What Power Binoculars?

[DavidLGCrawford]

Oh, and of course my references to brightness were "all other factors being equal". Obviously a high quality glass will give a clearer brighter image over a cheap plastic irregardless of lens sizes.

[noelex 77]

Originally Posted by DavidLGCrawford

8x42s must be pretty dark. Fine I suppose in bright sun, but I'd be worried using them in low light. They only have a brightness rating of 5.25.
The "standard" watch binoculars of 7x50 have a brightness of (a little over) 7. That would make me feel a lot safer in lower light situations.
For those who don't know, divide the lens diameter by the magnification for your brightness rating. So in the above two it's 42÷8=5.25 and 50÷7=7.14

It does depend on the size of your pupil.

The above equation gives the size of the exit pupil of the binoculars. So a 7x50 binocular has a 7.1mm exit pupil. If your own pupil size is say 6mm under dull illumination there is no extra light entering when going from binoculars with a 6mm exit pupil to 7.1mm.

In practice it pays to have a little leeway to compensate for some misalignment, but few adults have a 7mm pupil so a slightly smaller objective lens (or higher magnification) is fine.

You can measure your own pupil size.

The 7x50 rule is good guide as to the ideal size for boating. The 50mm objective is a bit larger than most people can use, but the extra weight and size is not so important for marine use. However, you should not be put off 7x42mm say unless your pupil size is large.

The 7x magnification is a good compromise for non stabilised marine use, but it sometimes quoted as golden rule. We all sail on different sized boats with very different stability. There are also personal differences depending on how steady you can hold the binoculars.

There are a lot of optically much better binoculars than the typical marine offerings and often these are in non 7x50 models. My own binoculars are 8x50 so it pays to widen your search.

Personally I find 10 x too high, 7 is a bit low and about 8 is ideal, but your results will vary.

[cabo_sailor]

For what it's worth. I have a pair of Fuji 7x50, a pair of 14x40 image stabilized and for years used my father's 7x50 Steiners. If I had to pick just one pair, it would be the Fuji's. They are extremely bright, you would almost think they are night vision. They are admittedly heavy, but that tends to improve image stability the same way as a target pistol.


The Steiners were much darker even in broad daylight than the Fuji's.

The stabilized binocs are fun to play with in broad daylight but when the light is going, they haven't been too useful.


No technical data, purely subjective. Maybe it will help narrow the field. Oh, two more items. First, I've had these glasses for many years and other companies are constantly improving. Second, if you wear glasses see how long the eye relief is. I hate to be putting glasses on and off to use binoculars.

Regards
Rich


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[roverhi]

Have a Steiner 7x50, not the super expensive commander version. Works great for most things at sea and the weight isn't too much to hold for long periods.

Bought a used pair of Fujinon/Nikon 14x40 stabilized binoculars. The stabilization really makes them useful for seeing small or distant objects. Turn on the stabilization and they lock on to what you are trying to see. Unfortunately, they are heavy and using them much more than a minute straight gets tiresome. Haven't tried them in low light/night situation so don't know how they work under those conditions.

[FamilyVan]

I have 3 pairs on board, a 7x30 and two 7x50's. I usually keep the 7x30 and the 7x50 in the cockpit with me. I generally go for the 7x30's because they're so easy to focus.

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[Orion Jim]

Nikon 7x50. Works for me, ocean passage proven.

[svmariane]

El-Cheapo West Marine 8x32 for harbour watch, shore diversions.
My wife calls them her "spyglasses" and prefers their light weight and one-finger focus.

Steiner "Marine" 7x50 for passage making / harbour entrance, etc..
You know, anytime it's serious.

I'm partially colour blind & wear eyeglasses. My experience is that the Steiners allow me to differentiate red/green buoys, pick up range markers, et al, quickly and clearly. They also work well at night - though not as good as thermal imagery units!

Went for a day cruise aboard a friend's sailboat and tried his Fujinon 10x50 binocs..... Nice kit, but didn't work very well for me. Purely subjective, of course.

Image stabilized binocs are only on my dream list.

James

[nukem]

A larger exit pupil is a benefit up to a point. If your eye cannot gather the light delivered by the optics a larger exit pupil is wasted. As we age (myself especially it would seem) our vision dims because our pupils don't adapt as well as they once did.

I like Celestron for economy but would love to be able to buy Fujinon...