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Victory HT 8x42 (1 Viewer)

PHA

Well-known member
Hello,

Visiting my son at London, after been with him at his PhD in Economics graduation in the EUI (European University Institute), Firenze, Italy, I made a visit at Harrods. Just to take a look at the place.
As the last year, they have DEALS in binoculars. Two were VERY GOOD SALE offers: Leica UV HD (non+) 10x50 and a Zeiss Victory HT 8x42. Each one GBP 998, around U$ 1400. New in the boxes....!
I left the place planning to buy both. Returning next day, the Leica was sold...
But I left with MY HT 8x42 in a bag...

Playing with them in London, mainly at Regents Park, and general views, they are a pleasure to use, with outstanding relaxed view, absolutely natural colours, outstanding contrasts and, also, outstanding resolution. As I expected having using 3 years the HT 10x42.

As I had with me the Meopta Meostar 8x32, my travel and carry everywhere binocular, I made a very interesting side by side "test".
I don't want to go in some extremely detailed descriptions. Only the, for me, the relevants ones.

HT 8x42 vs. Meopta 8x32

The main differences are: The shorter eye releif of the Meostar and his rather warm vision. And the slightly more relaxed view (perhaps the 5 mm exit pupil vs. 4 mm) with the HT. For me, nothing else. This confirm the OUSTANDING caracteristics of the Meopta Meostar 8x32!!! The resolution, or definition of details, of this "little" 8x32 is, AT LEAST, as good as in the HT.........! In all conditions.

The A few days after returning home, I made some very interesting side by side "tests" with the HT 10x42.

HT 8x42 vs. HT 10x42

The only difference to tell, apart the one related to the magnification, is the better veiling glare control (in hard sun at the front situations) of the 8x vs. 10x. I don't know the reason....May be the relation of the magnification vs. the exit pupil, I don't know...but is definitely better in the 8x42.
I think I have said before, this veiling (or milky) glare in extreme situation is the ONLY critic I made at the GREAT HT 10x42.

Sorry for the extremely short "report". But I don't want to repeat all that have been said about these binoculars.

Best Regards

PHA
 
PHA,
I enjoyed reading your impressions. I'm an FL user (8x42 and 10x56), and envy you the higher transmission experience.

But I look for larger trends. One, which your review supports, is that 8x32s don't suffer, in fact excel, in sharpness. This was also noted recently in a comparison of Leica HD+ 8x42 and 8x32. I experience it myself with my 8x30 Fujinon FMTR-SX, which both by day and night on the stars, is apparently to me the sharpest of several good binoculars in my stable..

Quite at the other end of the spectrum, the 7x50 has been lauded, in so many makes and models, that it has become clear that that specification has special advantages, and these have been largely understood or rationalized by more philosophical members of the binocular community. Similarly, the 8x30/32's day of analysis will come, if reports of impressive sharpness, across a wide range of brands and types, continue.

Enjoy your HTs!

Ron
 
PHA,
I enjoyed reading your impressions. I'm an FL user (8x42 and 10x56), and envy you the higher transmission experience.

But I look for larger trends. One, which your review supports, is that 8x32s don't suffer, in fact excel, in sharpness. This was also noted recently in a comparison of Leica HD+ 8x42 and 8x32. I experience it myself with my 8x30 Fujinon FMTR-SX, which both by day and night on the stars, is apparently to me the sharpest of several good binoculars in my stable..

Quite at the other end of the spectrum, the 7x50 has been lauded, in so many makes and models, that it has become clear that that specification has special advantages, and these have been largely understood or rationalized by more philosophical members of the binocular community. Similarly, the 8x30/32's day of analysis will come, if reports of impressive sharpness, across a wide range of brands and types, continue.

Enjoy your HTs!

Ron

Ron,

I have a sneaking suspicion that reports of 'sharper' 8× 30/32's has more to do with the smaller EP making better use of the user's better and less aberrated central part of their vision (before a dilated pupil delivers all manner of peripheral distortions and astigmatism that we are not usually aware of) than anything inherent in the format. :cat:

I know Henry raves about his big Zeiss 8×56 FL, which effectively becomes a higher focal length 8×20~25 during daylight with his older and less dilating pupils. I do recall (though can't put my finger on a link) that Ed once presented some statistical data showing that dilated pupil diameters were much greater than commonly thought for various age ranges, with from memory :brains: (increasingly dodgy! :) even 70+ year olds ranging up over 5mm .....

