Several days birding with Monarch HG 8X42 (1 Viewer)

Alexis Powell · Feb 28, 2017

henry link said:
There is a vagueness about field edge aberrations on this thread that I think is preventing a reader (at least this one) from understanding exactly how the HG performs off-axis.

Edge sharpness is primarily determined by two aberrations: field curvature and astigmatism. This old post attempts to explain how they interact.

http://www.birdforum.net/showpost.php?p=1879542&postcount=5

Geometrical distortions at the field edge are unrelated to edge sharpness. The first two posts in this old thread attempt to sort them out.

http://www.birdforum.net/showthread.php?t=161309

Some of Nikon's "flat field" binoculars (like the SE series) have employed an edge sharpness solution that corrected astigmatism well, but field curvature much less well (condition "c" in the first link), and a distortion solution that relied on a small amount of pincushion combined a small amount of angular magnification distortion (the Nikon EDG in the second link) . Are those approaches what the Monarch HG is using?

Henry

Thanks for this question--I was wondering the same. I'm guessing that the Monarch HG corrects astigmatism and doesn't correct field curvature much, but we don't have enough information to know whether anything at all is corrected. Can the Monarch HG view at the periphery be brought into sharp focus (even if not in synchrony with sharp focus in the center)? Is the periphery at its sharpest focus (even if still blurry) when the center is at its sharpest focus? I hope the former rather than the latter because I prefer a bin w/curved field and low astigmatism (e.g. Nikon 8x32 SE, Leica 8x32 BN) over a bin w/astigmatism but low field curvature (e.g. B&L 8x42 Elite waterproof, Zeiss 8x32 FL).

--AP

james holdsworth · Feb 28, 2017

I think what we know is - we all see the edge of the field in a different way - and using hard definitions just don't work in reality.

Same goes with 'sharpness' and 'contrast.'

henry link · Feb 28, 2017

james holdsworth said:
I think what we know is - we all see the edge of the field in a different way - and using hard definitions just don't work in reality.

Same goes with 'sharpness' and 'contrast.'

I can't quite agree with this, James. Some observations have more predictive power for the rest of us than others.

If I read that the edge is unsharp and distorted I really don't know what to expect. But, If I read that the edge has low astigmatism, combined with high field curvature and just enough pincushion to correct angular magnification distortion then I have a very good idea of what I will see.

Henry

Binastro · Feb 28, 2017

It may be that the current 8x42 MHG has been sorted out and performed better than my early production sample.

In mine the main source of blur at the edge is colour error. It is excessive and drowns out other errors.
CA? or spherochromatism. I don't know as I am not so familiar with binoculars compared to telescopes.
In fact the edge performance of my 8x42 MHG is slightly better than the 8x32 Conquest HD, but I just hate the false colour.

It may also be that the inner tubes are now matt black instead of shiny black. Or somehow they have eliminated the flare from just extraneous light sources.

Again I don't know and have no intention of trying a new model 8x42 MHG.

henry link · Feb 28, 2017

Hi Binastro,

I don't think it's spherochromatism. That would affect the entire field equally.

Usually, if the worst blur at the edge is from lateral CA that's a good thing in a binocular. That's the case with the Swarovski SVs, but of course in those binoculars the field curvature and astigmatism are so low that a moderate level of lateral CA is unmasked by their absence. It would be a different thing if the lateral color were so excessive that it "drowned out the other errors", even though the other errors weren't very low.

Henry

Binastro · Feb 28, 2017

Hi Henry,
I tried again.

Looking at a lit 6ft neon tube in the kitchen and using the white base also.

The tube is about 30ft distant.
The bottom is at 11 deg elevation the top 13 deg elevation, so foreshortened but vertical to me.

Placing the tube near the field edge of the 8x42 MHG.
The strong mauve/purple on one side of the white base and the strong green cannot be focused out. They remain the same colours but get more blurrred.

The tube remains vertical at the edge i.e straight. There is no detectable pincushion or barrel.

However, the tube gets quite a bit shorter as I move to the left or right side i.e. near the field edges.

I get afterimages from the bright tube, so don't want to do this for long.

