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Review of Canon 10x32 IS

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Old Thursday 14th February 2019, 16:37   #26
typo
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Henry,

Sounds an interesting idea.

Unfortunately I no longer have the image analysis program I knew and trusted, but for what It's worth, the colour analysis app on my tablet gives the R:G:B values for your Habicht as 200:198:203 and the Canon as 198:194:191.

Late this afternoon the sky here was virtually cloudless. A rare event for the UK. I first set up a white photo target in direct sunlight. The results were better than the other day but I was still getting about a 15% fluctuation in luminance over the course of two or three minutes. When I put the target on the ground and shaded from direct sunlight there was no detectable variation on my metre over a similar time frame. Of course the light was pretty blue from the Rayleigh scattering, but significantly more stable as a light source.

I recall reading some scientific papers a while back that used what I recognised as as a very common 12v auto sidelight bulb for their spectral studies. The power supply was calibrated I think, but I guess a low cost, plug-in regulated power pack might be adequate for our relatively humble needs?

David
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Old Friday 15th February 2019, 03:26   #27
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Henry:
A nice technical review, and how about your thoughts about handling and how you like them
in use.

Jerry
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Old Friday 15th February 2019, 21:19   #28
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Hi Jerry,

I'll have summary of my personal likes and dislikes at the end.

Henry
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Old Friday 15th February 2019, 21:21   #29
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Part Four: Resolution, Star-tests and Axial aberrations

I had planned to cover the aberrations revealed in star-testing and resolution measurements in the same post but I’m a bit stumped by some of the oddities in the star-tests and photographing them is proving to be so difficult that I’ve decided to report the resolution measurements now and add star-test information when that’s finished.

As usual I used a USAF 1951 glass slide placed a little over 10 meters from the binoculars. At full aperture the resolution of both sides was about 4.45”. In my experience that’s a solid enough result for a 32mm binocular, but a bit behind the best performing 32mm I have here (Nikon 8x32 SE, 3.9”).

I also measured resolution with the objectives stopped down to 25mm to simulate the effective aperture imposed by the eye in bright daylight. That dropped the raw resolution to about about 5”, which actually indicates an improvement in the optical quality from 142.4/D to 125/D (where D is the aperture in millimeters). Hand holding the binocular, using either IS mode, I find that I can resolve line pairs on the USAF chart to about 8.8”, the same as when the binoculars are tripod mounted.

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Old Saturday 16th February 2019, 08:45   #30
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Henry,

Thank you for the resolution results. Food for thought!

I think we established a few years back that your results are significantly different to mine for some reason, (possibly the choice of target?) so I'm not sure if those are good or bad results. I remember you reporting a result of 110/D. Wouldn't that make the 125/D stopped down result quite poor by comparison?

In that same thread I reported an apparent acuity of 85" with a 10x42, hand held, but again we are probably not comparing like with like.
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Old Sunday 17th February 2019, 21:29   #31
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Hi David,

I'm not sure why my resolution measurements tend to be higher than yours. Possibly because the glass slide I use can be set up to have very high contrast between the darkly shadowed black bars of the glass slide back lit by as bright a white surface as I can manage from either sunlight or by placing a halogen task lamp close to a white board. The extreme contrast of the target is definitely helpful to me for resolving the tiniest line pairs at the very high magnifications and small exit pupils I use.

To check myself I went back and remeasured everything about setup and introduced a reference telescope. I found the measured binocular to target distance was too long by about 1% and what I had thought was a 25mm mask was closer to 26mm. Off course there is always a 12% gap between the size of adjacent elements on the chart, so unless the the binocular to target distance is constantly adjusted the true resolution is likely to fall somewhere between elements. I've come to consider about 116/D as a perfect score on the USAF 1951 in my set-up, so I think if I ever reported 110/D there must have been a 6% error of some sort.

For a reference scope I used a Takahashi FC-50 Fluorite APO fitted with the same 26mm mask as the binoculars. Equal magnification of 80x was used for all three instruments.

