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Canon 10x42 IS L Tripod vs hand-held vs IS testing (1 Viewer)

kabsetz

Well-known member
Today I had some time to start my part of the hand-held vs tripod-mounted vs Image-stabilized resolution testing. For the sake of clarity, I decided to start a new thread rather than post this into the existing 8x25 IS thread. David, maybe you could summarize your tests from that thread and post the summary here.

My test setup was indoors, with a credit-card size Edmunds ES magnifier quality resolution chart that was on a window-sill lit by indirect outdoor light from one side and a halogen desk lamp from the other. This gives a glare-free illumination that I have not measured, but that typically yields visual resolution levels at or at least very close to my visual acuity maximum. Today’s resolution readings were such that I doubt there would have been much room for improvement with even better light, but I will later duplicate these tests using a back-lit glass slide target and then we’ll know.

Testing distance was 11.1 meters, which was measured after the tests and before the calculations. Binoculars were a Nikon 10x42 SE, #002394, so a very early unit, but one that I have used as a test reference for 15 years now and that has very good optics. The other binocular was a Canon 10x42 IS L, #72600xxx, that I acquired last fall.

I started by placing another target where the test target would be, and focusing as well as setting the diopter exactly right for both binoculars (on tripod) for the exact testing distance. After this, neither focus nor diopter was touched on either binocular, and with the Canon care was taken to keep it horizontal at all times, since hanging it vertically can cause focus creep.

For each resolution reading, I used a timer set to 1 minute of viewing time, and the order of testing was 1) hand-held, 2) hand-held with a finnstick, 3) hand-held with a finnstick that has horizontal handles at the bottom end, 4) hand-held with IS on (obviously only with the Canon) and 5) on tripod. I tested the Nikon first, then the Canon, and in the end re-checked the Nikon on the tripod to see if my eyes or the light level had changed enough to alter the results, which they had slightly but not enough to change the reading.

Nikon 10x42
Tripod mounted, pattern (group) 1, (element) 4 @ 11.1m which gives 6.6” (apparent VA 66”)
Hand-held, pattern 1,1 (not easily) @ 11.1m => 9.4” (app.VA 94”)
Hand-held with Finnstick: same as hand-held, but a bit easier.
Hand-held with Finstick that has handles – same pattern but considerably easier, almost next level. If simple hand-held was 1,1-, then Finnstick was 1,1 and Finnstick with handles was 1,1+

With the Nikon 10x42 SE, the loss of detail from tripod-mounted to hand-held tripod-mounted was 42%. This is not the whole story, though, since what can be resolved is very much more difficult to see, and takes quite some concentration to get. On a tripod, you pretty much immediately get the second-smallest reading, and the rest of the time is spent hunting for glimpses of the smallest readable one. However, having more time for the hand-held readings would not help (I tried this), since pretty quickly your arms tire and shaking increases. Using a Finnstick, even with handles, does not seem to help me see significantly smaller detail, although it does make viewing much more pleasant and almost fatigue-free. Others may have different results, though. For some reason, the 10x42 SE has always been a difficult binocular for me to get steady views with, and I would expect to do better with a roof that has equally good optics.

Canon 10x42 IS L
Tripod-mounted: pattern 1,4+ @ 11.1m which gives ca 6.3” (app.VA 63”)
Hand-held with stabilizer engaged: pattern 1,4- => ca 6.8” (appVA 68”)
Hand-held with Finnstick: pattern 1/1+ => ca 9.0” (appVA 90”)
Hand-held with Finnstick/w. handles: 1,2- => 8.6” (appVA 86”)
Hand-held: 1,1+ => 9,0” (apparent visual acuity 90”)

In this test, the loss of detail from tripod to hand-held was 43%, from tripod to image-stabilized hand-held 8%, and from IS to non-IS hand-held 32%.

These results are across the board a little better than the ones I got for the Nikon. It is possible that this is partly due to the shortish distance, which could compromise the wide-objective-spacing Nikon somewhat. However, the Canon is for me easier to hold steadily than the Nikon, and its eyepieces give me the optimum view much more easily.