This is a very bright binocular, about the only thing going for it in my books. At least my sample. And a reasonably wide field.

Does this help?

henry link · Feb 28, 2017

Binastro said:
The tube remains vertical at the edge i.e straight. There is no detectable pincushion or barrel.

However, the tube gets quite a bit shorter as I move to the left or right side i.e. near the field edges.

Try using a small circular object at a distance so that it subtends about 3º of AFOV. Move it from the center to the edge at 3:00. How does its shape at the field edge compare to the examples at the extreme right end in this photo?

http://www.birdforum.net/attachment.php?attachmentid=551747&d=1437327988

In the photo the top line is a Swaro 8x32 SV, the middle is a Nikon 8x32 SE and the bottom is a Zeiss 8x56 FL.

Binastro · Feb 28, 2017

Hi Henry,
My server? crashed.
But back.

I usually use the full Moon, so I know how this works.
I don't usually use near objects.
I'll see if I have something suitable.

Binastro · Feb 28, 2017

Henry,
Quick test cotton reel round end 34mm diam at about 5m.
Squashed like Swaro 8x32 SV but not as bad perhaps half as squashed as end picture.
But out of focus like 8x56 FL end picture.

No false colour noted in room light not very bright.

The out of focus edge image can be partly refocused.

Rather more out of focus edges than I remember from distant targets unless my pupil size might be big?

Not used to close targets.

I don't want to get migraine aura messing around with bright lights so will try another day if suitable.

P.S.
Distance binocular to cotton reel target 5.1m Leica Disto.
Illumination 2 60W tungsten pearl candle bulbs at about 10ft not measured.
Illumination of target rather dim.

Cotton reel base ~3.05 degrees AFOV (8x assumed).

adhoc · Mar 1, 2017

chill6x6 said:
...Trinovid HD's best assets... ... ...adequate FOV. The MHG has all that...also features... ... ... much larger FOV...

Chuck, are you able to comment on the ease of eye placement for a spectacles wearer in using the Trinovid HD vs Monarch HG? Thank you. Perhaps it is not mentioned because you do not find much of a difference.

chill6x6 · Mar 1, 2017

adhoc said:
Chuck, are you able to comment on the ease of eye placement for a spectacles wearer in using the Trinovid HD vs Monarch HG? Thank you. Perhaps it is not mentioned because you do not find much of a difference.

I was going to get to that...but I'll mention it now... Every binocular I have is at least USEABLE for someone that wears glasses. Some more or less than others. The Canon 10X42 L IS and SV 12X50 are pushing it. Some of the others accommodate eye-glass wearers with ease...such as the ones in this comparison.

All three of these binoculars are just what the doctor ordered for eye-glass wearers. The Trinovid HD is the champ in this regard. The typical Leica multi position eyecups and eye-relief galore make these binoculars just about perfect. I even have to click the eyecups out one click. The MHG could use another position just off of all the way in/down as they have extra eye-relief as well. The Maven B.1 is a perfect fit for me all the way in/down. Eye placement is second nature and is done without even thinking. All three are a delight for the eye-glass wearer to use!

The-Wanderer · Mar 1, 2017

Chuck,

I get easily confused. Like you, wearing glasses, I find the 12x50 SV's eye relief too short with its specified 19mm ER. The 8.5x42 with its specified 20mm ER is OK, just. These models have the glass recessed by about 5mm, sO I assume the available eye relief is about 15mm.

I have never seen a store with a Trinovid, but with a specified ER of 15.5mm have always assumed that it would not work for me. Does Leica's quoted ER refer to the available ER?

Has anyone measured a Leica ER and can report the eyecup down ER and the recess from the rim to the glass please?

crinklystarfish · Mar 1, 2017

henry link said:
Try using a small circular object at a distance so that it subtends about 3º of AFOV. Move it from the center to the edge at 3:00. How does its shape at the field edge compare to the examples at the extreme right end in this photo?

http://www.birdforum.net/attachment.php?attachmentid=551747&d=1437327988

In the photo the top line is a Swaro 8x32 SV, the middle is a Nikon 8x32 SE and the bottom is a Zeiss 8x56 FL.

