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- Magnification and move vision:

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Old Thursday 9th January 2020, 07:20   #76
Rico70
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as a general reply to your responses thus far, it doesn't seem to me that you experience motion blur as I and others do. As I noted before, magnifying the image increases both the apparent amount of motion as well as the _speed_ of the motion. It is the latter that is so destructive to the magnified view. The speed is too fast for me to process most of the time. When you watch movies, does it blur into continuous motion for you, or do you see stop-action frames? :)
I don't know for sure, but I don't think it's a question of speed. The angular speed is proportionate and certainly my view also sees blur.
But I only see the flickering at 24fps of the cinema, and not every single frame, I think like everyone (or almost). Not you?
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Old Thursday 9th January 2020, 08:31   #77
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Post 71.

The 120 arcsecond movement at 10x will still be 120 arcseconds at 100x, not 1200 arcseconds.

The crab nebula pulsar has a pulse time of 30 per second.
A decade before it was discovered a female member of the public at an observatory public showing said that the star was pulsing.
The director told her this was incorrect.
She said 'I am a pilot and that star is pulsing'.

Had she been believed she would have discovered it a decade earlier.

With old T.Vs I could easily see pulsing at perhaps 50 or 60 cycles per second with side vision, but not with central vision.
Neon tubes bother me.

Generally 24 fps is acceptable.

I would think that keeping a 100x binocular within a half degree field is fairly easy hand held.
I will try it hand held if I can with my 25x-135x80 binocular at 100x.

But all of this post does not answer the fundamental questions of hand held binocular views and hand shake in practice.

And as anyone knows a 3x binocular has very little apparent blur, despite it moving a small amount.

Also I think that a 400g binocular shakes more than a 1300g binocular, because of inertia considerations.

I have no problem hand holding the 15x70 Revelation, the same more or less as the 15x70 Skywatcher.
I also had no problem with 20x60 or 20x80.

I repeat.
Using the 100x binocular hand held unbraced will not show the fine detail if the 100x binocular was firmly mounted on a good tripod.

Also the Canon 18x50 IS will show more fine detail with the stabilizer on than with it off unbraced.

B.
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Old Thursday 9th January 2020, 10:13   #78
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Test 1.

10.45 a.m.

25x70 Skywatcher.
Chinmey pot 124m distance.
Bright sunshine.
Eyecups folded down to minimum.

Initially very unpleasant holding body with two hands.
Then held end of left barrel with left hand and right hand holding the body.
Steadier but still unpleasant dancing of image.

Yes, the bird dropping on the chimney top was seen for the first time in a bright image.
But the fine detail is lost because of the dancing image.

Switching to Swift 8.5x44 HR/5.
What a relief.
The bird droppings are visible, but I haven't really noticed them before.
But the finest resolution for me is similar hand held with both 8.5x44 and 25x70.

The Canon 18x50 IS is in a different class altogether when it comes to fine resolution when the IS is switched on.
The Canon 10x42L is also streets ahead of the 8.5x44 and 25x70 with fine resolution.

So yes, the larger scale and bright image with the Skywatcher 25x70 immediately showed bird droppings on the chimney in a bright image.
But the fine resolution is just not there hand held.
However, a better example of the Skywatcher 25x70 should do better.

For me, the dancing image hand holding this 25x70 is just unpleasant.
If someone doesn't have an IS binocular, I suppose this is what they put up with.

I have seen though that the Zeiss 15x60 is much brighter than the Canon 18x50 IS on the night sky or in dull conditions, but hand held the Canon beats the Zeiss 15x60 with fine resolution.

B.
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Old Thursday 9th January 2020, 10:34   #79
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Test 2.

Thought this was the 25x-135x80, but unboxing it is the as new Helios 15x70 Waterproof long eye relief binocular.
I think this is the Quantam under a Helios name.

This 15x70 is high quality and heavier than the Skywaycher 25x70.
It is rubber armoured.
The Skywatcher 25x70 has a foam support between the barrels when boxed, because they are so fragile.

I see the bird droppings on the chimney top very well in a bright image.
Fine resolution similar to Skywatcher 25x70 hand held.
Image steadier, but too heavy for me nowadays hand held.
It has an Opticron tripod adapter, and this is what I used some years ago on a tripod when it gave excellent views.