Because the above measurements have an element of interpolation guesswork in them due to the tripod-mounted and hand-held stabilized readings being of the same pattern but with pluses and minuses assigned (by me), I decided to also check for limiting distance for detecting the next smaller pattern, group 1 element 5. Here, I would move the tripod incrementally closer and re-focus, until I could detect the pattern, and then measured the distance. I then repeated the procedure hand-holding with IS. The tripod limiting distance I got was 10.84 meters, which equals just a hair over 60”, and the IS limiting distance was 10.7 meters. This test did not follow the time limit protocoll, though, but the difference between these readings is under 2%.

I’ll be interested in seeing what the next tests show with the glass slide, and later when the weather cooperates, outdoors at longer distances.

Cheers,

Kimmo
 
Kimmo,

Thanks for the test results. Very interesting!

I posted my test results as I got them in the Canon IS 8x25 thread and added a number of comments, but I'm only selectively posting here for comparison with Kimmo's data.

In my case the tests were conducted outside using a high quality print of the USAF 1951 chart. Rather than using a separate target for setting the focus and dioptre I simply used the numbers on the chart. I didn't use a timer but in the main comparison I'm posting here all the patterns were decided in the in the first 10-15s and could not be improved on with longer observation. I normally make a note of the light levels when I perform acuity or resolution tests as I know my old eyes are very particular these days.

I'm not going to copy across all the results from the three comparisons, but as there were conducted under progressively improving light conditions I think it's worth a quick look at the apparent VAs for the three tripod results for Vanguard Endeavour EDII 8x42 I used in the test. They were 81.6”, 65”, and 60”. It illustrates why I find using optimum light levels is crucial in binocular comparisons and testing as the first set of results in relatively poor light I consider rather unreliable. I know my acuity drops more rapidly in low light than it did when I was younger but it is a phenomenon that applies to everyone.

The last test was conducted with a meter reading of 500cd/m2 for the luminance of the chart which is a little higher than I consider ideal.

Zen-Ray Prime 10x42
Tripod mounted, pattern 0,4 @ 21.7m which gives 6.74" (apparent VA 67")
Hand Held, 0,2@ 21.7m which gives 8.5" (apparent VA 85") or 27% worse.

Eden XP 10x56
Tripod Mounted, pattern 0,[email protected] which gives 7.5" (apparent VA 75")
Hand held,pattern 0,[email protected] which gives 9.5" (apparent VA 95") or 27% worse.

Vanguard Endeavour EDII 8x42
Tripod mounted, pattern 0,[email protected] which gives 7.5" (apparent VA 60")
Hand Held, pattern -1,[email protected] which gives 10.7" (apparent VA 85.6") or 43% worse.

I think most people would judge all three binoculars to be sharp hand held and indeed they give similar VAs of 85” to 95” or about 20/15 but I was able to detect differences in optical quality on the tripod with small but significant differences in apparent VA. This paralleled values I've previously measured for 20mm stopped down resolution. The Vanguard was 6.2" both barrels, the Eden 8.1" both and the Zen-Ray 6.3" left and 7.2" right barrel. These difference were evident in hand held viewing but not really reflected in the VA estimates.

Comparing Kimmo's with my results, the tripod and hand held values for the Canon match my Vanguard and the Nikon the Zen Ray very closely which is in itself very interesting. However the Canon stabilised value is very close to tripod result which is very impressive. I hadn't expected than level of improvement in view of comments made by other users. Indeed from previous comments it sounds like it exceeded Kimmo's expectations. This comparative study came about because I commented that when I had tried the Canon IS range I saw little if any benefit unlike many happy owners claim, including Kimmo. It's now quite a while since I tried the Canons, but at the time I asked the Canon rep to check two of them as I saw no effect at all and he confirmed they were fine. If I recall correctly I thought the IS was damping the pulsing in my arms due to heart beat and not the micro-oscillations from my hands. Even hand held I am normally able to readily tell a difference in effective resolution of less than one arcsecond which would translate to under 10 arcseconds with a 10x. I can say with absolute confidence that I would have seen a 30” improvement in an instant. It didn't happen. Perhaps the demo ones were all faulty or the batteries were flat, but rep didn't think so and on another occasion they fitted new batteries for me to test a couple. Maybe it's the nature my hand shake that cause the IS system a problem. I just don't know why. I do know I will check them again when I get a chance. Kimmo's results look pretty exceptional to me.

