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Binoculars

 
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  #8  
Old 11-07-2007, 07:35 PM
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Join Date: Apr 2004
Location: N Y.
Posts: 53
Not exactly for long range, but...


LEUPOLD YOSEMITE 6X 30MM
PORRO PRISMS BINOCULARS

Hi Guys:
Some things are changing in the world of optics. It uses to be that you had to spend a good chunk of money to get good optics; after all, it is difficult and requires expensive lenses, expensive anti-reflection treatment, some quality components, and precise work to mount it all and to get the optics to perform as they should.

Some optical aberrations and distortions can only be corrected the best possible. It is difficult to make good glasses to deliver a flat picture of good quality when the light ray has to pass through curved lenses.

But the new computerized optics programs than the optical engineer is using these days has brought a solution to the trial-and-error and time-consuming work that was needed to produce decent binocular blueprints in the old days.
They are several factors, beside objective size, that will determine how good the image quality in binoculars will be.
They include optical coating, quality of optics, distortions and aberrations, optical alignment, and manufacturer tolerances.

THE LEUPOLD 6X30MM YOSEMITE



Back in 1970, I came back from the jungles of South America in one piece, but minus my good Zeiss binoculars. In seventy-one, freshly married and planning a trip, I was in need of a binocular, but my budget was $25.00 (you bought a lot of gasoline with $25 in the seventies).

After looking at several on that price range, I selected a 7x35 Porro prisms Sunset (Japanese). It says in big white letters that it is an extra-wide angle (10 degrees), which, at the time, didn’t affect me since my young eyes in those days didn’t need prescription glasses (wide angle will reduce the eye relief, an important consideration to eyeglass wearers). But poor eye relief means that you have to get your eye very close to the lens to see the whole picture, which can put a drop of perspiration on the glass in hot days or fog them in the cold climate.

It also makes it impossible to focus the edges of the glass. The center will be in focus, but the edges will be blurry: this distortion is called “curvature of field,” so keep in mind to stay away from wide field-of-view glasses if you want your picture to be relatively sharp all around.

It also says that it has coated optics, which means (and I can see it) that only the exterior lenses have been coated on the outside, and that translates that a good amount of light is going to be lost throughout reflection, making them inferior to glasses that used multi-coating lenses to see in deep shadows and at dusk .

LEUPOLD YOSEMITE AND SUNSET BINOCULARS




So brightness and sharpness are affected by the amount and quality of the coating that are used in binoculars- the more the better (as much as seven coats for glass surfaces are been used now). When you think that as much as 4 % of light is lost through reflection from uncoated surfaces and that a binocular uses a total of 14 or more optical glass inside them, you will understand why multi-coats are so important for light transmission.

YOU CAN SEE THE DIFFERENCE IN THE COATING BETWEEN THEM





I can see that the lenses in the Sunset haven’t been corrected for chromatic aberrations, which means that the colors will be more muddled if I were looking at birds. Of course, correcting for color needs a set of different glass, all keyed to a certain spectrum on the color scale, which makes binoculars more expensive and will have taken me out of my $25.00 budget in those days.

Be careful of cheap binoculars with big lenses (50 to 60 or more mm of objective), as the bigger the lenses are, the more intense the chromatic aberration will be, unless it is corrected by low dispersion glass that will make the binoculars much more expensive.

Good glasses should be corrected for another aberration called “astigmatism,” which is the effect of the light at the edges of the glass that is elongated into an oval that points toward the center. This together with the “curvature of field” tends to make glasses fuzzy toward the edges. I believe my Sunset 7x35 glasses shows a good degree of astigmatism.
Of course, my 38 year-old glasses also show a good deal of spherical aberration. There is no way that ray of light passing trough the center of a normal glass can be in the same focus as the ones passing through the edges. This makes the image loss detail. Newer binoculars are now using an aspheric lens (usually in the oculars) that corrects the focus by bringing the center light rays to the same focus as edges rays of light, making the glass brightest and with increased contrast.

My Sunset glasses show some “barrel distortion.” Were a straight line placed on the edge of the field of view, it will bow outwards at the center. If that line will bow inwards at the center, it will be called “pin cushion distortion.” Good glasses correct for this distortion with quality glass, although you can still find just a little of it even in expensive glasses.

