Ht 8x54 (1 Viewer)

See my post #11.

Chuck,

I wonder if you could do a star-test and test for lateral color in the same way I did in my old review of the 8x54 HT. If there have been improvements in spherical aberration and lateral color since the early specimen I tested I might want to give the 8x54 HT another shot. No hurry.

Henry

Gijs and Dennis,

You may have seen claims that the eye is able to detect a 2% difference in luminance, but this is rather misleading. The only studies I've been able to track down that come up with such a value are within the same field of view. This is obviously not the same as comparing quite separate fields of view, with a time gap between them, as it would be when comparing binoculars. I've not managed to find any scientific study that might shed light on this kind of comparison. My own tests on friends and family suggest if luminance was the only difference, then the figure would be considerably higher than 2%.

Brightness perception is quite a different can of worms. Something considerably more complex. Numerous studies on colour temperature on the other hand, show that increasing the blue to red colour balance is perceived as brighter. This is sustained across different views and even over time gaps of 24 hours or more. Other work has suggested wavelength maxima and depth of contrast have a role. Even differences in peripheral light levels play a part. That might suggest a binocular apparent field of view might have a role, but it's not somthing I've tried to check out. The discovery of a new class of light sensitive receptor in 2003 has added another dimension to the subject. It has sensitivity in the blue part of the spectrum and is thought to have multiple roles including control of pupil diameter, melatonin regulation and, surprise, surprise.... brighness perception. Overall, transmission maxima tells you little about how bright a binocular appears. Spectral distribution tells you more, but not necessarily enough to predict how bright a binocular might appear to any particular individual. Not only do we now know the spectral sensitivity of the visual visual receptors more variable than previously appreciated, but because the brain is responsible for the perception, all kinds of influences, from time and place to price and reputation will have a role to play. A binocular that appears to be bright to one person might just seem blue and glarey to another.

David

Binastro said:

There are coated opera glasses that probably beat that.
Maybe 97% or 98%.

B.

Click to expand...

Yes, but how many air to glass surfaces do they have?

Gijs van Ginkel said:

Dennis, post 18,
Your statement that the 8x54 HT is the brightest binocular in the world is not correct: it is even beaten bij the Zeiss Victory FL 8x56 according to our measurements.
Gijs van Ginkel

Click to expand...

That is Zeiss making that claim so i would assume they are basing it on their transmission testing or they are using false advertising. The FL doesn't use SCHOTT HT lenses either so that would seem to give the HT's a transmission advantage over the FL's or Zeiss seems to think so.

https://www.zeiss.com/sports-optics...victory-binoculars/victory-ht-binoculars.html
https://www.bestbinocularsreviews.com/blog/ht-glass-from-schott-06/

chill6x6 said:

I like it! I haven't used it that much since I use 32/42mm binoculars for birding and there hasn't even been a whole lot of birding with work/abnormal heat to consider. But I've taken it out a few times....played with it around the house. I think my example is a quality instrument. CA is well controlled. Center 50-60% is about perfect with impressive image quality. Field curvature comes into play a little earlier than some other 8X binoculars that I have. When I purchased the HT 8X54 I wanted the brightest 56mm or under binocular around. I believe this is it. As Fall/Winter progress...I'll use it more and have more of an opinion.

Click to expand...

Thanks for your observations sir... you're both an experienced birder and an optics enthusiast, so you have a great perspective to appreciate binoculars by. I had a look through the 8x54 HT two years ago at Birdfair - note this was two years ago, so a lot may have changed - and though its handling was superior to the 8x56 SLC which was, and is, heavy and bulky, the SLC was distinctly better optically. I didn't, and still don't, have the terminology to explain what I perceived as Henry and Kimmo can, but the 8x56's view was, for want of a better word, more satisfying. I didn't try any of the HT models at this year's Birdfair (I would have if I'd read Chill's latest post!) but did have a look through the 8x56 again and it was just as good as I remembered it, a most impressive view really. Perceived brightness, for what it's worth, seemed similar between the two.

PS. the 10x54 HT seemed better than the 8x54, much closer to the 10x56 SLC which is a binocular I later became quite familiar with.