David
 
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Kimmo:

Very impressive results you got there. Very. I knew the loss of conventional 10x binoculars handheld is something like 40% for most people (even though some people claim they can use 10x easily handheld). That's what most of the literature says as well. But I would never have guessed that the loss of the 10x42 IS hand-held is only 8% over tripod-mounted. That's a huge difference, it really is.

I'm also quite surprised the Canon was better both on the tripod and hand-held than the Nikon. Alright, I don't know the Canon that well, but from the little I've seen in the field I would've thought the Nikon would be as good as or better than the Canon, at least on the tripod. Hand-held is a different matter, when you only use the binoculars for a short time the higher weight of the Canon may provide a somewhat steadier view.

Another (to me!) surprising result is that the results with the Finnstick aren't really better than hand-held, both for the Nikon and the Canon (with the stabilizer off). I thought the results would be better when you use the Finnstick. I've got to check that for myself, my impression was there's some clearer difference than the one you got. Looks like some self-delusion on my part, I think.

Lots of food for thought. Lots. It would be interesting to see similar test for other binoculars with different magnifications, but then they may not really be necessary. What you results show is that a stabilized binocular blows any conventional binocular clean out of the water.

I don't think there can be any doubt at all that even the "lowly" Canon 10x30 IS would simply kill even the most expensive alphas when it comes to actually showing detail in the field - even if the optic of the 10x30 isn't anywhere near as good as that of, say, the Swaros or the Zeiss.

Thanks again. That's great stuff.

Hermann
 
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This comparative study came about because I commented that when I had tried the Canon IS range I saw little if any benefit unlike many happy owners claim, including Kimmo. <snip> Maybe it's the nature my hand shake that cause the IS system a problem. I just don't know why. I do know I will check them again when I get a chance.

I think it's well possible that you're "different" in some way from other users. Maybe you hand shake is at the root of the matter, as there's probably some considerable variation there as well.

An example: I know someone who was able to hand-hold a 15x60 very well indeed (until he turned about 70); he actually got more detail with the 15x60 hand-held than I did with a 10x50 (of similar optical quality) tripod-mounted. That shouldn't really be possible according to the literature AFAIK.

Hermann
 
If the advantages are so huge - then why have none of the big 3 alpha makers jumped on board? Surely they would see the same things as this test illustrates and realize a huge market opportunity.

Or is the reality that birders [or binocular users in general] will never embrace the technology, no matter the benefits, even if it comes from one of the big 3?

Personally, I don't want any optics with batteries - ever. A re-do of Zeiss's mechanical stabilization [smaller / lighter] would be the only thing that would be tempting to me....

....which begs the question - just why Zeiss hasn't done a thing with their 20x60S in over 30 years, not a hint of advancement or tweaking? I would think that Zeiss could have slimmed / lightened / improved their system considerably if they just applied incremental changes over the decades.
 
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Personally, I don't want any optics with batteries - ever. A re-do of Zeiss's mechanical stabilization [smaller / lighter] would be the only thing that would be tempting to me....

....which begs the question - just why Zeiss hasn't done a thing with their 20x60S in over 30 years, not a hint of advancement or tweaking? I would think that Zeiss could have slimmed / lightened / improved their system considerably if they just applied incremental changes over the decades.

Two reasons I can think of:

  1. There's been a study by the Fachhochschule Aalen that shows that the opto-electrical stabilizer of the Canon is more effective than the mechanical stabilizer of the Zeiss: http://www.htw-aalen.de/dynamic/img/content/studium/a/publikationen/doz/2004/07_04_verwackelt.pdf.
  2. The cost involved in refining the mechanical stabilizer is too high, especially when you take into account that a binocular with such a stabilizer will always be more prone to damage than a conventional binocular which means the majority of users won't buy it anyway. Developing an opto-electrical stabilizer would also be very expensive for a company that hasn't already got another line of consumer products that uses the same technology. Canon basically used existing technology in their binoculars. I think I heard years ago they used a stabilizer that was originally developed for use in video cameras.

Hermann
 
I think it's well possible that you're "different" in some way from other users. Maybe you hand shake is at the root of the matter, as there's probably some considerable variation there as well.