I know that I myself regularly have a pupil diameter over 4mm during our bright daylight, with canopies and shadows bringing fairly rapid expansion. At the extremes of low light, visual acuity drops dramatically (something like about 10x .... I recall David presenting a nice graph somewhere along the way) corresponding neatly with the purkinje shift. It becomes a question of brightness vs 'apparent sharpness', and I think there will be many individual permutations and preferences (along with favourite binocular formats and EP/ Twilight Factors) within that spectrum :h?:


Chosun :gh:
 
Hello,

Thanks, ronh.
Agree with you Ch Juan. I do not say the Meopta M 8x32 is "sharper" than the HT 8x42. May be I was not too accurate when put "...in all conditions...". At dusk or in very, very low light conditions, the more "relaxed" view wiew with the 8x42, leeds to slightly better details definition.
Anyway, I am delighted with the HT 8x42!!! Great all around binocular more, "perfect", for me, than the 10x42 (perhaps my sample...), if possible!!!! And, I repeat, this allows to show, also, the optic quality of the M. Meostar 8x32!!!!

PHA

PS I have, just, received, another HT 8x42....!!!! Brought by my cousing from the USA, since I asked him to buy one for me some six month ago. I almost forgot it...He never told me he had bought it...!!!!! So, after some brief "sample variation test", interesting, this new one is put on sale here. I would not have any problem because I KNOW few friends would jump to it at the USA price but down here...crazy things happens....!
 
Chosun,

Yes, I expect something like that is going on as well, certainly in low enough light that the user's pupil are wider than those of the binocular. I expect this is tied up with another commonly reported 8x32 effect, that it is dimmer than binoculars of larger exit pupil, even in conditions so bright that conventional wisdom (which your example seems to refute) would suggest that the irises are contracted to 2mm or so, making a bit of a mystery.

Speaking of amateur philosophers, I think it was Kenny Jones over on the dark side (Cloudy Nights) who posed the problem of "What is the eye pupil's diameter at the binocular, the majority of whose field appears, to the eye, as perfectly dark?" The great area of darkness surrounding the binocular field of view is bound to make the iris open up a more or less, compared to the fully wide bright naked eye view of the same scene. If the difference was sufficiently great, this could be the solution to both the 8x32's sharpness and dimness effects.

An interesting opportunity for the amateur investigator would be the measurement of eye pupil diameter in different lighting circumstances, both naked eye (pretty easy) and at the binocular (bit of a challenge there).

Ron
 
Hi Ron :hi:

Yes, you may have something there :brains: and "bit of a challenge there" is a 'bit' of an understatement! hahaha :-O That would be some impressively small little camera or sensor to measure that ......

I'm afraid I don't have a rule small enough for that measurement, but I agree, it would be absolutely fascinating to find out if there is a significant difference in pupil diameters with the eye cup engaged. I think in my case it is mostly due to age (or relative lack of it :), as I always wear eyeglasses to correct short sightedness, so plenty of ambient light leaks in from the side. The lenses are the 'transition' type though (automatically darkening for bright light), although they are a bit old now and have lost most of their range - seeming to settle somewhere around a permanent light brownish 'Roy Orbison' type tint! |8)| |:d|

Apart from the higher magnification reduction in brightness, I've always found the 4.2mm EP of the 10x42 format a bit too dim for my liking ..... it will be interesting to see what PHA has to say on the brightness comparison - having both 8x and 10x42 HT's to compare. :t:


Chosun :gh:
 
There have been a number of studies that relate luminance (light levels) to pupil diameter and also angle of view. This paper is a bit daunting but if you go to figure 16 and just look at the dashed black lines, the left graph is for a 60° view and the right for a 10° view. A bright computer screen is around 200 cd/m2. If it formed 60° of your view in an other wise darkened room your pupil would be about 2.5mm. If you stood back from the screen so it was only 10° of your view then your pupil diameter would be around 4.3mm. Unfortunately the calculators which include adjustments for age and one eye/two eyes don't appear to work any more.
http://jov.arvojournals.org/article.aspx?articleid=2279420

I think I've put up a link for Koenig's study on light levels and acuity before, but I haven't found anything that directly looks at pupil diameter and acuity. For 60° and 10° at about 200cd/m2 my own acuity would drop about 50%!