I just tried this with my 10x version looking through the right barrel only. I looked at something akin to a cotton reel, indoors, at about 4 metres. The object was on a windowsill, so strongly backlit.

The image presented is - to my eye - most like the middle row, the Nikon SE. I see a slight compression of the right side of the circular object used, which also slips out of focus as it is 'moved' to the 3 O'clock position. The object can, however, be brought back into pin-sharp focus with a shift of the diopter adjustment.

I also looked at a vertical window frame and could see no obvious deflection - the edge of the frame seemed - to me - to remain vertical.

I agree regarding the colour fringing observation. This was green-ish to one side / mauve-ish to the other of the circular object, but was only evident when viewing the object at the extreme 3 O'clock position, and could not be 'focussed out': it steadfastly remained no matter the level of re-focussing.

I use rather than study optics and present these observations in purely layman terms. The technicalities of astigmatism / rectilinear distortion / angular magnification distortion are not concepts I would presume to wield freely.

Whatever Nikon have done I find the result very pleasing and - in actual use in the field - my 10x consistently refuses to throw up any distractions that have been a source of huge disappointment for me whilst using 'Alphas'. The control of veiling glare when looking into dark 'walls' of vegetation under otherwise open skies is a particular winner for me. This phenomenon ruins my enjoyment of so many bins.

Usual caveat - I fully accept different people will have different perception.

adhoc · Mar 1, 2017

henry link said:
...Edge sharpness is primarily determined by two aberrations...Geometrical distortions at the field edge are unrelated to edge sharpness...

Henry, thank you for a beautiful explanation. When the two linked posts were both read I understood "field curvature", "astigmatism", rectilinear, and angular magnification distortion, in binocular optics, together for the first time. May I suggest it to others to whom the terms may not be too clear.

However, I do not yet understand what makes an image look flat, which some find unnatural. Is it sharpness across the field (achieved by correcting both "field curvature" and "astigmatism"), or the correction of rectilinear distortion, or the creation of a.m.d. in correcting r.d., or a combination of these? Thank you!

adhoc · Mar 1, 2017

chill6x6 said:
...All three of these binoculars are just what the doctor ordered for eye-glass wearers. The Trinovid HD is the champ in this regard... ... ...Eye placement is second nature and is done without even thinking. All three are a delight for the eye-glass wearer to use!

Thanks, Chuck, I am ticking off the points in Monarch HG vs Trinovid HD (although I am thinking of 10x42) one by one in your revelations, enhanced by comments from others such as those on veiling glare by Crinklystarfish in the last post. Awaiting CA report!

chill6x6 · Mar 1, 2017

The-Wanderer said:
Chuck,

I get easily confused. Like you, wearing glasses, I find the 12x50 SV's eye relief too short with its specified 19mm ER. The 8.5x42 with its specified 20mm ER is OK, just. These models have the glass recessed by about 5mm, sO I assume the available eye relief is about 15mm.

Correct. Swarovski tends to over-state the actual, useable eye relief. ALSO...the figures are not consistent. The SV 12X50 is JUST BARELY useable for me. BARELY. The SV 8.5X42 and 10X42 are both listed at 20mm. In actuality, the 10X42 has more eye relief. The 8.5 is useable for me but with no room to spare. The SV 8X32 is also listed with 20mm eye relief. It's again more than the 8.5 and about the same at the 10X42. So as far as eye relief goes 10X42/8X42>8.5X42>12X50.

I have never seen a store with a Trinovid, but with a specified ER of 15.5mm have always assumed that it would not work for me. Does Leica's quoted ER refer to the available ER?

Has anyone measured a Leica ER and can report the eyecup down ER and the recess from the rim to the glass please?

That 15.5mm eye relief is for the Trinovid, not the Trinovid HD. The Trinovid HD 8X42 is LISTED at 17mm. The PREVIOUS model Trinovid is listed at 15.5mm. I have both. I find the Trinvoid useable, JUST. The Trinovid HD is much better. I even have to twist the eyecup out a little.

My responses are in RED. Eye relief figures are not consistent brand to brand and sometimes WITHIN brands. Zeiss seems to list 16mm for everything. You can almost bet if Zeiss list 16mm, it is at LEAST 16mm and more times that not MORE than 16mm and very eye glass friendly.

