Low Light Binocular...
 

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[Closed] Low Light Binoculars?

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OK, I admit it - I have no binoculars.
I need to sort that out but:
a) don't want to spend a fortune
b) would like to use them indoors (at an event in an arena)

I know I will only use them once inside so it's a balance between price, overall quality and low light performance.

As I understand it binoculars are specified as AxB where B is the size of the light-gathering lens and A is the magnification. I guess for use indoors I want a big B and a reasonable A

Any advice?

p.s. I'm not talking about thermal imaging or peeping on my neighbours here.


 
Posted : 14/01/2013 6:56 pm
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Hawke hd.


 
Posted : 14/01/2013 6:59 pm
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a) don't want to spend a fortune

How long is a piece of string?

Regardless, for pretty much anything (in the best Q:'what frame size do I need' A: 'eighteen inches' style) I would recommend 8x30 for 90% of users nowadays.


 
Posted : 14/01/2013 7:03 pm
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Hawke HD

price is an issue.

This has all the hallmarks of a 'wouldn't it be useful if....' purchase where I find them little used in the drawer five years from now.


 
Posted : 14/01/2013 7:04 pm
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10x40 will cover most bases.


 
Posted : 14/01/2013 7:04 pm
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So am I right that the x21 etc ones will struggle more indoors?

Obviously a generalisation - I'm sure you can get good (expensive) small ones and poor (cheapo) big ones.


 
Posted : 14/01/2013 7:07 pm
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warning - this could be complete rubbish, but i was once told that your fully dilated pupil is about 6 or 7mm so to maximise low light performance, B/A as close to 7 would be good. Downside is more weight for bigger lenses, and expense maybe?


 
Posted : 14/01/2013 7:22 pm
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I would recommend 7x50 for low light.

Bulky but very good clear and sharp images.

If you afford it get something made by Steiner.


 
Posted : 14/01/2013 8:28 pm
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As winston_dog says, 7x50 is the magic number. The larger the exit pupil, the greater the performance in low light. Hold a pair of binocs up in front of you, the exit pupil is the bright dot of light you see in the eyepiece lenses, the bigger the better, and 7x50 gives the biggest.
Edit]

supersaiyan - Member
warning - this could be complete rubbish, but i was once told that your fully dilated pupil is about 6 or 7mm so to maximise low light performance, B/A as close to 7 would be good. Downside is more weight for bigger lenses, and expense maybe?

That's about right, divide 50 by 7 gives you an exit pupil of 7.14mm. You can pick up Poroprism binocs fairly cheap, because they're big and heavy, by comparison with Roof prism types. I have a pair of 7x50's that I bought 30-ish years ago for £14. They still work fine, and at night the view through them is amazing.


 
Posted : 14/01/2013 8:34 pm
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You have to be quite young to use an exit pupil of 7mm. Even then its questionable whether you can really get exit that well aligned with the hole in your iris. So lots of astronomey types are topping out at a 6mm exit pupil and even 4mm being OK as the image is then larger which offsets it being dimmer

My daughter and I took 2 pairs of cheap binoculrs to the O2. Lits shows aren't that dark

The pentax 7x20 aren't that great, partly poor construction. But still way better than the naked eye

I think the other were 7x25 and they were fine

Helios do good cheap binos

I,m sure any of these will be fine

http://shopping.rspb.org.uk/binoculars-scopes/binoculars.html?dir=asc&order=price


 
Posted : 14/01/2013 9:41 pm
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If the binocs are really only likely going to be used indoors at large-scale gigs, or outdoors in bright light, then a little pair of roof-prism 7x20's like Pentax or Nikon would be fine. I've got a pair of Pentax 7x20's that must be 20-odd years old, they broke two years ago and I had them repaired, cost £60, about what they cost new. Great pocket-size glasses, perfect for general use. Not multi-coated, but pretty good for what the OP probably needs. Gig lighting is pretty bright, overall, so low-light capability is secondary, really.


 
Posted : 14/01/2013 9:53 pm

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