An example: I know someone who was able to hand-hold a 15x60 very well indeed (until he turned about 70); he actually got more detail with the 15x60 hand-held than I did with a 10x50 (of similar optical quality) tripod-mounted. That shouldn't really be possible according to the literature AFAIK.

Hermann

Herman,

I used to do competition archery and I'm very aware that my hand shake varies day to day. One week I'd be picking up medals and another lucky to be in the top 50.

In a very casual way I've compared the level of detail I can see with my various binoculars several times. Most of the time between 6x and 10x I see virtually no increase in detail. However on a good day when my hands are steadier it's clear that some binoculars are notably more stable than others. I picked the Zen Ray for this test as it's given me good results hand held, better than an 8x on a tripod, though I failed to do so in this test. My 12x50 has beaten a 10x on a tripod as well. I've not tried it with a 15x. I'd hoped to do better to make a point ;) , but there is no way I could make the 20/10 (or 6/3) hand held that Kimmo got with the Canon.

Making comparison like Kimmo and I have are extremely difficult and I was expecting our apparent VAs to be quite different. It's quite remarkable we both produced matching very good acuities. However I needed very good light to do it. My first set of results would look woeful by comparison. It all relates to our baseline acuity at the time. I know I've beaten someone on detail with my 12x50 hand held vs. a Nikon ED50 on a tripod in someone else's hands. Even hand held my effective eyesight was something like 3x sharper than theirs on the day. These days, the tables are easily turned in poor light.

David
 
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David, as a trained archer you may be able to hold a binocular exceptionally steadily, at least for testing.

Kimmo, the surprise is the Finnstick mainly prevents fatigue, but does not improve optimium resolution much.

We all brace binoculars. There must be a reason we do this.

I used to shoot at Bisley. I was good but not exceptional. Lee Enfields.
 
Thank you all for nice comments, and special thanks to David for challenging me to do this trial. I’ll comment on some of your comments here, in the order of the posts in this thread thus far.

First to David’s post #3, no, I wasn’t that surprised by the stabilized Canon values being so close to the tripod values. But I need to qualify that this applies to the present unit, and with some of the earlier ones I’ve tried I have obtained lower absolute resolution values and also more typically closer to one element difference in resolution between IS and tripod. The unit in this test has higher base resolution, especially in the better (right) tube, and a stabilizer that mostly remains centered around the true optical axis and therefore does not soften the image much. When the binocular is on a tripod, and a booster is attached to the eyepiece, the boosted resolution remains nearly the same with IS engaged, which is a good indication of only very slightly compromised peak performance in handheld IS viewing. We’ll see what happens in tests with the glass slide and outdoor tests, but I wouldn’t be surprised if I better the 8% that I got in these first trials.

If you do go try the Canons again, take a pair of lithium AA batteries with you, and have the stabilizer on for a half-minute or so before you start testing seriously. It does seem that if the binocular has been unused for a while, it needs a bit of warm-up time. Someone on another forum explained that this would be due to the liquid within the bellows of the vari-angle prisms needing to be shaken a bit before it works optimally, but I don’t know if this was fact or myth. However, the effect seems real.

Hermann, post #4

About the Canon being better than the Nikon in tripod-viewing also. Firstly, my Nikon is probably first or second-year SE, meaning its AR-coatings are not as good as in the later series, and consequently it is certainly no brighter and may be less bright than the Canon. In a Vögel test of 10x bins a few years back, lab tested transmission for the Canon was 85% or better between 490 and 670 nm, with a maximum value of 87%. In that same test, the SE has a 4% higher peak, but averaged very close to the Canon. For the samples I have, the Nikon has very slightly better boosted resolution in the better barrell, but the Canon has much less CA, better perceived contrast and significantly less flare, all of which helps the eye. The subjective image quality superiority of the Canon is very clear to my eyes, and even if it did not have IS, I would take it out over the Nikon every time.

About the Finnstick, I think the strengths of a Finnstick don’t come out in a test where you are trying to see the smallest possible detail, but would become more apparent if we were trying some other observation tasks. It also may be that I’m not that good at holding a Finnstick steady. Allready before my first stabilized binocular, I was experimenting with different kinds of binocular supports, with handles and shoulder braces, trying to find a solution that would significantly stabilize the view, and always thought that the results were incremental at best. But at reducing fatigue a Finnstick is unbeatable and a must in prolonged viewing, without or with a stabilizer.

