Thread: Vintage Binoculars

Google Genius, John! Field of view!

Talk to me about the 5x30 and the 7x50?

The first number is magnification. So Images in Bob's pair of binoculars appear 8 times closer. I think the second number is the diameter of the lens. The large the lens the more light is gathered which makes seeing in low light possible. It probably makes the images clearer but I'm not sure.

Fun fact I learned in astronomy: you can see the moons of Jupiter with 10 power binoculars.

Here is another tidbit for ya Tom. If you take the power of the binos and divide that into the size of the objective/front lens you get the exit pupil size at the ocular/back lens. That tells you something about the amount of light the binos can get to you eyes. Your 7X50 has a 5mm exit pupil so it should be better in low light than my 8X30 which has an exit pupil of 3.75mm. Older eyes may not be able to use more light than a 5mm exit pupil provides.

The fly in the ointment is that not all binos with the same exit pupil size will allow the same amount of light through the exit pupil. That depends on how good they are at transmitting the light through all the different pieces of glass in the bino.

Sorry, I know information overload. Couldn't help it.

Bob

Dammitt! The size of the apertures! Well- Done!

Indeed, what is in-between makes a big difference.
These old things work pretty well, it seems!

I've used a similar pair of Nikon binoculars to the ones in this thread. My Dad bought them in the early 1980s to take on safari in Africa. They are a joy to use. I have some of the newer, cheaper Nikons and the quality isn't there.

One other thing that may be important in some cases is how flat, distortion free, the field of view (FOV) is. Most binos are good in the center but deteriorate towards the edges. Some start deteriorating sooner than others. Look at a vertical line in the center of you view and it should be straight. As you move that straight line to the edges you will see it bend and the bending is usually worse in wide angle binos just like in wide angle camera lenses.

Bob

The bottom line is when you look through a pair of real quality binos (and the same applies to all optics whether microscope, telescope, binos or hand lens) the appliance you are using essentially disappears and it seems like it is an extension of your eyes. If you have the opportunity, go to an optical or good sporting-goods store and look through a pair of Steiners for instance and you'll never want to use cheap optics ever again.

For the price of a good custom razor you can get a really high quality pair of binos and like a razor it's a forever purchase. (and you don't have to hone it or strop it)

I tried Swarovski binos in a large outdoor store and was blown away.

Yep! It's what you see which seems important!

Lots of tech involved these days!

Stop and think for a moment how similar binos are to razors. Instead of grinding steel you are grinding glass of varying qualities and like polishing the steel you are polishing the glass and just like a razor there is a precise geometry to the steel and the same with the glass.

Then like the razor is mounted in scales the lenses are mounted in the metal frame just that this has to be more involved so the lenses don't go out of alignment so it has to be shockproof and maybe water resistant and various coating are involved with the lenses and the frame.