I have a 10x42 Diamondback I acquired 5-29-07. Here's a series of posts I made about it on another forum:
1. After being shocked at just how well the imaging provided by the 8x30 Leupold Yosemites stacked up against my Pentax 8x32 DCF-WP (FrankD over at BirdForum didn't lie), I embarked on an effort to evaluate newer 8x bins which embodied improved coatings and glass over my older WP model.
Unfortunately there aren't a lot of samples to look at out here in the Black Hills. I'd really need to drive 5.5 hours to Denver or 9.5 hours to Minneapolis to avail myself of a decent selection. [Addendum: I'd forgotten but there is a Cabellas 3.5 hours away] The Vortex Viper with its XD glass and XP coatings seems to have garnered very favorable comments thusfar. Uncertain if Vortex is going to introduce a like featured 8x23 I've emailed a query. The Fury looks promising too but as the web site indicates: specifications are not set yet.
For the heck of it I ran the Vortex dealer locator and was surprised to find a dealer a bit over an hours drive away. I decided to pay him a visit even though he had no 8x bins of any make in stock (he serves the hunting crowd) and the best model within the Vortex/Stokes line he had was a 10x42 Diamondback (formerly known as the Sidewinder).
I took my DCF-WP and used a number of his inventory including a Leica Trinovid 10x42BN to compare with the Diamondback. I gotta tell you that I was most surprised. I have read favorable comments from some buyers as well as hunting optic authority John Barsness about the Sidewinder. Then there is what appears to be the less laudatory test results at optyczne.pl. The barrel distortion was negligible (I really had to look hard to find any at all which was very very minimal) in the 6.6* FOV and the images were bright and crisp. And an epiphany... I could hand hold the puppy without issues unlike a cheap Tasco 10x50 that soured me on 10x + bins decades ago. (I do have a heavy 42 ounce set of Orion 9x63s which I had thought was the limit of what I could reasonably handle.) Yeah there is a difference between the Diamondback and the Leica but very surprisingly it sure wasn't $1300 worth. Maybe the sample optyczne.pl had was substandard. I'm not even sure if there were any substantive changes when Vortex changed the model name either. Suffice it to say that although I was not looking for a 10x42, I was sufficiently impressed that I left the shop with one in hand. I don't think I'll regret this move in the least.
I'd still love to get my hands on the Viper as well as a high grade XD/XP 8x32 I hope they'll market.
2. Bob,
I think the Diamonbacks set a new world record for the widest FOV in mid-priced 10x42 roofs. The question that begs to be asked, and even though no one begged me to ask it, I will: How good/bad are the edges (i.e., at what percentage from the center does the focus sour, and does it drop off steeply or gradually)?
"Edge"
Agreed. The 8x42s have a 420' FOV and these 10x42s with their 6.6* give 345' wide views. It was quite obvious when doing the comparo with the Leica and it's 6.3* FOV. As to your question frankly it has me questioning my soon to be 60 year old eyes because things appear far better than they have a right to be for the price. Sweet spot is generous with focus changing very gradually out at the edges and the total delta is what grabs me as it isn't that great meaning that the focus is ever so very soft at the edges and to me only noticeable in the last oh 15% or so. Heck noticeable is a real misnomer here because it is not distracting in the least. If you don't look for it you don't notice it. I really wish one of you optical gurus lived close so that this particular unit could receive a full blown sanity check. There is no USAF resolution chart available, etc. to really evaluate this pair objectively.
I didn't mention it before but the shop owner and one of his younger hired hands had been comparing this particular piece over the last two weeks to the Leica Trinovid 10x42BN they also had on display. They both were fairly dumbfounded as well. He's a brand new Vortex dealer having received his first stock but 3 weeks ago. No one expects the snap, clarity, color, brightness, FOV, and edge performance this cheap puppy provides. So from three non-experts here we had consensus that the performance exceeded the MSRP of $259.95 and that they gave a good account of themselves side by side with a four figure pair from Leica. Of course this doesn't prove a darned thing nor should it. BTW it's been raining here so I haven't had a chance to star test them yet. All I can say in summary is that I wasn't looking for any 10x42s and simply was so impressed for the tariff that I couldn't walk away without them. Perhaps I simply got very lucky... dunno.
My Pentax DCF-WP 8x32s remain my primary use bins (unless and until I find 8x32s superior enough to warrant acqusition) and I expect these Diamondbacks will serve twilight field and general backup duty. The Leupold 8x30 Sams ride in my hiking daypack and the 9x21 UCFs that used to be in my briefcase before I retired will now go in a car glovebox. The Orion 9x63s are parked near my MN56.
3. First I had a break in the cloud cover last night well after midnight and was able to do a star test as well as observe Jupiter and the Moon with the Diamondbacks. Nice No artifacts, diffraction type spikes, elongations, etc. Viewing the moon really helped refine my answer to your earlier query about focus. Two moon diameters each side constitute the "softer" area. So instead of 15% that'd be what? About 20% per? Regardless I think it still is an excellent result for the price.
I also played around with non optimal eye positioning to see what would happen. On the Moon I got a very thin CA effect with a purple highlight line on the circumference from about one o'clock to 4 and yellow from about 7 to 10. Not quite sure what the significance of the different colors means, but.... Of course with proper IPD and centered eyes none of this is visible.
As for your interest in the Broadwing and mine originally in the Viper, I still would have liked to have handled those too. Brightness? Comparisons with the Leica were done on a semi-overcast day. Dimmer? Sure but not enough for me to feel it was a detriment at all. They are comparable to my first generation Pentax phase coated WP series roofs and much much brighter than my Pentax non phase coated 8x42s. I think you really need to handle the Broadwing and Diamondback to see things for yourself. Eagle Optics, which has the same address and family ownership as Vortex, gives a 30 day return so if there is no local dealer this might be a way to test the waters.
With the better coatings and in the case of the Viper better glass, no doubt there is an incremental improvement in brightness between the Broadwing and Viper compared to the Diamondback. Still I'm a big FOV fan so (witness my Speers-Waler and Russell scope eyepieces), even if there is some marginal brightness difference, if it were a choice between slightly worse edges with a larger FOV or crisper edges with a narrower FOV (which may be the case between these models), I'd be popping for the wider FOV without hesitation.
The 8x30 Leupold Sams? No blackouts for me at all. I haven't consciously compared them to the Diamondbacks so I hesitate to comment about their edges in this context right now. They do offer a nice 7.5* FOV and overall crispness which compares closely to that of my Pentax 8x32s. Biggest issue is some stiction with the focus knob which I'd hoped would have worked out by now but hasn't. Certainly not a deal breaker at all.
The Diamondbacks are of the green flavor and the Sams the dark earth NWTF.
4. Well let's add a second nit to this evaluation. One that may simply be endemic to 10x bins, but still.... The depth of field is fairly shallow requiring much more refocusing than my 8x bins demand. The collective impact of these pre-corrected out of focus views during an extensive viewing session induce much more eye strain and fatigue than I've been accustomed to. Since I haven't been a 10x aficionado it may simply be a matter of my needing to acclimate. I'll let others opine here. In the interim I do not find this an endearing quality.
5. Almost a month now and I've resigned myself to the fact that at a few months shy of 60 I really can't hold 10x bins steady enough to obviate eye fatigue. For short periods ranging from the near hour in store evaluation to other brief stints things were relatively okay. But any extended use ultimately proved uncomfortable. Again it isn't these bins but me.
So with regret I've listed mine for sale in the classified area.
--Bob