There was a recent thread here on boosters and, encouraged by some measurements made by Steve (Mooreorless), I went and purchased a Vortex Doubler.
I had taken my 10x42 FLs (good fit) and 7x42 SLCs (less good) with me to the dealer and when I got home was impatient to try out the Doubler on my wife's 7x42 Meoptas. It promptly fell off onto a hard wooden floor suffering a large dent in the front of the housing.
I mailed it to the German importer hoping that the repair would not be too lengthy or costly and was surprised to receive a 'phone call from him the following day explaining that Vortex had an unconditional guarantee, and that he would be sending me a replacement free of charge. This is really outstanding service, particularly in view of the fact that the damage was solely due to my own clumsiness.
Needless to say that the first thing I did on receiving the replacement was to attach a neck cord.
The housing has a stepped internal diameter of 41,5 mm near the field lens and 42,5 mm in front of that and fits over the eyecup and part of the rubber armouring of my Zeiss 10x42 FLs. This was the intented usage anyway but a check with non-Vortex bins before buying is advisable.
I find that 10x bins profit from a support and often use mine on a Manfrotto 685B monopod, 234 tilt head and Leica bino adapter. The 685B is unique in that the largest diameter tube is at the foot and that it is extended by standing on a foot pedal and pulling up to the desired height, where it self locks. It is collapsed again by a grip release.
The Vortex Doubler has a twist-up rubber eyecup, which is rather loose and lots of eye relief, in fact rather too much for me wearing glasses in the collapsed state, but this was solved by putting a rubber O-ring under the eyecup.
I did a very rough measurement of AFOV viewing through the objective lens of the FLs and using the panorama head on my tripod. It came out at about 38°, which doesn't sound much but is comparable to the Swarovski booster and the Zeiss 3x monocular/booster. The Swaro can, however, only be used on Swaro bins and is very slow to deploy and the 3x magnification of the Zeiss is really too much for most applications with the attendant 3x reduction of the exit pupil. It might work well with a 7x42 or 8x56 but how many of those users will be taking a support with them?
The Vortex is quick to deploy, can be used almost universally and is a lot cheaper than the alternatives. On the FLs it did not really compete with my Diascope 65 at 20x (19 mm Panoptic) but that would be an unfair expectation and the bins no doubt also played a role.
It does, however, provide that extra bit of reach for an ID, when one is not carrying a scope and can be thoroughly recommended as a useful and inexpesive accessory.
John
Hi John, That is outstanding service I would say! The Eagle Optics extender I have the ER works with glasses and without. I bought this on close out EO no longer lists them. I wondered if you would get a new one and I am glad you did.
Perhaps I was a little harsh on the Vortex Doubler. On another thread I noted that there was little to be gained by hand-holding it behind the 23x eyepiece of a scope.
However, last night I put my 10x42 FLs on a tripod and aimed them at Saturn.
There were times I thought I could just discern the rings but it was mainly conjecture.
On placing the Doubler behind an eyepiece, though the rings were still very small at 20x but clearly apparent.
Repeating the experiment with a monopod was a no go as it was too unsteady.
This exposes the dilemma of using a doubler or tripler. No-one is going to put 10x bins on a tripod if they can use a scope, and putting 7x or 8x bins on a monopod to enable the occasional use of a doubler is inconvenient compared to hand-held use.
John