Just trying to find out more about the differences between these confusing designations so I can understand which ones are worth owning or not. As near as I understand so far the latter designation is the most advanced, and I assume the t* has no phase correction, or is that mistaken?
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What is a Zeiss B T* and how much difference does it have with the t*p* ? (1 Viewer)
- Thread starter Trinovid
- Start date
garymh
Binocular Engineer
Hi,
B = "Brille" (German for spectacles) The binocular has rubber or twist up eyecups to use with spectacles.
T = The Zeiss designation for their lens coating.
T* = A later version of the above coating.
P = Phase corrected prisms.
If the binocular does not have a "P" on it then it is not phase corrected - although there was a short period after this technology was introduced when the "P" was not engraved onto the binoculars.
Gary
SeldomPerched
Well-known member
I definitely read on here when I got my 7x42 Dialyt B G/A T*P* the first time round that there is no difference optically between the 7x42 Bs (like mine just mentioned) that have T*P* on the serial number dial and the ones that have T*P (without the asterisk after the P) i.e. the phase coating is the same.
Whether this asterisk addition to the P happened with other models, I don't know. * Gary will know *
I also have read more recently that the versions without a P or P* are not so impressive optically. To quote Roger Vine on ScopeViews Zeiss 7x42 Dialyt ClassiC Review:
The Dialyts only got phase correction coatings at the end of the Eighties. Binoculars with this feature modern performance and will have T*P* on the front of the bridge in red that you see on this pair. Binoculars that don’t have phase coatings will give an inferior view, yet often carry a similar price tag. Beware!
Tom
Whether this asterisk addition to the P happened with other models, I don't know. * Gary will know *
I also have read more recently that the versions without a P or P* are not so impressive optically. To quote Roger Vine on ScopeViews Zeiss 7x42 Dialyt ClassiC Review:
The Dialyts only got phase correction coatings at the end of the Eighties. Binoculars with this feature modern performance and will have T*P* on the front of the bridge in red that you see on this pair. Binoculars that don’t have phase coatings will give an inferior view, yet often carry a similar price tag. Beware!
Tom
tenex
reality-based
Like this what? Are you suggesting that you've tested this non-P-labeled bin and it seems indeed to have phase coating?
My understanding is also that P* and P labeling are not meaningfully different, although T* and T are.
Some here have said that absence of phase coating is no issue at magnifications of 8x or lower; from my own use of an 8x30 Dialyt, I disagree.
Nah not suggesting anything. Posted to see if this was what Trinovid was talking about. Is this model and that marking it? See it? Pics worth a thousand words thing...
I have no idea, as these were bought, (as i recall), the year before Phase Coating came out, whether these might have it or not. Those sorts of things are sometimes running changes that don't get badged till start of next year along with rest of new and improved announcements. Friend at Zeiss offered to have it modded for me, but I never went there. No matter, they were my one and only for 35 years.
Hi Gary, this is the 'badging' on my 7x42 B Dialyt. If you pick up this post, could I ask you to look up the year of manufacture for me please? I assume no phase correction, but optics are stunning, I've rather fallen in love with them! 😍
Fab, thanks Gary, so one of the last without phase coating, presumably.
Hi,
it should be noted though, that Zeiss seems to omit the P in a lot of models of the mid 2000s at least. Neither my Conquest Pocket 10x25 nor my FL 8x32 have it - but both are phase coated...
As for current models like the SF - there seems to be no coating information at all printed on the instrument... or did I just not find the right images?
Joachim
it should be noted though, that Zeiss seems to omit the P in a lot of models of the mid 2000s at least. Neither my Conquest Pocket 10x25 nor my FL 8x32 have it - but both are phase coated...
As for current models like the SF - there seems to be no coating information at all printed on the instrument... or did I just not find the right images?
Joachim
Pinewood
New York correspondent
Hello,
There is no coating indication on my SF bought in May. The FL models had the indication near the hinge, if I recall correctly.
Stay safe,
Arthur
tenex
reality-based
That was to distinguish the LotuTec models. Zeiss still mentions T* (though not P) in their SF/SFL brochures, as other manufacturers often have their own trade names (Swarotop, Highlux, Meobright), but there's no point labeling the binocular anymore because no serious instrument lacks multicoating or phase coating today. I think Swarovski was the last to drop the old "W" and "B" designations too, for similar reasons.
There's a test that can be done to identify whether your roof binocular has phase coating. Can't remember what it is, but a quick search will find it, I'm sure. But if you're delighted with the view already, who cares?
I recall reading somewhere here that the very first phase-coated Zeisses did not show the P mark on the binocular itself (using up existing binocular bodies, presumably) but had a sticker on the box to identify them as such. No idea exactly when phase-coating was introduced, though. Gary or someone else will know.
