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ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

New scope from Zeiss... (1 Viewer)

The exit pupil is given as 2.50 at 23x or 22x.
What does this mean?

The filter thread of the 95mm aperture is M95 x 1.00. Does it slightly cut down the aperture?
 
Another link since the one already mentioned isn't working https://www.zeiss.com/sports-optics/en_us/nature/spotting-scopes/victory-harpia.html#features ...

Unfortunately it seems that there is no straight view versions :C...

My astro combo concept that Joachim mentioned http://www.pt-ducks.com/cr-telescopes.htm#Test%20of%2082%C2%BA,%20100%C2%BA%20and%20102%C2%BA%20AFOV%20zooms was well observed by Zeiss and I'm glad I gave ideas to them - they probably didn't needed these but I made it first and with 3.5x zoom ratio...:king: Future owners of these models will see what I have be seeing for some years but even with wider AFOVs...;)

So it will be possible to use higher mags than 70x by replacing the eyepiece. Don't know if the system allows the use of 2" astro eyepieces but at least 1.25" will be possible and I'm remembering the Docter 12.5mm with 84-88º AFOV...
A Zeiss ep with higher magnifications can have wider AFOV...o:D

Don't know if will be possible to Zeiss to develop a binoviewer to these models but, if so, it will zoom and that would be an advantage compared to the BTX.

The links posted so far is working fine...

Big AFOV is not always a good thing, especially if wearing glasses and the ER is not enough. But the diameter of the EP-glass looks pretty large so hopefully it will be usable with glasses also, and as good as in the SF bins.

What worries the most is edge sharpness though, let's hope it's better than the Diascopes.

Zeiss could even make a zoom EP and then you would have the first zoom-zoom scope...would it be weird enough for you? :-O

Or they could make the usual TC I guess. But 70x or even 65x mag is probably sufficient for 90% of all users under normal viewing conditions.
 
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Zeiss could even make a zoom EP and then you would have the first zoom-zoom scope...would it be weird enough for you? :-O
...

It would not be the first since I have it already...3:)
I even tried my combo with the Leica Zoom...;)
It would be fun to use the Diascope 3.75x zoom on the new models (resulting on a 11.25x zoom equivalent...), but as told on my last post it probably will vignette at lower mags... You can always try a nagler zoom but these have only 50º AFOV and 10mm eye-relief...:-C
And yes, would be interesting that Zeiss would produce a new zoom eyepiece for these, increasing the zoom range and allowing higher mags...o:D
 
I would want a straight view version and have to assume it becomes available.
Would be a huge mistake on Zeiss's part, not to offer a straight version !
 
Seems that the new model Harpia is amazing regarding the optical qualities, but the pricing is ridiculous. It will be a good scope for professional purposes, but somewhere unreachable for regular birders. I imagine that does we see as many Harpias as Nikon EDG scopes on the field? Hahahaha.8-P
 
The exit pupil is given as 2.50 at 23x or 22x.
What does this mean?

The filter thread of the 95mm aperture is M95 x 1.00. Does it slightly cut down the aperture?

Unless the calculation for exit pupil (objective diameter / magnification) has changed recently, the exit pupil spec means somebody doesn't know how to divide 95 by 23 or 85 by 22.
 
The exit pupil is given as 2.50 at 23x or 22x.
What does this mean?

The filter thread of the 95mm aperture is M95 x 1.00. Does it slightly cut down the aperture?

The former is hopefully an error... don't know about the filter thread... one will loose a few mm aperture with a filter...

Joachim
 
Just got off the phone with Zeiss. They don't have US pricing yet and the scopes won't be released here until early next year.
 
Seems that the new model Harpia is amazing regarding the optical qualities, but the pricing is ridiculous. It will be a good scope for professional purposes, but somewhere unreachable for regular birders. I imagine that does we see as many Harpias as Nikon EDG scopes on the field? Hahahaha.8-P

All larger alpha-scopes is above 3000€, at least around here, so it's not a huge price difference to ATX or Kowa for example. And price in stores might be a bit lower than recommended price.

And the scope will last for 25 years so the cost per month will be lower than cable TV, candy, cigaretts or whatever people tend to buy even without thinking...o:D
 
I took at random a Minolta XD7 with a Tamron 28mm f/2.5 lens.
Using vernier calipers I make the 49mm thread actual internal diameter about 48.34mm.
I have not made repeated measures to ensure an exact measure.
I haven't checked roundness.
Also other lens threads may differ.

I don't have a 95mm filter to hand but it may mean that the actual thread internal diameter is less than 94mm.
If this is so then the true aperture of the 95mm Harpia might be less than 94mm.
But it needs to be measured to find the real aperture.

I can't easily find specific dimensions of a 95mm thread. 1.00mm pitch. But clearly some measurements are different to 95mm.
Thread shapes also vary as do angles of threads.

P.S.
Nikon 52mm lens thread measured as 51.24mm internal diameter with some variation. Not so easy to measure. 1.5% reduction.
Tamron 49mm thread internal diameter 1.35% reduction.
 