With the 26mm mask in place I measured both the Tak and the Nikon at 4.48" or 116.5/D. The Tak showed a little sharper image, with essentially zero chromatic aberration. The Canon was one element off at 5.02" or about 130/D using the new 26mm aperture value and had more longitudinal chromatic aberration than the Nikon. I would say the Tak performed as expected for a Fluorite doublet stopped down to about f/16, the Nikon performed superbly well for a binocular with fast achromatic optics and the Canon was about average for a binocular, not good enough for any bragging rights nor bad enough to be considered a lemon.

I've given up on good photos of star-tests, so Ill put together what I have and try to wrap this up in the next few days.

Henry

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Old Monday 18th February 2019, 05:52   #32
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Henry,

I did try to send you a PM explaining my questions and concerns, but unfortunately it bounced.

I'm hesitant to post the link, as some of the ensuing discussion became somewhat nonsensical , and is probably best forgotten, but your 110/D result was for an AP Stowaway. In the same thread Kimmo claimed 106/D for his Leica 8x20. I've always suspected that these bizarre results were most likely due to your use of a backlit, negative USAF 1951 target.

Many years ago I was told that that the original 1951 military manual contained quite rigid regulations on the nature of the light source, it's luminance and spectrum, but I don't known if positive and negative targets were mentioned. It would make little difference to a camera, (at the correct exposure), but scientific reports tell us that the eye adapts differently to positive and negative targets. It significantly alters parameters like visual contrast sensitivity. How much will depend on the luminance, and presumably the exit pupil. Unfortunately the publications don't predict what would happen in this case. I don't have a negative USAF target to compare, but have seen spurious patterning at very high luminance when I've tried to mimic one. It might be a plausible explaination for those very odd results. Perhaps something to be aware of. Personally, I will stick with a positive target.

I've got as close as mentally debating whether a result might be closer to 115/D or 116/D ( by juggling the distance), but never better than that, so our current results now appear to be more closely aligned. The 130/D for the Canon should be a quite acceptable resolution for the large majority of users, even with the IS engaged. Can't help hoping for better though.

I known you have set great store by your star tests in the past, but my experience has been rather the opposite. The Airy disks have been normally highly distorted in the binoculars I've checked, even on one binocular that was borderline 115/D. I can't find a relationship with effective optical performance myself, but will try to keep and open mind on the subject.

Thanks again for the interesting data.

David

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Old Monday 18th February 2019, 15:08   #33
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David,

FWIW, I think what I have is also a positive target, at least that's the way it's labeled by Edmund Optics (opaque bars and numbers deposited on transparent glass).

I guess I'll have to remain an advocate for using a very bright light source for the background in these high magnification tests, either sunlight or as close as possible with artificial light. Whatever the Air Force thinking was about light levels for their purposes it seems appropriate to me to use a source with a reasonably repeatable light level and color spectrum corresponding to the field conditions the optic will be used under. As a practical matter it's also useful to start with a very bright source since it will wind up looking pretty dim at very small exit pupils anyway.

It's certainly true that choosing a lower light level will affect the results. Just now I repeated measurements for the Tak FC-50 and the Canon 10x32 with the halogen lamp pulled back and slightly turned away from the white board behind my target. For my eye both suffer a loss of resolution at the lower light level, one element worse for the Canon and two worse for the FC-50. The Tak image looks "better", but it still can't resolve (or more properly my eyesight can't resolve) the next smaller element. If these results are to be believed both are now rather poor 147/D telescopes. Surely this has to be in inaccurate representation of the actual resolving power and the difference between these two telescopes, caused by the eye receiving insufficient illumination at high magnification. One is, after all, diffraction limited and essentially aberration free while the other has obvious chromatic and spherical aberrations revealed by a star-test. I guess we'll get around to our differences on that subject next.

Henry

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Old Monday 18th February 2019, 19:08   #34
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Henry,

Seems I misunderstood you about the negative target. The mystery over the 110/D result deepens!

Naturally, there is the risk of errors with both excess and too little light.

The US eye test should be conducted with a chart luminance or 300cd/m2, which would typically correspond to a 2.5mm pupil. From my own tests this seems to be a reasonable guide to work from. As you reduce a binocular (or telescope) exit pupil below 2.5mm through boosting and/or stopping down, the target luminance appears to need a proportional increase in luminance to maintain retinal illuminance (trolands). So if I boost an 8x42 seven times, the EP will be 0.75mm and the change in effective EP area will need a luminance increased of 11 fold or ~3300cd/m2 (compared to the 2.5mm eye pupil) to compensate. If that binocular is stopped down to 20mm as well it should be almost 50 fold brighter at nearer 15000cd/m2. Fortunately things probably don't need to be too precise, but I like to get within +/- 30% if I can. Some days It's just not possible.

