Is it exit pupil size that affects ease of alignment with eyes? (1 Viewer)

I have been trying out a few binoculars and with some even slight movements bring the black shadows over the sides/ top/middle etc of my view.

Is it the exit pupil size that determines this?

I.e the larger the objective the easier they stay in the sweet spot on your eyes?

An example of a significant difference is the

Nikon Monarch 7 8x30
Vs
Vortex Diamondback 8x32

The diamondback doesn’t show any black shadows no matter how much I move them around yet the Monarchs require very precise alignment to avoid the black shadows flashing into view.

whitedragon101 said:

I have been trying out a few binoculars and with some even slight movements bring the black shadows over the sides/ top/middle etc of my view.

Is it the exit pupil size that determines this?

I.e the larger the objective the easier they stay in the sweet spot on your eyes?

An example of a significant difference is the

Nikon Monarch 7 8x30
Vs
Vortex Diamondback 8x32

The diamondback doesn’t show any black shadows no matter how much I move them around yet the Monarchs require very precise alignment to avoid the black shadows flashing into view.

Click to expand...

The size of the exit pupil is responsible in a secondary way. The major culprit is positioning both in distance from the rear eye lens and IPD. Also, the size of the objective is responsible in only a peripheral way. Some binoculars are better than others, but the brand has nothing to do with it.

A long eye relief is preferable. However, you must learn WHERE to place the bino! The distance won’t change, so you need to!

As a younger fellow, I used to scan a huge section of sky in order to find M31. Today, it’s a matter of throwing the bino to my face and it magically appears first time ... every time. It just takes practice. :cat:

Cheers,

Bill

Hi White Dragon,

Bill is right, as usual.:t:

I have the Monarch 7 8x30 and I get those "black shadows" you are talking about if I don't have the IPD set right and have the eye cups placed precisely under my eye brows.

On other binoculars with longer eye relief and a larger exit pupil like my Opticron WP PC 7x42 the "black shadows" are much easier to keep away.

It is a very good binocular for its modest price of $285.00 USA Dollars. It has a 6mm exit pupil, 25mm eye relief and a 408'@1000yds FOV. You should try one out.

https://www.opticronusa.com/Pages/discovery_wp.html

Bob

WJC said:

The size of the exit pupil is responsible in a secondary way. The major culprit is positioning both in distance from the rear eye lens and IPD. Also, the size of the objective is responsible in only a peripheral way. Some binoculars are better than others, but the brand has nothing to do with it.

A long eye relief is preferable. However, you must learn WHERE to place the bino! The distance won’t change, so you need to!

As a younger fellow, I used to scan a huge section of sky in order to find M31. Today, it’s a matter of throwing the bino to my face and it magically appears first time ... every time. It just takes practice. :cat:

Cheers,

Bill

Click to expand...

Thanks for the help. I just tried the Monarch 7 8x30 again this evening and it was perfect. Absolutely amazing image. I'm not sure if the lower light helps or if I just got the alignment right this time with the IPD.

Would evening light have helped (larger pupil size)? Or do you think the alignment was the change?

ceasar said:

Hi White Dragon,

Bill is right, as usual.:t:

I have the Monarch 7 8x30 and I get those "black shadows" you are talking about if I don't have the IPD set right and have the eye cups placed precisely under my eye brows.

On other binoculars with longer eye relief and a larger exit pupil like my Opticron WP PC 7x42 the "black shadows" are much easier to keep away.

It is a very good binocular for its modest price of $285.00 USA Dollars. It has a 6mm exit pupil, 25mm eye relief and a 408'@1000yds FOV. You should try one out.

https://www.opticronusa.com/Pages/discovery_wp.html

Bob

Click to expand...

Thanks for that. The weight of those is a bit high for me (690g) as I am trying to get the best £300 or less travel binocular so less than 500g is ideal 550g probably the max.

However, I had a look at Opticron and noticed they make a model just like the monarch 7, the Opticron Traveller BGA ED 8x32
Same
ED glass, Dielectric, phase coated, 8.2deg FOV (monarch 8.3)

However, the Traveller BGA ED has a 4mm exit pupil vs the Nikon 3.75mm. Objective 32mm vs 30mm. And eye relief of 19mm vs 15.1mm.

Same price point of £299 so I have ordered one of those.

Fingers crossed.


(I did try the Monarch 7 again this evening and they were perfect, no shadows, sharp and very wide FOV. Really impressive. As I said to WJC, I'm not sure if that is because the evening light enlarging my pupils helps with alignment or if I just got the knack of setting them up properly this time).

whitedragon101 said:

Thanks for the help. I just tried the Monarch 7 8x30 again this evening and it was perfect. Absolutely amazing image. I'm not sure if the lower light helps or if I just got the alignment right this time with the IPD.

Would evening light have helped (larger pupil size)? Or do you think the alignment was the change?

Click to expand...

I would say getting the IPD right had a lot to do with it. A larger pupil size will help the image stay centered IF you have the bino positioned correctly. :cat:

Bill

PS Don’t go looking for optical trouble! If you do ... you’ll find it. Case in point: Some experts ... who aren’t ... will tell you that if you see overlapping fields, your bino is out of collimation. And those guys ALWAYS find an audience full of folks who know equally as much about optics. If that happens while observing a distant target, then the bino IS out of alignment. But just seeing overlapping fields is not the tell-tale some believe. When you SPECIFICALLY look for overlapping fields, you are looking at the FIELD STOPS just in front of the field lens. That means you are focusing INSIDE the bino, just 2 ½ to 4 inches in front of your eyes. Hold your finger that close without the bino involved. What happens? You cross your eyes. And what happens when you cross your eyes? You get a double image. The bino had nothing to do with it and is NOT necessarily out of collimation ... you are! Often, well-meaning people propagate very bad information.

Part of it is design also for instance my SF's as well as the various Swaros and Conquests that I've played with all have some kidney beaning but any one of my three Kowa Genesis I just throw them up any old way and no problem. They ae the best eye cups I've ever seen.
Steve

What I have learned is that setting the IPD correctly makes all the difference when fine tuning. I think it is overlooked often.

Andy W.

The design of the eyecups of a binocular (being too short) can cause the shadowing.

nacmancer said:

The design of the eyecups of a binocular (being too short) can cause the shadowing.

Click to expand...

I think this is definitely part of it. I notice that dropping the eye cups down one click from max and the shadowing becomes so severe it’s not usable.

However I think I’m getting the hang of the placement. I tried them today in daylight and the FOV of the Monarch 7 blew all the others away (I am testing quite a few thanks to amazon prime). The only one I think could better it arrives tomorrow, the Opticron Traveller BGA ED 8x32.

Stephen Mark said:

Part of it is design also for instance my SF's as well as the various Swaros and Conquests that I've played with all have some kidney beaning but any one of my three Kowa Genesis I just throw them up any old way and no problem. They ae the best eye cups I've ever seen.
Steve

Click to expand...

Stephen

Do you wear glasses? I do and when I changed prescription and frames and lens type a while ago all of a sudden I had kidney beaning on binos that had formerly been fine. I solved this by fitting some rubber o-rings by pushing them over the eyecup and down until they were under the overhang and this meant that the eyecup was extended a bit instead of screwed all the way in. This cured the problem and I hope it will help you.

Good luck.

Lee