How good are the new Diascopes? (1 Viewer)

Dispite having swaro binos , ( and i think they are the best on the planet ), i have never been too keen on swaro scopes , perhaps its the "barrel" focusing ,i have looked through them , whilst nice , they didnt blow me away , like the binos do ,

i read an article recently, about the new ziess diascopes, i think it was from a site by michael and diane , birdwatching something or the other, and they were absolutely raving about the new diascopes , said they knocked spots off the kowa , resolution wise ,

now if this was a sales promo , i am not too sure , but like your comment , the new diascopes have been taking a bit of a hammering , in the few reviews that i have seen ,

i love my little opticron hr ed 66 , it is my first ever scope , but i am so bitten by the bug now , that i want only the best !! ,

thats why every body i work with , said i was mad . going out spending all that money on the swaro binos ,

but the obvious thing to do , is to try all the scopes out side by side , at a bird fair /exhibition , but the trouble is then, i would want to take them all home !! .

spacepilot,
I was waiting for some new Diascopes users to reply to your comments but I would like to add some also:
- it is me or the photo taken with the Diascope is out of focus? This might explain the CA visible...;
- I find strange the non parfocalness of the new zoom. When you decreased the zoom it also loosed focus?
Still didn't tested this new ep but I'm searching a way of using it in my Optolyth or Pentax 100 scopes - it seems it will not be easy...
Anyway I must congratulate Zeiss for doing a 3.75x zoom and wish other brands followed them!

David, I don't digiscope much. The photos I uploaded were taken with hand-held camera with automatic setting. So I'm sure they are not the best photos one can obtain form the two scopes. They probably have different ISO and shutter settings as well. That said, I think they illustrate very well the amount of CA in the Diascope. If you look at the star pattern on the top left corners of the photos, which was in the center of the field in both scopes, it has the same sharpness (or fuzziness) in both photos, no yellow or blue fringes in either one. That indicates that (1) both photos are more or less in focus, (2) the effect of my hand-holding the camera are about equal in both photos, and (3) both scopes controls CA pretty well at the center. However, once we move away from the center, the Diascope is showing progressively worse CA than it's competitor. This is clearly visible by comparing the white and dark triangles scattered in the resolution chart. The damage of CA and other aberrations away from the center is evident in the checkered patterns at the bottom of the resolution chart. The competitor still shows the finest pattern rather well, but in the Diascope the finest pattern is all but reduced to a block of gray.

As far as parfocalness goes, none of the eyepieces I tested with the spotting scopes were parfocal enough to eliminate the need of refocusing when changing zoom. I notice the need to refocus more when I got from low zoom to high, presumably because of the much shallower DOF at high magnification. However, switching from high zoom to low zoom usually requires some refocusing as well. The gripe I have with the Diascope is the combination of lack of parfocalness and the implementation of the dual-speed focus. It felt unintuitive and clunky for me, but may well be a favorite for others.The 3.75 zoom range is nice on paper, but in practice, the 75x didn't provide more details than 60x, probably partially due to a subpar scope body sample that I got, and partially due to the small exit pupil. I cannot comment on its use for astsonomy, but the utility of 75x is probably not that much in the field for most people, as a lot of people were very happy when they switched from 20-60x to 25-50x. If you wear glasses or have deep set eyes, there is a good chance that you'll be unhappy with the 20-75x zoom eyepiece. The useable eye relief is much less than the 16mm spec would suggest, and the eye relief is much shorter in the middle range of the zoom, so you are pretty much left with only the 20x and 75x options. The competitors' 20-60x and 25-50x eyepieces have much better useable eye relief. Their eye relief curves felt flatter across the zoom range as well, and I had an easier time using the magnifications in between, such as 35x, during my informal testing.

DRodrigues said:

spacepilot,
Still didn't tested this new ep but I'm searching a way of using it in my Optolyth or Pentax 100 scopes - it seems it will not be easy...

Click to expand...

David,
with original accessories this could be possible. At Zeiss there is the EP-1 1/4" Adapter. http://sportsoptics.zeiss.com/nature/en_de/spotting-scopes/accessories.html , see at the bottom.

At Optolyth there is the astro-EP adapter. http://www.optolyth.de/english/products/accessories/adapters/index.php
Don't know if the Optolyth and Pentax scopes do come into focus with the Zeiss-EP, though.

Steve

spacepilot,
Thanks for your reply and additional info.
I continue to think that the Zeiss photo is not so well focused but I have to look through one!
Is natural for you to notice more focus difference when zooming a 3.75x zoom than a 3x one. Users of the 25-50x zooms prefer them because of the AFOV (in addition the difference in focus when zooming a 2x zoom is also smaller than a 3x zoom ep), but unlike some owners of 2x zoom ep say, a 20-60x zoom is capable of higher resolution at 60x than a 2x at 50x, assuming that the telescope and atmospheric conditions allow it...

Steve,
I know about the adapters (and have the one of Optolyth - see it at http://www.pt-ducks.com/cr-telescopes.htm#Test of 100mm telescopes). The problem is that the Zeiss with the adapters will not reach focus both in the Pentax or Optolyth. The solution would be to machine the Zeiss ep to 1.25" but that is a bit too risky...:-C

David, feel free to think what you want. I didn't say my photos are well focused. I just argued that both the photos are in focus enough to show some of the difference between the Diascope and the competitor scope. As I said, both photos show the same level of sharpness or fuzziness at the center of the field (the star pattern at the top left of the photos), so the focus error and shake introduced by me should be about the same in both photos. The Diascope shows significantly more CA away from the center, and the resolution of the Diascope takes a much bigger hit away from the center because of CA and other aberrations. The photos are just for illustrative purposes. In my experience, looking through the eyepiece, the CA in the Diascope is even more alarmingly evident than the photos show.

I understand that on a decent 80mm scope under a perfect condition, 60x will allow you to see more details than 50x, but this perfect condition does not happen often in the field around here. The larger AFOV is apparently significant enough for plenty of people to happily choose the 25-50x over the traditional 20-60x. I'd also argue that if 60x vs. 50x makes the difference of whether or not you can identify the bird in your mind, you may want to just leave the bird unidentified, walk a little bit closer, or get a higher magnification eyepiece. I'd happily do the first two if the occasion arises. The third option brings us back to the wide range zoom again. If there were a 25-75x eyepiece that (1) has decent useable eye relief across the range, (2) provides > 60 degrees of AFOV across the range, (3) weight less than a pound, I'd be all over it. There doesn't appear to be such eyepieces on the market, and I'm not sure how technologically possible it is. But as the Zeiss eyepiece stands, I just cannot live with its compromises for the 1% of time that I may need and can actually push to 75x in the field.

I didn't come here to bash the new Diascope. I'm just relating my experience with it compared to some other top scopes on the market. Frankly, it didn't live up to my expectations, especially considering the price and the quality of its direct competitors. On the other hand, my intended use of carrying it into the field for visual observation of birds maybe vastly different than yours. I'm also sensitive to CA and value edge sharpness. So you may be able to accept a completely different set of compromises than I can. If you are interested in the new Diascope eyepiece, by all means look through one. It may be the best one that suit your purposes.

Hmmm... If one could rig up a way of using the 20-75x zoom on the 88mm Kowa, I wonder how that'd look if it could reach focus. The Kowa with a higher mag zoom... Wonder if the CA and edge problems described are the eyepiece's fault, or the Diascope body's.