The interesting thing is that while the low light levels or narrow angles of view will cause your pupil to dilate, artificially restricting the pupil can improve your effective acuity. If you were looking at a small but bright target on a dark background an, 8x20 would appear much sharper than an 8x42. Nothing to do with binocular resolution, it's visual acuity.

David
 
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Hi,

Last night I compared the 10x HT vs. 8x HT. And the Swaro Habicht W GA 10x40...
Before to reach the moment of total, or almost, darkness, I cannot find any clear difference in what I can see with the 8x and not with 10x due to, by the way, "clarity" of the former because the bigger exit pupil diameter....
In fact, at the critical moment, I tend to favor the higher 10x magnification with 4,2 mm than the 8x with little more than 5 mm....I can see more details with the 10x. For others this could be the opposite.
The clear winner between this three is the Swarovski Habicht. Its clarity is awsome for a 10x and, more relevant for me, its 3D view allows to discern details and separate planes amazingly at very low light levels!!!!

About the two HTs 8x42, perhaps I am lucky. I checked the colimation and in both is very good. Only very little horizontal discolimation that is irrelevant for me (in the last top roof and Porro binoculars I checked, allways found this little horizontal discolimation...the only PERFECT COLLIMATED binocular I have had has been the Leica Trinovid BA bought new in 2001...).
Trying, hard, to find differences in resolution or differences between barrels between this to 8x42 HTs, I must say I couldn't find any....Including star testing both. Perhaps at this magnification level, tiny differences cannot be seen simply with naked eyes.

Best Regards

PHA
 
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David,
Thank you for the link to that paper which looks very interesting in a quick glance. I'll give it a good read tomorrow.

Chosun,
If you point a binocular at a mirror and focus on your reflection, you will see your eye pupils within the objective lenses, in focus and magnified to a diameter of (their innate size) x (the magnification). This provides an easy external measurement method. For an example, if the binocular is a 7x50, and your eye pupil at the eyepiece measures 3mm, the pupil will appear 21mm across, or about 2/5 the diameter of the objective. This could be flash photographed.

Ron
 
David,

I did read the paper, and my impression is that the pupil diameter vs adapting field size work is not useful for the binocular user issue under discussion. It is based not on differences between pupil diameter for full naked eye field vs a binocularish 60deg field, but on tiny sub-degree vs binocularish fields.

I still think there is a rich furrow to plow here for a "Henry Link type". (Anybody vaguely fitting that description out there?)


PHA,
I'm sorry to derail your 8x42 HT thread, but I enjoyed all your comments and am envious and happy for you.
Two in the house at once is just sinful!

Ron
 
Ron,

I was addressing the point that you, PHA and particularly CJ made that an x30/32 can look sharper than larger formats. What CJ wrote in #3 is quite correct.

"I have a sneaking suspicion that reports of 'sharper' 8× 30/32's has more to do with the smaller EP making better use of the user's better and less aberrated central part of their vision (before a dilated pupil delivers all manner of peripheral distortions and astigmatism that we are not usually aware of) than anything inherent in the format."

This is particularly obvious when looking at the night sky, though it's often attributed to the binocular aberration in articles I've read. Nonsense of course. Acuity with a fully dilated pupil is pretty woeful and a decent 7x50 will usualy have 5 to 10 times the effective resolution of the eye.

It's normally assumed that this is not a factor in normal daylight viewing where a small pupil would be expected to be the norm. However, CJ then makes the very astute point.

"I know that I myself regularly have a pupil diameter over 4mm during our bright daylight, with canopies and shadows bringing fairly rapid expansion."

That paper indirectly explains CJ's observation. Even when the scene illuminance is high it's not just the luminance of the the subject you are looking at but the angle it subtends to the eye that dictates pupil diameter and acuity.

We will all have different aberration patterns in our eyes, so quite how acuity will relate different pupil diameters/exit pupils will vary. I have noticed a more significant difference between 3.2mm and 4.2mm than between 4.2mm and 5.2mm, but judging from many anecdotes on the forum, it appears that 'sharpness' difference in the latter is more commonly reported.

