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

Zeiss Diascope 85 FL vs. Kowa TSN 824 vs. Nikon 82 ED (1 Viewer)

iporali said:
The eyepieces of the Kowa are much better suited for digiscoping than the others (except the zoom!). Their superior eye-relief increases the options from which to choose a camera. Even the otherwise brilliant Zeiss zoom has only average eye-relief, and the Nikon zoom is even worse. Both Nikon & Zeiss have 30x wide-angles, which are better for digiscoping, but they simply don't have the best fixed power: 20/21x.

Ikka,
Would you please elaborate a bit on how superior eye relief generates more digiscoping camera options? And, in this context, does superior eye relief equal greater eye relief, or is there some other variable involved?
Thanks,
El Puffino
 
elpuffino said:
Ikka,
Would you please elaborate a bit on how superior eye relief generates more digiscoping camera options? And, in this context, does superior eye relief equal greater eye relief, or is there some other variable involved?
Thanks,
El Puffino
El Puffino,

Yes, with that "superior" eye-relief, I meant "having significantly more ER than its competitors". I had to go and check my notes and to my embarrassment, in my memory, I had over-estimated the ER of the 21x Kowa. It "only" has 20 mm ER, which is good, but not superior (Leica's 20x has the same ER). OTOH the Kowa 27x eyepiece does have superior ER to any other native eyepiece from the "big five", but at the cost of field-of-view.

Here are the ERs and fields-of-view of the fixed "low-power" eyepieces from five manufacturers:
Kowa 21x: 20 mm 54 m/1000m
27x 32 mm 35 m/1000m
32x: 20 mm 38 m/1000m

Leica 20x: 20 mm 54 m/1000m
32x: 19 mm 40 m/1000m

Nikon 30xDS: 19 mm 42 m/1000m

Swaro 20x: 17 mm 60 m/1000m
30x 20 mm 42 m/1000m

Zeiss 30x 18 mm 40 m/1000m
zoom 43-20m

As mentioned previously (by Henry and Kimmo) the ER-data seems to be somewhat variable according to sources, but these figures correspond to my experience with my non-scientific ;) "digiscoping-ER-standard": the Nikon CP4500.

The measured eye-reliefs of the zooms can be seen here:
http://www.tvwg.nl/testrapporten/telescoop/zeisstelescopen65tflen85tfl.htm
Unlike shown in the graph, the new Kowa zoom should behave like the Zeiss zoom (not tried myself).

What this data IMHO means in practice:

1) If you are mainly a birdwatcher and only occasionally need digiscoping or use digiscoping as a means to document some of your observations, you can forget almost all my musings about ER. They all are just fine (including zooms): choose the scope/eyepiece you like most and you can surely digiscope with it. In good conditions you can get fantastic results with any of them.

2) If you become seriously interested in digiscoping as a form of high-power nature photography, you may start to wish for a wider field-of-view. You may see that for good pictures you have to get close to the target. This is something that many may not realize until they have done it for a while. Higher power eyepieces are easily available from every manufacturer (Nikon even calls those fixed 50x and 75x "digiscoping" eyepieces), but a 20/21x can only be had from Kowa, Leica and Swaro - and the Swaro 20x suffers from vignetting with the CP4500.

3) Eye-relief of the eyepiece is THE feature that determines whether a camera works with the scope or not - and then 2-3mm may mean a lot. "Professional" digital cameras have often large, high-megapixel sensors and thus usually large and long lenses, which require more eye-relief from the eyepiece. If you want to use one of these cameras for digiscoping, a short-ER eyepiece causes vignetting and you may end up wasting megapixels or having too much power & narrow fields-of-view. Practically only Kowa 27x allows you to use cameras like Canon G6 for digiscoping.

I hope I was able to elaborate my point a little further and I apologize the previous misinformation about the Kowa 21x wide-angle.

