Blackouts? (1 Viewer)

[Curiouswind]

Buy a glass with a larger exit pupil.

I'm confused. That's not actually uncommon but perhaps I can get this one cleared up. Do all 8x42 binoculars have the same size exit pupil? Or does exit pupil refer to the diameter of the ocular lenses? I'm asking because it sounds like some 8x42 devices have trouble with blackouts from eye placement within the exit pupil and others do not. Thanks for helping me out with this.

 

[Maljunulo]

Yes, all binoculars with the same magnification and objective diameter have the same exit pupil diameter.

No, it is the column of light which enters your eye. (sort of)

In many cases, you may be able to fix it by fiddling with the interoccular distance, but people get insulted when you say that.

 

[Curiouswind]

Yes all binoculars with the same magnification and objective have the same exit pupil diameter.

No, it is the column of light which enters your eye.

That's what I understood. However, some people say they get blackouts with one 8x42 binocular but not with a different model of 8x42. If that's correct, the size of the exit pupil is not related to blackouts but the size of the lens is. Have I got it straight now? Thanks.

 

[Maljunulo]

The model is irrelevant. Forget that.

No, neither is correct.

The exit pupil(s) of the binocular should be aligned with the pupils of your eyes in order for things to work right.

Start by reading a fundamental glossary, or elementary text on how binoculars and telescopes work, and that should explain away your confusion. There is lots of information floating around on the internet that will help you.

 

[Curiouswind]

The model is irrelevant. Forget that.

No, neither is correct.

The exit pupil(s) of the binocular should be aligned with the pupils of your eyes in order for things to work right.

Start by reading a fundamental glossary, or elementary text on how binoculars and telescopes work, and that should explain away your confusion. There is lots of information floating around on the internet that will help you.

 

[Curiouswind]

I read WJC's screenshot and thought I understood. Then I saw another poster say they had blackout problems with the NV but not the Ultravids. In other words, for that person, the model was relevant. That was confusing because I thought that it was the exit pupil size that matters.

 

[Maljunulo]

I’m only going to say it once more, the model is irrelevant.

Read what Bill posted, and believe it. Do not give equal weight to other posts, what Bill said is fact.

There are people in this world who would have trouble putting their fingers into a bowling ball, but that doesn’t mean that bowling ball is different or behaves differently.

 

[Eranou]

I read WJC's screenshot and thought I understood. Then I saw another poster say they had blackout problems with the NV but not the Ultravids. In other words, for that person, the model was relevant. That was confusing because I thought that it was the exit pupil size that matters.

Have a look at this link, which may help to explain the effect/reasons.

What cause the kidney bean? - Eyepieces - Cloudy Nights

What cause the kidney bean? - posted in Eyepieces: Hi, What cause the kidney bean effect? The eyepiece or scope/e.p. combination? Thanks, Scott

www.cloudynights.com

 

[Maljunulo]

Quote from that which absolutely says it all in one sentence.

“It's your mis-aligned eye's pupil intersection with the aberrated exit pupil of your telescope/eyepiece combination.”

 

[tenex]

That was confusing because I thought that it was the exit pupil size that matters.

No, small exit pupils work quite well in a good optical design that tolerates a bit of variation in alignment. What seems to have got lost in this discussion is the fact that some models have more spherical aberration of the exit pupil (SAEP) which makes them more fiddly and prone to such blackouts than others with a more generous eye-box. But hopefully that isn't the OP's problem with Noctivids at all, and he merely needs slightly deeper eyecups.

 

[Maljunulo]

If you prefer lots of words, try this one.

astronomical optics, part 4: optical aberrations

It sort of “explains the explanation”.

 

[WJC]

If you prefer lots of words, try this one.

astronomical optics, part 4: optical aberrations

It sort of “explains the explanation”.

230328

Hi Richard:

Over time, I have noticed that so many people who think they must know everything about everything ... when they get through swimming in the 55-gallon barrel of optical jargon that they are ill prepared to understand, often return to one my 4 oz. explanations that they are.