AT LEFT IS A REGULAR OPTICAL GLASS WITH CURVED SURFACES, AT RIGHT IS THE NEW AESPHERICAL LENS



My Sunset 7x35 binoculars did fine for a few years (I didn’t use them much in low light) until I replaced them in my neck for a Bushnell Custom Compact 6x 25 CF in 1974, which then started my love affair with 6x lenses.
The Bushnell Custom Compact are beautiful binoculars; light, small, and highly good optics that still sells today and is highly sought after by those that don’t want to carry full binoculars when birding or hunting.

The street price on the Custom Compact is around $250.00, and it is well worth it. I have used mine for years in hikes into the high peaks of the Adirondacks. I think so highly of them that I had bought a pair for my wife in 1976.

The only thing I always wondered was how it would perform in poor light if the objectives were as big as 30 mm instead of 25mm.
Now, after so many years, another 6x binocular has fallen into my hands, thanks to the advice of FirstFreedom, a member of TFL forum.
The Leupold Yosemite Porro prisms 6x30 is in my hands now and a beauty it is, both physically and optically.

This Leupold is miles ahead of my Sunset 7x35, the comparisons I made in low light gives a great edge to the Leupold even than the objectives are 5mm smaller in the Leupold, and the numbers for exit pupil gives both the same 5mm value (35 mm divided by 7x = 5mm and 30 mm divided by 6x = 5mm of exit pupil). The Leupold outperforms my Sunset glasses, due to better coating and better optics.

I was surprised when I put both in my fish scale because both weigh 1 lb. 1 oz., but the Leupold feels much lighter. The rubber covering and the twist up eye-piece guards are a big asset for the Leupold, as the Sunset doesn’t have any eye-piece guards at all. The Leupold Yosemite comes with a rain guard that is tethered to the elastic strap and regular caps in the objectives. That is one thing I would like to see changed; objectives should be protected with covers, such as the ones find in my Nikon Monarch, that are attached to the binocular body and not by caps that are easily lost.

Optically, the Leupold Yosemite is very superior to the Sunset glass. Some aberrations and distortions are still in the glasses, but only in a reduced amount and in the edge of the field of view, and it is okay, because only very high quality glasses like the Swarovski and Zeiss can make those defects disappear almost completely, and after all, most of us look through the center of the field anyway, and not through the edges.

Color seems to be fully corrected in the Yosemite, although I have yet to find a proper test medium to judge it (hummingbirds or woodpeckers).

Sharpness and definition are well up in the scale, leaving the Sunset glasses in the dust. That all this optical quality is attained at the cost of only less than a hundred USD is a miracle of new manufacturing techniques. I am well pleased with the new Yosemite binoculars by Leupold, I took a calculated risk when I bought them, based on the Leupold name in others optics and I am well satisfied with what I got and for the little money I got them.

Cheers
Watchmaker
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  #9  
Old 11-12-2007, 01:00 AM
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Join Date: Apr 2004
Location: N Y.
Posts: 53
LEUPOLD KATMAI 6X32
BINOCULARS

I must be off my rocker. I have binoculars coming out of my ears and I just went out and ordered another.

This time the culprit that captured my heart is the Leupold Wind River Katmai binoculars, a roof prism model that is quite compact and light but offers superior viewing compared to full sized premium binoculars.

I had seen them before in catalogues such as Cabela’s and Red Head, but I never got interested because I thought they were only available in 8x32.
Having recently bought the Leupold Yosemite 6x30 binoculars, I became interested in seeing what others models they offered and discovered that the Katmai were also available in 6x32.

The reason that I am particular about the six power binoculars is that they offer a perfect magnification for the kind of close woods hunting I do.
When available in the 32 mm sized objectives, I am getting a 5.33 mm of exit pupil, giving good quality optics; the right pupil opening for the low light condition that I often glass under. I never saw any reason to own them in 8x32, as I will be getting only a 4 mm of eye pupil: no doubt good for daylight, but no good for the use I put binoculars through.
If I am going to use an eight power, then it will have to have 42 mm objectives to give me 5.25 mm of eye pupil. I already have two great pairs of glasses in that size (the Pentax and the Nikon) and I use them often, but the new Leupold Katmai is going to fulfill the same task, using less bulk and weight, which is important for me in certain instances.

