Interview with Harpia Team Leader (1 Viewer)

[Troubador]

The question still remains as to whether all production Harpias would give really sharp images at 120x.
This is because I think that it would be difficult with a complex objective to achieve good enough quality control for all of them to be sharp at 120x.

David

I am not now sure if the objective will turn out to be all that complex. Light transmission of 88% doesn't suggest a massive increase in glass/air boundaries.

Lee

 

[Binastro]

Hi Lee
I quite often lose whole posts because of computer or my own malfunction.

Usually I don't bother to rewrite, as it is only words floating around in space.
Eventually, all the words we write will be gone, unless we go back to clay tablets.

 

[Hermann]

I found that very interesting, too. If I remember correctly, the keeper of the German Juelich-Bonn forum years ago pointed out that the majority of the big scopes he sold in his shop were angled, but the majority of the smaller scopes (like 65 mm) were straight, because so many people like to use the small scopes from car windows.

I actually got a straight Nikon Fieldscope EDIII in addition to my angled fieldscopes because it's so much easier to use a straight scope from the car.

Hermann

 

[Troubador]

I actually got a straight Nikon Fieldscope EDIII in addition to my angled fieldscopes because it's so much easier to use a straight scope from the car.

Hermann

This is dead right Hermann. I have a Meopta S2 Angled on test at the moment and it is definitely more awkward swivelling it around to use the angled eyepiece 'sideways'. Its awkward but by no means impossible.

Lee

 

[Hauksen]

Hi Lee,

This is dead right Hermann. I have a Meopta S2 Angled on test at the moment and it is definitely more awkward swivelling it around to use the angled eyepiece 'sideways'. Its awkward but by no means impossible.

I wonder whether combing a prism with a reflex sight would make it less awkward to aim the angled scope out of a car window

Regards,

Henning

 

[Troubador]

Hi Henning

It wasn't the aiming that was the problem although that was a little tricky at first, its just that the extent of the traverse available is limited by needing to get your head alongside the angled EP in the limited space of a car window. Although this limits where you can point the scope, taking off your seat belt and shuffling around in your seat helps a lot and a small adjustment of the car's position makes a huge difference.

The point is, it is not impossible to use an angled scope in this way.

Lee

 

[Hauksen]

Hi Lee,

The point is, it is not impossible to use an angled scope in this way.

I tried it once and found it inconvenient, but certainly not impossible.

I also met a guy who is doing a lot of serious bird-counting, and he swears by his small-ish angled scope for observing from the car. Not sure what his secret is, but I suspect it has something to do with the small size of the car, and using both front seats at once

Regards,

Henning

 

[Troubador]

Hi Lee,

I tried it once and found it inconvenient, but certainly not impossible.

I also met a guy who is doing a lot of serious bird-counting, and he swears by his small-ish angled scope for observing from the car. Not sure what his secret is, but I suspect it has something to do with the small size of the car, and using both front seats at once

Regards,

Henning

If I was to get really serious about scoping from a car (which I am not) then I would empty the back seat of backpacks, walking poles, camera gear and waterproofs and put them all in the boot/trunk and sit in the back, preferably behind the front passenger's seat, having pulled this seat as far forward as possible. In this way I would greatly improve my and the scopes 'mobility' within the car and so be able to aim it over a much wider range.

This would work if you were positioning your car overlooking a good birding site, but might not be usable if you suddenly see a bird or something else from your car and want to stop and get a look at it immediately without getting out of the car. On the other hand if there are two of you in the car, it is likely that the scope is on the back seat so it will not magically be in your hands immediately you stop the car. Providing the bird is some distance away so you won't scare it, you might as well get out of the front and into the back where the scope is waiting. Its probably just as quick if not quicker than struggling to reach around and get the scope off the back seat.

Lee

 

[Steve O4B]

Harpias have started shipping

Hi All,


We received our first Harpia 95 here at Optics4Birding on Tuesday 8/7. It went almost immediately to a customer who ordered it last November. He did give us permission to try it out first. It certainly ranks up with the Swaro 95 and Kowa 883. Each has their pros and cons. I'll summarize those later as it's almost time to go home for the evening.



I was surprised to see the zoom ring is marked 1, 1.5, 2, 2.5, and 3, rather than 23 ... 70. I think this portends more than one eyepiece. It will be interesting to see.


We have some more orders to fill. It will be interesting to see how quickly they arrive.

 

[Troubador]

Thanks Steve, looking forward to your comments.

