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

BTX Binoviewer for ATX scopes (1 Viewer)

Kimmo, post 134,
The BTX test report is now corrected with regard to the subscript of figure 1, (that is now figure 2) and I have added some more historical information. It is again on the WEB-site of House of Outdoor,
Gijs van Ginkel
 
Kimmo, post 134,
The BTX test report is now corrected with regard to the subscript of figure 1, (that is now figure 2) and I have added some more historical information. It is again on the WEB-site of House of Outdoor,
Gijs van Ginkel

Gijs,

Would you please post the link again. I can't find it on the site and the previously posted link doesn't work.
 
Steve O4B, post 142,
The WEB site given by Dipped, post 143 works very well.
Gijs van Ginkel

Thanks Gijs and Dipped. That link worked and I've read the review. It was very extensive and informative.

There are errors in your Kowa specifications:

  • The TE-10Z (20-60x) Zoom hasn’t been available for 4 years. The current zoom, TE-11WZ, is 25-60, has 2 XD elements, and an FOV of 42-23m @ 1000m
  • The 30x WA eyepiece (TE-17W) has been discontinued due to lack of interest.
  • The 2 turns (720°) from close focus to infinity is for the coarse focus knob. The fine focus knob takes 6 full turns - a 3:1 ratio.
[FONT=&quot]I’m highly suspicious of the light transmission ratings for the Kowa TSN-883 as well. In our low light testing, though side-by-side visual rather than with measuring equipment, the Kowa is second in brightness to the ATX/STX-95, beating all other scopes, including the ATX/STX-85. It is unfathomable to me that the TSN-883 could be so much worse in light transmission than scopes that are nowhere near as bright. [/FONT]
 
Steve O4B,
The specifications and measured data from the Kowa telescope are from some years ago, as you can see from the eyepieces that either or not available anymore or discontinued. We were at that time (as we are now) very careful with the transmission measurements and if we did not trust them we measured them again, so at that time the transmission was as we presented it. The sample we had at that time was certainly not perfect as far as color reproduction was concerned and that fully understandable also from the transmission spectra. But Kowa most likely has improved its telescopes as seems also from observations from recently produced telescopes. The problem in The Netherlands is, that Kowa telescopes are difficult to find in binocular/telescope shops, so we have not investigated recent productions.
As you can see from the other data, we also measured older Zeiss telescopes and these data are undoubtedly different from the recent ones, since Zeiss also improved its instruments over the years.
Gijs van Ginkel
 
Steve 04B, post 142,
In addition to my post 146: I tested the Kowa telescope in the beginning of 2009 and the image was slightly yellow, not so strong as the image of the first Zeiss Diascope but it was without any doubt the case. The transmission spectrum confirmed that observation. I had borrowed the Kowa telescope from the shop of the Dutch Bird Protection Association, where the telescope at that time was available. (A short time later the shop discontinued selling Kowa telescopes, because the service level was not up to the standards the organisation wanted). Other shop volunteers who worked in the shop as well also observed he slightly yellow bias of the telescope image. In the test I used a clear ranking method, which was made in such a way, that it would rule out preferences of the tester and every reader could check it and perform the same ranking method using his/her own weighing factor. I did that to avoid that personal tester preferences (every tester can have his/her own darlings) received any weight.
My conclusion was and is, that at that time the transmission spectrum of the Kowa telescope was fully correct, but that does not tell how it is for newer Kowa telescopes, since I did not test them.
Gijs van Ginkel
 
Recently had a chance to try the BTX with the 95&85mm modules, whilst I thought the viewing experience was very comfortable I was surprised by the overall lack of image sharpness. Certainly didn't have the sharpness of my Swaro bins or the ATX naked, the guy demonstrating agreed with me. Was I expecting too much? I haven't seen too many comments re the image quality, curious what others think!
cheers
 
wildoat, post 149,
I have tested the BTX 95 thouroughly and I did not have the experience you describe, the image was crystal clear and sharp, so there may have been something wrong with the sample you looked through.
Gijs van Ginkel
 
I had the occasion to compare the btx 85 and ATX side by side this very weekend with sunny weather and wanted to cheque the potential difference in contrast or brightness and I could not find any , nor in shadow , nor in sunny condition
Highly impressed with BTX performance
A few weeks ago I looked through a BTX with 65 objective , and optically just fine, but balance is not so well
 
I have the BTX 85 and it is every bit as sharp as my former Leica 65 25-50x. The viewing experience is not comparable though. Being able to use two eyes, the view is highly enjoyable and relaxing, like binoculars, but that's obvious. Also, it seems that there is a higher 'apparent magnification'; the brain distinguishes more details with two eyes. 30x seems like watching at 40x using only one eye. Very satisfied with this amazing scope!
 
wildoat, post 149,
I have tested the BTX 95 thouroughly and I did not have the experience you describe, the image was crystal clear and sharp, so there may have been something wrong with the sample you looked through.
Gijs van Ginkel
Thanks for sharing that!
I would definitely try another unit before coming to a difinitive conclusion, I love the concept and viewing comfort was really top notch!
cheers
tony
 
I like the idea of the BTX, hell of a price! But I don't think it would work for me.. i tend to sit down, and scan, I don't know, 50 degrees either side of straight ahead. With one eye, I can look at an angle into the scope.
I'm pretty sure I'd need an extendable, extremely flexible neck to continue to look with both eyes.

it's as if a typical tripod is not designed for the BTX.. you need the pivot point to be where your spine is, if that makes sense. (or sit with tripod on a rotating base!)
 
Might be late here. I just got the BTX with 1.7x extender. Tried it on the 95mm, no loss of details. Best balance with BR balance rail and PTH tripod head which is similar with the gimbal head.

I usually do not extend the eyecup to get wider FOV and with the indispensable built in forehead rest, as it makes viewing for longer period comfortable hahaha ;)

IMG_20180301_070251 BTX.jpg IMG_20180301_070705 MY BABY PA.jpg

Will report soon after using it in the rainforest next after my birding tours.
 
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