About these Meade binoculars....

I have just bought a pair of the Mead 10x50 binoculars not only because of
the price but because with my other bins I couldn't see though both lens so
had to close one eye. Also I had to take off my glasses to get a decent
sized image.

I am very pleased with my new bins. However, all this talk about using
them with glasses and the technical stuff about optics prompts me to ask
about using bins with variable lens glasses. I would guess that using them
with ordinary glasses would be OK because the lens would be the same curve
and thickness throughout but what about variable focus lenses?

Regards.

Bill Ridgeway

In ,
aquaria typed:

I've got a similar prescription to you (astigmatic too, but I think
that's beside the point) and I've never been able to use binoculars
without my glasses; partly I think purely because it's a weirdly
counter-intuitive thing to do and I convince myself I can't (and I
hate the transition form glasses to not-glasses) but also in a few
cases definitely because I just can't far enough focus through the
bins. I have no explanation, but I have noticed it is always related
to cost.

I'm only -2.0 but have found one pair of expensive bins that I couldn't
focus without glasses. They happened to be a very posh N2 filled pair sold
at a high price by the RSPB for birding. Apparently, they are designed to be
able to focus in to shorter distances than many binos. Fine, but I couldn't
focus distant objects without my glasses.

Jo

On Thu, 28 Apr 2005 16:04:32 +0100, Holly in France wrote:

I'm crossposting this to uk.sci.astronomy and uk.rec.birdwatching since
these binoculars have been discussed on both groups, hope that is OK with
everyone.

I bought two pairs of these binoculars this morning and I have a slight
problem with them. I am just about to research this on the net but I doubt
these are the only binoculars which cause this issue, just the first I've
come across and I'm sure I'm not the only person affected, so I thought it
worth posting.

I am very short-sighted, -8.5, -9. I know very little about optics but I
have two other binoculars and a telescope and have used microscopes,
rifle-scopes, sights on engineers levels etc. On all of these I can focus
both with and without my glasses. I usually prefer to take the glasses off,
I get a clearer focus and avoid light getting in at the sides of the
eyepieces. If using bins with the family I tend to leave my glasses on,
makes it easier for passing them round etc, we don't have to re-focus so
much and since they all have very good vision we don't usually worry about
the left/right eye difference adjustment. For this purpose, which is mainly
why I bought these two pairs, they are excellent. But..... I am completely
unable to focus these with my glasses off at a distance greater than about
30m. Have rtfm, which talks about how to use them with glasses, but as far
as I can see (it's all in French) it doesn't explain if it is possible to
use them without the glasses.

Does anyone else have the same experience with these or other binoculars
with similar magnification, or please could someone explain whether this is
normal and why it happens?


Im not as short sighted as you (around -5 I think but with about 2 dioptre
astigmatism so I cannot use bins without glasses).
Anyway, tried my Zeis 7x42 and Nikon 10x40HG bins-both high end,last
night without glasses and could barely reach infinity with them. I also
tried Vixen 11x80's and they were not as good, I coulnt quite focus on
infinity.
As far as close focussing goes, there is some advantage, but its
only about two feet for me, so there is no real benefit.
Phil

On Fri, 29 Apr 2005 13:05:03 +0100, Phil wrote:

On Thu, 28 Apr 2005 16:04:32 +0100, Holly in France wrote:


Does anyone else have the same experience with these or other binoculars
with similar magnification, or please could someone explain whether this is
normal and why it happens?


Im not as short sighted as you (around -5 I think but with about 2 dioptre
astigmatism so I cannot use bins without glasses).
Anyway, tried my Zeis 7x42 and Nikon 10x40HG bins-both high end,last
night without glasses and could barely reach infinity with them. I also
tried Vixen 11x80's and they were not as good, I coulnt quite focus on
infinity.

As far as close focussing goes, there is some advantage, but its
only about two feet for me, so there is no real benefit.


Hmm, this has got me thinking. Before I make a fool of myself and say any
more I have a question. How far is 'infinity' as far as binocular focus is
concerned? I suspect this depends on the magnification/power of the bins,
I'll have a google.

I tried the Meades last night too, lovely clear dark night here, luckily.
They are much better at night than in the daytime as far as light getting
and reflections bothering me are concerned. I left house lights on and the
window shutters open to check this. I was very pleased with them although
will have to practice holding them steady or fish out a suitable tripod!
They will be perfect for locating objects which I then want to look at with
the telescope. So, for me, a better buy for astronomy than for
bird/wildlife watching.