Lee

 

[In Focus]

We now also have stock - and plenty of it - just in time for Birdfair.

First impressions are that as Steve mentions, optically it compares very favourably against the ATX. In our opinion the lower starting magnification is a plus in practical use.

But the best way to know if you like it is to visit one of our shops, go along to one of our field events or come along to Birdfair to try it. Also available to order online:

https://www.at-infocus.co.uk/product/zeiss-victory-harpia/

Regards, The In Focus Team

 

[Steve O4B]

We received our first Harpia 95 here at Optics4Birding on Tuesday 8/7. It went almost immediately to a customer who ordered it last November. He did give us permission to try it out first. It certainly ranks up with the Swaro 95 and Kowa 883. Each has their pros and cons.

For our tests, we set all zoom magnifications to 30x, matching the minimum for the ATX 95. In bright sun, all three scopes showed virtually equal brightness. The Kowa had a very slight edge in contrast. FOV seemed about the same for all three scopes at this power.

Testing for brightness in the deep shade inside a hedge produced similar brightness results. The 883 had a bit more contrast and depth of focus. The extra contrast may have been a result of the smaller aperture allowing in a little less light.

These scopes are very close optically. Ergonomics and flexibility of design will likely determine more choices than optical quality. Swarovski ATX/BTX/STX will rule the system people who seek modularity and camera adapter options. Zeiss will be the choice of those who are concerned with having a smaller eyepiece or a wider AFOV at high magnification. And Kowa will be the choice of those who prefer a lighter weight scope with dual focus knobs, and lower price.

 

[Sagittarius]

Thanks for the comparison of the 3 scopes, Steve. :t:
I appreciate it, greatly !
I've always felt, the Fluorite lens of the Kowa was the best available.
If Kowa made a 95mm of their own with Fluorite, I would have to have it !
I've seen where some dealers list Fluorite glass for the new Harpia but heard it's not true.
Have you seen the Fluorite claims for the Harpia, Steve ?

 

[henry link]

For our tests, we set all zoom magnifications to 30x, matching the minimum for the ATX 95. In bright sun, all three scopes showed virtually equal brightness. The Kowa had a very slight edge in contrast. FOV seemed about the same for all three scopes at this power.

Testing for brightness in the deep shade inside a hedge produced similar brightness results. The 883 had a bit more contrast and depth of focus. The extra contrast may have been a result of the smaller aperture allowing in a little less light.

These scopes are very close optically. Ergonomics and flexibility of design will likely determine more choices than optical quality. Swarovski ATX/BTX/STX will rule the system people who seek modularity and camera adapter options. Zeiss will be the choice of those who are concerned with having a smaller eyepiece or a wider AFOV at high magnification. And Kowa will be the choice of those who prefer a lighter weight scope with dual focus knobs, and lower price.

Thanks Steve. I hope you don't mind if I take issue with a few of these statements.

Firstly, the 88mm 883 doesn't have a smaller clear aperture than the 95mm Zeiss Harpia at 30x. Due to vignetting Kimmo estimated the Harpia's clear aperture at 29x is 70mm, so it's the Zeiss that has the smallest aperture in this test. It should look somewhat dimmer and lower contrast provided the eye is open wide enough to accept the full aperture of the Kowa or Swarovski at 30x. In very bright sunlight, with the eye open to 2.5mm or less, there might be no visible difference, but if the eye is open to 3mm or more the difference should be obvious.

At 30x the FOV of the Zeiss is substantially wider than the Kowa and the Swarovski because of its constant 72º AFOV. On the other hand the AFOV of the Zeiss at high magnification (70x) is not wider than the other two. It's about the same as the Swarovski (72º vs 71º) and probably about the same or possibly a little narrower than the Kowa at 60x (79.5º, using the naive method).

As always, star tests and resolution measurements would be welcome.

Henry

 

[Steve O4B]

Thanks for the comparison of the 3 scopes, Steve. :t:
I appreciate it, greatly !
I've always felt, the Fluorite lens of the Kowa was the best available.
If Kowa made a 95mm of their own with Fluorite, I would have to have it !
I've seen where some dealers list Fluorite glass for the new Harpia but heard it's not true.
Have you seen the Fluorite claims for the Harpia, Steve ?

