Date: 11/16/18 9:48 am From: Christopher Hill (via carolinabirds Mailing List) <carolinabirds...> Subject: Scope comparison
Since optics queries are a recurring thing on the list I thought I would summarize a test I did with a bevy of scopes just now. If you don’t care, you know where the delete button is.
Swarowski AT-80 with 20-60 zoom eyepiece, 80mm objective maybe 15 years old.
Kowa TSN 774 with 25-60 zoom eyepiece, 77mm objective 5 years old
Kowa 554 with 15-45 zoom eyepiece, 55mm objective, new
Vortex Razor HD with 22-48 zoom eyepiece, 65mm objective, new
Bushnell (spacemaster type) with 15-45x eyepiece, 60mm objective 15-20 years old.
We set up a couple fresh dollar bills in the shade (dollar bills have about 17 different font sizes and patterns, good for fine comparisons) and some pastel colored small things and lined the scopes up 45 yards away or so.
Results: the two big scopes up top killed the competition, and between them the newer Kowa was the nicer, sharper one. That’s the most important result because the Kowa is mine. :-)
Next tier was the other three scopes, and I would rank them
Vortex Razor HD
But the differences were not as great as I expected, and in one case were in a different direction than I expected. I thought the old Bushnell would be WAY worse than the brand new Kowa and Vortex, but the Bushnell was quite sharp, only a small step down. I expected the bigger Vortex to be great, partly because I have heard good things about that scope, and it’s significantly bigger, but it had noticeable chromatic aberration at high contrast (orange/purple fringing), and it didn’t seem sharper or brighter or better at seeing colors than the Kowa, which is MUCH tinier. I had even kind of expected the new Razor might be sharper than the old Swarowski, but no, size won out in that comparison.
So I’m happy for the results. For our purposes, I the little Kowa is great, the Vortex is also fine but a lot bulkier, and in a pinch the Bushnell would even do. We’re doing a lot of work with scopes on window mounts - small is good. But I can’t really love a scope like the Razor that has noticeable flaws like the color fringing, even if I will use it (gladly). I had the same issue with some Vortex 10x binocs I bought recently. Fine, sharp, but I don’t love them (they also have color fringing in bright contrasty situations like a backlit bird on a wire). If I really cared I would repeat the test on a dim cloudy twilight, where the small Kowa might show weakness, but that’s too much effort and I have the answers I need.