Swift EAGLET 825R 7x36 CFT prism (1 Viewer)

And the third nit for me was it has a fraction too much ER (or a curved exit pupil) as I was getting some blackouts (as a moderate myope with moderately close fitting glasses) when moving my eye around the field. Just enough to be annoying.

The usual expedient of adding an O-ring to raise the (fully down) eyecup up a couple of mm fixed the problem for me.

These and Steve's Audubons are probably the only two pairs of bins I would love to explore further at some point. With all of the other 7x's coming out though it is going to be difficult to justify the cost difference. I look forward to hearing both of your comparisons with the Eaglet and the Bushnell/Vortex models.

I've used these very lightly for a couple of days. I'm unable to compare side-by-side with the Discoverers, since those don't focus anymore, but I'm not yet as comfortable with looking through the Eaglets as I was with the Discoverers. The one thing I noticed right away is that blackouts and similar misalignment effects are far more severe with the Eaglets. I am still trying different eye cup positions, interocular distances, and such adjustments which might eventually fix most of that. It's made worse by the fact that I have a tendency to lazily hold my head slightly lower than in alignment with the binoculars - for instance, slightly down if the binoculars are level. The Discoverers were more forgiving of that, I guess. The diopter adjustment on the Eaglets is also stepped unlike the continuous adjustment on the Discoverers, and I have not figured out the best setting yet.

Another thing is that the barrel distortion seems much greater on the Eaglets, though I'm not concerned and will gladly accept barrel distortion for a wider FOV any day. Comparing with the one barrel of the Discoverers I can focus to the Eaglets the FOV doesn't look much different, but I should have compared the left eye only on both to get a real comparison - I had a "stupid moment" when I tested that.

One gripe I always had with the Discoverers was that anything out-of-focus was a bit "weird", and slightly out-of-focus things looked a little different through each barrel. (In-focus stuff was nice and crisp.) Sort of like "bad bokeh" in the camera world. I haven't had much opportunity to notice how the Eaglets compare on this.

See my earlier post about blackouts ... theyhave a bit to much ER for a myope like me but adding O-rings fixes that.

They don't have barrel distortion (no decent bins have barrel distortion ... that would be really bad). They do have rather less pincushion distortion that most bins though which slightly undercorrects for the rolling globe effect which you can see when you pan with the bins. Not sure if this is a part of their "surveillance heritage" (tweaked for for urban use where there are lots of straight lines that they like to keep straight(er) near the edge of field and not a lot of panning) or just the way the bin designer likes it (Holger's paper shows how you can characterize companies by the amount of pincushion they add).

Search for rolling globe or rolling ball in the forum (and on Google) as it's been discussed before (and you'll see why all modern terrestrial bins have pincushion distortion ... it's a feature).

I found it very annoying at the beginning along with the minor blacks outs but I don't find it bugs me so much. I think my visual system adapted (though it does see this effect on other bins now which I didn't before so I suspect I've modified my visual system a bit!).

The "odd bokeh" on the Discoverers I presume is spherical aberration out of focus. Almost like ring-like bokeh around the center of view.

I did notice the " bad bokeh" on the Discoverers,Another thing that was a bit strange is that the Sweet spot seemed to get smaller in size as the binoculars were focused closer..that effect was unique to the discoverer optics(together with the "bad bokeh")
The Discoverers also had a super short past infinity focus travel,perhaps in the 3 diopter range..
Anyway ,they were top of the Bushnell line,and if the focus snapped ,they will fix them for you for free ,almost for sure..If they are discontinued and no parts are available,perhaps you end with one of the new 7x36!!!!!
Good Luck

Kevin Purcell said:

They don't have barrel distortion (no decent bins have barrel distortion ... that would be really bad). They do have rather less pincushion distortion that most bins though which slightly undercorrects for the rolling globe effect which you can see when you pan with the bins.

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Yeah, I just pulled words out of the air to describe the memory of things distoring at the edges. It's just much stronger than the impression I had with the Discoverers. Perhaps I should also note that I never saw the full FOV with the Discoverers because I wear glasses, and the extra distance to my eye limited the FOV a bit.

The "odd bokeh" on the Discoverers I presume is spherical aberration out of focus. Almost like ring-like bokeh around the center of view.

Click to expand...

It's hard to describe it from memory but when things were out of focus it seemed like the two barrels were out of focus somewhat differently and came into focus at different rates, and colors became odd (fringes/auras?) out-of focus (possibly against bright backgrounds only, can't remember) suggesting different colors were effected differently. It just looked weird, and things looked a bit wonky until they were in focus. What was in focus was sharp and colorful, and everything within the DOF was sharp and had a nice binocular depth perception. I didn't pay it much attention to it, though. I always figured it was one of those optical trade-offs.

I should say that I have very little experience with binoculars, so I can't compare to any standard.

With the O-rings in place I just don't quite see the whole FOV ... this is one of those cases were ER and final aperture size seem to not be quite in sync for us glasses wearers.

What is your glasses prescription? I presume you are a myope ("near-sighted").

It's not strong, and both sides are pretty much the same.