and resolution is very good - however CA is still mildly discernable. As Gary says are other multible factors do go into making a superior bino. I guess ED glass helps that process.
Chris
--------------------
35 binos.
80mm Cat.
WO66ED
SV NH 80mm / EQ3
Meade 8in.LX90
Skywatcher Equinox ED120 / Goto HEQ5.
|
GaryS
super member
Reged: 10/30/06
Posts: 191
|
|
Quote:
Previous reviews on these W.O. binos appear to indicate that the ED glass is in the oculars not in the objectives ?
I have not been able to verify this.
From the description of the 10x50s on the William Optics web site:
"Extra-low dispersion glass objectives for an exceptional color correction (almost no false colour)." (Emphasis mine.)
Never heard the story about using ED glass in the eyepiece before.
Gary
--------------------
Sky & Telescope Contributing Editor
SkyNews Columnist & Blogger
www.GarySeronik.com
A place for stargazing enthusiasts.
|
charen
Pooh-Bah
Reged: 05/28/05
Posts: 1082
Loc: New Zealand
|
|
Hi there was a thread about a year or so ago regarding this subject re. the ED glass position - which I cannot find now. Sorry for the confusion.
Chris
--------------------
35 binos.
80mm Cat.
WO66ED
SV NH 80mm / EQ3
Meade 8in.LX90
Skywatcher Equinox ED120 / Goto HEQ5.
|
John F
sage
Reged: 02/16/04
Posts: 383
Loc: Washington State
|
|
I certainly feel that the 22x60 Takahashi Astronomers were well worth the $1050 I paid for them (new) back in 2005. They're outstanding binoculars in general and do provide false color-free images of the moon.
As to whether I think the 32x82 Kowa Highlander Prominar model (i.e., the fluorite one) is worth the extra $1400 it costs over the non-fluorite model I can't say. I've never seen a review of those two models and how they compare to one another. Obviously, for lunar and planetary viewing the Prominar model would have an advantage. However, for deep sky observing (which is what binocular are primarily used for) I'm not sure so sure that they Prominars are worth their extra $1400 cost. Are there any 32x82 Kowa Highlander users (i.e., of the non-Prominar model) out there who can speak for how well they think they perform in general as well as (in particular) they perform for deep sky observing?
--------------------
BINOCULARS
Nikon 7x50 Prostar
Swarovski 8.5x42 EL
Nikon 10x70 Astroluxe
Zeiss 15x60 B/GAT
Takahashi 22x60 Astronomer
SCOPES
Questar 3.5-Inch
Tele Vue NP-127 with TV Bino Vue
EYEPIECES
Deep Sky: 31Nagler, 17-13-10-8-6 Ethos
Lunar & Planetary: 16-10-6-4 ZAO-II
Binoviewing: 24Pan,16Nagler, 10ZOA-II,7.5Taks
|
nocturne
newbie
Reged: 11/08/08
Posts: 4
|
|
Quote:
I see that Leica and Zeiss make fluorite lens binoculars but I'm not sure if these are real fluorite or some sort of FPL low dispersion glass.
It's not flourite (CaF2) but fluoride-doted glass.
How good the effect is depends on the total configuration of the optical system it seems.
Most certainly, not all hyped "ED"s are equal.
There has been a very enlightening explanation of the background here:
http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/3193178/page/0/view/collapsed/sb/5/o/all/fpart/1
some additional discussion here:
http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/3016684/page/0/view/collapsed/sb/5/o/all/fpart/1
T
Edited by nocturne (10/20/09 05:11 AM)
|
edwincjones
Postmaster
Reged: 04/10/04
Posts: 5665
|
|
I have the Miyauchi 100mm fluorite binoculars, and the dark, crisp, constrast is very pleasing; and better optics than my Fuji 25x150MTs.
(but I still have color and APO is ?)
Other have pointed out that the fluorite is less important in lower magifications.
edj
--------------------
n w arkansas
|
Luigi
Post Laureate
Reged: 07/03/07
Posts: 4938
Loc: MA
|
|
In my experience, high quality ED bins produce very crisp, sharp, fine detail on objects like bird feathers, flowers and leaves, spider webs, surfaces of rock, etc.. The low CA preserves contrast on these fine details. For me, the benefits are less significant for bino astro observing.
--------------------
17.5" f/5 Dob. IM-715 MCT. 120ED. Lunt 60mm Ha.