Best regards,

Ilkka
 
Ikka,
You've given me something new to think about. Oddly, one of the factors pushing me in the direction of Zeiss has been the incredible sharpness of two photos taken with this scope in the BirdForum gallery. These are both by Faisca Sparky: One is of a black-shouldered kite, the other is a kestrel. Both were taken with Zeiss 85 Diascopes and the Canon 350 D. Obviously, these are just amazing photographs, and to produce them with any equipment would take terrific skill. However, I came across these photos by doing searches in the gallery using all three of my possible scopes (the Zeiss, the Nikon 82 ED, and the Kowa TSN 824), and after looking through 5 pages of photos taken through each of these scopes, neither the Nikon nor Kowa examples equalled these. Indeed, even aside from these photos, it seemed that in terms of sharpness, the Zeiss came out on top, with the Kowa very close behind, and the Nikon in third.
What do you think of this? Perhaps my sample size was insufficient (60 photos for each scope), and the photo was more a reflection of the particular photographers' technical abilities than their equipment (certainly, however, artistic ability was well distributed among all the users of all the scopes!).
Thanks again,
El Puffino


iporali said:
El Puffino,

Yes, with that "superior" eye-relief, I meant "having significantly more ER than its competitors". I had to go and check my notes and to my embarrassment, in my memory, I had over-estimated the ER of the 21x Kowa. It "only" has 20 mm ER, which is good, but not superior (Leica's 20x has the same ER). OTOH the Kowa 27x eyepiece does have superior ER to any other native eyepiece from the "big five", but at the cost of field-of-view.

Here are the ERs and fields-of-view of the fixed "low-power" eyepieces from five manufacturers:
Kowa 21x: 20 mm 54 m/1000m
27x 32 mm 35 m/1000m
32x: 20 mm 38 m/1000m

Leica 20x: 20 mm 54 m/1000m
32x: 19 mm 40 m/1000m

Nikon 30xDS: 19 mm 42 m/1000m

Swaro 20x: 17 mm 60 m/1000m
30x 20 mm 42 m/1000m

Zeiss 30x 18 mm 40 m/1000m
zoom 43-20m

As mentioned previously (by Henry and Kimmo) the ER-data seems to be somewhat variable according to sources, but these figures correspond to my experience with my non-scientific ;) "digiscoping-ER-standard": the Nikon CP4500.

The measured eye-reliefs of the zooms can be seen here:
http://www.tvwg.nl/testrapporten/telescoop/zeisstelescopen65tflen85tfl.htm
Unlike shown in the graph, the new Kowa zoom should behave like the Zeiss zoom (not tried myself).

What this data IMHO means in practice:

1) If you are mainly a birdwatcher and only occasionally need digiscoping or use digiscoping as a means to document some of your observations, you can forget almost all my musings about ER. They all are just fine (including zooms): choose the scope/eyepiece you like most and you can surely digiscope with it. In good conditions you can get fantastic results with any of them.

2) If you become seriously interested in digiscoping as a form of high-power nature photography, you may start to wish for a wider field-of-view. You may see that for good pictures you have to get close to the target. This is something that many may not realize until they have done it for a while. Higher power eyepieces are easily available from every manufacturer (Nikon even calls those fixed 50x and 75x "digiscoping" eyepieces), but a 20/21x can only be had from Kowa, Leica and Swaro - and the Swaro 20x suffers from vignetting with the CP4500.

3) Eye-relief of the eyepiece is THE feature that determines whether a camera works with the scope or not - and then 2-3mm may mean a lot. "Professional" digital cameras have often large, high-megapixel sensors and thus usually large and long lenses, which require more eye-relief from the eyepiece. If you want to use one of these cameras for digiscoping, a short-ER eyepiece causes vignetting and you may end up wasting megapixels or having too much power & narrow fields-of-view. Practically only Kowa 27x allows you to use cameras like Canon G6 for digiscoping.

I hope I was able to elaborate my point a little further and I apologize the previous misinformation about the Kowa 21x wide-angle.