It's unfortunate that the calculator in that paper doesn't work, so we can't readily get a value for wider angles. Publications on acuity, pupil diameter and luminance commonly use 60° in the lab environment to represent an unrestricted angle of view. It seems to suggest that wider angles than 60° make little difference, but I couldn't say for sure.

Cheers,

David

P.S. Retinal resolution and illuminance is another factor in this story, but I haven' quite figured out how it fits.
 
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Sorry to ruin the party, but forget the eye, it's all in the brain. o:D

"We assume that we can see the world around us in sharp detail. In fact, our eyes can only process a fraction of our surroundings precisely. In a series of experiments, psychologists at Bielefeld University have been investigating how the brain fools us into believing that we see in sharp detail. The results have been published in the scientific magazine Journal of Experimental Psychology: General. Its central finding is that our nervous system uses past visual experiences to predict how blurred objects would look in sharp detail."

"The experiments show that our perception depends in large measure on stored visual experiences in our memory," says Arvid Herwig. According to Herwig and Schneider, these experiences serve to predict the effect of future actions ("What would the world look like after a further eye movement"). In other words: "We do not see the actual world, but our predictions."

https://www.sciencedaily.com/releases/2014/10/141017101339.htm

So if you bins look fuzzy, just drink some coffee...
 
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We will all have different aberration patterns in our eyes, so quite how acuity will relate different pupil diameters/exit pupils will vary. I have noticed a more significant difference between 3.2mm and 4.2mm than between 4.2mm and 5.2mm, but judging from many anecdotes on the forum, it appears that 'sharpness' difference in the latter is more commonly reported.

Here is a study that suggest a correlation between exit pupil and visual acuity, but it's only a single observer and "astro conditions", and not even an complete optical system is used as far as I understand:

http://adsabs.harvard.edu/full/2004JBAA..114...73L

The VA differences suggested between 3 and 4 mm is small, but the optimum seems to be around that range.
3 vs 7 mm definitely looks significant. But it might be an effect of increasing brightness.
So if this is relevant in terrestrial conditions and light is hard to say.

Just wonder how big relevance this might have when choosing binoculars.
To me it doesn't seem reasonable to get a 10x32 before a 10x42 bin...
since a larger lens diameter should give better resolution and is brighter.
 
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Sorry to ruin the party, but forget the eye, it's all in the brain. o:D

"We assume that we can see the world around us in sharp detail. In fact, our eyes can only process a fraction of our surroundings precisely. In a series of experiments, psychologists at Bielefeld University have been investigating how the brain fools us into believing that we see in sharp detail. The results have been published in the scientific magazine Journal of Experimental Psychology: General. Its central finding is that our nervous system uses past visual experiences to predict how blurred objects would look in sharp detail."

"The experiments show that our perception depends in large measure on stored visual experiences in our memory," says Arvid Herwig. According to Herwig and Schneider, these experiences serve to predict the effect of future actions ("What would the world look like after a further eye movement"). In other words: "We do not see the actual world, but our predictions."

https://www.sciencedaily.com/releases/2014/10/141017101339.htm

So if you bins look fuzzy, just drink some coffee...

Interesting article. I wouldn't suggest it's wrong at all, it just paints a partial picture of what actually goes on in the brain. At the risk of over simplifying it further the brain sort of works at two speeds. Slow stuff, when it is acumulating fine detail information from the eyes. This is what we do when we read an eye chart or try to ID that distant spec in the sky. If you stop for a moment when you do this it's quite obvious that much of your field of view is low definition and/or out of focus. Most of the time we just glance at stuff and the brain only accumulates limited information, a low definition image even in the fovea. Much of the rest is simply made up by the brain as the article suggests.

This is where the ambiguity of the term 'sharpness' comes into play. Most people here would use sharpness to describle the combination of high definition acuity or resolution limited view and also the lower definition, brain manipulated view. They are both the product of the brain's image processing and not readily distinguished in normal use. The clue is in the definition of the visualised image. Most of us will have acuity limits in the range of 1 to 2 arcminutes, and it needs us to study the letters on an eye chart for a second or two to 'read' each of the smallest letters at the limit of our vision. If you scan the bark of a tree, feather structure or similar targets to judge sharpness, the result is a lower definition image, typically in the range of 5-12 arcminutes. Still pretty small, but uses only a fraction of the brains processing power and is much faster. This is the mode we are in most of the time in normal daylight. This is much more dependant on contrast. It's a perception, and has little to do with resolution or acuity.