My pleasure Sagittarius.
Remember that the Kowa 88mm objective is not Fluorite glass, it's pure Fluorite crystal. Zeiss has been using CaFl ion-doped glass since the first Victory FL. The Zeiss website states in their Harpia Features page " Elaborate Lens System

• FL glass and other custom glass ensure an absolutely sharp and colour fidelity image even at maximum magnification.
• Includes LotuTec and T*

"


I haven't heard anything other than idle speculation about a larger Kowa scope, but Kowa has announced that they can now grow Fl crystal up to about 120mm. Given the Kowa affinity for double numbers, I would expect the next Kowa scope version to be a 99mm.

 

[Steve O4B]

Thanks Steve. I hope you don't mind if I take issue with a few of these statements.

Firstly, the 88mm 883 doesn't have a smaller clear aperture than the 95mm Zeiss Harpia at 30x. Due to vignetting Kimmo estimated the Harpia's clear aperture at 29x is 70mm, so it's the Zeiss that has the smallest aperture in this test. It should look somewhat dimmer and lower contrast provided the eye is open wide enough to accept the full aperture of the Kowa or Swarovski at 30x. In very bright sunlight, with the eye open to 2.5mm or less, there might be no visible difference, but if the eye is open to 3mm or more the difference should be obvious.

At 30x the FOV of the Zeiss is substantially wider than the Kowa and the Swarovski because of its constant 72º AFOV. On the other hand the AFOV of the Zeiss at high magnification (70x) is not wider than the other two. It's about the same as the Swarovski (72º vs 71º) and probably about the same or possibly a little narrower than the Kowa at 60x (79.5º, using the naive method).

As always, star tests and resolution measurements would be welcome.

Henry

Thanks, Henry. Our tests were cursory, and didn't include any instrumentation or physical measurements, only impressions. I'm looking forward to having some substantial field time with one.

 

[Sagittarius]

Steve, I see where I was a dummy and called it fluorite glass instead of crystal. :eek!:
Thanks for the information on the Harpia lens system.
Of the 3 scopes, which would be your choice ?

 

[Tringa45]

At 30x the FOV of the Zeiss is substantially wider than the Kowa and the Swarovski because of its constant 72º AFOV. On the other hand the AFOV of the Zeiss at high magnification (70x) is not wider than the other two. It's about the same as the Swarovski (72º vs 71º) and probably about the same or possibly a little narrower than the Kowa at 60x (79.5º, using the naive method).

This figure of 79° AFOV for the Kowa surprised me but 23 m @ 1000 m is indeed 1,32° and 60 times that is 79°. Calculated according to ISO though, the AFOV would be 69°.
This discrepancy initially led me to suspect distortion. but that is not the case so the naive method and ISO diverge more, the greater the AFOV.
I have just repeated my measurements on the 883 with TE-11WZ eyepiece through the objective on a panorama head, and at the marked settings, had the following results:-
56° @ 25x
60° @ 30x
66° @ 40x
70° @ 50x
70° @ 60x

John

 

[jring]

I haven't heard anything other than idle speculation about a larger Kowa scope, but Kowa has announced that they can now grow Fl crystal up to about 120mm. Given the Kowa affinity for double numbers, I would expect the next Kowa scope version to be a 99mm.

Hi,

while a larger Kowa Prominar would certainly be nice, the story about Kowa growing CaF2 crystal is not true...

Kowa gets finished CaF2 lenses from Canon Optron, just like almost everybody else building scopes with CaF2 elements - most notably Takahashi.

And Takahashi has two fluorite models with 150mm clear apertur on offer, the FS 152 doublet and the TOA 150 triplet refractors. A fixed observatory is strongly recommended...

Joachim

 

[henry link]

This figure of 79° AFOV for the Kowa surprised me but 23 m @ 1000 m is indeed 1,32° and 60 times that is 79°. Calculated according to ISO though, the AFOV would be 69°.
This discrepancy initially led me to suspect distortion. but that is not the case so the naive method and ISO diverge more, the greater the AFOV.
I have just repeated my measurements on the 883 with TE-11WZ eyepiece through the objective on a panorama head, and at the marked settings, had the following results:-
56° @ 25x
60° @ 30x
66° @ 40x
70° @ 50x
70° @ 60x

John

Thanks John. When it comes to AFOV there's no substitute for real measurements.

What kind of distortion do you see in the Kowa at 60x? My recollection is of some barrel distortion at the low magnifications gradually decreasing to approximately zero rectilinear distortion at 60X, but with the expected large amount of angular magnification distortion. That would reasonably explain why the measured AFOV is so close to the ISO calculation.

Henry