Zeiss, Leica, Fujinon, Nikon, Pentax, Bushnell bins
|
Solar B
scholastic sledgehammer
Reged: 02/28/07
Posts: 911
Loc: By Edinburgh , Scotland
|
|
Quote:
I certainly feel that the 22x60 Takahashi Astronomers were well worth the $1050 I paid for them (new) back in 2005. They're outstanding binoculars in general and do provide false color-free images of the moon.
Well that would mean that i could have bought a new pair
a few years ago Stateside for about £550,you would be lucky to get a secondhand pair over here now for less than £800.
Brian
--------------------
" Gentlemen only ever use Refractors "
|
milt
professor emeritus
Reged: 09/13/04
Posts: 552
Loc: Arizona
|
|
Quote:
For me, the benefits are less significant for bino astro observing.
I would agree for low magnifications. However at higher mag's, the ability to bring as much of the visual bandwidth as possible to the same focus determines how many faint stars can be resolved in clusters - which are a popular target for me, anyway. This requires two things: ED glass (not necessarily fluorite) to bring the blue and red ends of the spectrum to the same focus as green, and good spherical correction to bring rays entering all parts of the objective to the same focus. You pay big bucks for binoculars that can do this, but they do have better stellar limiting magnitudes. As usual, the last 10% always seems to cost 10x as much...
--------------------
Clear skies, Milt
|
EdZ
Professor EdZ
Reged: 02/15/02
Posts: 14731
Loc: Cumberland, R I , USA42N71.4W
|
|
Quote:
at higher mag's, the ability to bring as much of the visual bandwidth as possible to the same focus determines how many faint stars can be resolved in clusters - which are a popular target for me, anyway. This requires two things: ED glass (not necessarily fluorite) to bring the blue and red ends of the spectrum to the same focus as green, and good spherical correction to bring rays entering all parts of the objective to the same focus. You pay big bucks for binoculars that can do this, but they do have better stellar limiting magnitudes. As usual, the last 10% always seems to cost 10x as much...
I commented on this in my recent tests with the Tak 22x60 vs the WO22x70 and GO22x85. A nice group to test since they are all the same power. Although the GO has significantly greater aperture, both the WO and the Tak have significantly smaller spot size. They can see just about equally deep in magnitude and can see significanly better close doubles.
The spot size in the WO is smaller than the GO, But to see the difference between the Tak spot size and the GO spot size is remarkable. However, it's been mentioned, that is not all just due to CA correction in ED glass, or in the case of the Taks, true flourite. Much of it has to do with the correction of the lenses, for instance the degree of spherical aberration. The GO spot size isn't twice as large as the Tak simply due to color correction.
Most people still don't get it, but Milt made a very significant point about color correction at low powers, a point being overlooked by a multitude of people. See the links above to ED in binoculars. Most of what you read from people about color correction in low power binoculars being attributable to ED glass is ...... well, go read that other thread.
edz
--------------------
Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
|
pcad
Carpal Tunnel
Reged: 01/17/05
Posts: 1767
Loc: Connecticut
|
|
I'd rather have a well corrected achromat than a poorly corrected ED/Fluorite doublet.
It doesn't hurt to have a slower focal length ratio either.
--------------------
Peter
Telescopes 25 - 318 mm
Binoculars 15 - 88 mm
Microscope 50x - 1000x
|
BillC
on a new path
Reged: 06/04/04
Posts: 2237
Loc: Washington, USA
|
|
"I'd rather have a well corrected achromat than a poorly corrected ED/Fluorite doublet.
Seems PCAD doesn't fall for the buzzword games!!! Good man!!!
Cheers,
Bill
--------------------
William J. Cook, Chief Opticalman, USNR-Ret.
Founding Editor, Amateur Telescope Making Journal
20-year vet. of Captain's Nautical Supplies, Optics Dept. Mgr.
Optics Machanic, WG11-3306, Ft. Lewis, Tacoma,WA
Yata, Yata, Yata . . .
|
Swedpat
Pooh-Bah
Reged: 02/18/05
Posts: 1120
Loc: Boden, Sweden, Scandinavia
|
|
Personally I doubt it's worth, when talking about "normal" handhold magnifications. I usually never become aware of CA of binoculars. But I understand that this really is a matter of sensitivity, which can vary between different persons.