I fully agree with what you say about stabilized binoculars versus any conventional binocular.

James (post #6),

Hermann answered you about the Zeiss 20x60S, the article he linked is well worth reading if you can divine German. He also gives what I would guess to be very likely reasons as to why the European biggies have not produced IS binoculars yet.

Obstacles preventing the Canon binoculars from becoming popular have been that their stabilization has not always been this good (it seems to have been developed quite a bit over the years), the fact that they require batteries, the undisputable fact that the binoculars don’t look enough like “real binoculars” and their short warranty. The biggest obstacle is conservative attitudes amongst us users, though.

I appreciate your personal choice to refrain from any optics with batteries, but that must make photography rather difficult and slow for you today.

Hermann (post #8),

Thank you for posting the Aalen Optometry school article, which seems to be from 2004. I don’t think I’ve seen it before. I read the whole thing (to the extent my less than stellar German allowed), and was fascinated to find a wealth of information especially on the workings of the Zeiss stabilizer, which I had pretty poor understanding of previously. Their graph of the Canon 18x50 IS UD shows the stabilizer “losing its hold” of sorts after about 15 seconds. This looks like the artefact which has led to users adopt a technique of clicking the stabilizer off and on every once in a while to prevent image softening, an artefact that is absent from my current 10x42 and from the couple of other recent 10x42’s I’ve had the chance to try.

David (post 9),

I was also expecting our apparent visual acuities (VA’s) to be more different than they were here. I had very good light, though, and may have been more lenient in my interpretation of what constitutes resolved than when I test telescopes with boosters. However, I was being as consistent between measurements as I could. These are also two pairs of very, very good binoculars. The Nikon has thus far held its ground against all the 10x binoculars I have tested at home, including top Swaro and Zeiss. I do know I have very good VA, but it has not been optometrist-tested in a long while. I’ll try to do glass-slide measurements soon to see if the results maintain. My problem with VA measurements is that I can no longe do them without some optical aid since my eyes don’t naturally focus on anything anymore due to presbyopia, and if I wore eyeglasses they would distort the results. Another factor that probably makes my results better than they really are is the shortish measuring distance of 11 meters, where the magnification of at least the Nikon is likely to be slightly higher than nominal. It would take Henry, though, to tell us exactly by how much.

Kimmo
 
Two reasons I can think of:

  1. There's been a study by the Fachhochschule Aalen that shows that the opto-electrical stabilizer of the Canon is more effective than the mechanical stabilizer of the Zeiss: http://www.htw-aalen.de/dynamic/img/content/studium/a/publikationen/doz/2004/07_04_verwackelt.pdf.
  2. The cost involved in refining the mechanical stabilizer is too high, especially when you take into account that a binocular with such a stabilizer will always be more prone to damage than a conventional binocular which means the majority of users won't buy it anyway. Developing an opto-electrical stabilizer would also be very expensive for a company that hasn't already got another line of consumer products that uses the same technology. Canon basically used existing technology in their binoculars. I think I heard years ago they used a stabilizer that was originally developed for use in video cameras.

Hermann

Seen that Zeiss has a good relationship with Sony, providing them with camera lenses, would it not be logical for Sony to return the favor and provide Image Stabilization modules to Zeiss? Sony has some very highly regarded stabilization systems in their cameras, well up to Zeiss's quality expectations.
 
I did a bit more today, this time with the 2" vapor deposited glass slide target back-illuminated with our light therapy lamp which gives 4000 K light at 10 000 lux intensity at distance of 31 cm. It gives excellent illumination for the slide, which I strap on the opaque surface of the lamp with a rubber band. If yo are interested, this is what the lamp looks like: http://www.innolux.fi/sites/default/files/Aurora_AureaV13C.pdf

I tested my only 8x alpha binocular, a cherry-picked Leica 8x20 Ultravid that was the sharpest of four samples available at the time. This unit has extremely clean diffraction patterns, with virtually no light spilling out of the Airy disc w. first diffraction ring in best focus. I didn't feel like using time constraints, and this time started with the binoculars on a tripod, looking for a distance where group 1 element 2 would resolve.

