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Tests of the Zeiss 8x54 HT (1 Viewer)
- Thread starter henry link
- Start date
Sagittarius
Well-known member
If Zeiss decides to build a 15x54 HT, I still might get one if it looks good to my eyes.
If it doesn't, I hope Zeiss builds a 12x50 SF to compete with the Swaro EL.
If it doesn't, I hope Zeiss builds a 12x50 SF to compete with the Swaro EL.
Chosun Juan
Given to Fly
Chosun Juan
Given to Fly
At 2 and a half Grand a pop I should bl**dywell hope not!
Perhaps not Brock ....... what's actually required could be market repositioning.......
If the 54mm HT's were repriced to that mid-priced roof level (I'm thinking something like Vortex Vulture 56mm's here), then perhaps the performance would be more acceptable ........................ although a shootout would be needed to confirm!
Chosun :gh:
Chosun Juan
Given to Fly
Bob, the 10x54 HT didn't fare too well in the trusty old MarkI eyeball test .....
Chosun :gh:
Chosun Juan
Given to Fly
Bob! seriously ..... |^|
MarkI, MrkI, MkI, unaided, naked eye, version1.0 even, but not to be confused with MachI |8.|
In this case Kimmo "I was surprised and disappointed by the image quality of this sample", etc, etc, etc ..... you can read the exact copy in Kimmo's post(s) above - paraphrased = basic lack of 'snap', crackle n 'pop' ! ..... and too much mush! :smoke:
A circa $250 image ..... NOT one costing 10x more (ah, that's independent of whether it's an 8x, or 10x 54 HT !!
||Chosun :gh:
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HT 42s
I don't wish to minimise the concerns expressed about the HT 54s, but regarding the 42s, I think we can rest assured.
I have personally spent extended periods with 4 units of the 8x and James and Eddy both have 10x, and optically they are all peaches: which means very, very good.
The 42s have been out on the market for a good time now and if there was really an optical problem with them it would have surfaced by now.
The 54s are recent arrivals and the findings of Henry and Kimmo are indeed cause for concern and we have already heard from Mike Jensen that this concern is shared by Zeiss.
In a perfect world we should expect that all manufactured items should do the job for which they are intended without faults or shortcomings and with a life-span in keeping with their purchase price.
In the imperfect world in which we live we have vehicles from that paragon of reliability, Toyota, being recalled, cars from those paragons of expensiveness, Ferrari, being recalled and Porsche replacing the engines in all of the current GT3s.
It's not what we expect, its not what we want, but it happens.
Lee
I don't wish to minimise the concerns expressed about the HT 54s, but regarding the 42s, I think we can rest assured.
I have personally spent extended periods with 4 units of the 8x and James and Eddy both have 10x, and optically they are all peaches: which means very, very good.
The 42s have been out on the market for a good time now and if there was really an optical problem with them it would have surfaced by now.
The 54s are recent arrivals and the findings of Henry and Kimmo are indeed cause for concern and we have already heard from Mike Jensen that this concern is shared by Zeiss.
In a perfect world we should expect that all manufactured items should do the job for which they are intended without faults or shortcomings and with a life-span in keeping with their purchase price.
In the imperfect world in which we live we have vehicles from that paragon of reliability, Toyota, being recalled, cars from those paragons of expensiveness, Ferrari, being recalled and Porsche replacing the engines in all of the current GT3s.
It's not what we expect, its not what we want, but it happens.
Lee
Henry, David,
This Zeiss episode is having the useful effect of highlighting the usefulness of stopped-down testing with binoculars. To make things more consistent and to make findings more easily comparable, What do you guys think would be a sensible "standard" stopped-down aperture we could maybe start using? Henry used 22 mm for the 8x54, giving a 2.75 mm exit pupil with 8x. That sounds a bit high to me, assuming that 2-2.5 mm is a typical eye pupil diameter for bright light and optimum visual acuity. I would offhand suggest 2.5 mm, but am open for other suggestions. I'm thinking that if we come up with some kind of an agreement, I'll make myself a series of masks to give a standard stopped-down exit pupil with the most common 8 & 10x objective sizes, and will try to gradually built up a reference set of somewhat carefully conducted resolution tests.
