I understand what chromatic aberration is, and both fluorite glass and a longer focal length reduce it. I have a Zeiss Victory 8x42 T*FL which has fluorite glass and a Leica 8x20 Ultravid (not sure if it is fluorite or not).
During a midsize binocular search last summer, I tried out about 6 different pairs including a Zen Ray 7x36 EDII and a Leupold 8x32 Gold Ring non-HD. These two were the best but there were several things with the Zen Ray that I didn't like - especially it's long length. Although it did have a bit more "pop" in the center of the view, I went with the Leupold because of it's ergonomics, size, quality of workmanship, bla bla, whatever, (mainly just mad at the Zen Ray).
So could one assume if a binocular is not an alpha brand that uses fluorite glass, and isn't overly long in length, that it would have to have some CA or are there other factors as well? Thanks.
tp,
Just to point out a couple of things... the "fl" you often seen referred to in advertising/literature when it comes to binoculars is actually referring to fluoride or extra low dispersion glass. "Fluorite" actually isn't a glass and isn't utilized in any consumer binoculars that I am aware of....and, actually, there are only one or two scopes on the market that utilize it.
Just wanted to avoid further confusion for anyone reading this thread who isn't necessarily an optics nut like the rest of us.
To answer your question, my experiences tells me that there are other factors besides the two you listed which influence how much of any given type of CA is present in the image. For example, I just picked up a non-ED, non-phase coated roof prism binocular with an extremely short overall design. I have not "pressed" the binocular to see if I could get CA to be produced but under regular use I have yet to detect a great deal of it.
Just my two cents.
One thing that's "clear" from my own experience with ED binoculars and from reading dozens of posts by others is that just because a binocular has ED glass do not expect another bin with the same configuration that also has ED glass to have the same level of CA control. Other factors such as focal length and the quality of the other glass elements enter into the "equation".
So some bins with ED glass control CA better than others regardless if they call it FL, HD, or ED.
I've also noticed with the two ED bins I've used in the past two years both show the best CA control slightly above the center rather than right at the center. Not sure if this is just a coincidence (two different brands, two very different price points, two different sized objectives, and 7x and 10x, respectively), or if it has to do with my eyes.
I'm glad you used the word "pop" to describe the EDII view. ED glass does more than just control CA, by greatly reducing the prismatic scattering of colors, it provides sharper, brighter views that "pop".
Why are you "mad" at Zen Ray?
Brock