Leica 8x20 Ultravid, tripod mounted, pattern 1/2 @ 10.95m which gives 8.5" or visual acuity through binocular of 65"

Leica Ultravid hand-held, pattern 0/5 @ 10.85m which gives 12.1 or VA of 97"

So yet again I end up with a 42% degradation from tripod to hand-held.

The little Ultravid is very light, and with some hassle can be braced against the brow although the eyecups are really too small for this. All in all, even though I know that this binocular has superb optics for its size, It is a pain to use since you have to get inter pupillary distance just right, and then hold them just right to align the 2.5mm exit pupil to your eye pupils, and then get diopter set just right etc. And then any movement tends to throw the binocular-eye alignment off a bit. The numerical results are very good, but I'm pretty certain that with an equally high-quality 8x42 binocular, I could get the same ca 60" VA I get with the 10x42 Canon. It is one of the things I still don't understand that even in such optimum conditions I cannot get the same VA from an 8x20 than from a full-size, but it matches my experiences with these binoculars in the field.

After the Leica, I was running out of time but had the Canon on the tripod briefly anyway. These results are therefore tentative for the glass target/Canon combo, but for what it is worth I got exactly the same results as previously with the printed card target, 60.5" tripod VA, 65" IS hand-held VA and 86" hand-held VA. I'll try to do these more carefully again in a day or two, and also check my old and beat-up 10x50 Jenoptem.

Kimmo
 
Kimmo,

Thanks for the new info.

That Ultravid sounds very good to me. The DIN ISO standard for resolution at 20mm is 12" so at 8x that would be 96". That makes the 65" result look pretty good, specially as the aberrations of your eye will have contributed to 8.5" result. I suspect it would be relatively easy to make an 8x20 which would equal your 60" figure if they were as long as a regular 8x42.

Have you done a boosted test on the Ultravid? My best stopped down boosted results for 20mm are about 6.2" and I can detect subtle differences by eye around the 6.8 level even if theoretically they should not be limiting to 20/10 acuity. In practice I normally find values around 8" are normally quite sharp enough for most situations hand held which would be theoretically 64" at 8x.

David
 
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The little Ultravid is very light, and with some hassle can be braced against the brow although the eyecups are really too small for this. All in all, even though I know that this binocular has superb optics for its size, It is a pain to use since you have to get inter pupillary distance just right, and then hold them just right to align the 2.5mm exit pupil to your eye pupils, and then get diopter set just right etc. And then any movement tends to throw the binocular-eye alignment off a bit.

That's very interesting. I've been experimenting quite a bit with a Leica Monovid 8x20 over the past few weeks, and my impression was that although the optics are perhaps not quite in the same class as those of the Ultravid 8x20, I found the Monovid if anything easier to use than the Ultravid for the same reasons - no problems with setting the interpupillary distance and no problem aligning the small exit pupil of both tubes and fewer problems with hand movements. I now think the Monovid is actually easier to use than the Ultravid.

It is one of the things I still don't understand that even in such optimum conditions I cannot get the same VA from an 8x20 than from a full-size, but it matches my experiences with these binoculars in the field.

Well, maybe the problems you outlined above are a part of the reason why 8x20s are so difficult in the field. In fact, I'm pretty sure these reasons play a major role there.

Hermann
 
Interesting thread! I think when considering the next binocular buy, I definitly have to have a close look at these Canon IS bins...

As for Zeiss, there are various recent patents filed related to stabilisation, so perhaps they are working on something...
 
It is one of the things I still don't understand that even in such optimum conditions I cannot get the same VA from an 8x20 than from a full-size, but it matches my experiences with these binoculars in the field.

Kimmo, there is another possible explanation. On average individuals peak acuity occurs when the pupil of the eye is 2.5mm diameter. The same as the exit pupil of an 8x20. However the peak performance covers a range of between 2 and 3 mm. In fact some of the best acuities recorded are for pupil sizes around three. We don't know the light levels or your pupil size for the test, but it might be that you are one of the 3mm guys and/or the light levels were a little low and the 8x20 2.5mm EP was in fact limiting. In stronger light when your pupil shrinks further then you might match your larger binoculars.