My main objective would be to gain a more precise understanding of what does the instrument resolution need to be for it not limiting the visual resolution seen through it. David had some pretty good estimates for himself in the posts above, and I recall Henry doing similar experiments with a progressively stopped-down scope some years back. It would be highly interesting to gather more data from a larger number of individuals who have different visual acuity. The last I tested mine, I got readings between 65.5-73.4" (line-pair formula), but that was a few years back when I did not need glasses for that yet. Now, I'd have to use an instrument (either glasses or a binocular or a scope) to reach focus, and that would mess up the results somewhat. So my VA is a bit less than David's but in the same ballpark.
Anyways, given an acuity of 70", matching that through an 8x binocular requires instrument resolution of 8.75" for an exit pupil that matches the eye pupil for that 70." What I'm not at all sure about is whether this would be anywhere near good enough to actually allow the eye to resolve that 70". It would be interesting to have a resolution chart that simulates a progressively aberrated image, and to see how much the visual resolution figures go down as contrast lessens and the image softens.
Kimmo
This Zeiss episode is having the useful effect of highlighting the usefulness of stopped-down testing with binoculars. To make things more consistent and to make findings more easily comparable, What do you guys think would be a sensible "standard" stopped-down aperture we could maybe start using? Henry used 22 mm for the 8x54, giving a 2.75 mm exit pupil with 8x. That sounds a bit high to me, assuming that 2-2.5 mm is a typical eye pupil diameter for bright light and optimum visual acuity. I would offhand suggest 2.5 mm, but am open for other suggestions. I'm thinking that if we come up with some kind of an agreement, I'll make myself a series of masks to give a standard stopped-down exit pupil with the most common 8 & 10x objective sizes, and will try to gradually built up a reference set of somewhat carefully conducted resolution tests.
My main objective would be to gain a more precise understanding of what does the instrument resolution need to be for it not limiting the visual resolution seen through it. David had some pretty good estimates for himself in the posts above, and I recall Henry doing similar experiments with a progressively stopped-down scope some years back. It would be highly interesting to gather more data from a larger number of individuals who have different visual acuity. The last I tested mine, I got readings between 65.5-73.4" (line-pair formula), but that was a few years back when I did not need glasses for that yet. Now, I'd have to use an instrument (either glasses or a binocular or a scope) to reach focus, and that would mess up the results somewhat. So my VA is a bit less than David's but in the same ballpark.
Anyways, given an acuity of 70", matching that through an 8x binocular requires instrument resolution of 8.75" for an exit pupil that matches the eye pupil for that 70." What I'm not at all sure about is whether this would be anywhere near good enough to actually allow the eye to resolve that 70". It would be interesting to have a resolution chart that simulates a progressively aberrated image, and to see how much the visual resolution figures go down as contrast lessens and the image softens.
Kimmo
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Bob! seriously ..... |^|
MarkI, MrkI, MkI, unaided, naked eye, version1.0 even, but not to be confused with MachI |8.|
In this case Kimmo "I was surprised and disappointed by the image quality of this sample", etc, etc, etc ..... you can read the exact copy in Kimmo's post(s) above - paraphrased = basic lack of 'snap', crackle n 'pop' ! ..... and too much mush! :smoke:
A circa $250 image ..... NOT one costing 10x more (ah, that's independent of whether it's an 8x, or 10x 54 HT !!
Chosun :gh:
Chosun
Thanks for the clarification. Seriously!
That was a "brief encounter" on 2 separate occasions not on a tripod or with a booster. I'm talking about a test like Henry did.
http://www.birdforum.net/showpost.php?p=3003198&postcount=7
Bob
stereotruckdriver
Well-known member
Lee, the one 8x42 HT I had a chance to try did show similar traits to what Kimmo and Henry have shown.
Compared to my 8x32 sv it lacked in overall sharpness and was dull in comparison.