Here is a picture of them together so you can appreciate the size difference. From left to right: the Leupold Yosemite 6x30 Porro prisms, the Leuopold Katmai 6x32, the Nikon Monarch 8x42, and the Pentax DCF 8x42.



I am fifty miles from New York City, so it is not possible for me to go to check binoculars every time I have a whim for them (and it happens often), so I ordered the Katmai over the mail knowing that you will not always get something over the mail that will fulfill your expectations. No such problem occurred with the Katmai binoculars, though: they are great and exactly what I expected them to be for a glass of this price and more.



I performed the usual checks and was amply satisfied with the optical quality and mechanical precision of the glasses. The ergonomics are also great for a glass of this size, and I was well pleased with my purchase.
One aspect of this purchase is worth mentioning: when looking at the Katmai 8x32 that Cabela's and Red Head have in their catalogues, the price for them was hovering around $400 to $420. I bought the Katmai 6x32 over the web for $289 shipped.
Now the question is how they compare optically with the lower priced ($98) Porro prism Leupold Yosemite binoculars, and if the $200 difference is noticeable in the optical quality.
If that difference is there, I can’t notice it! Both glasses performed well in my low light test and both are sharp and with enough resolution to satisfy the most rabid birdie.
We all know that roof prisms are more expensive and difficult to make well, so part of the money goes toward that end, perhaps of influence in the price is the fact that the Katmai are made in Japan and the Yosemite in China; we know that our money buys more Yuan than Yen.



So what is going to happen to the Yosemite 6x32 now that my new love is the Katmai? No problem on that end, since my son already declared ownership of the Yosemite, as he recently took them on a trip to Florida’s Everglades, using them in the Aninha trail and in the Flamingo point.
He came back saying, “Dad, you will never these back; they are great glasses!” Now if I can just hide the Katmai from him until he goes to college in September, I will be fine.

For those that don’t understand the obsession that possesses me, I am here to tell you that there is nothing better than to look through quality glasses. I am just in a rush to finish typing this to go and sit in my patio and look for the red-tailed hawk that has been visiting us here lately.

Cheers,

Watchmaker
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  #10  
Old 11-17-2007, 06:59 AM
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Join Date: Apr 2004
Location: N Y.
Posts: 53
HOW TO GLASS
Well, what now, you just put he binoculars to your eyes and look through them, right?

Just in case we have new binocular users here, I am going to explain the mechanics of glassing the right way. Not long ago a new hunter in the family was showing me his new binoculars that I noticed were adjusted in the interpupilary distance with a far greater length that I knew his eyes to be set.
When I questioned him if he was not seeing two uncompleted circles when looking through the glasses, he admitted it and was surprised when I told him that the binoculars are supposed to deliver only one circle. I guess he has seen too many movies where the view trough binoculars are shown that way.

So our first business with the binoc is to adjust the interpupilary distance by bending the barrels at the center hinge until our eyes see only one circle; that will ensure that the optical center of the glasses is in line with the center of our pupils.

Second is to adjust the diopter wheel that is usually in the right barrel; as not everybody has 20/20 vision, this wheel will adjust the focus for your right eye. To accomplish the adjustment cover the right objective with your hand or objective cap, look through the glasses and adjust the center wheel until the view is sharp and clear, now cover the left objective and adjust the diopter wheel until the view is sharp.

I used for years to do this in the reverse sequence, adjusting the diopter first and then the center wheel, you get the same results.
Look at the markings at the edge of the wheel to remember the settings in case somebody changes them, (I just put a small drop of white out correction fluid to mark the setting).

The eye relief is fixed and in modern binoculars quite generous, but the eye cups collapse to use the binoculars with your eye glasses, some models can be adjusted to stop midway or at increments so you can get your oculars lenses as far or as close as you want to your eye glasses.

Now you are ready to glass, if yours glasses are 10x they are marginal in how steady you can hold them, people varies but 10x is the magnification that can do with some serious help in holding the glasses.

