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ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

New 32mm Trinovid binoculars (1 Viewer)

406ft at 1000 metres. Not at 1000 yds.

It may well be that Leica has also got it wrong.

This 9% error appears repeatedly here and elsewhere.

Very simple. Measure it directly. Preferably against star separations.
 
Too many vids, and ultras are no longer ultra, so it makes sense they consolidate down to Trinovid and Noctivid.

I would not be surprised if the Ultravid hung on as a mid-tier line to compete with the HT and SLC. It definitely fits a certain need, as neither the HT nor the SLC offer midsized models (8x32, 10x32), or a 7x42 model.
 
406ft at 1000 metres. Not at 1000 yds.

It may well be that Leica has also got it wrong.

This 9% error appears repeatedly here and elsewhere.

Very simple. Measure it directly. Preferably against star separations.

David

Having trouble finding a pair of stars 1,000 metres away and about 400 metres apart.
What do you suggest?

Lee
 
Lee.
Maggie and Jake Gyllenhaal.

P.S.
400m at 1000m is 22.9 degrees.
Even the 4x21 (3.5x21) Xtrawide is only 18.5 degrees.
The Nikon afocal adapters recently mentioned and the 2.1x Vixens should manage this.
At such wide angles I am not sure that the two measurements are applicable as one is a flat plane measure, the other a spherical measure.

Jake would have the Leica rangefinder to measure his sister's distance and the 1000 metres to the observer.
Needs good light and no foliage in the way, as one tends to measure the distance to a leaf and not to the distant observer.
 
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Lee.
Maggie and Jake Gyllenhaal.

P.S.
400m at 1000m is 22.9 degrees.
Even the 4x21 (3.5x21) Xtrawide is only 18.5 degrees.
The Nikon afocal adapters recently mentioned and the 2.1x Vixens should manage this.
At such wide angles I am not sure that the two measurements are applicable as one is a flat plane measure, the other a spherical measure.

Jake would have the Leica rangefinder to measure his sister's distance and the 1000 metres to the observer.
Needs good light and no foliage in the way, as one tends to measure the distance to a leaf and not to the distant observer.

OK Maggie and Jake it is.
I'll get my people to talk to their people.
Lee
 
Comparing this new Trinovid to the CL isn't really that flattering IMO, as I find the Swaro CL to be their worst offering, by far.

Agreed JG. Looked at the CL 8X30 in several situations. Good binos, but was never really impressed with either their build or optics. At this price range, there is far better options!

Ted
 
Lee.
We are both crackers. :)
Well, at least I am.

If Leica are claiming fields at 1000m, they should do just that.
Build a straight wall exactly 1000m away centrally from an observing platform.
Scientific lasers measure the Moon's distance to 10cm, so 1000m can be known to 1/1000 mm. But 10mm is good enough, even 100mm.
Or surveyor's equipment.

Then measure off the markings on the wall.

At 8 degree field I think the wall is actually 1,002.5m distant from the observer at the field edge.
However, with a 20 degree field the wall is I think 1,015.5m distant at the field edge.

I have a problem with these linear field measures.
The real world is spherical. The horizon is round not straight.
The Earth is not flat, except for the flat Earth society.
For military use, I accept that reticles measuring linear sizes are useful.

But I think in degrees for field sizes.

I understand Wernher Von Braun was asked to believe that we actually live inside a spherical Earth.
I doubt he actually believed that.

P.S.
How many metres at 1000 metres is equivalent to a 180 degree angular field?
 
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Lee.
We are both crackers. :)
Well, at least I am.

If Leica are claiming fields at 1000m, they should do just that.
Build a straight wall exactly 1000m away centrally from an observing platform.
Scientific lasers measure the Moon's distance to 10cm, so 1000m can be known to 1/1000 mm. But 10mm is good enough, even 100mm.
Or surveyor's equipment.

Then measure off the markings on the wall.

At 8 degree field I think the wall is actually 1,002.5m distant from the observer at the field edge.
However, with a 20 degree field the wall is I think 1,015.5m distant at the field edge.

I have a problem with these linear field measures.
The real world is spherical. The horizon is round not straight.
The Earth is not flat, except for the flat Earth society.
For military use, I accept that reticles measuring linear sizes are useful.

But I think in degrees for field sizes.

I understand Wernher Von Braun was asked to believe that we actually live inside a spherical Earth.
I doubt he actually believed that.

I think you have to prove you are crackers before you get accepted onto Bird Forum, so since we are both here, that probably means we passed the test with distinction.

We do live on a spherical world Binny but at 1,000 metres (or yds) I think we can agree that for this purpose the earth may as well be flat.

With your head in the heavens I can understand why degrees of field are your measurement of choice but for me, stuck down here on the ground, I like to have a field of view measurement at 1,000 metres because this is, in effect, the diameter of the FOV at that distance and I can get my head around it. I find that easier to visualise the view encompassed by the binos. Probably I could learn to grasp degrees of FOV too but since most of my viewing is done at less than 1,ooo metres I am not sure this would add anything.