Regards, Patric
Off topic: I just noticed that BillC at the post before me had exactly twice the numbers of total posts than me. (2226 vs 1113) How big chance is that this shall happen at the same time and the posts beside each other...
Edited by Swedpat (10/21/09 12:24 PM)
|
pcad
Carpal Tunnel
Reged: 01/17/05
Posts: 1767
Loc: Connecticut
|
|
With the Tak's, which I expect will be back in my hands soon, I believe the performance has more to do with the objectives being well corrected and well figured compared to standard binocular objectives. Their long f/6ish focal ratio helps a lot also.
The Tak's objectives are high quality telescope objectives which likely could be used at 120x or more. At these magnifications having APO performance makes a differance. At 22x, not so much.
--------------------
Peter
Telescopes 25 - 318 mm
Binoculars 15 - 88 mm
Microscope 50x - 1000x
|
GaryHeath
super member
Reged: 08/13/09
Posts: 118
|
|
Interesting thread ....
Other than the colored rings on bright objects, it appears that you need to be at a power then can appreciate the benefit of the fluorite/ED glass.
Then the next gate is you have to have eyes that can appreciate whatever additional benefit is attributed to the somewhat limited increase at typical binocular powers, which (in most practical bino observing) is in turn further limited to the amount of targets that can benefit from which in practical use basically gets back to the color halo reduction as the main benefit of the additional expense.
So ...... unless you are already looking at large hi power binos, and bright targets viewed by younger eyes than mine, it appears to be something that one might be better off using the dollar difference to go ahead and buy those larger binos .... but as achro's, and using the "saved" money to purchase better mounting for them ..... both at significantly less cost than "premium glass". binos.
For example ...... the difference between the Fuji 25X150 MT and ED is enough to buy the MT's 'and' a delivered StarChair 3000 ...... with some left over to also buy a really nice "make-up" gift for the wife, to be presented at a 5 star restaurant prior to an evening of dancing and romance!
That's what I did ......... 
And it was all paid for with my settling for only a hint of colored rings, and then on a only a 'few' of the brightest bright objects (that aren't the typical target for my binos) and the most remote possibility of more faint stars for my old eyes to try and see. As almost certainly ...... any increase in detail of diffuse objects (my normal targets for binos) brought on by all of the spectrum being in better focus would be so elusive that I probably couldn't see the difference in these targets ....... even in my younger eye'd days.
Also ........ I have a W.O. FluoroStar 110mm refractor and an AP155EDF.
Although the TEC objective in the W.O. 'is' the premium glass version of this scope, and there is no false color to bright objects, there 'is' a yellow/warm cast to the image when looking through it, that I don't see unless I do a 'side by side' with my AP155EDF.
The original AP binoviewers did a similar thing to the image, they added a blue/cool cast to it that wasn't seen unless I compared it to a set of TeleVue binoviewers during the same session.
So I would add to this conversation, that even though a given set of optics is in fact premium, there can be more to it than that.
And both brand name and type of glass used, is not a guarantee that you will get what you might think you are, from only the advertisements and spec's.
At the price increase for premium glassed binos, I would want to do a 'side by side' to verify I was truly getting what I was paying that extra money for.
Best regards,
Gary
Edited by GaryHeath (10/22/09 02:51 PM)
|
milt
professor emeritus
Reged: 09/13/04
Posts: 552
Loc: Arizona
|
|
Quote:
At the price increase for premium glassed binos, I would want to do a 'side by side' to verify I was truly getting what I was paying that extra money for.
Gary, yours was a thoughtful post that I'm sure most here will agree with.
In Peter's case, his premium binocular glass is actually long-proven Takahashi telescope fluorite objectives. And since you are the extremely lucky owner of an AP155EDF you might appreciate this story: A friend of mine who owns several A-P's also collects binoculars and is an occasional poster to this forum. The first night I set my Kowa 32x82 fluorite up next to his 155EDF he was so impressed that he ordered one for himself along with the optional 50x eyepieces!
So, yes, premium glassed binos can play with the big boys.
Milt
PS - The warmer coloration you saw in the WO110 relative to the AP155 may have been due to the dimmer image. I noticed the same effect when comparing my 130EDT to a larger TEC on Saturn. In this case the A-P being smaller had the warmer coloration.
|
Previous
Index
Next
Threaded
Edit
Reply
Quote
[Re: 