Utterly unscientific and you may therefore think irrelevant comment, but by chance in all the rain and dull skies of the last two days I took the chance towards dusk to zero i.e. check the dioptre setting on my Zeiss and other glass (not having read this thread till just now) and my subjective, unmeasured but very definite impressions were as follows. Bear in mind that I tested the binoculars indoors at a focused distance of about 18 feet and on a solidly-fixed Manfrotto tripod. Lighting to the target - an absolutely flat stone slab with a shallow-carved inscription with tiny little holes and gaps in the black writing, showing the pale stone underneath - was evenly diffused and lacking contrast from a nearby side window and all other windows were curtained to cut out stray light distracting me at the eyepieces:

7x42 T*FL sharp, great resolution; snapped into focus clearly while adjusting dioptre and looked as expected even sharper after adjustment, viewing through both eyepieces as normal. Felt pleased to own a good pair of these discontinued binoculars;

8x42 HT as above; if anything apparently sharper but the greater magnification helped this by revealing more of the tiny detail of the flat stone's texture and the little faults of the paint filling in the inscription. I could not detect any brightness difference but did not expect to as light levels were probably dropping almost imperceptibly outside. I will just say that I also tested some non-Zeiss, non-Abbe-König glass and in all cases those examples gave less distinct results with poorer apparent resolution - whether this was from Schmidt-Pechan prisms or just QC I cannot say.

Now wait for it:

8x56 T*FL the great satisfaction at the results from both the 42s above was almost wiped away the instant I looked through the 8x56. The resolution was mind-blowing. I didn't even consider altering or checking the dioptre setting for fear of never managing to equal the quality of image again. Properly supported i.e. not relying just on arms, I always find these superb.

This brought to mind interesting considerations. Too old according to the statistics to gain the full benefit of the 7mm exit pupil (56/8) compared with the 7x42 (6mm) and 8x42 (5.25mm) I still found the view clearer through the 8x56 by a decisive margin.

As this is a Zeiss forum you may like to hear that the image with all three of these binoculars looked contrastier than with other makes. As a final 'let's just try something else' a 1999 7x42 BG/A T*P* was put on the tripod and came up as well as the other 42s, but again lagged behind the 56.

To get back to the thread: regardless of the design and manufacturing accuracy of the 8x54 HT, it is presumably up against one of the very best preceding designs if my experience with the 8x56 T*FL is anything to go by. It is a pre-owned example bought from Germany via eBay and apparently very little used. The 54 is not something I have seen or tried.

Can you remind me: is the 10x56 T*FL supposed to be every bit as good?

It should be added that this 'test', really as said just a settings check, concentrated only on the central, sweet spot part of the image. Outer field resolution was ignored, not really even noticed.


Tom

Tom,

Yes, the 10X56 FL is also that good, really...once you get by the weight, it one of my favorites, day or night.

Andy W.

Did I imagine it or did things really go bump in the night?


Tom,

Thanks for sharing your observations. I think it's a fairly natural to assume that resolution and sharpness are the same thing, but it fact they are quite different. Though I quess we all mix up the terminology from time to time.

It has been customary for manufacturers (and one or two here) to measure the optical resolution of a binocular. That is the limit of resolvable detail at full objective diameter. That diameter effectively changes as we put the binocular to our eyes. In bright conditions the iris of the eye blocks the peripheral light from the objective, reducing the affective objective diameter and altering the aberration profile and effective resolution. When Henry checked the HT 8x54 he found the performance to be unusually poor stopped down, particularly when compared to his FL 8x56.

Sharpness is a visual perception. To put it one way, it's your brain's ability to decipher the detail delivered by the binocular. Perhaps not surprisingly, work done Eastman Kodak in the 60s found that we were able to interpret an image more clearly when the detail was a bit bigger and with greater contrast and came up with an optimum for 'sharpness' of about 5 to 10 arcminutes. Compared to normal visual acuity in the 1 to 2 arcminute range it's 5 to 10 times coarser detail. Optical engineers routinely analyse resolution and sharpness by a method called MTF analysis for full aperture, but apparently not for the effective objective diameter in bright condition. Colour, stray light and other factors contribute to the sharpness story, but I'll skip those for now.

It is possible for those with very good eyesight to detect the resolution limit of some binoculars. My visual estimate was around 20/12 acuity for the HT 8x54 I tried, but as Henry notes, the FL is a much better binocular stopped down. However I note your comparison was approaching dusk. Our eyesight gets significantly worse as the light level decreases and it would be pretty much impossible for anyone to spot the effective resolution differences of those binoculars in low light. I can well believe you saw differences in sharpness, which is good to know.

Cheers,

David

Gijs is there a link for the transmission comparison for the FL 8X56 and HT 8X54.


Andy W.

typo said:

Did I imagine it or did things really go bump in the night?


Tom,

Thanks for sharing your observations. I think it's a fairly natural to assume that resolution and sharpness are the same thing, but it fact they are quite different. Though I quess we all mix up the terminology from time to time.

It has been customary for manufacturers (and one or two here) to measure the optical resolution of a binocular. That is the limit of resolvable detail at full objective diameter. That diameter effectively changes as we put the binocular to our eyes. In bright conditions the iris of the eye blocks the peripheral light from the objective, reducing the affective objective diameter and altering the aberration profile and effective resolution. When Henry checked the HT 8x54 he found the performance to be unusually poor stopped down, particularly when compared to his FL 8x56.