--
Holly, in France
Holiday home in Dordogne
http://la-plaine.chez.tiscali.fr

On Thu, 28 Apr 2005 21:35:47 +0000 (UTC),
wrote:

On 2005-04-28, aquaria wrote:
In message , Holly in France
writes
I'm crossposting this to uk.sci.astronomy and uk.rec.birdwatching since
these binoculars have been discussed on both groups, hope that is OK with
everyone.

I bought two pairs of these binoculars this morning and I have a slight
problem with them. I am just about to research this on the net but I doubt
these are the only binoculars which cause this issue, just the first I've
come across and I'm sure I'm not the only person affected, so I thought it
worth posting.

I am very short-sighted, -8.5, -9.

I've got a similar prescription to you (astigmatic too, but I think
that's beside the point) and I've never been able to use binoculars
without my glasses; partly I think purely because it's a weirdly
counter-intuitive thing to do and I convince myself I can't (and I hate
the transition form glasses to not-glasses) but also in a few cases
definitely because I just can't far enough focus through the bins. I
have no explanation, but I have noticed it is always related to cost.

I *have* to use spectacles with binoculars due to astigmatism...
everything is blurred at whatever the distance. Short and long sighted
people can normally use binoculars/telescopes without using their
glasses,

Apparently not according to many people here, although with the
bins/telescope that I have used up until now this would appear to be the
case.

this does not apply to anyone with corrective glasses for
astigmatism.

Quite. Although actually I do have corrective glasses for astigmatism,
can't remember how much, but when I got contact lenses (before weighted
ones became available) I was just on the limit of being able to use them.
In fact I have never been able to see as clearly with contact lenses, which
is why I choose to wear specs. Have never been sure if this is caused by
the astigmatism or is just a general issue with contact lenses. I think
that perhaps when one gets used to good corrected vision one doesn't want
to accept a loss of detail.

Now one of the great things about these cheap Meade binoculars (and it
is only one of the great things) is the large eye relief that is
obtained with the eyepiece optics used. This means anyone who *must* use
spectacles still has the normal wide field of view that non-spectacle
wearers enjoy.

Well, I'm afraid I have to disagree with that. I have just spent some time
with the Meades, looking at things at various distances up to about 50m
although I can only focus properly up to about 30m without the glasses.
Have tried with and without glasses, with the rubber flaps folded and
unfolded. It seems to me that the field of view is wider without the
glasses. But that wasn't my point, I wouldn't have noticed until you said
it. The point is that I can see (assuming I can focus!) better through
binoculars without my glasses than I can with them. I *think* this is
mainly due to more light getting in around the edges.

Without this long eye relief then it is like looking down
two seperate lengths of drainpipe with a greatly restricted field of
view.

Yes.

Meade have provided a superb pair of binoculars at a ridiculously low
price. They have made these binoculars so that those who need spectacles
can use them with the same benefit as non-spectacle wearers.

Yes, and well done to them for having done it.

Some are criticising them for having done something of great benefit.

Hang on a minute. Nobody has criticised them for this as far as I can see,
I certainly haven't, I said I was glad that I had bought them.

Leave your spectacles *on* and enjoy the benefit these binoculars give.

I accept completely what you are saying about their usefulness for people
who must use their specs. But...it seems to me that the point about buying
binoculars, telescopes etc is to enlarge and improve the view of whatever
one is looking at. People buy better instruments, pay alot more money
sometimes, to get the best possible view. If I can improve the view by
removing my glasses, which I most definitely can in most cases, then that
is what I prefer to do. I understand that unfortunately you and others
don't have that option. You can't see the difference in practice, but I
can.

The binoculars are designed to enable spectacle wearers to use them..
so some people take their specs off and then decry the binoculars !!!

No one is decrying the binoculars. I have never tried (other than in shops
when I have decided against cheap ones) any other 10 x 50 binoculars. I
might well find that others don't perform any better when used without
glasses than the Meades do with the glasses, particularly at longer
distances. But, for now, I still feel that anyone who *is* able to use bins
without specs, and who prefers to do that because they get a better 'view',
would be better investigating other options before they chose these
particular binoculars. Except.....if someone was buying solely on price,
in which case I doubt they would find anything better than this for the
money.



--
Holly, in France
Holiday home in Dordogne
http://la-plaine.chez.tiscali.fr

"Holly in France" wrote in message
...

Hmm, this has got me thinking. Before I make a fool of myself and say any
more I have a question. How far is 'infinity' as far as binocular focus is
concerned? I suspect this depends on the magnification/power of the bins,
I'll have a google.

