56mm Zeiss FL (1 Viewer)

Kevin Purcell said:

I have speculated before that bin designers restrict the FOV of larger bins to reduce prism sizes to reduce bin weight. The smaller the light cone the smaller the prism needs to be (and the prism will got up as the cube of the objective diameter unlike the lenses being roughly "2D" which will get heavier as the square of the diameter).

Just speculation.

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DO you really think that's the whole reason because they are still very heavy. Would they be 50 or 60 oz if they had the expected wide FOV?

And Kevin Admittedly you know way more about optics then I do but I can't get over the effect of when you pull a projector from 6 to to 12 feet the image gets twice as big and half as bright is not a big part of what is going on here. I'f I'm reading you right you're saying that's not at all the reason for the small FOV.

Could you maybe explain a little better for us guys that don't understand the optical construction of lens systems as well?

I think Kevin is right on about the prism size and weight being a limitation. The 56mm has a hard row to hoe in this department.

The beam from the objectives is big already because it is coming from the honking objective lens. The beam spot is really big as it enters the prisms. The prisms need to be bigger yet, the more the beam swings around through a wide field of view. Wide-field Porros bite the bullet and just put in big prisms. They're already uglier than pigs, you know? But how horrifying it would be if the body of a roof were to bulge to accomodate very large prisms! I know that I would simply faint at such a sight, and trust that most of you are similarly refined.

The eyepiece, too, is of longer focal length than the eyepiece giving the same 10x magnification in the 32mm, since, AK vs SP difference notwithstanding, the 56mm still has a longer focal length. A field stop with the same apparent width must be physically larger in an eyepiece with longer focal length. So, increasing the field also requires bigger, heavier, more expensive eyepieces.

Kevin was right, but this was SO much more complicated, don't you think?

Ron

I'm not sure Zeiss was concerned about the weight of the 56's. Heft helps stability (inertia and all that), and as a 10x is relatively difficult to hold steady, the lighter it is, the tougher to get the good view. Learning to hand-hold a bino over 10x or so takes a while, unless you are a rare physical specimen (that say takes no more than about 6 breaths per min and has a relaxed pulse of maybe 20 per min) and have substantially higher than normal powers of disciplined concentration. (Steve Ingraham had a couple good articles on this in BVD). So perhaps these two (and maybe more to come?) weren't intended for the beginning bino customer (the size, wt & cost would be immediate deterrents), but rather for the user who knows fully what he (or she, as the case may be these days....)is about. Much the same case would be a beginning shooter getting something like a .300 Weatherby (or whatever) as a first rifle after shooting his dad's .30-30 a few times....the first shot taken with a 200 gr factory load will be painfully remembered for a lifetime (and unless said shooter is very determined and has a stout constitution, a second shot likely won't be taken, due to the thunderous muzzle blast and about 50 ft/lb of recoil...about like having Tyson hit your shoulder full force, bare knuckled). Or a novice handgunner, after practicing a little with .38 target loads, picking up a .454 Casull, .50 Desert Eagle (etc), squeezing off a full charge 300 gr round, resulting in a dent in the forehead and a hand unusable for a couple days. A neophyte motorcyclist, fresh from learning on a Honda 250, hopping on, say, a VMax (again there are others), droppin' into 1st, grabbin' a handful of throttle and suddenly realizing the front axle is eye level (& going higher) and lots of things are happening REALLY fast...this can easily cause temporary cardiac arrest, possibly wet britches and in all likelyhood, a pantsful.

Now these may be extreme analogies, but the idea is, some consumer products aren't meant for all consumers. Most beginning birders will usually go for a more common 7 or 8x by 35-40....we here, being more discerning and knowledgable, are open to the wider range of available optics (some might say lunatic fringe) in search of some sort of....I think the term "optical nirvana" was coined in a previous thread, and understand the various ramifications and vicissitudes of the less mundane optics, i.e, the "rare air of the magnification stratosphere", to put it cryptic terminology......(sorry....this probably should have been put in Tero's binocular ramblings thread....oh well, too late now)

Heft helps stability (inertia and all that)

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A lot of people seem to think this but the measurements show that bin weight doesn't actually change the amplitude of the shake.

The heaviest thing when you are holding up your arms is your arms themselves. Try it with and without bins. Adding an extra kilo doesn't actually damp the arms/bin combo but does make the arm's muscles work a bit harder.

Bin weight matters when it dangling from your neck. In that case ounces make the difference!

Nessus said:

DO you really think that's the whole reason because they are still very heavy. Would they be 50 or 60 oz if they had the expected wide FOV?

