29 replies to this topic

[Bkoh]

I guess optics such as coatings and such must come into play as well at least with my eyes because there is a significant difference in bright daylight even between my 10x42 vs 8x42 roof prism binoculars. The 8x42 is quite a bit brighter. My family sees the same difference I do too and always asks me why the 8x42 is so much brighter!

Coatings make a big difference. In bright sunshine, my Swarovski EL 8x32 was brighter than a Leica BA 10x50. Both were in excellent condition with clear optics. But the EL transmission has been measured at 90%, the BA is no more than 77% (measurement of BN, successor to BA). The 20% relative difference was easily visible.

Edited by Bkoh, 19 September 2023 - 11:30 PM.

[binocular]

Coatings make a big difference. In bright sunshine, my Swarovski EL 8x32 was brighter than a Leica BA 10x50. Both were in excellent condition with clear optics. But the EL transmission has been measured at 90%, the BA is no more than 77% (measurement of BN, successor to BA). The 20% relative difference was easily visible.

 

Is there a list somewhere that has many binoculars and their relative brightness numbers?  I'd be really interested in it.

[Bkoh]

Is there a list somewhere that has many binoculars and their relative brightness numbers? I'd be really interested in it.

"Brightness numbers" are only based on aperture and therefore unhelpful. Actual transmission requires detailed measurement.

1. Allbinos.com

This website has a lot of binocular reviews. The recent ones show visible-spectrum transmission graphs so you can see how good the coatings are. You'll need to read the reviews one by one, but in general the saying that "you get what you pay for" holds true.

2. House of Outdoor

This is a Dutch binocular dealer which has done many measurements and comparative reviews. They can be downloaded from:

https://www.houseofo...en-vergelijken/

Again, the data mostly show "you get what you pay for" and "newer/better coatings make a big difference".

[binocular]

Very helpful thanks very much, I'll start reading to get a good grip on this.

[DunninLA]

I forgot to mention for "terrestrial" viewing, sorry about that as I've not dived into the stars as of yet.  So, there's no way image brightness of the b.5 15x56 for daytime use would be close to a decent 8x42, is that correct?

Why not?  For 90% of the day your pupil will be below 2.5mm.  In those conditions Is there any importance to  the  3.7ish exit pupil of the Maven and 5.25 exit pupil of the 8x42? 

 

Also, factor in if the Maven even has 10% better internal transmission, which is likely given the Abbe-Koenig prism design and excellent coatings, then the Maven would be very close in performance even in low light.

 

*edit* oops, I see that question was already answered.  nevermind 

Edited by DunninLA, 20 September 2023 - 01:10 AM.