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25585

Known binocular field lenses with no stop down or vignetting

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25585    823

You ofter read about how a 50mm field lens is effectively a 42mm due to vignetting or stopping down internally. 

So which models or ranges have been proven to give the full aperture's light at the eye lens end?

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Peter Drew    6,243

I think you could say, any that you pay a premium price for.  It could be argued that a cheapish 15x70 that actually works at 65mm is still going to collect more light than 40mm binocular operating at full claimed aperture.    :icon_biggrin:

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BinocularSky    1,798
On 27/03/2018 at 11:08, 25585 said:

Many thanks. I will avoid Oberwerk bins!

Oberwerk are just branded United Optics kit - as are Helios, Strathspey, TS, RA, Orion, APM, Lunt, and lots of other binocular brands.

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25585    823
2 hours ago, BinocularSky said:

Oberwerk are just branded United Optics kit - as are Helios, Strathspey, TS, RA, Orion, APM, Lunt, and lots of other binocular brands.

Must be different standards. Helion Lightquest - I have an 11x70 pair which are excellent, but some from the brands you listed, are not so good.

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BinocularSky    1,798
On 28/03/2018 at 18:29, 25585 said:

Must be different standards. Helion Lightquest - I have an 11x70 pair which are excellent, but some from the brands you listed, are not so good.

Different models are made to different standards and, even within the same model, branders can specify different levels of anti-reflective coating, prism material, eyepieces, etc. Even the same branded range can vary (eg Helios Apollo coatings changed)

For example, the Oberwerk Ultra line is the same as Helios Apollo, Orion Resolux, General Hi-T, and probably several more : all United Optics BA8. All good kit.

 

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BinocularSky    1,798
6 minutes ago, 25585 said:

Not sure, but I'd be surprised if there were any significant differences.

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Merlin    96

We also need to take into account the user's age when considering binocular vignetting. As we age, the pupil shrinks, so that a 10X50 binocular, for example, might only be equivalent to the light collected by a 8X30 glass.

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trynda1701    87
Posted (edited)
On 27/03/2018 at 10:55, BinocularSky said:

That link isn't working now. Brings up the error "We could not find the attachment you were attempting to view". Has something changed?

 

I know I've seen you mention on the forum about binos you know are stopped down, Steve. Would it be a resource if you had a consolidated list on The Binocular Sky site?

Edited by trynda1701

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BinocularSky    1,798
On 10/04/2018 at 16:55, trynda1701 said:

That link isn't working now. Brings up the error "We could not find the attachment you were attempting to view". Has something changed?

Either that, or I've messed up. I'll see what I can do and post back here. Might not be till tomorrow, though.

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On 4/4/2018 at 17:31, Merlin said:

We also need to take into account the user's age when considering binocular vignetting. As we age, the pupil shrinks, so that a 10X50 binocular, for example, might only be equivalent to the light collected by a 8X30 glass.

Maximal dilation does reduce with age, but there is a lot of variation. Between 50 and 59 years of age, 5.77 mm is the average value, I read somewhere, but but that is just an average. Even at age 90, your pupil does not shrink far below 5mm, and many people manage more. With an exit pupil of 5 mm for 10x50 binoculars, you should be OK, even at old age, but 7x50s would not be optimal.

 

pupil_size_chart(Mar2011).jpg

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25585    823

To get a larger FOV and sufficient eye relief, 7x50s are more numerous at reasonable prices, maybe because they are still the classic standard magnification. They have better depth of field, better 3D views because of that and are steadier for hand holding. 

Not always light e.g. Fujinon's upmarket range. Marine 7x50s are especially good for flat field, no astigmatism, anti-haze & light transmission. 

Name not seen on SGL much is Baush & Lomb/Bushnell. Their marine 7x50s have the above qualities & are affordable. 

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On 4/12/2018 at 21:09, 25585 said:

To get a larger FOV and sufficient eye relief, 7x50s are more numerous at reasonable prices, maybe because they are still the classic standard magnification. They have better depth of field, better 3D views because of that and are steadier for hand holding. 

Not always light e.g. Fujinon's upmarket range. Marine 7x50s are especially good for flat field, no astigmatism, anti-haze & light transmission. 

Name not seen on SGL much is Baush & Lomb/Bushnell. Their marine 7x50s have the above qualities & are affordable. 

7x50s can be great, but if you have slight light pollution, or you are older, the large exit pupil of 7.1mm is a bit of an issue. I have an older pair of 7x50 (Yashica built), and they are great in dark areas, but I prefer the 10x50s (mine old Bressers actually have a 7 deg FOV) when observing from my suburban garden, if I want to go for a wider field.

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