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The filter sizes seem to be nominal sizes, which don't relate to any actual measurement.

Generally filters up to 30mm diameter have 0.5 mm pitch, up to 86mm 0.75mm pitch and larger sizes 1.00mm pitch.

The glass in a filter may be about 3mm smaller than the nominal size and the clear aperture possibly smaller still.

There is the related problem of T2 threads and M42 threads. They have different pitches and some old lenses are T2 some M42. Also adapters can be different.

The shape of the thread can be different. Some more pointed tops, some rounded. The angle of the threads could be 60 degrees or something else.

If the 95mm Harpia objective has an internal clear diameter of 93.7mm about I think that this is acceptable. So long as it is not further reduced by internal obstructions.

The 85mm Harpia has an M86 filter thread, so should be full size hopefully.

It would be interesting to measure the clear aperture of all the competing scopes.

Size isn't everything. performance is what counts.
 
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Anybody at Birdfair in a position to determine if a generic astronomical eyepiece works properly if it is substituted for the removable Harpia eyepiece? Specifically, does it produce the expected magnification and are the off-axis aberrations and distortions "normal" when it's used on the Harpia? Also, does the Harpia eyepiece work like a normal 7.48mm eyepiece if it is placed on a different scope or does it act more like a 20mm eyepiece with some odd off-axis behaviors ?

I ask because I suspect the Harpia eyepiece may be designed to work properly only when it is combined with the zoom elements in the Harpia scope body, and that other universal type eyepieces cannot be substituted. What Zeiss is calling an "objective lens zoom" appears at first description to resemble the Swaro ATX zoom, at least in the placement of its movable elements between the focusing lens and the erecting prism.

The scope certainly looks interesting. I'm actually glad I won't be seeing one for another six months. By then perhaps there will be a new Kowa 95-100mm to round out the choices.
 
Troubador is here and he will give a full account of the scope after the weekend, I had a play around with it yesterday on the stand with the experts and its a great piece of kit.
 
One more question for Troubador or any other BF members at Birdfair. Are the odd exit pupil specs simply a mistake?

I ask because a possible, though quite bizarre, explanation for the 2.5mm exit pupil at 23x occurred to me. Could the "objective" zoom system cause increasing aperture vignetting at low magnifications so that the clear aperture is reduced to 57.5mm at 23x? Say it ain't so!
 
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I suspect the Harpia eyepiece may be designed to work properly only when it is combined with the zoom elements in the Harpia scope body, and that other universal type eyepieces cannot be substituted.
...

I hope not and I hope Zeiss will provide an adapter for 1.25" astro eps, as with the Gavia...:t:
I also hope that the quality control will be better than with the Diascopes, so less lemons, since the low mags are obtained with a very fast optic.
Technically is very interesting (since allows the use of smaller eyepieces), but probably is more demanding of quality control...

For those going to Birdfair, I'm also interested to know how is the eye-relief and how it varies with zooming?
 
Hi David,

I don't think those focal length specs for the objectives can be taken seriously. An f/1.8 telescope is just not workable. I think the objective specs are just a curious result of assigning the entire effect of the zoom system to the objective lens focal length on the spec sheet. The system (like the Swaro ATX) is more likely to work something like a moveable version the field elements in Teleview Nagler or Pentax XW eyepieces where the field group is distant from the other eyepiece elements and the effective focal length is changed by changing the spacing between the field group and the other elements. In a system like that the the apparent field would remain constant across the zoom range and so would eye relief.

I agree that the design needs to have lower aberrations and better QC than we have been seeing in Zeiss and many other high end scopes to fulfill the claim of really sharp high magnification images.

Henry
 
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One more question for Troubador or any other BF members at Birdfair. Are the odd exit pupil specs simply a mistake?

I ask because a possible, though quite bizarre, explanation for the 2.5mm exit pupil at 23x occurred to me. Could the "objective" zoom system cause increasing aperture vignetting at low magnifications so that the clear aperture is reduced to 57.5mm at 23x? Say it ain't so!

Exit pupil of 2.5 mm would make it one f-stop "darker" than competition. About the same as my ATS65 at 25x, seems to be a high price to pay for a 85/95mm scope...

Would an internal smaller stop improve the edge sharpness at lower mag? The huge FOV would be pretty meaningless if it's not sharp to the edge...just guessing here.

At least the exit pupil value at maximum magnification seem to be correct for the 85mm and in the right ball park for the 95mm. But the fact that both have a value of 2.5 at low mag is not logical, if it's not a fixed internal stop of some kind...

Let's hope it's a printing error...or more important, that it's a very good scope.
 
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Hi,

ok, from the focal length data of the objective and the exit pupils it seems that Zeiss has built a 174-523mm F4-5.5 zoom lens and strapped an errector prism and 7.5mm wide angle EP behind it... and got a spectacular wide field at low mag but bought this with a reduced effective aperture at low mag...

As Vespobuteo suspected, this will help with aberrations in the far out field, but light grasp at low mag is reduced.
During daylight that is probably not a problem as your eye's pupil will be smaller anyways but dusk or for astro use, it's not so nice...

Joachim
 
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