Unfortunately it's pretty difficult to guess luminance without a metre. Just to give you an idea. A piece of white paper 4" from a regular 40w incandescent light bulb gave me 300cd/m2. 4" from a 40w halogen spot gave me 2000 cd/m2. Frosted glass 2" in front of a 200w halogen tube gave me 20000cd/m2. A sheet of white paper in direct sunshine has given me readings well over 50000cd/m2. It is possible to calculate target luminance using camera settings. I can try to track down the formula again if you are interested?

Look forward to round 4, or is it round 5?

David

P.S. The equation relating camera setting to luminance is about half way down this Wikipedia page.
https://en.m.wikipedia.org/wiki/Light_meter

The K value for different makes of camera is given in the following section. Don't forget to use spot metering.

Last edited by typo : Monday 18th February 2019 at 19:17.
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Old Tuesday 19th February 2019, 16:13   #35
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Hi Henry,
I enjoyed reading this. I especially enjoyed reading about your CA test. I may have missed it(probably did) but at what distance from the binocular did you set up the white/black bar? I may try this myself.
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Old Tuesday 19th February 2019, 17:24   #36
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I just picked up the 10x30 IS II, which I know is not quite the same quality as this 10x32, but man are they interesting. Ease of view isn't the best due to the small EP, and Chromatic Aberrations are occasionally very poor (is this due to the way the lens adjusts?), but in terms of resolving fine detail these are very nice; additionally, once the IS settles in, eye-strain is greatly reduced.

I'd not buy them as my only binocular, but for my intended uses (waterfowl, eagle nest monitoring, general winter bird counts when foliage is gone) they seem to have a lot of value.

Justin
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Old Tuesday 19th February 2019, 17:40   #37
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Hi Chuck,

My target is 72" long with the centers of the 1/2" white plastic tape strips spaced 2" apart. I want the 2" spacings to correspond to about 2 of apparent field for every binocular tested regardless of magnification. The distance to the target doesn't have to be known as long as the AFOV is accurately known. For instance, if I know a binocular has a 64 AFOV I just move the tripod back and forth until I find the distance where 32 white bars bisect the binocular field and the cross bar is centered. Of course this means a 10x binocular has to be 25% farther away than an 8x binocular to maintain the same 2 increments.

I think a target scaled down to half the size of mine should work just as well and require less space.

Henry
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Old Tuesday 19th February 2019, 17:54   #38
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Originally Posted by jremmons View Post
I just picked up the 10x30 IS II, which I know is not quite the same quality as this 10x32, but man are they interesting. Ease of view isn't the best due to the small EP, and Chromatic Aberrations are occasionally very poor (is this due to the way the lens adjusts?), but in terms of resolving fine detail these are very nice; additionally, once the IS settles in, eye-strain is greatly reduced.

I'd not buy them as my only binocular, but for my intended uses (waterfowl, eagle nest monitoring, general winter bird counts when foliage is gone) they seem to have a lot of value.

Justin
That pretty much sums up my experience with the 10x32. An effective tool thanks to the IS, but thanks to the tiny exit pupil and the excessive lateral color often an unpleasant thing to look through.

Henry
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Old Wednesday 20th February 2019, 00:49   #39
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Thank you for this excellently comprehensive review.
Is there any chance that you might be able to give Canon's flagship 10x42ISL a similar workout?
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Old Thursday 21st February 2019, 03:41   #40
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Hi Chuck,

My target is 72" long with the centers of the 1/2" white plastic tape strips spaced 2" apart. I want the 2" spacings to correspond to about 2 of apparent field for every binocular tested regardless of magnification. The distance to the target doesn't have to be known as long as the AFOV is accurately known. For instance, if I know a binocular has a 64 AFOV I just move the tripod back and forth until I find the distance where 32 white bars bisect the binocular field and the cross bar is centered. Of course this means a 10x binocular has to be 25% farther away than an 8x binocular to maintain the same 2 increments.