Of course it could be something else entirely.

David

P.S. Oops! I've realised this was your slide/daylight lamp result so the light levels if anything will too high. So disregard.
 
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David,

I have used the little Ultravid enough on very bright days to be pretty sure that it is not about matching light levels. Your other explanation of me being a three-millimeter guy (a flattering characterization if ever there was one) is more likely.

It's true I haven't measured the light levels of the test, but the lamp is so bright that today when I used it with the Canon and the Zeiss big binoculars, I tried adjusting the level down a bit, and although it made very little difference to actual readings, I got the very best ones with reduced light levels and felt the viewing was easier and less straining. The lamp, being a light therapy lamp, has a potentiometer dimmer.

I tried boosted resolution today with the 8x20 Ultravid. The results are rather too good for comfort, since I got group 1 element 6 @ 10.9 meters which means just over 5.3". This would be 106/D which sounds implausible, although I must say that there was no space between the lines at this level, only enough of a contrast difference to know with certainty with the line orientation was. But this is the general rule by which I determine "resolved," so it also applies to the other measurements I've made. I guess I need to re-check this. The image the little Leica produces through this Zeiss tripler is exceedingly clean, though, and looks very much like that of a superb-quality achromatic telescope heavily stopped down. By which I mean that it looks like any and all lack of resolution in the image is diffraction-caused.

I don't have time to write more now, but will try to get back to this in the evening.

Kimmo
 
Kimmo and David,

You can easily measure your pupil size under various test conditions using nothing more than a de-focused artificial star and some masking tape. I've described the technique a few times, so maybe you recall it.

You just stretch two tape strips along opposite sides of the objective cell, leaving a space between them close to what you expect your pupil size to be when multiplied by the binocular magnification. Set the focus to infinity and approach the star point until you see a reasonably well focussed image of the objective lens (probably about 3-5m). Adjust the separation between the tape strips until you barely discern both tape edges and measure the separation. I've noticed that my left dominant eye always seems to open a little wider than my right eye eye under the same lighting conditions.

Henry
 
I'll re-test the Ultravid tomorrow, time permitting. But after going over my notes for today and re-doing the calculations I still get the same result. However, I noticed a typo in my first post about the 8x20. The VA should be 68", not 65".

I measured the old Zeiss Jenoptem 10x50 also. Same results as with the Canon: group 1 element 5 @ 10.9 meters, for 6.0" and VA of 60". Hand-held 1,2+ @ 10.9m, for 8.5" or a little under. I did not try the Finnstick with this binocular. This Jenoptem is very sharp in daylight, so sharp that I was initially disappointed when I got the Nikon 10x42 SE to replace it, since I felt that the Nikon was not at all sharper as I had expected based on BVD reviews.

I also re-tested the 10x42 Canon. Again, essentially the same results as in the first test with the card. 6.0" tripod mounted, 6.5" handheld IS. As an additional feature, I did a Finnstick with IS trial with the stick that has a horizontal handle on it. This yielded 6.3", or a little better than without the stick, but a little behind the tripod-mounted result.

Another reading I took while the Canon was on the tripod was edge resolution, tilting the binocular up and down so that the bar target that was focused for the center was now at the very top edge or bottom edge. No re-focusing done. Here, the readings for either top or bottom were group 1 element 1 easily @ 10.9 meters, or 9.5". An estimated 10-15% of the way in from the very edge gives 1,2 and progressively better from there. I consider this very good edge sharpness, although the image is of course visibly worse. As noted before, many binoculars don't resolve any patterns at the outer 10% of the view field.

David, could you post a picture of the test pattern you use if it is any different from the Edmund USAF pattern I have. While struggling with the hand-held readings, it occurred to me that more reliable results could be obtained if the patterns were not so tightly spaced. Now in very quick glimpses of elements 3&4 in a group in particular, with an unstable image and eyes flitting around in it trying to catch detail it is sometimes hard to be sure which element it was you were seeing. If you are more skilled at this or have a target with a wider spacing between the elements, that could explain why you have sometimes gotten better hand-held results even though our tripod results are almost identical.

Kimmo
 
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