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Thank you for that, I'll do some searching. In truth, contrast and resolution are very clearly not up to the level of current ranges of 'alpha' binoculars (phase coated examples may come a little closer), but a wider field of view than the current 7x42 options makes the viewing experience more immersive, and in conjunction with the attributes of a 7x regarding depth of field, they are incredibly relaxing and an absolute joy to use.
Hi,
get a polarizer as in ray ban shades or (better) the passive 3d glasses from 3d cinemas. Open a text editor with plain white background on a computer with an LCD screen (no CRT, no OLED etc). Place the EPs of the bins close to the screen and observe the white LCD screen (which emits polarized light) through the objectives. You should see white circles, if you place your eye on axis.
Now place the polarizer between the objective and the eye and slowly turn the polarizer.
With non phase coated roof bins, you will see each semicircle very distinctly darkened when tuning the polarizer 90 degrees. This is the phase shift from reflection at the roof edge and causes destructive interference which results into reduced resolution in the center. Less visible in 7x pairs, quite visible with good eyes in a 10x pair, or in any case with a doubler.
With phase coated pairs, the two semicircles are also distinct but one half slightly yellow and one slightly purple and not flipping at 90 deg difference... phase coatings are not perfect, after all
Obviously with porro pairs no distinct semicircles are visible as there is no roof edge to shift the phase...
Joachim
get a polarizer as in ray ban shades or (better) the passive 3d glasses from 3d cinemas. Open a text editor with plain white background on a computer with an LCD screen (no CRT, no OLED etc). Place the EPs of the bins close to the screen and observe the white LCD screen (which emits polarized light) through the objectives. You should see white circles, if you place your eye on axis.
Now place the polarizer between the objective and the eye and slowly turn the polarizer.
With non phase coated roof bins, you will see each semicircle very distinctly darkened when tuning the polarizer 90 degrees. This is the phase shift from reflection at the roof edge and causes destructive interference which results into reduced resolution in the center. Less visible in 7x pairs, quite visible with good eyes in a 10x pair, or in any case with a doubler.
With phase coated pairs, the two semicircles are also distinct but one half slightly yellow and one slightly purple and not flipping at 90 deg difference... phase coatings are not perfect, after all
Obviously with porro pairs no distinct semicircles are visible as there is no roof edge to shift the phase...
Joachim
SeldomPerched
Well-known member
Tenex,
Late to the party but have just seen this having been led to a shop demo unsold 8x42 Victory HT today. There are no markings on the HT other than serial no. just beneath the eyecup at the back, 8x42 just beneath the other eyecup at the back, VICTORY HT in the same place on the front , front end Z logo on the hinge axle (later replaced IIRC from a 2018 brochure by a plain capital letter ZEISS), and blue Zeiss badge on the metalwork of the bridge. Unless I have missed something there is no other script, T* or P (*) for instance, even underneath.
It is wonderful to be using one again for the first time in a few years. I tried it out today outside the country store / gunsmith, a rainsoaked day in Devon with heavy cloud, about half an hour before dusk and every detail in the dark undercover in a small wood stood out with absolute clarity. Very exciting: Schott HT glass and AK prisms. Sorry to get carried away!
Tom
Late to the party but have just seen this having been led to a shop demo unsold 8x42 Victory HT today. There are no markings on the HT other than serial no. just beneath the eyecup at the back, 8x42 just beneath the other eyecup at the back, VICTORY HT in the same place on the front , front end Z logo on the hinge axle (later replaced IIRC from a 2018 brochure by a plain capital letter ZEISS), and blue Zeiss badge on the metalwork of the bridge. Unless I have missed something there is no other script, T* or P (*) for instance, even underneath.
It is wonderful to be using one again for the first time in a few years. I tried it out today outside the country store / gunsmith, a rainsoaked day in Devon with heavy cloud, about half an hour before dusk and every detail in the dark undercover in a small wood stood out with absolute clarity. Very exciting: Schott HT glass and AK prisms. Sorry to get carried away!
Tom
This is interesting. Does this mean that porros (where phase shift doesn't happen) still have a theoretical advantage in contrast and [gasp] sharpness?
Short answer: Yes
Long answer: All image erecting systems based on roof prisms have certain optical disadvantages as compared to porro. Current technology has managed to mostly mitigate them so the difference is tiny. This and the fact that roof prism based systems are more compact and are being seen as state of the art by the general public leads to their dominance on the market.
Long answer: All image erecting systems based on roof prisms have certain optical disadvantages as compared to porro. Current technology has managed to mostly mitigate them so the difference is tiny. This and the fact that roof prism based systems are more compact and are being seen as state of the art by the general public leads to their dominance on the market.
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