Hi Holly,

Infinity is a long way away when talking distances :-), but when talking
about being focused at infinity, it means the light "rays" from the object
being observed can be considered to be parallel, i.e. not diverging from a
source closer to the observer. In reality, there is little difference
between being focused at infinity, and being focused on something a few
miles away.

Very best wishes, and clear, dark skies.

--

/Paul B, York, UK.
http://homepages.tesco.net/paul.buglass/astrohome.htm
York Astronomical Society
www.yorkastro.co.uk

Holly in France wrote:
very pleased with them although will have to practice holding them
steady or fish out a suitable tripod!

Good grief, do they have a tripod mount too?! I'm going to have to search
around some more Lidl stores...

Mike.
--
If reply address = connectfee, add an r because it is free not fee.

On 2005-04-28, Bill Ridgeway wrote:
I have just bought a pair of the Mead 10x50 binoculars not only because of
the price but because with my other bins I couldn't see though both lens so
had to close one eye. Also I had to take off my glasses to get a decent
sized image.

I am very pleased with my new bins. However, all this talk about using
them with glasses and the technical stuff about optics prompts me to ask
about using bins with variable lens glasses. I would guess that using them
with ordinary glasses would be OK because the lens would be the same curve
and thickness throughout but what about variable focus lenses?

Regards.

Bill Ridgeway


Hi Bill,
I use vari-focal (tri-focal in USA) lenses and I find no problem
with using these binoculars. If the focus is set when using the long
distance part of the lens then if the head is moved in relation to the
eyepieces you would then be using the intermediate distance part of the
lens... a slight touch on the focusing will restore the crisp image
again... alternatively move the head slightly again :-)

Reg

On 2005-04-29, Holly in France wrote:
On Thu, 28 Apr 2005 21:35:47 +0000 (UTC),
wrote:

On 2005-04-28, aquaria wrote:
In message , Holly in France
writes
I'm crossposting this to uk.sci.astronomy and uk.rec.birdwatching since
these binoculars have been discussed on both groups, hope that is OK with
everyone.

I bought two pairs of these binoculars this morning and I have a slight
problem with them. I am just about to research this on the net but I doubt

I am very short-sighted, -8.5, -9.


I *have* to use spectacles with binoculars due to astigmatism...
everything is blurred at whatever the distance. Short and long sighted
people can normally use binoculars/telescopes without using their
glasses,

Apparently not according to many people here, although with the
bins/telescope that I have used up until now this would appear to be the
case.

In the majority of cases most telescope and binocular eyepiece optics
will allow long/short sighted people to use them without also using
their spectacles. This is not so for those with astigmatism and/or
more severe eye defects and eyepiece optics can vary depending on
model/manufacturer.

If you are short/long sighted then using eyepiece optics that have been
designed to give "long eye relief" will probably cause a problem if you
try to use them without your spectacles.... the eyepieces have been
designed specifically to work properly for people with normal vision
and those people who wear spectacles - for whatever reason.

The eyepiece optics are designed to produce a cone of light which then
brings the object viewed to focus at a *specific* point behind the
eyepiece. The "long relief eyepiece" has a broader cone of light and is
designed to bring the image to focus further behind the eyepiece... this
allows for the increased distance of the eye away from the eyepiece due
to the spectacle lens (distance from eyepiece to lens and distance from
lens to eye). The "long relief eyepiece" works normally for those with
normal sight, it will however work against those with long/short sight
who remove their spectacles.

It is too complicated to explain here, apart from the very simplified
explanation above. If you can get hold of a good book on say..
Astronomical telescope making.. then you will find a full explanation
of eyepiece optics and all will become clear :-)

The *apparent* limitation on focusing distance is actually a combination
of your sight defects and using the eyepiece optics differently than
than the original designer intended.

Having made several Newtonian Reflectors some years ago I have now all
but forgotten the detail and would have to delve into it again.....
senility probably ! A good book on the subject will explain far better
than my simplified comments, it will also show how complex the eyepiece
optical design can be.

Reg

On Fri, 29 Apr 2005 18:40:17 +0000 (UTC),
wrote:

I use vari-focal (tri-focal in USA) lenses and I find no problem
with using these binoculars. If the focus is set when using the long
distance part of the lens then if the head is moved in relation to the
eyepieces you would then be using the intermediate distance part of the
lens... a slight touch on the focusing will restore the crisp image
again... alternatively move the head slightly again :-)

I use Varifocals and find that wearing them when using binoculars
gives some observable chromatic aberration.

The field of view also looks narrower, but I suspect is not. If you
use the spot in the lens directly in front of the pupil, then you
should be using the long distance/infinity focus of your specacle
lenses.
--
Terry Harper
URL: http://www.terry.harper.btinternet.com/