I'm sure it was a bad sample and stated so several times.
I know it was only 1 binocular but it soured the notion of buying the 8x42 HT.
Bryce...
Vespobuteo
Well-known member
I agree completely,
good viewing comfort is expected from high end glass,
but the eye/brain is pretty smart...
i'm glad I gave my new progressive eyeglasses a chance before ditching them…it took 3 weeks to adapt completely but, now my eye sight is razor sharp again, from near to far!
|8)|
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Bob,
If you read post #29 on this thread we are in, you'll see that I have had more than a brief encounter without a tripod or a booster with the HTs. Chosun is not referring only to the post you linked, that one was indeed about my first look with the Zeiss, before Henry did his tests.
However, I wouldn't mind if Chosun would calm down a bit in the way she quotes Henry, me and whoever has questioned the quality of the Zeiss HTs. We are yet to hear Zeiss' take on this.
Kimmo
Chosun Juan
Given to Fly
Soz Kimmo, was only quoting (sometimes in a bit of a cheeky || way, but entirely seriously) people who had actually eyeballed the x54mm HT's (especially where observations with the naked eye are made, and then backed up through further boosted testing and photographic evidence). I think it's fair to say there's a fair bit of interest out there, and a lot of folks had high hopes and expectations for the HT's (myself included). I think when poor performance is readily detectable by the naked eye, then something is crook in Muswelbrook! When the ask is 2 and a half G, well, then something is rotten in the state of Denmark! (no offence intended to Jan, or other nearby neighbours!
I have found the whole episode disappointing and remarkable! (in a bad way .....
The horse has bolted, but Zeiss's silence on this has been deafening.....
It will be interesting to follow the next lot of developments :cat:
Chosun :gh:
| way, but entirely seriously) people who had actually eyeballed the x54mm HT's (especially where observations with the naked eye are made, and then backed up through further boosted testing and photographic evidence). I think it's fair to say there's a fair bit of interest out there, and a lot of folks had high hopes and expectations for the HT's (myself included). I think when poor performance is readily detectable by the naked eye, then something is crook in Muswelbrook! When the ask is 2 and a half G, well, then something is rotten in the state of Denmark! (no offence intended to Jan, or other nearby neighbours! I have found the whole episode disappointing and remarkable! (in a bad way .....
The horse has bolted, but Zeiss's silence on this has been deafening.....
It will be interesting to follow the next lot of developments :cat:
Chosun :gh:
Kimmo,
I'd put in a vote for a 2.5mm EP or 20mm aperture test for an 8x. So far 20mm still seems as useful for 7x and 10x if my purpose is to rank resolution against perceived sharpness and might just be a more obvious way of communicating results. Of course the method Henry uses of multiplying the measured resolution by the aperture used works as well if you do use different apertures.
It took me a little while to realise how important light levels are when judging sharpness and also going boosted tests. Even a cloud going over can cause a 5 fold shift and change acuity by 20%. I found even a very cheap light meter improved reproducibility enormously. It does cut down the days I can do decent testing though.
My magnified acuity would be 8.1" but but comparing it to stopped down results the threshold for detecting softening might be a little better when compared to boosted results. I can just see that 7.5" is not as sharp as a 6.8" bino when the light conditions are perfect. I think stopping down must cut down stray light, improve contrast and flatter the results slightly.
Using Henry's calculation of resolution x aperture the current ISO standard for high quality binoculars is 240. My best stopped down results are 125-130 which agrees with the best result Henry recorded. I personally think a "high quality" binocular would need to be at least 140 stopped down to qualify for the category. That's 7" at 20mm. I suspect that broadly the average user would find 10" at 20mm or 200 acceptable for sharpness. If Henry's figure for the HT 8x54 of 12.4" unboosted is accurate then that would be around 248.
David
CJ
Dear Friend, perhaps you missed Mike Jensen's post in this very thread, but Zeiss have picked up on this issue and it is being investigated. I doubt whether it is a 5-minute job to assess what is happening, the full extent of it and the best remedial action.