Not sure where the 25x-135x80 is.
So that's all for now folks.

And I don't like either the Skywatcher 25x70 or the Helios 15x70 Heavy hand held.
But others might especially if they eat their spinach.

B.
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Old Thursday 9th January 2020, 12:47   #80
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In the above tests in bright sunshine the 8.5x44 binocular was probably acting as an 8.5x22 binocular.
The 25x70 as a 25x63 or 24x60.
The 15x70 as a 15x38.

The coarse detail was better seen in the 25x70 than in the 8.5x44.
The coarse detail was about the same in the 15x70 and 25x70.
This coarse detail was just bigger and brighter in the bigger binoculars.

But the fine detail was similar in all three binoculars.

In the 25x70 the full amplitude of the oscillation was about 4 arcminutes, with wild swings to 8 arcminutes if I didn't try to hold it steady.
The amplitude was larger up and down than sideways.
The binoculars were all completely unbraced and I was standing unbraced.

So I would expect the oscillations to be well inside a 100x binocular field hand held.

I was not rested.
When I am well rested I can do about 50% better hand held.

Normally when using a high power binocular I would brace it as well as possible.

B.
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Old Thursday 9th January 2020, 13:29   #81
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Thank you for these posts Binnie.

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Old Thursday 9th January 2020, 17:58   #82
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I tried handholding at 80x over the holiday by plugging an 8x binocular behind a 10x (monocular view only). I’d done this as a kid years back when I had no telescope. I could keep the moon fairly well centred, but no way was any real detail visible.
One thing that I don’t remember being mentioned is people looking at stars at night, this really makes minor shake clearer, try looking for the faintest stars in clusters (eg the Pleiades). For me even at 10x I prefer using a monopod to give me the better views.

Peter
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Old Thursday 9th January 2020, 18:45   #83
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Hi Peter,

With the Canon 18x50 IS I gain 1.5 magnitudes on faintest stars when the IS is switched on, compared with switched off.
That is 4 times fainter.
The faint stars are tiny.

The same with most of the Canon IS and other stabilized binoculars.

I could not read a hotel sign with my Celestron 20x80, best of three.
The binocular was supported on several thick telephone catalogues.

So I viewed with one side of a Russian 7x binocular, just hand holding behind.
140 times magnification.

I easily read the hotel name at 11 miles, from the eighth floor over suburbia.

What I find surprising is that the pocket Canon SX730 IS camera easily outresolves the Canon 18x50 IS.
I don't think people realise how good IS is, either with a binocular or a camera.

I compared the hand held 25x70 Celestron Skymaster to the Canon 18x50 IS reading a sign with small print in a window about 40 metres away, about an hour ago.
The Canon is almost twice as good as the Celestron for me. I.e. twice the detailed resolution hand held.

However, the Skymaster is supplied with a tripod mount, and if anyone uses this binocular it would in my opinion be sensible to use it.
Why make life difficult?

I did find that sweeping the sky with the Celestron 20x80 hand held, faint galaxies were picked up.

Comet Halley was better seen by all of us on La Palma using the Celestron 20x80 hand held unbraced compared to a mounted 6 inch Newtonian.

Regards,
B.

Last edited by Binastro : Thursday 9th January 2020 at 18:52.
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Old Thursday 9th January 2020, 19:19   #84
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The 120 arcsecond movement at 10x will still be 120 arcseconds at 100x, not 1200 arcseconds.
Forgive me if I insist, but if the Moon appears 5 wide with 10x, with 100x it will appear 50 wide.
And once again math is not an opinion.

Whenever you give your opinion, try to make a better distinction between what you find written. It is not possible every time to have to discuss what 2+2 does.

Do you agree?
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Old Thursday 9th January 2020, 19:30   #85
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I thought you are talking about binocular movement.

If the binocular amplitude due to hand movement or shake is 120 arcseconds then it is 120 arcseconds for any magnification.
With the same binocular, but various magnifications.

An eyepiece lens could be removed.
It would still be 120 arcseconds amplitude.

B.

P.S.
I suppose the difference is the real movement and the apparent movement.