Lee
 
Binastro, Lee

I doubt if manufacturers set out distances to measure FOV. More than likely they are done in the lab using a collimator lens set.

See the picture of my homemade setup with a scale I made and printed, the squares represent 1 degree.

The picture is of a Nikon 8x20 XL and specified FOV is 356’ at 1000 yards (6.79°).

You can make this test on top of your refrigerator; all you need is a lens of known focal length and print a grid for that focal length.

The problem with images, eye or photograph is that they contain only angular information, no distance information. To get distance information from images, you need two converging images with a scalar reference, process known as photogrammetry.

Best
Ron
 

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Thanks Ron.

Does the Nikon 8x20 XL have a distortion free eyepiece?

I am not sure if your photo shows slight barrel distortion or no distortion.
The problem in real life is that I think people measure the field at much closer distances than 1000 yds or 1000 metres, where the field size differs slightly.

Also hand held I find that the field is slightly larger than tripod mounted because of slight movement and eye memory.
And the IPD makes a difference if not set perfectly. Plus eye positioning.

My problem is that I think in angles whereas birders may think linearly.

Yet the AFOV even for birders is in degrees, which doesn't seem consistent.

And how does one describe a 180 degree field in feet at 1000 yds or metres at 1000 metres?
Is it infinite, or maybe not, as space is curved.

My professional telescope making friend used a collimator and pinholes at about 15m representing close double star to test his telescopes. And also to examine the star images in and out of focus.
 
Hi Binastro

I do not have exact answers for your questions, only observations.

Does the Nikon 8x20 XL have a distortion free eyepiece?
I am not aware of any optics that are distortion/aberration free. The aberrations may not be measurable with the equipment at hand though. Eyepieces in general have far more distortions than the objective just because of the number of elements and short focal lengths.

I am not sure if your photo shows slight barrel distortion or no distortion.
The problem in real life is that I think people measure the field at much closer distances than 1000 yds or 1000 metres, where the field size differs slightly.

The distortion does not matter as FOV only pertains to one tube, due to tolerances, each tube may have different FOV's. For you to measure FOV of two overlapping images, it would only be valid at the exact point of convergence of the two images for a given focus distance. The FOV accounts for all aberrations visible at the field stop.

Also hand held I find that the field is slightly larger than tripod mounted because of slight movement and eye memory.
And the IPD makes a difference if not set perfectly. Plus eye positioning.

To me, what you are describing is more of an issue of eye placement in relation to the optical axis with differing locations at the field stop rather than a FOV issue.

My problem is that I think in angles whereas birders may think linearly.

Yet the AFOV even for birders is in degrees, which doesn't seem consistent.

Can not argue the above two lines. Personally, I only think of FOV in angular terms since I can not see delineated distances in the image, only an apparent angular width.

And how does one describe a 180 degree field in feet at 1000 yds or metres at 1000 metres? 3141.6 meters for a 1000 m radius, half a circle with a 1000 m radius. In a flat linear sense, probably infinite.
Is it infinite, or maybe not, as space is curved.
Valid point, you cannot make direct linear measurements of a curve, it has to be done by a remote method by establishing a radius for a simple curve or a delta radius for parabolic forms or chord measurements for nonstandard shapes, fractal geometry is best method for highly irregular shapes. Or the focal length of the lens, think fisheye lens here.

My professional telescope making friend used a collimator and pinholes at about 15m representing close double star to test his telescopes. And also to examine the star images in and out of focus.

Thanks for the thoughts, best
 
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Thanks Ron.

What I mean is that some eyepieces are designed to be like high quality macro lenses, having less than 1% barrel or pincushion distortion. Although near the field edge these eyepieces suddenly have severe changes in magnification. Say the 7 element Russian eyepieces on 7x30 and 10x42? I am not talking about other aberrations only rectilinear.

With regard to hand holding, the increase in field size is because of slight hand movement so that one sees slightly past the stationary field edge. Because we remember views for fractions of a second two stars can be seen with just slightly larger separations than possible on a tripod.

If the IPD is deliberately set slightly wrong one can increase field size horizontally.

High quality binoculars usually have both tubes overlapping almost exactly on the stars. Less than 1% overlap. Cheap binoculars such as 6x18 Chinese can have massive overlaps even though, or because, they are more or less aligned to cope with poor mechanical parallelism.

Can you supply a simple minimalist drawing of the set up you describe in post 50, thumbnails. What sort of focal length lenses. Simple achromats or photo lenses?
I am not good with computers.
 
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Re post 53.
Hand held binoculars typically have 1% larger fields when I measure them compared to tripod mounted.

The two tubes generally have fields with a difference of less than 1.5% when I have measured them. Often I cannot discern any difference.

However, star images are often slightly better in one tube, maybe because one has been slightly skewed for collimation. In really good binoculars it is sometimes difficult to see any differences between the two tubes.