I think a target scaled down to half the size of mine should work just as well and require less space.

Henry
Thanks Henry!
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Old Friday 22nd February 2019, 16:50   #41
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Originally Posted by etudiant View Post
Thank you for this excellently comprehensive review.
Is there any chance that you might be able to give Canon's flagship 10x42ISL a similar workout?
Probably not, unless I run in to somebody locally who has a pair.

Henry
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Old Friday 22nd February 2019, 16:59   #42
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Part Five: Star-Test and Summary

Sorry, I haven’t been able to add anything for the last few days. I’ll try to wrap things up now.

The full aperture star-test photo below is the best I could do. Outside of focus is on the left. As usual, the patterns were clearer to the eye and a bit less colorful. Monochromatic spherical aberration, (viewed through a narrow band green filter) was good for a binocular at full aperture, but spherochromatism (as seen in the very colorful out of focus images) was probably higher than usual and continued to look about the same with the binocular stopped down to 26mm to simulate the effect of the eye’s pupil in bright light. A 15mm stop down cleared things up nicely, but of course that is far below a 10x32’s effective working aperture range of 32mm to about 25mm in the brightest light.

The odd anomaly of multiple center spots seen in the photo appears between 2-3 rings outside focus and dissipates between 5-6 rings. There’s an extra pink spot and an extra violet spot, which revolve around the center, sometimes merging at the center. I’m going to guess that this has something to do with the complex objective design, but I have no idea how it might affect performance. Other defects where minimal in this sample, the worst being slight astigmatism in the right side.

Overall, the star-test didn’t reveal anything too surprising about the axial aberrations (except those odd spots). By far the most visible aberration at or near the field center is the normally non-axial aberration of lateral color. I think that it along with a healthy amount of longitudinal CA are the main things that prevent the binocular from achieving a completely cleanly focused star at the field center. There is always at least a little lateral color, magenta and green flaring from different directions of a focused star point no matter how carefully it is centered and focused.

In the end, I found the Canon 10x32 IS to be a binocular with some excellent, even state of the art qualities, but with one quite severe flaw (excessive lateral color), which unfortunately often mars the view for me in bright high contrast light. More personally, after using a 7mm exit pupil 8x binocular for many years, I‘m not really keen on any binocular with such a small fiddly exit pupil and 10x has some disadvantages compared to 8x (like narrower depth of field) that are not addressed by image stabilization. For pure visual pleasure I was always happy to return to the world of a very low aberration 8x view whenever I switched back to my 8x56 FL.

I know I haven’t said much about the 600 lb. gorilla here, image stabilization. I think I still don’t have enough experience with it to have a very informed opinion. There are many situations I haven’t tried like a rocking boat or moving car. I had expected some advantage in long range scanning over our local lakes, but I’ve found that to be somewhat disappointing. Even a stabilized 10x doesn’t have enough advantage over 8x at the distances I usually encounter waterfowl, so the scope is still needed for IDs about as often as before. Maybe I’ll find a more effective use for IS when spring migrants start showing up. I’m hoping to get easier IDs from glimpses of warblers in trees too distant for a conventional 8x. My experience so far with small winter birds at such distances looks promising.

I will say that I find the “Stabilizer” mode more useful than “Powered IS”. “Stabilizer” is very forgiving of both inadvertent binocular movements and those needed to follow a moving target, while still offering an effective level of stabilization. “Powered IS” seems to be capable of tripod like stability, but only if the binocular is quite still. Even small binocular movements will disturb the stability and lead to swimmy over and under corrections that cause queasy sensations, at least for me.

Finally, I’ll say a little about my experience using a 3x booster with the 10x32. The stabilization mechanism can keep up well enough at 30x, but the image quality problems from CA are naturally worse. If the lighting conditions allow it the image can be reasonably clean if somewhat dim, but high contrast situations will show very vivid longitudinal and some lateral CA. Still, with only the addition of a pocketable booster it’s a pretty nifty way to see smaller details hand held than can be seen at 10x.