Last edited by Binastro : Thursday 9th January 2020 at 19:37.
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Old Thursday 9th January 2020, 20:44   #86
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the physical shake will be the same, but the apparent angular motion will be amplified by the magnification. Alton really do need a fixed optic when using high powers. Of course the ability for the eye/brain to deal with motion depends on the amplitude and smoothness of the motion. My 12x IS bins give a “floaty” residual motion, which is fairly easy to live with and resolve small details.

Peter
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Old Thursday 9th January 2020, 22:17   #87
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The binoculars to which you refer, is a fancy binoculars to give an example.

If instead you refer to the 25x, it is the Celestron SkyMaster 25x70 which that actually weighs 1350g (and not 1200g as I had written elsewhere).
I just wanted to know what high power (e.g. 25X) binocular you're talking about.

For the record, how many people do you think use a 25X70 bin for birding?
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Old Friday 10th January 2020, 06:49   #88
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I just wanted to know what high power (e.g. 25X) binocular you're talking about.

For the record, how many people do you think use a 25X70 bin for birding?
Pileatus, thank you for reminding us that we are posting on Birdforum as a birding community. On visits to nature reserves and on ferry boats sailing out to the islands off the west of Scotland I always try to see what make and model of binos other people are carrying. I have never seen anyone carrying binos with an objective size bigger than 42mm so I conclude I have never seen anyone with a higher mag than 10-12x.
Apart from myself on one mad visit to Suffolk when all I took was a Conquest HD 15x56. The view seemed to indicate permanent earth-tremors were shaking Suffolk constantly.

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Old Friday 10th January 2020, 08:59   #89
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Originally Posted by Troubador View Post
......
...... On visits to nature reserves and on ferry boats sailing out to the islands off the west of Scotland I always try to see what make and model of binos other people are carrying. I have never seen anyone carrying binos with an objective size bigger than 42mm so I conclude I have never seen anyone with a higher mag than 10-12x.

.....
.....
Lee
Tks Lee.
Same experience here.
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Old Friday 10th January 2020, 22:55   #90
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how many people do you think use a 25X70 bin for birding?
However, it seems more of a rhetorical question than a useful one.

The Celestron SkyMaster 25x70 was born (obviously from the name) as an astronomical binocular. Otherwise they would have called it "BirdMaster".
But this does not mean that it can't also be used to observe birds, especially at greater distances.

Of course, the 25x70 format is substantially too bright for daytime and also too heavy to held hand and carry.
But I am instead open to the fact that lighter formats, such as 25x56 and 25x42, can represent excellent tools, ideal both for playful observations, and for long-range identification and recognition.



There are also practical supports, effective and light, designed to support and improve tremors ...
http://www.fieldopticsresearch.com/s...o-x4288958.htm

https://media.rainpos.com/833/binopo...0819100555.jpg

Last edited by Rico70 : Friday 10th January 2020 at 22:58.
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Old Saturday 11th January 2020, 18:20   #91
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However, it seems more of a rhetorical question than a useful one.

The Celestron SkyMaster 25x70 was born (obviously from the name) as an astronomical binocular. Otherwise they would have called it "BirdMaster".
But this does not mean that it can't also be used to observe birds, especially at greater distances.

Of course, the 25x70 format is substantially too bright for daytime and also too heavy to held hand and carry.
But I am instead open to the fact that lighter formats, such as 25x56 and 25x42, can represent excellent tools, ideal both for playful observations, and for long-range identification and recognition.



There are also practical supports, effective and light, designed to support and improve tremors ...
http://www.fieldopticsresearch.com/s...o-x4288958.htm

https://media.rainpos.com/833/binopo...0819100555.jpg
A couple of points...
1. A 25X70 with a 2.8 mm exit pupil would not be "too bright" during daylight. Commonly used birding bins have 4-6 mm exit pupils.

2. 25X56 (2.24mm exit) and 25X42 (1.68mm exit) bins would probably be too "dark" for most birders.

3. You are correct; it is too heavy for normal birding and, I will add, handshake would render it totally useless for most users.

4. Support systems like those in your links are exceedingly rare among birders. I have never seen one in the field.

https://imaging.nikon.com/lineup/spo...c/basic_05.htm

Last edited by Pileatus : Saturday 11th January 2020 at 19:09.
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Old Monday 13th January 2020, 00:27   #92
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points 1 and 2: the exit pupil is not the only factor to calculate the "light power" of binoculars, but it is essential to also use the magnification value. And in daytime hours (from sunrise to sunset), in the open field, the minimum power more than sufficient is on average equivalent to 7x17 = 8x18 = 10x20 = 25x32. Where to satisfy people with the lowest retinal sensitivity, simply increase the values to 7x21 = 8x22 = 10x25 = 25x40.

