Focusing Problems and Glare, Flare & Ghosting (1 Viewer)

[Ireneibm]

Hello all! I recently joined your forum and was hoping I could get some help and answers in a couple of areas.

My girlfriends talked me into joining the local nature club and I have appropriated my fathers 6x30 Sans & Strieffe porro prism binoculars until I decide on a better pair to buy. The right barrel focuses razor sharp, but the left barrel does not seem to get that sharp. What might the problem be and how could it be corrected, if at all?

In researching various posts on different binoculars, I keep running across the terms glare, veiling glare, ghosting, haze and stray light. I suspect some of these are the same. Can anyone explain them more fully as to how they would evidence themselves, and a good test to check for them?

thanks
Irene

 

[rdmadison]

Is it too much to assume you're in central MD or on the Eastern Shore? In either case you have a perfect excuse to drive over to Cape May and visit CMBO's shop where they can go over your existing binoculars. If you splurge for the fall weekend coming up there'll be a whole auditorium full of optics to learn and yearn from.

Meanwhile, you can take your S&S to your optometrist. S/he can check the diopter setting for your eyes and also see if the binocular is clean. It probably isn't, or it may be slightly out of alignment (collimation). If I were you, I'd put the $75 you might spend on cleaning them towards a mid-range binocular in the 7x-8x range (we all have our favorites; I'll refrain). Your 6x might be a little frustrating for looking over the reservoirs, the Bay, and the Blackwater marshes. If by chance you have great eyes and no optometrist, bring your binoculars to one of the Maryland Ornithological Society regional meetings: Anne Arundel Bird Club, Talbot County Bird Club, the Baltimore group that meets at Cvlburn Arboretum, etc. Then ask for the group's binocular expert.

Even if you get a new pair sooner rather than latter, you may eventually want to get the S&S cleaned. Several of us use Nicolas Crista, on the web at NRC Optics. He's in Massachusetts.

You might like a book called PETE DUNNE ON BIRDWATCHING, not only for what it says about binoculars and scopes but also because it has a lot of good advice for wandering around looking at nature. And he's connected with CMBO, so what you read about binocular choice you can see in action at one of the two stores.

For the sake of truth in advertising, I should say that I'm a CMBO member but Pete doesn't know me from Adam. They don't give me a percentage!

 

[Tero]

A lot of people do not really care. But I can take various pairs and test indoors, approaching a bright light bulb and some I can get closer than others before blurry rings appear in the periphery. So you can test it, but stores have weird light that is all over the place. Too bright.

It comes into play when the sun is badly behind the target. But then, the birds are black silhouettes anyway and the sun is bad no matter what.

 

[John H.-S.]

Dear Ireneibm,
Forgive me for asking what might seem to be a silly question, but is it your problem that you can't get both halves focused at the same time, or just that you can't get the left side sharp under any circumstances?
May I suggest that before you do anything else, you try the following?
Cover the right-hand objective (or close your right eye) and focus on a distant object through the left side alone, using the centre focusing wheel. When you are satisfied that focus is correct on the left side, cover the left objective and focus on the same object through the right half using the adjustment on the right eyepiece but without altering the setting of the centre wheel (very important this). When you have a sharp view through the right half, uncover the other objective and view normally using both eyes. You should now get a sharp view because you have adjusted the binocular for the variations between your two eyes. If, however, you still can't make this work then there are two possibilities: either there is a fault in the right half of the binocular (far from impossible) or, your right eye has a problem (extremely unlikely).
I hope this helps and I hope that you will be able to get good service from the binocular that you have "appropriated" from your father. Best wishes, John.

 

[Ireneibm]

I started off focusing the left barrel, but when switching to the right to set the diopeter it became evident that the left barrel is just not focusing as sharply as the right. One of my birding buddies has a Nikon 8x30 eii and she was impressed with the sharpness and clarity except for the left side. Thats why I was wondering if the softness in the left focusing is something that is inherent to the lenses, or if it was something that could be fixed simply and cheaply as these S&S 6x30's are pretty neat and lightweight binoculars.

Today I was looking thru some 8x32 Fury binoculars - the sun was overhead slightly off to the right, and in the left barrel I could see what looked like a narrow semi circle of fog or haze from about the 6 to 10 oclock position at the outer edges. What do you call this and what causes it?

thanks
irene

 

[ronh]

Irene,
Welcome to the forum, and to the pursuit.

There's a chance the problem with the blurred left side of the S&S could be your left eye. Or it could be the left telescope.

Look through the right telescope with your left eye, and if you can focus the image sharply, your eye is good, the left side is bad. For confirmation, look through the left side with your right eye, and if that side is bad, you won't be able to get a good focus with that eye either.

If it's your eye, you may need to wear glasses while using binoculars, like many people with a bit of astigmatism.

When off-axis light comes in the front of the binocular, it illuminates the interior in places where it may reflect and eventually reach the eye, causing what is usually called glare or flare. Some binos are built better, with partitions or "baffles" to interfere with the path of such unwanted light.

A common offense that is impossible to completely escape is the case you described with the Fury. The magnitude of the effect depends on the precise positioning of the eye, and with experience, a user will learn to place the eyes to minimize it. (Thanks to member Henry Link for explaining this, as it is a very useful technique, and I hope not to steal his glory but only to save him the trouble of continually repeating it.) I doubt there's any difference between the two barrels of the Fury, and would guess you just happened upon different eye placement in the two sides.

Please forgive me, as I have done my best to blame everything on you, haven't I? Oh well, we like binoculars better than people here!
Ron

 

[Simon S]

If you can, view the binocular upside down and see if the problem moves to the other eye.
Also ignore what the dioptre says try different settings, see if that resolves the problem.
It could well be a faulty binocular.