Henry Link

Oops, almost forgot to mention a partial solution to the problem of the terrible eyecups. I and I think most people will find it necessary to fold down the eyecups even without glasses. This leaves my brows as the only contact area between my face and the binocular and my eyes fully exposed to side glare from a wide angle. I happen to have a "Bino Bandit" glare blocker that I bought a few years ago and quickly relegated to a drawer full of rejected eyecups. Finally a binocular has come along that works with it (see photo below). New ones appear to come with buckles that allow the thing to be folded into a sort of rain guard.

https://alpineproducts.com/product/b...glare-blocker/
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Old Friday 22nd February 2019, 21:52   #43
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Thank you for all the hard work, Henry, and for the good write-up!!!
Your five part review has been a revealing and very interesting read for me.

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Old Saturday 23rd February 2019, 07:00   #44
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Henry,

Thanks again for your in depth look at the Canon. Much appreciated.

The IS did not work well enough to tempt me on their old IS models, or the couple I've seen using Kamakura technology, but it sounds like it may have improved in this model. I'll take a fresh look when I get a chance.

The star tests do seem a little curious, though not as bad as many I've done. As I said I'm not convinced of the value at binocular resolutions, but I've never been sure if I had the set-up quite right. I found a copy of Harold Suiter's book this week. He seems to stipulate some some very precise test conditions. I think I was mostly in the right ball park, but perhaps not close enough? Something I'll look at again.

Cheers,

David
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Old Saturday 23rd February 2019, 15:33   #45
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Thanks Canip and David,

It's too bad the Suiter book is all black and white. A chapter with color simulations of the effects of longitudinal CA and spherochromatism on out of focus patterns would be very helpful for understanding short achromats like binoculars. In my experience spherical aberration affects the image quality long before it actually degrades measured resolution. At high magnification the unfocused rays look like a fog partly but not completely obscuring a focused core image.

Looking back on the last part I think I gave the advantages of IS too little credit. I spent some time with the USAF 1951 trying to determine at how much greater distance I could resolve the same line pairs hand held with the Canon vs my 8x56 and a conventional 10x. I found the distance increased about 1.6 times with the Canon 10x32 vs the 8x56 and the view of the resolved line pairs was much steadier through the Canon. I could only get occasional unsteady glimpses of the same line pairs at 1.2 times the 8x distance with a conventional 10x. Overall, the experience with the Canon IS convinced me that a 10x hand held binocular would only work for me if it included image stabilization. The 10x32 may be the second or even third best Canon 10x binocular, but I think I would still prefer it to any conventional 10x binocular for daylight birding.

Henry

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Old Sunday 24th February 2019, 10:26   #46
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Henry,

Would it be right to assume that by "fog" you mean contrast at lower spatial frequencies?

There is much of Suiter's book I still need to digest, but it was interesting to see that modest levels of spherical aberration affects lower frequency contrast has virtually no effect on resolution, yet It's pretty obvious that loss in resolution frequently results in loss in contrast. That would make spherical aberration a poor predictor of resolution.

I'm a bit short of time at the moment, and so far I've only located your assessment of the Zeiss HT 8x54. I know we both had a very low opinion of that model but I still can't square your star test assessment with either my visual assessment or the brief look I had of the Zeiss stopped down MTF result. That was a few years ago would. Would you still draw the same conclusions? I know we both had a low opinion of the Swarovsli CL 8x30 as well, but I haven't been able to find what you posted on that occasion. Can you point me in the right direction for that as well?

On a number of occasions when I have attempted a star test the resultd have been disrupted by a significant diagonal distortion which it's tempting to think is due to some issue with the roof prism edge. Unfortunately Suiter seems to be silent on prisms. Have you seen anything similar?

Cheers,

David
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Old Sunday 24th February 2019, 18:19   #47
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Henry,

I was about to ask you about the IS benefits as I had thought that you glossed over that part of the performance rather briefly before, but now you have re-visited the topic. Thank you for that.

A 1.6 times difference, or even 1.33 times difference (normal 10x vs stabilised 10x) is in my view a pretty big factor when considered against the minute differences we usually tend to obsess about when comparing an alpha W against an alpha Z. Also, its in line with what I have observed time and again when testing the 10x42 IS L, and does a nice confirmation bias number on me.

With the 10x42 IS L, you would get rid of the excessive CA while retaining the IS benefits, so I feel you really ought to try it out eventually.

