Zeiss Diascope successor (1 Viewer)

[SzimiStyle]

Where in the UK can I see the new Gavia in August (I'm in London) I'm thinking of selling my 85 Diascope I like the idea of it being lighter

British BirdFair Zeiss stand in the Optic Marqee

 

[alan kennedy]

Good to see they've switched to a single helical focuser. I've never been keen on dual systems and why I opted for Swarovski. It will be interesting to compare at BF.

Alan

 

[SzimiStyle]

Good to see they've switched to a single helical focuser. I've never been keen on dual systems and why I opted for Swarovski. It will be interesting to compare at BF.

Alan

I wonder when Swarovski will sue Zeiss for this focusing design.

 

[Ratal]

I wonder when Swarovski will sue Zeiss for this focusing design.

Ouch.

That said, the Zeiss had better be light years ahead of the Viking scope, as the ones I tried were barely better than my old Hawke Frontier 85 ED. As in 'Nah thanks, that's not an upgrade'
barely better.

 

[Troubador]

I wonder when Swarovski will sue Zeiss for this focusing design.

Well, they haven't sued Meopta over S2.............

In any case you would only sue if a product was a direct competitor of your own product and not if the product was very significantly cheaper or more expensive. Legal cases aren't cheap.

Lee

 

[henry link]

Helical focusing collars have been used on spotting scopes for a very long time. Nikon Fieldscopes before Swarovski, Bausch & Lomb Discoverers long before Nikon. I'm sure there are others.

 

[Troubador]

Helical focusing collars have been used on spotting scopes for a very long time. Nikon Fieldscopes before Swarovski, Bausch & Lomb Discoverers long before Nikon. I'm sure there are others.

Of course you are correct Henry, I used to own a B&L Discoverer until about 1983 so I should have remembered this.

Lee

 

[Vespobuteo]

Now it's official:

http://www.zeiss.com/sports-optics/en_de/nature/spotting-scopes/conquest-gavia.html

The name is Conquest Gavia and the glass is HD, not FL.
And as expected, it's not a Diascope successor.

 

[dipped]

Thanks for the link Vespobuteo. So no straight model which is a shame. That's the end of my interest in it.

 

[henry link]

I have a request for those who will get a look at the new Zeiss scope at Birdfair.

Could someone among you try to do a quick 60X star-test? Ideally someone who is familiar with star-testing can do this, but anyone can learn how do do it by Googling something like "telescope star-test" and practicing a little.

Hopefully there will an example of a glitter point of the sun returning from some small round shiny object between maybe 20m and 50m (too close and it may not be small enough to act as a point source, too far and there may be too much air turbulence to see clear diffraction rings). A car in sunlight has many such glitter points in the head/tail lights and trim areas or you could bring your own little shiny object. Rack the focus back and forth and observe the diffraction rings on either side of focus and the point of light at best focus. These reveal the level of spherical aberration and various defects like astigmatism, coma, turned edge, zones, pinching and poorly made roof prisms. One accurate description of a star test is far more informative of the true optical quality of a particular scope specimen than all the subjective descriptions we are likely to read of what birds look like through it.

Henry

 

[Troubador]

I have a request for those who will get a look at the new Zeiss scope at Birdfair.

Could someone among you try to do a quick 60X star-test? Ideally someone who is familiar with star-testing can do this, but anyone can learn how do do it by Googling something like "telescope star-test" and practicing a little.

Hopefully there will an example of a glitter point of the sun returning from some small round shiny object between maybe 20m and 50m (too close and it may not be small enough to act as a point source, too far and there may be too much air turbulence to see clear diffraction rings). A car in sunlight has many such glitter points in the head/tail lights and trim areas or you could bring your own little shiny object. Rack the focus back and forth and observe the diffraction rings on either side of focus and the point of light at best focus. These reveal the level of spherical aberration and various defects like astigmatism, coma, turned edge, zones, pinching and poorly made roof prisms. One accurate description of a star test is far more informative of the true optical quality of a particular scope specimen than all the subjective descriptions we are likely to read of what birds look like through it.