The distinction between resolution and 'sharpness' is frequently exploited in photography but largely goes unacknowledged in our binocular world. A small percentage of users might have the acuity to be able to spot effective resolution differences between most binoculars. Sharpness perception is in the range of almost everyone. The difficulty is that unlike effective resolution the contrast necessary for different degree of perceived sharpness appears to be highly influenced by the light conditions at the time and moderated by the learning experience of the user as that article points out. Not really transferable information, unlike effective resolution. Just be wary if someone claims a one binocular is sharper than another.

Limiing an exit pupil will affect acuity, but if there is a parellel change in lower frequency contrast then it will also alter perceived sharpness. Not something at all easy to distinguish even if you are aware of the difference.

David
 
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Hi,

Very good information, indeed!

I am aware about the differences, subtles, between "sharpness" and "resolution". So, I mentioned "resolution, or definition of details", trying to be the most accurate I can...I am refering to distant definition and separation of lines in buildings, both horizontal and vertical (anatismatics...), leaves and branches in trees, contours and feathers/furs in birds and mammals, etc.
I understand that, "that" "definition of details" depends on good optical qualities and corrections about, well: intrinsic resolution, contrast, chromatic aberrations, astigmatism, as the main ones. Plus, of course, the interaction of those with my own eyes. As simple, or complicated, as this...

PHA
 
Here is a study that suggest a correlation between exit pupil and visual acuity, but it's only a single observer and "astro conditions", and not even an complete optical system is used as far as I understand:

http://adsabs.harvard.edu/full/2004JBAA..114...73L

The VA differences suggested between 3 and 4 mm is small, but the optimum seems to be around that range.
3 vs 7 mm definitely looks significant. But it might be an effect of increasing brightness.
So if this is relevant in terrestrial conditions and light is hard to say.

Just wonder how big relevance this might have when choosing binoculars.
To me it doesn't seem reasonable to get a 10x32 before a 10x42 bin...
since a larger lens diameter should give better resolution and is brighter.

Thanks PHA,

Vespobuteo,

I've tried something very similar to that approach but found a few issues, some of which are mentioned but not corrected in the report. Like the author I use glasses and the use of apertures like that created some complications. Easier to progressively stop down a binocular. It certainly looks like the light levels, particularly constant brightness, and targets chosen have sevely flattened the acuity responses. Credit to the guy though for completing and reporting a systematic study.

I've done a lot more on acuity effective resolution and light levels as I've totally failed in attempts to measure my own pupil diameter for reasons I'll skip for now. I've got a few pupil diameter points with the help of others, and as I mentioned earlier, I get a 50% reduction in acuity between 2.5mm and 4.5mm which corresponds to around 300cd/m2 and 50cd/m2 respecively. That is pretty noticable. (I get a fairly abrupt change between 100 and 200 cd/m2). It plumets like a stone after that. Just to give you some idea how that might relate to birdwatching conditions. At breakfast time this morning it was bright but cloudy. Pretty good bird watching conditions. Standing on my back lawn, a meter reading of my white painted garage I got 1000cd/m2 so my pupil would have been just under 2.5mm. The reading from the foliage on the trees at the foot of the garden was 30cd/m2 and my pupil should have been just over 4.5mm.

No I wouldn't suggest anyone get a 10x32 as their main binocular but having a set of objective covers with 25mm holes in them can really 'sharpen-up' the view on occasions. ;)

Cheers,

David
 
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Very interesting discussion, guys. I can’t add much, but some images I recently made through two binoculars might be relevant.

For the last week I’ve been working to try to improve my ability to accurately photograph the the true measured resolution of binoculars on a 1951 USAF resolution chart. By using a 600mm FL telescope behind the binocular eyepiece with the camera sensor at prime focus I’ve finally come pretty close. The images below (reduced in size to fit here) show the chart at 400” imaged through an 8x30 Swarovski Habicht (left) at full aperture and an 8x56 Zeiss FL stopped down to 30mm to match the aperture of the Habicht.