Ernest Hemingway’s shortest novel consisted of only 6 words. Yet, it brought grown men to tears. For the AVERAGE person, the trick is RARELY in the large QUANTITY of words presented. But in the judicious selection of a few words targeted to the PRECISE question.

Bill

 

[Bentley03]

It is all true, everything Bill (and several others) repeat on here time after time. However, I often feel that it is implied that it is entirely the inability/incompetence of the binocular operator, not the characteristics of the particular model of binocular, which is the root cause of the problem, with replies sometimes verging on being dismissive or even patronising.

Historically, whenever this topic arises on BF, the same (heavyweight) members impart the same wisdom, yet it is invariably one of several specific models of binocular which has prompted the discussion in the first place. The 8x42 Noctivid, the eyecups of which have many closely spaced click stops and are very 'eye relief flexible' by design, is one of those models (therefore a culprit!).

I'm sorry, but not all binoculars of a specific magnification and aperture are equally free from susceptibility to blackouts, regardless of the IPD setting and alignment of the operator's eyes, and that is also a fact.

These threads offer assistance in how to minimise blackouts and why they occur, but fall short of recognising that not all binoculars are born equal in this regard, and why some (or in some cases many) operators have difficulties with them. There are some real shockers out there, very expensive shockers!

Apologies, I probably got out of bed the wrong side this morning, but feel oh so much better for having a little rant. 😁😇

 

[Maljunulo]

It is all true, everything Bill (and several others) repeat on here time after time. However, I often feel that it is implied that it is entirely the inability/incompetence of the binocular operator, not the characteristics of the particular model of binocular, which is the root cause of the problem, with replies sometimes verging on being dismissive or even patronising.

Historically, whenever this topic arises on BF, the same (heavyweight) members impart the same wisdom, yet it is invariably one of several specific models of binocular which has prompted the discussion in the first place. The 8x42 Noctivid, the eyecups of which have many closely spaced click stops and are very 'eye relief flexible' by design, is one of those models (therefore a culprit!).

I'm sorry, but not all binoculars of a specific magnification and aperture are equally free from susceptibility to blackouts, regardless of the IPD setting and alignment of the operator's eyes, and that is also a fact.

These threads offer assistance in how to minimise blackouts and why they occur, but fall short of recognising that not all binoculars are born equal in this regard, and why some (or in some cases many) operators have difficulties with them. There are some real shockers out there, very expensive shockers!

Apologies, I probably got out of bed the wrong side this morning, but feel oh so much better for having a little rant. 😁😇

Can you tell us what must be different in order for one model to differ from another in susceptabulity to blackouts?

 

[Bentley03]

Can you tell us what must be different in order for one model to differ from another in susceptabulity to blackouts?

Unfortunately not, and nor am I going to try.

My observations regarding different levels of susceptibility to blackouts between binoculars of the same aperture and magnification are based purely on hands on experience, either through ownership, or through trialling them over a reasonable period of time. There are several specific instruments I have revisited, to double check that my experiences with them the first time I tested them were indeed correct, and in each and every case, I concluded that I had been correct in my perception the first time.

That said, there was one, however, which despite the irritation of 'too easily' provoked blackouts, that I enjoyed using so much, that I bought it. That 'one', is the 8x42 Noctivid.

 

[tenex]

Can you tell us what must be different in order for one model to differ from another in susceptabulity to blackouts?

It depends on what sort of blackouts, but in this case of kidney-beaning, the principal factors regularly mentioned are those cited above, insufficient eyecup depth and finicky alignment due to SAEP. (The specifics of what leads to more SAEP in some eyepiece designs would have to be described by experts.)

 

[jafritten]

That said, there was one, however, which despite the irritation of 'too easily' provoked blackouts, that I enjoyed using so much, that I bought it. That 'one', is the 8x42 Noctivid.

Do you still get blackouts with them? Perphaps I returned them to hastily. The sample I had was supposed to be "like new" but it reeked of fags and it was burnt in one place. I wonder if I could get views with no blackouts if I tried again.