David,

Diagonal distortion artefacts are common in star-test patterns of roof prism binoculars, and a thin diagonal line can usually be seen even in the best models and samples although it doesn't necessarily compromise the image quality if it is small enough. Lower-quality roof prism binoculars can have any levels of prism-induced flaws, worst being severe spiking and astigmatism. The angle of the diagonal artefact is different in left and right barrels, and comparing the two also helps you guess something about quality variations in prisms for that make and model.

On Suiter, my sense is that his instructions for a star-test setup are more precise than is necessary for practical binocular or even spotting scope testing. Most of the essential information for a fast focal length objective with more than moderate levels of aberrations (which most binocular lens systems are) can be obtained with a glitter point or such that is bigger, smaller, brighter or less bright than what Suiter proposes as necessary. With boosted images, best focus Airy disks (if the quality of the objective allows for one) don't work so well if the artificial star is too large, and obviously it cannot be so dim that you stop seeing diffraction rings outside of focus, but other than that one can get quite a bit of information with less than professional setups.

That said, I'm considering getting a "proper" artificial star instead of the .08 mm hole in a metal sheet I'm currently using indoors.

Kimmo
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Old Sunday 24th February 2019, 23:11   #48
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Henry:
A very nice review, and it seems the small exit pupil of a 10x32 is important in this model as well as it
is in any binocular. Ergo's are important also, so it is hard to move beyond that.

I am wondering if you are keeping this binocular or will return it.

Jerry
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Old Monday 25th February 2019, 08:49   #49
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Regarding CA, I have noticed before that when using binos with some CA, after a while I can hardly see it. I think my brain somehow adapts and process the view. I have some Vortex binos where that happened. Really did not like them because of CA to start with, but now I cannot see any. Takes a lot of use for that to happen maybe. I hope for that with my Canon 14x32s and will give them a chance in 2019. I do think the CA in these are a bit too much for my brain though ;-) But who knows!
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Old Monday 25th February 2019, 14:01   #50
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Regarding CA, I have noticed before that when using binos with some CA, after a while I can hardly see it. I think my brain somehow adapts and process the view. I have some Vortex binos where that happened. Really did not like them because of CA to start with, but now I cannot see any. Takes a lot of use for that to happen maybe. I hope for that with my Canon 14x32s and will give them a chance in 2019. I do think the CA in these are a bit too much for my brain though ;-) But who knows!

That's an interesting comment.

I've been an amateur astronomer as long as I've been a birder. One of the realities of using telescopes is learning to see - teaching your eye/brain to ferret out all the detail the telescope can reveal and detecting the faint objects that are at the border of perception.

I've recently been wondering if learning to see goes beyond that. Some time ago I had a Celestron SPC102 here, a 4-inch f/9.8 achromat. Out of curiosity, since it had been years since there was an achromat available, I spent some time observing Jupiter with it. At first I found the secondary color - the magenta halo of the unfocused red and blue ends of the spectrum surrounding Jupiter - obvious and annoying. With time behind the eyepiece its presence slowly receded and became less intrusive. It seemed my eye/brain was learning to partially ignore it. (At their lower powers color errors in binoculars are less obvious.)

In the astronomy community there are claims that some people are simply more sensitive to chromatic aberrations. That may be true, but perhaps the eye/brain can learn to tune them out, or become better trained to spot them.

I spend the vast majority of my binocular time looking at, enjoying, and identifying birds. I rarely notice any color fringing, even along high contrast borders. When I do it's usually near the edge of a field.

My wife once complained about color fringes in my 12x36 IIs when we were out hiking on a bright, sunny day. I suggested she had the IPD set wrong. She adjusted it and said the fringing vanished.

I've long been a strong advocate of 'Trying before buying,' but I ignored my advice and bought a pair of the new Canon 12x32 IS. I hoped they would be a good replacement for my 12x36 IS IIs, which has been my main birding binocular for more than 16 years (their only curse being horrid close focus). Based on some of the reviews I was apprehensive, but I find them quite satisfactory and am very happy I took the chance.

I do agree that the rubber eyecups are horrid if you leave them up, but I wear glasses. Folded down I like them better than the eyecups on my 12x36s.

Clear skies, Alan
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