Sharpness is a visual perception. To put it one way, it's your brain's ability to decipher the detail delivered by the binocular. Perhaps not surprisingly, work done Eastman Kodak in the 60s found that we were able to interpret an image more clearly when the detail was a bit bigger and with greater contrast and came up with an optimum for 'sharpness' of about 5 to 10 arcminutes. Compared to normal visual acuity in the 1 to 2 arcminute range it's 5 to 10 times coarser detail. Optical engineers routinely analyse resolution and sharpness by a method called MTF analysis for full aperture, but apparently not for the effective objective diameter in bright condition. Colour, stray light and other factors contribute to the sharpness story, but I'll skip those for now.

It is possible for those with very good eyesight to detect the resolution limit of some binoculars. My visual estimate was around 20/12 acuity for the HT 8x54 I tried, but as Henry notes, the FL is a much better binocular stopped down. However I note your comparison was approaching dusk. Our eyesight gets significantly worse as the light level decreases and it would be pretty much impossible for anyone to spot the effective resolution differences of those binoculars in low light. I can well believe you saw differences in sharpness, which is good to know.

Cheers,

David

Click to expand...

David,

Fair enough. I'll admit when reading all the terms such as resolution, sharpness, definition, delineation, drawing, detail rendition in a description or advertisement the differences are sometimes not at all obvious to me, nor probably to others.

When I wrote 'sharp, great resolution' I mentioned sharpness and resolution in the same breath because I was aware there might be a difference but to me as an interested user looking for clarity of textures and edges without needing or always being able to compartmentalize the different features that draw a good image the thing that counted here was how well the detail drawing showed minute breaks in the paintwork on the stone. (That was a long sentence!) These tiny hairline cracks in the paint revealed sharp focusing in all the binoculars from Zeiss but looked that much clearer again through the 8x56 FL. Now in this instance I can't see the difference between resolution and sharpness, unless it is that there was an improved local or micro-contrast - assuming I'm using that terminology correctly. Overall contrast I would estimate - I can't do better than that without any instruments or the know-how how to use them - to have been very similar among the Zeisses, unlike with some other units I tried that showed poor overall contrast.

Tom

typo said:

The discovery of a new class of light sensitive receptor in 2003 has added another dimension to the subject. It has sensitivity in the blue part of the spectrum and is thought to have multiple roles including control of pupil diameter, melatonin regulation and, surprise, surprise.... brighness perception.

Click to expand...

Thanks again for making us aware of this, it's fascinating. Why would these receptors be keyed to blue light rather than green? Do they have to work in moonlight too, or did they evolve in aquatic ancestors?

Hi Andy (post #29),

Yes, Gijs has posted some useful graphs in his tests at: https://www.houseofoutdoor.com/verrekijkers/verrekijkers-testen-en-vergelijken/


The first 4 attachments are all from ‘Test van 8x56 kijkers van Leica, Swarovski en Zeiss’, March 2016:
- Zeiss 8x54 Victory HT vs Zeiss 8x56 Conquest HD and Swarovski 8x56 SLC HD (i.e. all new post-2013 model)

- Leica Geovid 8x56 Rangefinder (i.e. the current 3rd generation Perger prism version - with the characteristic long wavelength dip due to the RF system)

- a table showing the data for the above, and

- a table from an earlier 2007 test, showing various models - including transmission data for various Zeiss 8x56’s


The last is from ‘Test Meopta Meorange 10x42 HD, Meopta Meopro HD 8x56 . . . ‘, July 2017:
- 8x56 Meopta Meopro HD (i.e. the mid-price model)



John

tenex said:

Thanks again for making us aware of this, it's fascinating. Why would these receptors be keyed to blue light rather than green? Do they have to work in moonlight too, or did they evolve in aquatic ancestors?

Click to expand...

An interesting question. I've not found any research so far that has addressed that directly, but I have seen stuff that suggests that there was a nocturnal phase in our ancestry, but there have been numerous genetic adaptions since then. I suspect it has more to do with the spectrum of ambient natural daylight. It is a rather more variable comodity than most would imagine. Our brains continually work to rebalance the spectral fluctuation, rebalancing the signals from our eyes, so that objects we recognise as white stay white and reds stay red etcetera. I guess it's probably easiest to think of think of daylight having two components. The direct light from the sun and the scattered, blue shifted, light from the sky. It's this scattered light that illuminates shadow, and dominates after sunset. I imagine in the evolutionary sense if the things you might want to eat, or might want to eat you frequently hide in the shadows or come out at dusk. Then to have your retinal light levels fine tuned to the bluer end of the spectum might make some sense, but there are probably many other explainations too.