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The prism weight goes up as the cube of the size of the prism ... that's pretty quick:

For a SWAG from 42mm to 56mm is 1/3rd bigger (56 / 42 = 1.3333) so the prism weight goes up by 2.37 whilst all the optics goes up by 1.78. The enclosure weight will go up by about the square too (it's pretty thin). A quick handwave and you can see the bin might weight approaching double the weight of the 42mm. That would be 46 to 50ish oz for the Zeiss FL. All the bits contribute so you have to slim it down somewhere.

Nessus said:

And Kevin Admittedly you know way more about optics then I do but I can't get over the effect of when you pull a projector from 6 to to 12 feet the image gets twice as big and half as bright is not a big part of what is going on here. I'f I'm reading you right you're saying that's not at all the reason for the small FOV.

Could you maybe explain a little better for us guys that don't understand the optical construction of lens systems as well?

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Toilet role example is the simplest one I can think of. Just limit your FOV with your hands. The brightness of the image doesn't change just the amount of image you can see changes.

The same would be true if you put a toilet roll in line with the projector: smaller circle on the screen but the same brightness on the screen.

Changing the magnification does change the brightness of the image. When you move a projector back from a screen you are changing the magnification (move it twice as far back the image gets twice as big (i.e. 2x magnification) and the image is 1/4 times as bright because it's got twice a big vertically and twice as big horizontally).

But you can change the FOV of a bins (by changing the size of the aperture stop) but keep the magnification constant. The brightness doesn't change in that case.

Tell me, Kevin.....what "measurements" and taken by who? Ya ever do much target shootin'? The rifles and shortarms used for that, even tho' many of them are custom-built versions of production guns, are substantially heavier than "stock" (no pun intended), and not just because of the usually heavier barrel (installed to reduce barrel whip). Shooting from a rest, prone, or braced the gun weight doesn't matter to any degree, but shoot offhand (standing alone, downrange targets over 100m away) and the resistance offered by the weight will give you a steadier sight picture every time.

It's the same with binos. I have a 12x50SE & a 15x50IS and looking at distant objects, whether still or moving, I actually get an ever-so-slightly steadier hold with the Canon (and I almost never use the IS any more....a set of batteries now lasts over 6mo. If I do use it, it's because of wind gusts, and then no more than 4-5 sec), perhaps in small part because of the body shape, but more due to the 14oz extra weight. I've had both for several years (8 & 7 respectively) and have done dozens of my own tests....the heavier glass consistently shows a steadier image, this in spite of each movement being magnified 15times vs 12times. And I'm not talking about resolution of the image; naturally with the extra 3x the Canon wd have a slight advantage (that said, I've placed both on sturdy rests side by side and the Nikon, due to having as good an optical complement as has likely ever been put in a consumer bino, will show all the detail at, say 400m, that the Canon will...). It's just the image is just less "busy". And, finally, it takes a fair amount of practice and trial 'n error to find your own best method for a steady hold. But believe me, the little extra weight helps.

I suppose this could be argued ad infinitum and there'll always be some test or comparison done somewhere by some one or some group that says such-and-such is this way or that. My observations are based on long (too long....) experience and practice. Don't take that to mean I'm an "expert", just a seasoned practitioner....


'v

Spyglass,
The measurements (I believe EdZ has performed such experiments over on Cloudy Nights, and reported that weight made no difference at least to "him") that weight doesn't help steadiness fly in the face of common sense, physics, and long accepted target shooting practice. In fact that raises a flag to me--your experience with heavy rifles may have in some way conditioned you to take better advantage of heavy binoculars. More work is required to jiggle something around when it is longer and more massive, that much is simple. But, as your arms tire, the muscles will start to spaz, and work harder to jiggle.

I don't doubt EdZ's results, but the whole business of resolving detail while hand holding is so dependent on the individual, duration of the observation, perhaps on the ergonomics, perhaps on the particulars of the quality of the view, perhaps on experience, that I'm not convinced either that mass independence is a simple nor universal truth. If you are an experienced observer, sensitive to such details, and more mass seems steadier to you, then it IS steadier for you. To insist otherwise is to fly in the face of subjective experience, which is the supreme decider in the land of binoculardom. So flow with it, and enjoy, but it's not the same for everybody, all binoculars, nor all usages.
Ron

Ron - Target rifles have more mass for several reasons: to reduce recoil, and to stiffen the barrel by adding weight by diameter and length which helps steady the rifle from various positions. Competitive shooters wear padded jackets and gloves to help lessen the pulse factor, which all of us in a steady position sense when using our binoculars.
Longer barrels are actually an asset in shooting (not for pure accuracy - bench rest shooters now use very short barrels to reduce barrel whip) as the shooter counteracts the forward weight pulling down.