I'm sure it's possible but I can't imagine an eyeglass wearer having an issue with the 8X42 Trinovid HD or the 8X42 MHG since I have to twist the eyecup OUT some.

The-Wanderer · Mar 1, 2017

Chuck,

Your comments on understatement of ER in Zeiss binoculars is reflected elsewhere on this forum. I also have the EL 10x50 and all three were bought used. If hand holding, the ER is just enough, but not when tripod mounted as I need to hold the eyepiece hard a gainst my glasses. All three Swaros were bought used the proceeds from the sale of photogear that I no longer have the strength to carry. Its a bleep getting old.

I would like to try a Zeiss SF, but dealers holding stocks are not within easy reach.

henry link · Mar 1, 2017

adhoc said:
Henry, thank you for a beautiful explanation. When the two linked posts were both read I understood "field curvature", "astigmatism", rectilinear, and angular magnification distortion, in binocular optics, together for the first time. May I suggest it to others to whom the terms may not be too clear.

However, I do not yet understand what makes an image look flat, which some find unnatural. Is it sharpness across the field (achieved by correcting both "field curvature" and "astigmatism"), or the correction of rectilinear distortion, or the creation of a.m.d. in correcting r.d., or a combination of these? Thank you!

Thanks adhoc.

Sorry to say when it comes to understanding complaints about "flat fields" looking unnatural I'm nearly as much in the dark as you. The afocal light that enters our eyes directly doesn't have any distortion, astigmatism or field curvature. Eliminating field curvature and astigmatism from the binocular image would seem to be all to good. Distortion, unfortunately can't be eliminated from the binocular, only changed from one type to another, so I suppose a distortion profile with zero pincushion and high a.m.d. must be what is somtimes found "unnatural".

Henry

henry link · Mar 1, 2017

crinklystarfish said:
I just tried this with my 10x version looking through the right barrel only. I looked at something akin to a cotton reel, indoors, at about 4 metres. The object was on a windowsill, so strongly backlit.

The image presented is - to my eye - most like the middle row, the Nikon SE. I see a slight compression of the right side of the circular object used, which also slips out of focus as it is 'moved' to the 3 O'clock position. The object can, however, be brought back into pin-sharp focus with a shift of the diopter adjustment.

I also looked at a vertical window frame and could see no obvious deflection - the edge of the frame seemed - to me - to remain vertical.

I agree regarding the colour fringing observation. This was green-ish to one side / mauve-ish to the other of the circular object, but was only evident when viewing the object at the extreme 3 O'clock position, and could not be 'focussed out': it steadfastly remained no matter the level of re-focussing.

I use rather than study optics and present these observations in purely layman terms. The technicalities of astigmatism / rectilinear distortion / angular magnification distortion are not concepts I would presume to wield freely.

Whatever Nikon have done I find the result very pleasing and - in actual use in the field - my 10x consistently refuses to throw up any distractions that have been a source of huge disappointment for me whilst using 'Alphas'. The control of veiling glare when looking into dark 'walls' of vegetation under otherwise open skies is a particular winner for me. This phenomenon ruins my enjoyment of so many bins.

Usual caveat - I fully accept different people will have different perception.

Both yours and Binastro's observations are consistent with low pincushion and better correction for astigmatism than field curvature, the traditional Nikon approach in its flat field binoculars.

The CA descriptions are spot on for lateral color, which might be expected to be higher than average at the edge of of such wide apparent fields.

Henry

Binastro · Mar 1, 2017

Henry,
If my 8x42 MHG doesn't have higher CA than other samples, why is nobody bothered by coloured fringes on say a crow sitting on a chimney pot at 124mm, especially near the edges, but from memory even centrally?
It may be more obvious because the MHG is so bright, and I perceive edges even when looking centrally.

And if my sample is typical, which it may not be, why does nobody see the flare I do?
Maybe Nikon has tweaked the performance.

It could be simply that my observations are different to birdwatchers.

But as far as I am concerned the Canon 10x42 L is in a class above the 8x42 NMH even without IS.

Several days birding with Monarch HG 8X42 (1 Viewer)

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