Allbinos, new Nikon binocular reviews (1 Viewer)

Arek · Mar 9, 2015

Even in case of the same transmission in both 8x32 and 8x42 models, the latter should give the bighter image due to the higher surface brightness.

Situation with Zeiss has just changed a little bit. Polish dealer will send me Terra ED 10x42 for testing. So a least one Zeiss will be tested

Tom Bombadil · Mar 9, 2015

Arek said:
Even in case of the same transmission in both 8x32 and 8x42 models, the latter should give the bighter image due to the higher surface brightness.

If one is out in bright sunlight and their pupil size is down to 2.0 mm, then wouldn't you be using only 16mm of the objective, through an 8X bino? That is, in an 8x32 the exit pupil is 4.0mm, and through the 8x42 it is 5.25mm. But if your own eye pupils are only open 2mm, then most of the light gathered by the objective will go unused. Same for if you had an 8x56.

Wouldn't the perceived image brightness be the same through 32 or the 42 if they had the same transmission?

If your pupils were open to 6mm, then it would make a big difference.

Arek · Mar 11, 2015

Tom, you are absolutely right. In case of making observation during sunny day when your pupil is 2-3 mm wide, there should be no difference between 8x32, 8x42 and 8x56 binoculars. However, in bigger bino you collect light from the exact center of the objective lens where optical aberrations are smallest. Thus the image form bigger bino, even in sunny day, may look slightly better and sharper.

Pileatus · Mar 11, 2015

Arek said:
Tom, you are absolutely right. In case of making observation during sunny day when your pupil is 2-3 mm wide, there should be no difference between 8x32, 8x42 and 8x56 binoculars. However, in bigger bino you collect light from the exact center of the objective lens where optical aberrations are smallest. Thus the image form bigger bino, even in sunny day, may look slightly better and sharper.

I've seen images in so-called "bigger bino's" (larger objectives) that don't begin to compare to a few 32mm's I've owned and used. Also, are there different exact centers?

What did you mean by higher surface brightness in post 21?

FrankD · Mar 11, 2015

John,

I could be wrong but I think he is talking about a discussion of illumination of the exit pupil. I have vague recollections of reading about it over on Cloudy nights but I think it was more in reference to roofs versus porros rather than differences in objective diameters. I could be wrong of course.

Pileatus · Mar 11, 2015

FrankD said:
John,

I could be wrong but I think he is talking about a discussion of illumination of the exit pupil. I have vague recollections of reading about it over on Cloudy nights but I think it was more in reference to roofs versus porros rather than differences in objective diameters. I could be wrong of course.

That discussion assumed vignetting was blocking light from the edges of the objective. When discussing a 4mm versus a 5mm exit pupil I doubt that's a concern when your eye is at 2.5mm. Mystery terms do, however, provide nice cover for one's opinions.3

Allbinos, new Nikon binocular reviews (1 Viewer)

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