I prefer a binocular with some heft when birding, but then I am always seeking an improvised rest, whether it be a tree limb or sitting down, etc. I would love to use my Zeiss 15x60 BGA birding with its stunning view, but my skinny neck can handle only so much weight - 55 ounces is too much!

Question. Is it the reluctance of the optical engineer to add larger prisms to the Zeiss 10x56 because of weight? Or perhaps there is a cost factor, too?

John

A comparative 8X56 FL versus 8X56 Classic, this latter a brand new if posible, is waited.

ronh said:

Spyglass,
TI believe EdZ has performed such experiments over on Cloudy Nights, and reported that weight made no difference at least to "him") that weight doesn't help steadiness fly in the face of common sense, physics, and long accepted target shooting practice.
Ron

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I was repeatedly told that my Zeiss 12x45 wold be too light and therefore jiggle much more than heavier glass but have not found that to be the case. The lightness helps me hold them for longer periods of time and if i make a a proper bridge against my face I can hold them steadier than any other 12 I have ever tried.

Plus my 23oz 12x are with me while a lot of the people who so love their heavy steadiness have left their massive tanks at home.

to complicate things further (and I probably missed the announcement in another topic), the conquest series has just given birth to a 10*56. I had a quick look through them, and they feel very solid, but not overly heavy (950 grms). They have a wider! FOV than the victory, and should be an excellent choice for the price-sensitive and non-weight-lifters who want low light performance in a 10 magnification...

temmie said:

to complicate things further (and I probably missed the announcement in another topic), the conquest series has just given birth to a 10*56. I had a quick look through them, and they feel very solid, but not overly heavy (950 grms). They have a wider! FOV than the victory, and should be an excellent choice for the price-sensitive and non-weight-lifters who want low light performance in a 10 magnification...

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No, No no no, I promised myself this was it no more, aww damm.

temmie said:

to complicate things further (and I probably missed the announcement in another topic), the conquest series has just given birth to a 10*56. I had a quick look through them, and they feel very solid, but not overly heavy (950 grms). They have a wider! FOV than the victory, and should be an excellent choice for the price-sensitive and non-weight-lifters who want low light performance in a 10 magnification...

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Temmie,

Did you experience a wider field in the Conquests comparing them to the Victory's? I looked up the specs ( pure matter of interest, I need good owling bins...) and the 10x56 Conquests have 105m/1000m but the Victory's have 110m/1000m.

Best regards,

Ronald

I first wrote smaller FOV from my own observations, but it turns out in their specs they should have 344ft/1000 yards whereas Victory has 330 ft/1000 yards... The eye relief is the same, but close focus is not as close as Victory (13+ft), so that would be the only real difference in terms of optics.

Some other facts: ABK prisms, made in Hungary with glass produced @ Zeiss in Wetzlar.

I had the occasion to compare the FL range aginst the conquest series in a local optics shop.
What i could see was that the conquest had a much smaller sweet spot.
The overall building quality is more careless and sloppy.
Rubber coating gets easily dirty and stick which gives an unpleasant feeling after some time.Spot resistance is also bad after some time used.
They told me they are made in Hungary.
Though very bright and high contrast and resolution , they were not my cup of tee.

OK,

Thank you Temmie and Arran.

If I decide to spend big bucks I'll rather have the Dialyt 8x56.
Or a cheap Nikon Action 10x50 porro.
There's not much sense in spending aroud 1300 euro's for a sloppy binocular.

Best regards,

Ronald

Depends on your needs and style. the 10x56 conquests might suit me very well. I'm shocked to hear they are ABK, thier potential for lowlight performance is very good, whether they live up to that, that"s another thing entirely.

I could be wrong, but I think there is an error on the Zeiss USA website that lists the FOV of the 10x56 Conquests as 344'. This erroneous spec is also on the Eagle Optics and the B&H Photo sites as well.

The German Zeiss website lists the FOV as 105 meters, which translates angularly to 315', not 344'. I think someone made an error by simply converting 105 meters linearly to 344 feet and calling it a day.

So if I'm right, their lineup looks like this:

10x50 Conquest has a 300' FOV
10x56 Conquest has a 315' FOV
10x56 Victory FL has a 330' FOV

I've been laboring on an Excel spreadsheet of the big four binocular makers' top-end offerings, listing FOV, weight, close focus, and eye relief. The 10x56 Conquest FOV spec stuck out as perhaps being in error.

Thanks for the post Ken I was wondering about that myself, you're probably right on this one. I'm also still unsure if their ABK or not, They'd be awful close to the Victory in performance if they were.

According to the Zeiss website ( www.zeiss.de) both Conquest 8x56 T* and 10x56 T* have
Abbe - König prisms.
I think I'd like to compare the Conquest 8x56 to the ClassiC 8x56, to see which one I'd like to have.

Regards,

Ronald