David

[email protected] said:

Chuck. is that your SLC 8x56 to the right of the HT? Is the HT brighter than the SLC? With 95% transmission Zeiss says the HT's are the brightest premium binocular in the world. What is nice about the 8x54 HT is how light they are for a big aperture binocular. They are only 36 oz. which isn't much more than an SV 10x50 and they are a lot lighter than 8x56 SLC(44 oz.) and the 8x56 FL(41 oz.).

Click to expand...

Dennis, that's actually a SLC 10X56. I agree about the size/weight of the HT 54. Quite a handy large objective binocular.

henry link said:

See my post #11.

Chuck,

I wonder if you could do a star-test and test for lateral color in the same way I did in my old review of the 8x54 HT. If there have been improvements in spherical aberration and lateral color since the early specimen I tested I might want to give the 8x54 HT another shot. No hurry.

Henry

Click to expand...

In June I played around with my iPhone and took a few pics. Was a quick and sloppy effort and after viewing the results learned what NOT to do when taking pictures thru binoculars. I wasn't gonna post the pics as I was going to to another set "when I got "around to it." It's been a busy summer and of course I never did. HOWEVER, I guess some results are better than none. Tried taking pics of Jupiter and the moon and photos were pathetic.

Well, the resolution is so low on the uploaded picture, that it certainly doesn't help. However, the bg pincushion distortion looks to be the OPPOSITE of what my Iphone does so well when shooting flat art, which is barrel distortion. Is it the placement of the camera, the camera itself, or the actual spatial distortion of the binocular optics, or some delightful casserole of all 3? What a kettle of variables.

I think best you can do is to compare the chart with different binos and report back. Or just enjoy the dang things!

-Bill

wdc said:

Well, the resolution is so low on the uploaded picture, that it certainly doesn't help. However, the bg pincushion distortion looks to be the OPPOSITE of what my Iphone does so well when shooting flat art, which is barrel distortion. Is it the placement of the camera, the camera itself, or the actual spatial distortion of the binocular optics, or some delightful casserole of all 3? What a kettle of variables.

I think best you can do is to compare the chart with different binos and report back. Or just enjoy the dang things!

-Bill

Click to expand...

Yeah photo quality is only so so. LOTS of variables. The photo isn't perfectly centered which bothers me. You CAN see it's pretty CA free until you get to the edge of the FOV.

So far back to back with similar binoculars(ie UVHD+ 8X50) it fares very well! As you say, just enjoy the dang binoculars!

typo said:

Did I imagine it or did things really go bump in the night?


Tom,

Thanks for sharing your observations. I think it's a fairly natural to assume that resolution and sharpness are the same thing, but it fact they are quite different. Though I quess we all mix up the terminology from time to time.

It has been customary for manufacturers (and one or two here) to measure the optical resolution of a binocular. That is the limit of resolvable detail at full objective diameter. That diameter effectively changes as we put the binocular to our eyes. In bright conditions the iris of the eye blocks the peripheral light from the objective, reducing the affective objective diameter and altering the aberration profile and effective resolution. When Henry checked the HT 8x54 he found the performance to be unusually poor stopped down, particularly when compared to his FL 8x56.

Sharpness is a visual perception. To put it one way, it's your brain's ability to decipher the detail delivered by the binocular. Perhaps not surprisingly, work done Eastman Kodak in the 60s found that we were able to interpret an image more clearly when the detail was a bit bigger and with greater contrast and came up with an optimum for 'sharpness' of about 5 to 10 arcminutes. Compared to normal visual acuity in the 1 to 2 arcminute range it's 5 to 10 times coarser detail. Optical engineers routinely analyse resolution and sharpness by a method called MTF analysis for full aperture, but apparently not for the effective objective diameter in bright condition. Colour, stray light and other factors contribute to the sharpness story, but I'll skip those for now.

It is possible for those with very good eyesight to detect the resolution limit of some binoculars. My visual estimate was around 20/12 acuity for the HT 8x54 I tried, but as Henry notes, the FL is a much better binocular stopped down. However I note your comparison was approaching dusk. Our eyesight gets significantly worse as the light level decreases and it would be pretty much impossible for anyone to spot the effective resolution differences of those binoculars in low light. I can well believe you saw differences in sharpness, which is good to know.

Cheers,

David

Click to expand...

David,

Thank you for putting me straight on resolution as against sharpness. Fair point! If we read sharpness instead of resolution in my original post that should hopefully give a correct summary of how the binoculars compared as seen by me in this rough and ready test in poor lighting conditions.

Addition: I have just realized I already answered you! There's been a lot going on in the last few days... my excuse anyway. Anyway, this post is a bit shorter.



Tom

chill6x6 said:

As Fall/Winter progress...I'll use it more and have more of an opinion.

Click to expand...

How have those winter viewing opportunities with the HT 8x54 been, Chuck, if you don't mind me asking?