Hello All,
Another reason to like binos for astronomy occurred to me in the wee hours this morning: It seems to me that all other things being equal, binos should show less color than single objective spotters or other refractors. My reasoning is that when the light gathering gets split between two objectives totalling the same area as one, the lenses don't have to be as fast to produce the same FOV.
Take 16x70's, for example, which have the same light gathering area as a single 100mm objective. Let's say their focal length is 300mm (I'm guesstimating since the f.l. is seldom given for fixed-mag binoculars). Dividing 300 by 70 yields f/4.3, already a fast lens. Now try to maintain the same focal length with a single 100mm objective, and you would need an f/3 lens! More bending equals more color, right? Or am I missing something here?
Thinking too much,
Milt
Another reason to like binos for astronomy occurred to me in the wee hours this morning: It seems to me that all other things being equal, binos should show less color than single objective spotters or other refractors. My reasoning is that when the light gathering gets split between two objectives totalling the same area as one, the lenses don't have to be as fast to produce the same FOV.
Take 16x70's, for example, which have the same light gathering area as a single 100mm objective. Let's say their focal length is 300mm (I'm guesstimating since the f.l. is seldom given for fixed-mag binoculars). Dividing 300 by 70 yields f/4.3, already a fast lens. Now try to maintain the same focal length with a single 100mm objective, and you would need an f/3 lens! More bending equals more color, right? Or am I missing something here?
Thinking too much,
Milt