How are streetlights supposed to look through good binoculars? (1 Viewer)

[mgp13]

I am completely unfamiliar with binocular use at night and just had my first experience of it.

I have two pairs of binoculars. Through the first, if I look at the moon or streetlights at night, there are no large rays of light projecting off it that extend all the way to the field edge. My feeling is that's how it's supposed to be. The image is also the same in both barrels.

Through the second pair, large narrow rays project off the moon and streetlights that extend all the way to the field edge. It's particularly apparent with streetlights, the rays are blue-white, intense and distracting. What's more, this occurs in the left barrel only. I have a feeling this isn't quite normal.

Can anyone comment on what's going on here?

 

[Binastro]

Is the offending binocular a roof prism type?

Then it is a poor quality prism.

There are also many types of street light.
Sodium, LED of various types and others.
They also have different dimensions and different shaped filaments, elements or covers.

Some very good binoculars show little effect of glare or ghosting.
The Canon 18x50 IS is very good as are some other Canon IS and Leica binoculars.

Some binoculars have a little or a lot of ghosting and also lines from street lights.
These include some very well regarded binoculars, that to me are almost useless near street lights.

Car headlamps also can be terrible or quite good.

Your first binocular seems good, although it could still have ghosting or other defects.

Regards,
B.

 

[Patudo]

Without meaning to be facetious, what are you trying to spot around those streetlights? Bats?

 

[Binastro]

Comets.

Noctilucent clouds.

Aurorae.

Street and other lights in towns have resulted in an overall reduction in star visibility of 6 times in the last 30 years at the zenith and even more at lower elevations.

In addition, they have impacted wild life and even human health.

And yes, you are being facetious.

B.

 

[Alexander Stöhr]

Hello,

I agree with Binostro, the observation you describe is the result of a less then perfect phase correction and a less than perfect polished roof edge of a roof prism.

You made a quick and rough test to check the quality of the roff prism, and even the most distinguished experts have done this test, see here:

Erfahrungsbericht: Ferngläser der 8x32 Klasse

But I agree with Patudo, a binocular with a suboptimal prism can still provide a pleasant and detailed view. And I am sure=I hope that you have fun with this binocular. Please note, that the winner in Holger Merlitz´s test shows a "medium" degree of the artefact you described.
( I am confident thats what Patudo wanted to say).

And yes light pollution is a serious topic, and having spent many nights under incredible stars at the "Sternenpark Westhavelland" and experienced a still better night sky many years ago around Hof (comparable only to Hawaii and Chile according to the staff of the local observatory, I totally agree with Binastro.

 

[Swedpat]

mgp13,

Intense light sources is a challenging test for even the best binoculars. When you say: "narrow rays project off the moon and streetlights that extend all the way to the field edge" it sounds like you describe the spikes who are typical for roof prism binos. I have detected these against streetlights even in high class binos like Swarovski SLC 7x42 and NL Pure 8x42.
According to my experience these spikes use to be less noticeable with higher class binos.
In cheap junk roof binos it use to be much more noticeable. So if you here describe such spikes it is not a sign of bad or defective optics.

 

[Thotmosis]

My Habicht 10x40 Porro is terrible for using near (street)lights, all my Leica‘s however perform outstanding under difficult light situations. Day or night.

And i agree: light pollution is an ever expanding curse. As are satellites.

 

[mgp13]

Interesting. I am fine with it as long as it doesn't affect daytime use of the binoculars.

 

[mgp13]

mgp13,

Intense light sources is a challenging test for even the best binoculars. When you say: "narrow rays project off the moon and streetlights that extend all the way to the field edge" it sounds like you describe the spikes who are typical for roof prism binos. I have detected these against streetlights even in high class binos like Swarovski SLC 7x42 and NL Pure 8x42.
According to my experience these spikes use to be less noticeable with higher class binos.
In cheap junk roof binos it use to be much more noticeable. So if you here describe such spikes it is not a sign of bad or defective optics.

Why are the spikes only in the left barrel? They're really quite severe- in the right barrel everything is fine. And the comparison pair of binoculars don't have the issue at all.

 

[Alexander Stöhr]

Hello again,

from what I have read: it's because the prism in the left barrel has a bad polished roof edge (should be the thinnest possible line. I hope that's understandable) and/or the phase coating applied is not perfect.
In the right barrel, the roof prism is better.

 

[mgp13]

Hello again,

from what I have read: it's because the prism in the left barrel has a bad polished roof edge (should be the thinnest possible line. I hope that's understandable) and/or the phase coating applied is not perfect.
In the right barrel, the roof prism is better.

Is this a defect that would affect daytime use?

 

[takitam]

Don't let people, and especially the manufacturers, tell you that's normal. It has only become 'normal' because we dropped our standards and agreed to the 'norm'. You have seen with your own eyes that it is possible to have bins without this issue. It sucks to have a binocular that produces stray light this way, especially in one barrel. I enjoy using bins at night occasionally and the lack of stray light is important to me.

edit. - It does not affect daytime views. That's why it is acceptable to many people.

 

[Swedpat]

Since long time I have a wondering. 7x50 marin binoculars are almost always in porro design, very few exceptions. I suspect the reason is to avoid spikes.
When using a binocular on dark sea with bright light sources like lighthouses, spikes are very indesireable.

 

[tenex]

I think it's just cheaper to build a Porro design and make it waterproof with independent focus, which is no handicap for marine use.

 

[Maljunulo]

Or astronomy.

 

[Swedpat]

Why are the spikes only in the left barrel? They're really quite severe- in the right barrel everything is fine. And the comparison pair of binoculars don't have the issue at all.

I think the explanation is that the precision in the manufacturing is uneven. And especially with cheap optics, where it can be a noticeable difference not only when it comes to spikes. It can also be a noticeable difference in image sharpness between left and right barrel.
With good quality control this should not be.

 

[jring]

Hi,

it's a manufacturing defect - the left barrel has a roof prism with an imperfect roof edge. Not visible in daytime use unless you habitually observe bright light sources or (heaven forbid) the sun. Certainly not normal as demonstrated by the right barrel...

Lack of of proper phase coating would be visible at day time as a lack of resolution in the center - more visible at higher magnifications. A 7x roof w/o phase coatings might be fine for most users, a 10x is usually not.

Joachim

 

[Scott98]

Can anyone comment on what's going on here?

These are what we call "prism spikes", I hate seeing them, since I do a lot of astronomy and night observing. Is it the 10x42 SF that has them? From what I've heard online, the 8x32 SF show the spikes, but the 8x42 don't and I didn't think the 10x42 showed them either.

The current NIkon EDG also show the spikes, apparently some of the older ones are clean. I don't see them in my 10x56 SLC or any of the Nikon porros I've used, although all the older porros have ghost images & reflections around bright lights & the full moon. I call these the "torture test" of optics because something usually shows up. My 8x42 SF's would be the cleanest binos I own, no scatter or ghosting at all, with the 10x56 SLC in second place.

This 8x32 SF article has good photos of the phenomenon:

Zeiss Victory SF 8x32 – first impressions - First impressions

When it comes to production of 8×30/8×32 binoculars the Zeiss company has had many years of experience under their belt. Every fan of binoculars has heard of such models as the Deltrintem 8×30, launched as early as 1920, or the Dialyt 8×30 which, in many variations, reigned on the market from...

www.allbinos.com

 

[Swedpat]

These spikes are only present in roof binoculars because of the edges of the prisms. I have seen these even in very high class models. But I never noticed it in my Zeiss 6x20B monocular(regret I sold it), neither in Zeiss Victory FL 7x42 when I tried it against sun reflexes against cromed parts.