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The Top-left Shadow problem. (1 Viewer)

M

mskb

Well-known member
Hello Everyone,

Have you experienced this shadow issue on the FoV illustrated with a nice figure by Tobias Mennle here: http://www.greatestbinoculars.com/allpages/articles/itsthebaffling.html . Basically, one doesn't get a clear sharply bounded image circle, but the best image circle formed has a deep shadow on the top-left of the image, and the right side boundary is well defined.

I am experiencing this problem with all three of our 8x MHG copies (with very close serial numbers). In my case, the shadow occupies a little more area than what is shown in Tobias's figure, but overall I am finding it in the same position. I wasn't able to overcome the issue completely by varying barrel distances / eye cup settings within reason.

I don't experience this with the 10x MHG, 8x M7, the Maven B2 9x and several other 8x s. So my interest in this problem is piqued, and I wanted to inquire if anyone else has experienced this issue with their bins, and how they solved it.

Any thoughts/advice is greatly appreciated!

Thanks,
Kumar
 
Instead of worrying too much about the issue, I'd advise that you simply move on from the 8x42 MHG. That is not said to demean the MHG, but every binocular will have weaknesses that will bother some viewers more than others. In my case, I simply moved on from the Swarovski SV EL because of rolling ball. I'd guess that since this phenomena occurs to you with multiple MHG 8x, then the binocular is likely not for you. Lots of other good glass from reliable suppliers. I'd not worry much unless you start to notice it in more and more specimens. Just remember the harder you look for imperfections, the more likely you are to find them.
 
I have the MHG in 8X42 and I do not observe the described visual. Perhaps the diameter of the eye-cups are not a good fit to your facial features. Do you own a MHG 10X42, and/or have you used it as frequent as your 8X42?

Andy W.
 
Thanks Steve and Andy. I own a 10x; I haven’t used it as extensively as the 8x. I am starting to.
 
I just tried my Nikon MHG 8x42 quickly on a cloudy bright sky.

With perfect eye placement there are no shadows or prism cut off, but I'll try a longer test.
Just round large circles.

With the left barrel there is a blue fringe slight cut off top left if I am sloppy about eye placement.
But in my case this seems to be a problem of eyelids and eyebrows maybe.
My left eyelid has slight droop and doesn't open quite as far as my right eyelid.
First thing in the morning I notice this with unaided eyes, maybe larger pupils?
My pupils with this test might be 3mm or 4mm, not sure.

I don't wear glasses with binoculars.
 
Thank you so much binastro for your help! We got ours from LL BEAN with single digit differences in serial numbers (probably same batch). I must find a way to try out an 8x from another store.
 
Mine is a very early one with problems of flare and false colour.
Poor internal blackening, shiny instead of matt black.

I don't like it although it is great for shadow detail.

But I thought I'd see if I could duplicate your findings.
 
Hi,

thank you Kumar for bringing a very interesting article by Tobias to my attention that had I had not seen so far...

Unfortunately I can't really comment on the MHG or the untitled image of the truncated exit pupil at the top of the article - I'd assume it is from a Leica Ultravid HD Plus 8x32 as this is the only pair actually mentioned to have truncated exit pupils in the text?.

Actually if you see a sharply defined field stop or not, really depends on whether it is placed in the focal plane or not - both ways are valid. But of course it should be circular - that is if the observing eye or camera is placed correctly.

Joachim
 
I don't have the "cut off" problem shown in the 1st post above when I use my Monarch 8x42 HG.

I don't wear glasses while using the binocular. When I use the binocular I brace the eye cups up against and slightly underneath my eye brows while I turn my head when following the bird I am watching.

Bob
 
jring said:
Hi,

thank you Kumar for bringing a very interesting article by Tobias to my attention that had I had not seen so far...

Unfortunately I can't really comment on the MHG or the untitled image of the truncated exit pupil at the top of the article - I'd assume it is from a Leica Ultravid HD Plus 8x32 as this is the only pair actually mentioned to have truncated exit pupils in the text?.

Actually if you see a sharply defined field stop or not, really depends on whether it is placed in the focal plane or not - both ways are valid. But of course it should be circular - that is if the observing eye or camera is placed correctly.

Joachim
Click to expand...

The article from Tobias - is it factual or speculation? I ask because what he is suggesting certainly hasn't [to my knowledge] been discussed as fact by anyone that might know - Henry etc.
 
Good question, James.

I've attached a few pages from Warren J. Smith's book "Modern Optical Engineering" (1990) that address glare stops and baffles. Although the ideal design is easily explained, not all engineering attempts at glare/baffle control are equally effective, and some poorly designed systems could certainly introduce problems such as vignetting.

I'm afraid I have to disagree with Tobias about the relationship between baffling and brightness, however, which after all is a perceptual response to the light (photons) reaching the retina, independent of image quality. Frankly, his use of words and concepts is somewhat baffling. :)

Ed

PS. Rotate the .pdf file clockwise to read.
 

Attachments

  • Baffling.pdf
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Last edited:
Ed, Lee,

I found Tobias' account somewhat confused, but I think It would be quite wrong to dismiss his notions entirely.

A few years back I spent an afternoon comparing the Swarovski models with other binoculars, including the Nikon EDG. It became evident that all the Swarovski models exhibited a higher level of diffuse light scattering, particularly at shorter wavelengths, (in certain viewing conditions), than the EDG and the Kowa Genesis for example. You might say the shadows appeared brighter. I don't know it it was all down to differences in baffling. All those Swaros have been replaced or updated so I wouldn't know how they would compare now..

Ed, I think you do know very well that perceived brightness is certainly not as simple as just the number of photons reaching the retina.

David
 
james holdsworth said:
The article from Tobias - is it factual or speculation? I ask because what he is suggesting certainly hasn't [to my knowledge] been discussed as fact by anyone that might know - Henry etc.
Click to expand...

Hi,

that is an interesting question - discussion on this would be interesting.

But I have found that for me personally in the vast majority of viewing situations I prefer a darker image with very good contrast (e.g. my Nikon SE) to a brighter image with less contrast (e.g. some Swaro).

After all the eyes are really good in compensating for various levels of image brightness (at least as long as you don't leave the domain of photopic vision). Not so much for contrast, though.

It might also be partially due to the fact that my eyes are fairly sensitive to bright light - it has gotten a bit less severe with the years (yay, some property of my eyes that gets better with age) but I am still usually the first person to search for my sunglasses.

Joachim
 
typo said:
Ed, Lee,

I found Tobias' account somewhat confused, but I think It would be quite wrong to dismiss his notions entirely.

A few years back I spent an afternoon comparing the Swarovski models with other binoculars, including the Nikon EDG. It became evident that all the Swarovski models exhibited a higher level of diffuse light scattering, particularly at shorter wavelengths, (in certain viewing conditions), than the EDG and the Kowa Genesis for example. You might say the shadows appeared brighter. I don't know it it was all down to differences in baffling. All those Swaros have been replaced or updated so I wouldn't know how they would compare now..

Ed, I think you do know very well that perceived brightness is certainly not as simple as just the number of photons reaching the retina.

David
Click to expand...

Thanks for this David. Still struggling with the notion that non-image-forming light can be helpful though.

Lee
 
Lee,

I didn't say it was helpful. It reduced contrast and obscured detail. Nevertheless it could appear brighter, and evidently some prefered it.

David
 
typo said:
Lee,

I didn't say it was helpful. It reduced contrast and obscured detail. Nevertheless it could appear brighter, and evidently some prefered it.

David
Click to expand...

I understand that. I was referring back to Tobias's article. Thanks again.

Lee
 
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