Henry

Henry, the Zeiss booth overlooks a short area of grass (with no access), then water and reeds and beyond a wide area of lake with some islets. There are no twinkly metal or glass bits out there as far as I can remember. There will be highlights off water but I wouldn't think this would be of a constant quality.

Lee

 

[Troubador]

Henry I have just remembered there is a single-storey building about 30 metres away and I think it has windows so there could be a glint off the glass at some time during the day.

Didn't remember this at first because, well, you know how it is: you go to Bird Fair, set in the middle of a bird reserve, in order to assess bird-watching instruments by looking at, yes, birds, and you tend to ignore buildings .

Anyway I have found a great tutorial on star-testing on the internet and printed it off and will give it my best shot if I get an opportunity.

Lee

 

[henry link]

Lee,

DO NOT USE A REFLECTION OF THE SUN FROM A FLAT GLASS PANE!! Sorry for yelling, but that would send a full sized dangerously bright reflection of the sun into your eye that would be plenty bright enough to destroy your eyesight!. A small spherical or convexly curved object MUST be used, so that the reflection of the sun seen through the scope appears as a tiny star like point. The smaller the object (ball bearing, glass bead, Christmas tree ornament, light bulb, etc) the closer it can be placed to the telescope and still form a point source. I sometimes use a small silvered glass ornamental ball about 20mm in diameter at about 50m for star-testing small telescopes and binoculars. A good place would be near the building with the sun behind you. Place the object in the open air with no hot surfaces like pavement between you and it. It's best if it's at least a few few feet above the grass, perhaps on top of a tripod or dangling from the tripod handle.

Thanks for volunteering and please be careful.

Henry

 

[jring]

just wonder why not start the zoom range at 25x...
FOV will suffer a bit from it,

Hi,

that question is easily answered - they traded a smaller zoom range for higher AFOV at the low maginification end, as did all manufacturers with wide-angle zooms to varying degrees.

With the new Zeiss we have a 2x zoom with an AFOV of around 60 degrees at the low mag end and around 80 at the short end, as with Leica, Meopta and the Swaro ATS/STS wide angle EPs.
The Kowa WA zoom for the big bodies and the Swaro ATX/STX eyepiece module have 2.4x with about the same AFOV range as the 2x models mentioned above, which makes them quite sweet.

For astro scopes there's 1.7x zooms with a constant AFOV of 80 degrees (Speers Waler Zoom or the discontinued Astro Zoom Kit).

Joachim

 

[Troubador]

Lee,

DO NOT USE A REFLECTION OF THE SUN FROM A FLAT GLASS PANE!! Sorry for yelling, but that would send a full sized dangerously bright reflection of the sun into your eye that would be plenty bright enough to destroy your eyesight!. A small spherical or convexly curved object MUST be used, so that the reflection of the sun seen through the scope appears as a tiny star like point. The smaller the object (ball bearing, glass bead, Christmas tree ornament, light bulb, etc) the closer it can be placed to the telescope and still form a point source. I sometimes use a small silvered glass ornamental ball about 20mm in diameter at about 50m for star-testing small telescopes and binoculars. A good place would be near the building with the sun behind you. Place the object in the open air with no hot surfaces like pavement between you and it. It's best if it's at least a few few feet above the grass, perhaps on top of a tripod or dangling from the tripod handle.

Thanks for volunteering and please be careful.

Henry

Thanks Henry and you can shout as loud as you like about this.
You don't get to carry intruments outside at Bird Fair and there is no access to the grass area between the Optics Marquee and the lake to place an object.

But I will take the star-test tutorial printout and see what opportunities arise.

Lee

 

[Mark9473]

Perhaps take an artificial star along?
http://www.rothervalleyoptics.co.uk/geoptik-small-artificial-star-for-collimating.html

 

[dipped]

I have a request for those who will get a look at the new Zeiss scope at Birdfair.