Best regards,

Ilkka
 
elpuffino said:
What do you think of this? Perhaps my sample size was insufficient (60 photos for each scope), and the photo was more a reflection of the particular photographers' technical abilities than their equipment
Those hawk photos are truly amazing, but in this case the equipment is also not a typical digiscoping setup. The DSLR was connected to the scope with an adapter that turns the scope to a (500-600mm) tele-lens with fixed, small aperture (f/11 ?). This leaves out several lens elements (eyepiece), decreases magnifying power (->10-12x) and does not allow normal use of the scope. It is also quite dark in many conditions, but in sunny Portuguese weather and with a large DSLR sensor it is capable of much higher sharpness than any "afocally coupled" digiscope. The same way I think you would have "more potential" in digiscoping with a fixed 20x, but it wouldn't necessary be as good in other kind of birdwatching.

I have sometimes tried to judge the optics by the digiscoped images, but I am afraid there are just too many uncontrolled variables to draw reliable conclusions. Eg. most of the Kowa images in the gallery are taken with the "previous generation" eyepieces, which had terribly low eye-relief. The new digiscoping-friendly eyepieces were not introduced until spring -04. The Zeiss Diascope has been on the market longest and its wide-angled zoom eyepiece may be better in digiscoping than the other zooms.

I think you should just listen to your heart and at least not think about money. The Zeiss and Nikon ED82 are maybe optically more advanced than the Kowa, but Kowa's excellent eyepiece selection makes it a worthy contender for serious digiscopers.

Best regards,

Ilkka
 
Thanks again, Ikka. I'm still quite undecided regarding my scope decision. I'm going to try to do some testing on my Nikon (to see if it's a bad unit), do side-by-side comparisons of my top contenders, and also consider the scopes' digiscoping merits (including the issues that you raised).
All the best,
El Puffino

iporali said:
Those hawk photos are truly amazing, but in this case the equipment is also not a typical digiscoping setup. The DSLR was connected to the scope with an adapter that turns the scope to a (500-600mm) tele-lens with fixed, small aperture (f/11 ?). This leaves out several lens elements (eyepiece), decreases magnifying power (->10-12x) and does not allow normal use of the scope. It is also quite dark in many conditions, but in sunny Portuguese weather and with a large DSLR sensor it is capable of much higher sharpness than any "afocally coupled" digiscope. The same way I think you would have "more potential" in digiscoping with a fixed 20x, but it wouldn't necessary be as good in other kind of birdwatching.

I have sometimes tried to judge the optics by the digiscoped images, but I am afraid there are just too many uncontrolled variables to draw reliable conclusions. Eg. most of the Kowa images in the gallery are taken with the "previous generation" eyepieces, which had terribly low eye-relief. The new digiscoping-friendly eyepieces were not introduced until spring -04. The Zeiss Diascope has been on the market longest and its wide-angled zoom eyepiece may be better in digiscoping than the other zooms.

I think you should just listen to your heart and at least not think about money. The Zeiss and Nikon ED82 are maybe optically more advanced than the Kowa, but Kowa's excellent eyepiece selection makes it a worthy contender for serious digiscopers.

Best regards,

Ilkka
 
elpuffino said:
Greetings,
So, here's my situation: I bought a Nikon 82 ED with a 38 X WA eyepiece several weeks back to use primarily for hawk watching. When I took it to the hawk watch I was disappointed because 1) it was very difficult to quickly focus on the birds; and 2) even when focused on the standing, and cooperative waders that also occur at the site, the image never seemed completely sharp.
No doubt these problems stemmed at least in part from the scope's infamously hypersensitive helical focus (coupled with stiffness of the focusing ring). However, I wonder if, a) the depth of field for these scopes is particularly shallow, and b) if my scope (and/or eyepiece) was the victim of unit to unit variation.
Thanks,
El Puffino

I´m an very happy owner of the Nikon ED82 with 30xW eyepiece. It´s sharp and the focus is the best I ever have tried on a scope. It´s fast, but also really smooth and nice. Not difficult at all to get it right (at 30x power). BUT.."right out of the box" the "focus-knob" can be rather stiff. My unit was stiff in the beginning..and I was also dissapointed. It was hard to get a perfect sharp image of the birds. But after 2-3 days the focus began to get smoother and now..I´m very pleased. For me it´s the perfect scope/eyepiece combination, but of course..for you maybe it isn´t. My advice is: give the ED82 some time to know it and you probably will fall in love with it! :eat:
 
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