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- Magnification and move vision: (2 Viewers)

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
 
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.
 
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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?
 
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.
 
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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
 
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?
 
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.

Lee
 
......
...... 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.
Canip
 
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/shop/BinoPOD/p/BinoPOD-Harness-Pack-System-XL-Camo-x4288958.htm

https://media.rainpos.com/833/binopod_harness_camo_h001_h014_20140819100555.jpg
 
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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/shop/BinoPOD/p/BinoPOD-Harness-Pack-System-XL-Camo-x4288958.htm

https://media.rainpos.com/833/binopod_harness_camo_h001_h014_20140819100555.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/sportoptics/how_to/guide/binoculars/basic/basic_05.htm
 
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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.
 
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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.
 
"light power?" in my next 45 years as an optical engineer and tech I hope to learn what that is. :cat:

BC
 
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
 
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 :) :-O
View away ! :cat:
Watch the 'fireflies' dance all over shop !

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




Chosun :gh:
 
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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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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