There has been no 'silence' from Zeiss, and 'deafening' is therefore an unhelpful exageration.
You are very excitable these days, dear lady, and it is gratifying that you are in such vigorous form :eek!:
Lee
Chosun Juan
Given to Fly
Lee, ol' bud, have you been puffin' muffins? or perhaps even muffin puffins! :smoke:
Mike's last comment was in the "zeiss 8/10x54 HT" thread here: http://www.birdforum.net/showpost.php?p=3012199&postcount=58
and that was on the 17th June .... near as dangnabbit 1/2 a month ago!
(in round terms that's 20 odd thousand minutes! ... or just over 4000 of those 5 minute jobs!!
:cat:This is bigger than Ben Hur |8.|
and, ..... Zeiss were an Alpha brand ......................................
So, at the risk of splitting hares (ouch!
and appearing over exciteable, let's just say relatively silent ..... well virtual silence really ..... actually it's near enough to silent!In the absence of any official word, there's starting to be a loud echo in here ........... the 'deafening' part is the footsteps of potential x54mm HT customers headed for the door ......
Chosun :gh:
Hello Henry,
Good work you did...!!!!
It leads me to try a star test in my own 10x42 HT and 10x40 Habicht W GA.
The circles in the my HT, defocusing in both directions, are more like the ones in your FL 8x56 than in the HT 54 you tested. And the view vs. my former FL 10x42 (early one pre Locu-Tec) in regard the resolution is as good in the center, austanding!, and with a bigger sweet spot in the HT42. The contrast and colours are nothing dull or near that!!!
An the Habicht shows something strange in the circles of the light defocused: A "slice" cutted in each circle, located at 4,30 hour in the left tube and at 7,30 in the right one. Seems to be something related to the prisms...
Anyway, the central view is almost as good as in the Zeiss but with a little smaller sweet spot in the Habicht. The colours and contrast and the brightness at dusk / down are really great in the Habicht!!! On par, clearly, with ANY top quality binocular of the size...Including the HT.
PHA
Good work you did...!!!!
It leads me to try a star test in my own 10x42 HT and 10x40 Habicht W GA.
The circles in the my HT, defocusing in both directions, are more like the ones in your FL 8x56 than in the HT 54 you tested. And the view vs. my former FL 10x42 (early one pre Locu-Tec) in regard the resolution is as good in the center, austanding!, and with a bigger sweet spot in the HT42. The contrast and colours are nothing dull or near that!!!
An the Habicht shows something strange in the circles of the light defocused: A "slice" cutted in each circle, located at 4,30 hour in the left tube and at 7,30 in the right one. Seems to be something related to the prisms...
Anyway, the central view is almost as good as in the Zeiss but with a little smaller sweet spot in the Habicht. The colours and contrast and the brightness at dusk / down are really great in the Habicht!!! On par, clearly, with ANY top quality binocular of the size...Including the HT.
PHA
henry link
Well-known member
David and Kimmo,
20mm is fine with me for 8x. I've been opportunistically using whatever masks happen to be around and are about the right size. For 22mm I use the center opening of an eyecup from a Swarovski Hacicht Porro.
David, I would expect good binoculars, certainly ones with large objectives, to be essentially diffraction limited when they are stopped down to 20mm. That would by 5.75" or 115/D using the USAF chart. 125/D is what I've seen in the best binoculars at full aperture.
Henry
20mm is fine with me for 8x. I've been opportunistically using whatever masks happen to be around and are about the right size. For 22mm I use the center opening of an eyecup from a Swarovski Hacicht Porro.
David, I would expect good binoculars, certainly ones with large objectives, to be essentially diffraction limited when they are stopped down to 20mm. That would by 5.75" or 115/D using the USAF chart. 125/D is what I've seen in the best binoculars at full aperture.
Henry
henry link
Well-known member
Thanks, PHA.
I'm not sure what you mean by "slices", but I've seen flat spots on the outer diffraction ring when the prism is a little too small for the objective light cone when it strikes the first reflecting surface.
What magnification did you use for your star tests?
Henry
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