Could someone among you try to do a quick 60X star-test? Ideally someone who is familiar with star-testing can do this, but anyone can learn how do do it by Googling something like "telescope star-test" and practicing a little.

Hopefully there will an example of a glitter point of the sun returning from some small round shiny object between maybe 20m and 50m (too close and it may not be small enough to act as a point source, too far and there may be too much air turbulence to see clear diffraction rings). A car in sunlight has many such glitter points in the head/tail lights and trim areas or you could bring your own little shiny object. Rack the focus back and forth and observe the diffraction rings on either side of focus and the point of light at best focus. These reveal the level of spherical aberration and various defects like astigmatism, coma, turned edge, zones, pinching and poorly made roof prisms. One accurate description of a star test is far more informative of the true optical quality of a particular scope specimen than all the subjective descriptions we are likely to read of what birds look like through it.

Henry

I may get to have a look at this scope on Friday as it's being released to the RSPB optics shops as soon as its released at the Bird Fair. I think it will depend on Viking Optical bringing a sample over to my local reserve and they may all be busy/at the Bird Fair.

In any case I will get a chance to artificially star test it in due course as there is a roof light in the reserve shop that makes a good artificial star and I'm there in my volunteer capacity every two weeks, (and if a good bird turns up sooner).

This is the first Zeiss scope the RSPB shops have stocked (to my knowledge), so it will be interesting to see how it it received.

 

[Vespobuteo]

Hi,

that question is easily answered - they traded a smaller zoom range for higher AFOV at the low maginification end, as did all manufacturers with wide-angle zooms to varying degrees.

With the new Zeiss we have a 2x zoom with an AFOV of around 60 degrees at the low mag end and around 80 at the short end, as with Leica, Meopta and the Swaro ATS/STS wide angle EPs.
The Kowa WA zoom for the big bodies and the Swaro ATX/STX eyepiece module have 2.4x with about the same AFOV range as the 2x models mentioned above, which makes them quite sweet.

For astro scopes there's 1.7x zooms with a constant AFOV of 80 degrees (Speers Waler Zoom or the discontinued Astro Zoom Kit).

Joachim

I guess you could draw that conclusion.
Perhaps bigger AFOV looks a bit more impressive and is more "modern".
Not sure it's the most versatile in practical use. A larger exit pupil and FOV (@20-25x) for example is sometimes preferred.
But it might be better for digiscoping.

Nikon and Meopta (and Swaro on ATS) offers two different zooms, one with larger AFOV and one with a bigger zoom range, so one can pick what suits you best (or both).
I guess Zeiss will not for the Gavia. They offer the Diascope with a 25-75x zoom instead.

 

[SRVD]

Hi Zeiss Team,

Do you have any plan for New 65 mm scope in Conquest Gavia series in near future.

 

[dipped]

I had a chance to try the Gavia out in my local reserve shop today, priced at £1595.

First impressions, good build quality but maybe easily scuffed rubber armoring. Smooth even focusing clockwise to infinity. There appears to be no case supplied in the box, maybe it's coming.

I tried it out on the internal artificial star in the shop, I'll do my best to describe what I saw. Outside focus pretty good circular rings well defined, maybe slightly thicker at ten o'clock but only slightly. Purple flare to outer edge of "star".

Inside focus the inner rings were missing replaced by a white disc and were not so well defined, so spherical aberration not as well corrected as some scopes I've tested. Don't know what the disc indicates but the rings were still pretty round so good collimation.

The artificial star was not resolved as well as some scopes I've tested and I got the impression there was a bit of CA there too.

The scope had a bit of vignetting at the very close focus end. I checked this a few times as I wasn't sure if there was any at all but I'm pretty sure it's there I'm guessing there is a way of knowing for sure by shining a light inside the objective lens end?

I couldn't manage to take any pictures of the star images.

In the reserve shop the Gavia is pitched against the Swarovski 65HD with 25-50 zoom or for £400 more you can buy a cased Kowa 88 with 25-60 zoom. I know what I would do if I was in a position to spend that sort of money (on a new scope).