Sit down and brace your elbows against your knees or sunk them into your stomach looking for the best stable position, grasp you binos with both hands but leave your index fingers free and anchor them against your temples, or alternatively grasp the edge of your cap’s bill to add another anchor point. What you are looking for is to minimize or cancel any tremors, as a jumping up and down picture magnified 10x will not let you appreciate the detail that you bought the glasses for.

With the 8x you have a little more freedom from those tremors, I have a very steady hand (I am a watchmaker) and can hold 8x glasses with one hand for relatively quick looks, but it is not recommended, after all glasses are not for quick looks.

Don’t scan with glasses, your vision should be concentrated in the center of your view, and the glasses when moving, should be moving in very small increments when you are sure that the picture that you are seeing is completely understood by your brain.

The part of the eye that does the stationary looking and captures detail is very small; it is called the macula and covers only two degrees of your vision. When looking through 8x glasses this angle decrease to ¼ of a degree, so if you want to capture the detail that you pay so much money for, keep your glasses steady and look through the center of them.

The crouch and the belly down position are also glassing positions that should be not overlooked, take a tip from African hunters and steady your glasses in the standing position with the aid of a mono pod or shooting sticks or even a walking stick.

In carrying your glasses you can do as the African white hunters do and use a long strap to place them out of the way in the left side of your body at waist level and under your arm, or hang them from your neck but with a very short strap, so they ride high on your chest and will not swing and strike another object when you bend down.

There are in the market some harnesses that will keep your binoculars close to your body when you move around, but they usually interfere with other equipment, at least in my case as I wear a back pack most of the time but for those that carry only the glasses those harnesses work well.

Cheers
Watchmaker
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  #11  
Old 11-17-2007, 11:43 AM
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Join Date: Jan 2004
Location: Blackfoot, Idaho
Posts: 8,121
Ok, all of above being said;

I need to upgrade my binocular situation. I'm using a set of 10X25s that are of reasonable weight, quality and functionality. They serve me well during the brightness of the day. The downers are too small of a field of view and usefulness during the critical low light conditions.

The fellow I was with had a set of Swaro 10X50 EL(??) which I would rate at top of the line for usefulness in all respects. Limiting conditions to this Swaro bino are cost and weight (They weigh a ton.)

I have been doing the shopping thing for the last few days inspecting whats available (Sportsman's Warehouse and local sporting goods stores)

What would be a good recommendation for a LRH use bino where distances are, at times, measured in miles and shadows are prevelant, such as large deep canyons were one side is dark most of the day. Also during the early and late part of the day, the sun is a real bother when low in the sky.

I found a set of Nikons that seemed to me to out do a set of Leicas for about a third of the cost???


Thanks

Roy
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  #12  
Old 11-17-2007, 09:30 PM
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Join Date: Jun 2006
Location: Memphis, TN. Soon to be Casper, WY.
Posts: 494
I bought a pair of Leica Geovids. I've never been sorry. The resolution is the best I've ever seen. Low light is great, too. I got the 10X42. Plus I don't have to carry an extra lrf...
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  #13  
Old 11-18-2007, 11:22 PM
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Join Date: Jun 2004
Location: MS.
Posts: 171
Quote:
Originally Posted by royinidaho View Post
Ok, all of above being said;

The fellow I was with had a set of Swaro 10X50 EL(??) which I would rate at top of the line for usefulness in all respects. Limiting conditions to this Swaro bino are cost and weight (They weigh a ton.)

Thanks

Roy


Roy,
The 10x42 EL's are one of the lightest weight full size binos on the market. I'm pretty sure you were looking at 10x42 SLC's or 10x50 SLC's. I have had them all literally (Swarovskis, Leicas and Zeiss) and I can tell you from experiece that the Swarovski EL's are the best class on the market to day! IMHO.......... I have the 8.5x42 EL's and a pair og Leica 10x42 BN's right now and average daylight viewing is close to the same but early morning and later evening the EL's shine bright. BIG DIFFERENCE!!! Now.........I know the exit pupils are slightly different but but the difference is amazing. I will be trading the Leicas in for another set of the EL's ASAP.
Your milage may vary........
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