BT100 Binoculars for Birding
Posted 06 December 2005 - 12:36 PM
very nicely written report.
You may find that next eyepiece in the TV radian, perhaps an 18mm. 20mm er and 60° fov.
Posted 06 December 2005 - 02:27 PM
Congratulations on this review , which was very interesting and particularly well presented .
The role which these BT100s are performing for you and your wife is similar to ones I often wonder about myself .
IF ONLY my Zeiss 85mm diascope could be transformed into a BINOSCOPE with the wave of a magic wand :-)
I've also found , over many years of using spotting scopes , that for medium to long distant terrestrial viewing , MOST of the time , what I consider to be OPTIMAL viewing in terms of overall " ease of view " , " brightness " and " sheer pleasure " comes about when utilising exit - pupils between 4mm down to around 2.5mm .
In fact , with the Zeiss , 20 x 85 to around 40 x 85 gives me the strongest WOW factor , MOST of the time .
A further problem on brighter ( and hopefully warmer ) days will be mirage , or heat haze , which again will be minimised with the lowest possible magnification .
Your quest has been a very interesting one to read , Graham , but for ME , all that bulk and weight would be TOO much to consider lugging around ( my better half being less enthusiastic than yours in sharing my hobby ! )
All things considered , IF I were to decide upon a true BINOCULAR to satisfy this kind of viewing , I would still probably be more tempted by something like the 30 x 90 offering from same Chinese supplier , and mount it on my Manfrotto 055B tripod with Bogen 501 head .
Thanks again Graham for a very welcome addition to my favourite REVIEW site , on CLOUDY NIGHTS , of course !
Regards , Kenny
Posted 07 December 2005 - 04:41 PM
Kenny, being a Trinovid owner and fan, I actually wrote to Leica a few years ago with a proposed binocular design, based upon their large Televid scope. Their reply was interesting, suggesting such a design would be too complex. Well Kowa have done it and I still reckon it can be done even simpler by just joining two straight-through EP scopes together with a hinge, to allow an adjustable IPD. I wish I had the equipment at home to make it possible, but had to wait until something affordable came along. There is no reason why Zeiss shouldn't do something like it....
Ed, turning to EPs I am still apprehensive! There are many likely candidates of very different price and I have yet to produce a short enough list, also find a dealer with the right stock, to venture forth and try some out. Poor light is so crucial to selecting daytime optics that I must make a move this winter, while our daylight hours are shorter than the trading day.
I keep reading through CN topics in search of that eureka moment, but note how many have commented on the quest for that cheap yet superior EP that is never found! I would like to find the perfect compromise somewhere between budget EP and Panoptic that still provides that WOW! Maybe a Radian will do it? Perhaps, but I really want that to keep 4mm apperture!
So little time...
Posted 07 December 2005 - 06:32 PM
but I really want that to keep 4mm apperture!
For that, you may know that I searched out, and eventually bought separately, for about ($75-$80 each) two 26mm Televue plossls. I know, it doesn't meet your wider field criteria. But the light throughput is outstanding. You may recall this pair of eyepieces in the BT100 is the only combination with which I have ever seen the merope nebula. Two modified rubber eyecups (about $3.99) allow me to use them with my glasses on without hitting the metal.
Posted 20 December 2005 - 02:30 PM
but I really want to keep that 4mm apperture!
For that, you may know that I searched out, and eventually bought separately, for about ($75-$80 each) two 26mm Televue plossls.
I do remember reading your account and have been giving your suggestion serious consideration. I could find no TV Plossls available over here, until I had committed to buying alternatives, then found an advert for a pair just a few miles away. (If you saw the news about a huge fuel depot fire here in the UK, we are not far away - the TVs are in the neighbouring town).
A feature of those TV EPs is the simplicity of their construction and high light transmission, which drew me to Harry Siebert's Ultras, one of the few current possibilities. His 24mm has only 3 elements, the 17mm just 4, both having 20mm ER and modest prices. We now await, with mounting excitement, the arrival of a pair of each.
More news when they arrive.
Posted 05 September 2006 - 02:04 PM
More news when they arrive.
Well they have (our 24mm and 17mm Siebert Ultras) and I have written an update of our Review which is available now for your entertainment! It follows after the original text.
We are also about to order 13mm and 9mm Ultras...
Posted 05 September 2006 - 06:26 PM
As a birdwatcher and astonomer I really enjoyed your experiment and your writeup. Thanks
Posted 26 September 2006 - 11:48 AM