 

[Bentley03]

It depends on what sort of blackouts, but in this case of kidney-beaning, the principal factors regularly mentioned are those cited above, insufficient eyecup depth and finicky alignment due to SAEP. (The specifics of what leads to more SAEP in some eyepiece designs would have to be described by experts.)

Yes, there was an excellent thread about this last year (Kimmik's thread?). It answered a lot of questions regarding blackouts in considerable depth as I remember.

 

[Bentley03]

Do you still get blackouts with them? Perphaps I returned them to hastily. The sample I had was supposed to be "like new" but it reeked of fags and it was burnt in one place. I wonder if I could get views with no blackouts if I tried again.

The simple answer is yes, to a degree, but for the most part I am able to manage them sufficiently to really enjoy them. It is only a side by side comparison, or when I switch between the Noctivid and a more 'friendly' 8x42 that I become aware of it and a little irritated by it. The 10x Nocs I find more forgiving, in terms of blackouts.

I can't remember if you wear glasses while using binoculars, or not, but when I've passed my Nocs to non glasses wearers to try, they have invariably experienced some difficulties with blackouts, more so than those who do wear glasses. Of course, there are some big fans of the Nocs on here who don't wear glasses, so...

I think you just need to try them again and see if 'the view' is a sufficient trade off for any necessary compromises in 'viewing comfort'. Certainly the copy you had sounded very unpleasant, no wonder you returned them, regardless of their characteristics in use. But, have some 8x42's which you find really comfortable to use to compare them with side by side, so that you can evaluate any trade off/compromises the characteristics of the Nocs might require.

The day I took the decision to go and potentially purchase a pair of 8x42 Nocs (based entirely on my experiences with my 10x Nocs) the dealer had just taken in a pair of used 8x40 'Retrovids'. He handed them to me to test and get my opinion on them, alongside his 8x42 Noctivid display/demo copy. By the time he'd finished dealing with the customer who was already in the shop when I arrived, trying to choose between different formats of NL's (eventually choosing 8x42's for their calmer view over the 10x42's which he felt were better balanced in the hands), I knew I wasn't going to buy the 8x42 Nocs, because I'd bonded with the 8x40 'Retrovids' immediately and was enjoying them so much more. I struck an excellent deal for the Retrovids and returned home very happy. I have, of course, subsequently purchased a pair of 8x42 Nocs too (green edition), at the second attempt.

Not sure if any of that helps, but despite the relatively negative reporting I've made above, I do genuinely love using my 8x42 Noctivid, it's just not quite as easy/comfortable in use as some, so needs to be tested carefully before purchase, to ensure any trade-offs required are acceptable to you. 🙂

James

 

[Hermann]

The simple answer is yes, to a degree, but for the most part I am able to manage them sufficiently to really enjoy them. It is only a side by side comparison, or when I switch between the Noctivid and a more 'friendly' 8x42 that I become aware of it and a little irritated by it. The 10x Nocs I find more forgiving, in terms of blackouts. [...]

The day I took the decision to go and potentially purchase a pair of 8x42 Nocs (based entirely on my experiences with my 10x Nocs) the dealer had just taken in a pair of used 8x40 'Retrovids'. [...] By the time he'd finished dealing with the customer who was already in the shop when I arrived [...] I knew I wasn't going to buy the 8x42 Nocs, because I'd bonded with the 8x40 'Retrovids' immediately and was enjoying them so much more. I struck an excellent deal for the Retrovids and returned home very happy. I have, of course, subsequently purchased a pair of 8x42 Nocs too (green edition), at the second attempt.

Not sure if any of that helps, but despite the relatively negative reporting I've made above, I do genuinely love using my 8x42 Noctivid, it's just not quite as easy/comfortable in use as some, so needs to be tested carefully before purchase, to ensure any trade-offs required are acceptable to you. 🙂

One of the problems many people here have is that they use too many different binoculars. Most binoculars are sufficiently "different" that you have to get used to them. That may take a few days in the field, it's not something you can do in a shop. And if you only use one or, at most - two different binoculars, you'll get so familiar with them that all those "difficulties" mysteriously disappear. Provided you found the correct IPD and so on in the first place.

Hermann