So, 25x70 = 7x37 (ep 5.3mm) = 8x40 (ep 5mm) = 10x44 (ep 4.4mm) are values that are far too "bright" for anyone. Mostly unnecessary and too heavy compared to the real need.

Last edited by Rico70 : Monday 13th January 2020 at 00:32.
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Old Monday 13th January 2020, 03:02   #93
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points 1 and 2: the exit pupil is not the only factor to calculate the "light power" of binoculars, but it is essential to also use the magnification value. And in daytime hours (from sunrise to sunset), in the open field, the minimum power more than sufficient is on average equivalent to 7x17 = 8x18 = 10x20 = 25x32. Where to satisfy people with the lowest retinal sensitivity, simply increase the values to 7x21 = 8x22 = 10x25 = 25x40.

So, 25x70 = 7x37 (ep 5.3mm) = 8x40 (ep 5mm) = 10x44 (ep 4.4mm) are values that are far too "bright" for anyone. Mostly unnecessary and too heavy compared to the real need.
It is apparent you are not a birder. Enjoy your 25X70.
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Old Monday 13th January 2020, 03:06   #94
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"light power?" in my next 45 years as an optical engineer and tech I hope to learn what that is.

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Old Monday 13th January 2020, 03:19   #95
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"light power?" in my next 45 years as an optical engineer and tech I hope to learn what that is.

BC
Get a light saber and you'll understand!
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Old Monday 13th January 2020, 03:30   #96
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Get a light saber and you'll understand!
I can't. Those things are almost as costly as a WX.

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Old Monday 13th January 2020, 06:36   #97
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points 1 and 2: the exit pupil is not the only factor to calculate the "light power" of binoculars, but it is essential to also use the magnification value. And in daytime hours (from sunrise to sunset), in the open field, the minimum power more than sufficient is on average equivalent to 7x17 = 8x18 = 10x20 = 25x32. Where to satisfy people with the lowest retinal sensitivity, simply increase the values to 7x21 = 8x22 = 10x25 = 25x40.

So, 25x70 = 7x37 (ep 5.3mm) = 8x40 (ep 5mm) = 10x44 (ep 4.4mm) are values that are far too "bright" for anyone. Mostly unnecessary and too heavy compared to the real need.
Rico it seems that you are really saying is that no one needs an exit pupil bigger than the size of their own pupil on a bright day.

But I have been out on the islands of the west of Scotland where the sun was super bright in the morning and the sky covered with heavy black clouds in the afternoon while heavy rain was falling. In late autumn and in the winter when days are short and the day darkens rather early in the afternoon, you sometimes need all the light-gathering power you can get.

Lee
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Old Monday 13th January 2020, 07:59   #98
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Exclamation

Does any of this stuff pass the Jupiter moons test ?!?!

Grab your favourite bins (magnification irrelevant),
Line them up on Jupiter and it's moons -
Handheld, completely unsupported,
(yeah use your best super dooper stable grip - lol :)
View away !
Watch the 'fireflies' dance all over shop !

Now tell me again about the finer points of all these calculations ?




Chosun
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Old Monday 13th January 2020, 08:15   #99
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Lee, re. #97

This is to do with Rico's magic formula for Light power. The numbers in that first series all come to about 63. So between dawn and sunset when terrestrial luminance can vary a thousand fold, and the pupil of the eye might range from less than 2mm to over 4mm, the number 63 ensure your eye gets a constant level of brightness. Those combinations listed have an EP of between 1.6 and 3mm.

In #90 he claims "Of course, the 25x70 format is substantially too bright for daytime...." This has a Light power of 196 and the other combinations are similar, and even with EPs ranging from 2.8mm to 4.4mm they are all be "substantially too bright" for daytime birding. What do you think?

David

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Old Monday 13th January 2020, 08:17   #100
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I am a birder and vastly enjoy my (tripod mounted) 30x70 binoculars, two eyes is certainly better than one as we all know. If it gets a bit dim I swap down to 16x70 and keep going until you need more than optics to see stuff.

PEter
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