P.S.
I am not sure that the FOV accounts for all the aberrations at the field stop, in practice.

If using very bright stars like Rigel, I think that the light can spill in from just outside the field stop.
I.e. It is impossible to determine when the star is at the field stop, or just within or just outside. Maybe the light spills in from poor atmospheric Seeing or reflections. I don't know the reason, but determining if the star is at the field stop is almost impossible.

P.P.S.
It may be because the collector, the eye and entrance pupil is not a point source but 4mm or 5mm across that the field stop is seen from slightly different positions that I cannot determine when a bright star is at the field stop. The star reduces in brightness as one moves near and across the field stop, but may vanish beyond the theoretical field stop.

It is late now.
 
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Hi Binastro,

This information is probably already somewhere on the forum so I will give an abbreviated overview of simple collimators.

A collimator is nothing more than lens (better quality lens give better results) with an image or reticule at the prime focus.

See the pictures attached. The simplest form for most is the 50 mm diameter lens with a 200 mm focal length set on top of the TV. The two pictures are of two different USAF targets. The glass target you can see group 5 element 2 or 3 pretty well. Element 3 at this focal length would be about 26 arc seconds per line pair. This is not the most accurate/stable setup, but good enough for comparing a couple of cameras or binoculars in a hurry without going outside.

The picture of my messy optics bench shows my 5” multi element lens at the top of the picture. It has about a 450 mm focal length and to the right of it, mounted on the optics rail is the target shown earlier. I use this open setup because I change the targets for different measurements. On the table you can see other collimator tubes of various purposes.

The picture of the collimator tube is my resolution collimator. For stable accurate results the elements have to very solidly mounted and accurately adjustable. The objective on this tube has very fine threads to adjust to the focal length of the objective.

There are many advantages to collimators over outside work, light control, temperature control, wind currents, etc. Plus you can do all the measurements on a table top instead of wandering all over the yard and trying to measure things off.

For the example we are discussing, if I put a paper with a grid with lines spaced 3.49 mm at a 200 mm focal length then each grid square would represent 1 degree.

The big advantage of a collimator is that all measurements are made a infinity focus, the optics design point.
 

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Thank you very much Ron.

For astro scopes the easiest method for me is the star drift method.
Using a star on the celestial equator, such as Orion belt stars, if the time to drift from one side of the field to the other, with the star crossing the centre field as nearly as possible, takes 4 minutes then the field size is 1.003 degrees. Say 1 degree. The mount has to be very steady.

For spotting scopes this is a bit tedious as a 2 degree field takes about 8 minutes.

For a 7.5 degree binocular field, very tedious, about 30 minutes. Like watching paint dry, especially if the star misses the centre of the field. And binocular tripods move.

As you say a set up indoors has much more control.

Why are field size measures useful?
I suspect that Leica's figure might be wrong, so measuring it will give a correct value.

For me most useful.
I saw a satellite pass fairly near Jupiter using the Canon 18x50.
I was able to give an accurate estimate of its closest angular distance from Jupiter timed by radio controlled clock to 3 second accuracy.

My astro satellite specialist was able to tell me that it was an obscure rocket stage with full details.
 
A couple of observations on the Leica - without having seen it yet

  • A lot of people moan about the weight of the Leica. It's still a heck of a lot lighter than most modern 42mm roofs. And yes, the difference between 650gr and ~800gr (and more) is *very* obvious in the field. At least to me. It's also smaller than any 42mm roof. The weight is, at least to some extent, the price we have to pay for being able to watch our knees through binoculars now, rather than just the feet as with most other 8x32s. Now, that's *real* progress ... ;)
  • Others get their panties in a knot over the field of view. Sure, 124m/1000m doesn't seem that generous, but if Leica managed to keep the veiling glare down to a minimum - and that's a lot easier with smallish fields of view - I'd take that over an additional 15m of field of view anytime. No questions asked.

So, forget about the weight and the field of view for a moment. the really interesting questions, at least as far as I'm concerned, are:

  • What's the optical quality like, compared to, say the Zeiss Conquest HD? Or the Zeiss 8x32 FL? Contrast, colour, glare resistance, ability to resolve fine detail?
  • How robust is the 8x32? Still among the best binoculars made, or did Leica cut some corners?
  • Where is it made? Is it a "real" Leica or some Kamakura model with a red sticker?

Anyone got any answers?

Hermann
 
I saw CameralandNY has these for sale, hadn't heard they were coming out. Maybe it's a sign of the successful sales of the new Trinovid Hd 42. Curious to see reviews, to me it seemed priced a little higher than the competition, like a Zeiss conquest HD or the Cabelas instinct Hd. My wife has the latter and it's a great bino, but the ergonomics aren't great for me.
 
At the risk of repeating myself: Anyone seen the 32mm Trinovids yet? Either the 8x32 or the 10x32?

I find it rather curious there's been so little comment after the initial flurry of posts.

Hermann
 
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