10X50 vs. 7X50

Izar187 wrote:
I would suggest a telescope store or a camera store that sells
high end
binos. I would stay away from sporting goods stores as the binos that
they
sell are usually Bushnell junk.


One doesn't need _high end_ to get started with binos.
Sporting goods retailers do sell them of course, because outdoor gear
gets just
as expensive as telescope gear. If it's junk, then don't buy it.
Compare
before buying!
john

One doesn't need high end, but then again, if one sticks to porro prism
binocs there is a good return in performance for a rather modest price.
I am something of a fan of the Swift Audubans. 8.5X44 with a really
wide field and good on axis performance. The 8.5X is usefully larger
than the 7x but still very hand holdable.

--
Bill

I don't worry about wasted exit pupil. The big exit pupil on the 7x50 means I
can shake and wobble a bit and my eye stays in the sweet spot. Not so for
10x50. A long eye relief model like the one on andahammer.com works well with
glasses and is spectacular without - clear to the edge of the field. Also weigh
well under a pound IIRC. I can weigh mine I anybody wants to know.

-- Charlie Springer

wrote:

Zoom binoculars have historically been optically inferior to fixed
power bioculars.
So the fixed power binos have always been recommended over zoom types.
The same has usually held true with fixed versus zoom telescope
eyepieces.
Perhaps the high-end zoom eyepieces have broken the rule?

Regarding allen wrenches (UK allen keys) I supopose you have noticed
they are hexagonal?
It seems too obvious to point out that they must be larger across the
"points" than they are across the flats.
Presumably deliberately laying the "handle" flat on one's cheek largely
eliminates this error? ;-)

Chris.B

I have some Celestron 10x-30x zooms that are at least as good as my B&L
10x50 fixed ones.


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"Regnirps" wrote

I don't worry about wasted exit pupil. The big exit pupil on the 7x50
means I
can shake and wobble a bit and my eye stays in the sweet spot. Not so for
10x50.

I agree with you in principle, but not in specifics. I have trouble staying
in the sweet spot with 9x25's. With 8.5x44's and 15x70's I have no such
problems with their exit pupils.

Howard Lester

The quality of binoculars varies, even within the same model. The goal of
quality control is not to make every item the same, but to make them close to
some standard, so some deviance from the ideal is to be expected. Take a
hundred binoculars of one particular model from one manufacturer, measure the
variance in image clarity, do this for every model from every manufacturer, and
you'll find the fixed power ones have more consistent quality than the variable
ones. This is because it is particularly hard to make variable power optics and
keep those optics in line. Not impossible, just more difficult, so binoculars
in a particular price range can be made to tighter tolerances if they're fixed
power rather than variable power.

Yes, you're moving the optics already to focus the binoculars, but adding more
moving parts to the assembly makes it harder to keep the optics in line.

Also, isn't it true that in making variable power optics in general, it's harder
to keep image clarity across the various powers? Something about different
powers require different surfaces on the optics themselves, not just changing
the distances between them? I mean, look at eyepieces. As the focal length
gets shorter, the spacing between the elements of the eyepiece gets shorter, but
the focal length of the various elements also gets shorter, and this requires a
change in their surface curvature, doesn't it? The main telescope doesn't have
to change, since it is set to a fixed focal length.

--
Sincerely,
--- Dave
----------------------------------------------------------------------
It don't mean a thing
unless it has that certain "je ne sais quoi"
Duke Ellington
----------------------------------------------------------------------

"starman" wrote in message ...
wrote:

Zoom binoculars have historically been optically inferior to fixed
power bioculars.
So the fixed power binos have always been recommended over zoom types.
The same has usually held true with fixed versus zoom telescope
eyepieces.
Perhaps the high-end zoom eyepieces have broken the rule?

Regarding allen wrenches (UK allen keys) I supopose you have noticed
they are hexagonal?
It seems too obvious to point out that they must be larger across the
"points" than they are across the flats.
Presumably deliberately laying the "handle" flat on one's cheek largely
eliminates this error? ;-)

Chris.B

I have some Celestron 10x-30x zooms that are at least as good as my B&L
10x50 fixed ones.


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