When looking directly through the binoculars the smallest line pairs I can resolve with my 20/15 acuity are Group 0/ Element 6 and they look very tiny. If you can move back from your computer screen until you can barely resolve those line pairs in the Zeiss image you will see something like what I see. If your acuity is 20/20 then back up until you can resolve Group 0/ Element 3 to see how the chart would appear to you and if, like David, you have super 20/10 acuity use Group 1/ element 3.

Even in these slightly degraded images I think it’s obvious why the Zeiss image at normal magnification looks “sharper” and "cleaner" than the Swarovski image. Not only does the Zeiss resolve higher spatial frequencies than the Swarovski, frequencies beyond anyone’s eyesight acuity, but it also looks sharper and higher contrast even at the lowest spatial frequencies on the chart that are easily resolved by both binoculars. There is no trade-off here between low frequency contrast and high frequency resolution; the Zeiss is better at both, which is just what you would expect from an instrument with lower spherical and chromatic aberrations..

I also made images with both binoculars stopped down to 22mm to simulate bright daylight. Both show lower aberrations and reduced resolution when stopped down, but the Zeiss is still obviously better.

On the subject of pupil dilation in daylight I tested my own today using a method I’ve described before in which a binocular prefocused to infinity is used to examine a defocused artificial star at about 3m. Two pieces of black masking tape are stuck to the trim ring in front of the objectives to form an open slit between them. The width of the slit when it barely shows on both sides of the defocused star disk tells you how much of the objective lens diameter is entering the eye. For me that was 18mm of the Swarovski Habicht objective (indicating a 2.25 mm eye pupil) when the artificial star (glitter point on a small shiny ball) was placed in bright sunlight. It increased to 24mm in open shade (pinhole in front of an LED light) and 28mm in deeper shade underneath a rhododendron. So, it’s obviously quite possible to use the full 30mm objective of an 8x30 in normal daylight or probably even the full 42mm objective of an 8x42 on really dark days.

Henry
 

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Henry,

This is one of the best posts on Birdforum in quite a while. Thank you!

There is lot to think about here, but I'm reminded of our discussion some years back about whether or not a binocular needs to be able to resolve better than the eye through it can resolve, and by how much. In these two photos, the 8x30 barely reachers my minimum limit of twice the resolution my eye gets through the bino, while the 8x56 comfortably exceeds it.

One can also see how CA influences contrast in pretty coarse detail also.

Kimmo
 
Henry,

Nice photos! I've had a go at using a scope objective myself but found it very cumbersome to focus and control stray light so put it on hold pending further purchases. Well done for sorting it out.

I know you've reported very good results for your Zeiss before but that really does look rather special. The Swaro is still very good. I made those 121/D and 136/D. Is that right? With those resolutions it's clear both are going to exceed my magnified acuity at 20mm (~ 160/D), but I'd be interested in your 22mm results all the same. (My single eye acuity is 20/11 by the way, though I can occasionally do a bit better with two.)

I've tried the Habicht a few times but never had the opportunity to do any testing. Your results seem to confirm my impression that the effective resolution was very good but perhaps not the best I've seen on contrast.

Your boosted results do appear less sharp than the Zeiss, but as far as I can determine, this kind of measurement cannot show differences in sharpness perception alone. According to the books the critical angular range would be between -1,1 and -2,1 at that distance. Something that can be easily seen or potentially photographed without boosting. In photography they traditionally used images such as fallen leaves or spilled coins as test targets for sharpness. It's comparable random pattening of the right size range that seems to be most revealing to my eyes. However the range of colours and tones of the target, swings in illuminating colour temperature appear to favour different binoculars at different times. It seems to me that colour contrast seems is at least as important as black and white contrast. I've experimented with various test images with limited success but still looking for something better. Any ideas?

I've tried your pupil diameter method, and it does work, but I firstly want to plot luminance, pupil diameter and acuity.... without a binocular in the first instance. On top of that, as soon as you look away from the test target to look at a defocussed point source the pupil diameter changes. To complicate it further I mostly use natural light which also changes constantly, so even a minute or two after or before is generally not good enough. Most other methods fail because my iris is mostly black. My optician struggled, even using a slit lamp.

David
 
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Why is it, when I test binoculars with resolution charts, that the sharpest view is almost always slightly above, below or to either side of dead centre?

It matters not which binocular I test - new, old - the area of absolutely sharpest focus is almost never dead centre.
 
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