Grading Binoculars and Telescopes

How to evaluate the condition of binoculars and telescopes for buying / selling or for repairs
Is a telescope or binoculars worth repairing? Antique binocular repairs.



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Price list for clean / overhaul / repair of binoculars, click here

The Basics

The power (magnification) and physical size of each item e.g. 10X50. The first figure is the magnification, the second figure is the diameter of the big lens (objective lens) in millimeters. So 10X50 would mean 10X magnification (objects will appear 10X bigger, as if you have moved 10X closer) with 50mm diameter objective lens.

The field of view is the area you can see left-to-right / top-to-bottom whilst holding the binoculars steady. Low power binoculars have a wide field of view, high power binoculars have a narrow field of view, irrespective of the size of the objective lenses. The field of view can be given in degrees (eg "Field of View 8.5 ") or in feet and yards (eg "262 feet at 1000 yards").

The size and weight

The product description includes the size and weight. Please think about this before buying. Is it pocket-size? Can it be comfortably held in the hand or will it need a tripod? We have had many items returned because the buyer didn't read read (or notice) the size and weight, e.g. they wanted something that would fit neatly into a bag and found that it was too large to fit into the boot of a car!


The external condition

I don't list the external condition where there is a good photograph, but please do look at the photograph to see the condition, if it is visible in the photograph, I shan't take time to describing it in writing. High-value items will have several photographs, low-value items will only have two.

If the condition needs a special mention, I describe it as follows; and please use this system of descriptions if you are offering me items for sale:


If you put it back on the shelf in a shop, no customer would ever question it - it is new!

If it was 'only used once' but now the display box is slightly torn, the instruction manual has been thumbed and the strap has been removed from its cellophane packaging - then condition is not 'as new'.



Although it is, really, like new - if you were to look closely through a magnifier you could say, quite rightly, that it had some minor scuff marks as if it has been on display; or that the outer box is tatty and / or the instructions are missing and / or the case shows signs of use.


Obviously not new but the amount of wear is minimal, fabric / leather covering is in good condition, surface paint is at least 90% intact, appearance quite respectable.


Leather / fabric covering scuffed and scratched but mostly intact, surface paint is coming off. This is typical 'secondhand' condition, most items that you will ever see are in this condition, many say, "Excellent condition considering the age". I say, "Fair".


Leather / fabric covering torn or peeling, surface paint has largely come off, maybe also small dents, worn eyecups, wobbly knobs. Many say, "in perfect working order" but I say "tatty"...even if it IS in perfect working order.

The condition of the optics

CLEAN: No dust inside, no haze, no scratches, scuffs, chips, crazing, or signs of damp or mould. This does not mean 100% perfect, unless described as "as new" - because if you look at the lenses with a good jewellers loupe or a microscope, you will see imperfections.

HAZE (This is a very fine, and often imperceptible, layer dust on the prisms, as you might see in window glass when the sun catches it at the right angle. Never visible in use but can lessen performance if bad).

- SLIGHT HAZE: a perfectionist might give this a Clean & Overhaul, most wouldn't bother

- HAZE: will lessen performance, would benefit from Clean & Overhaul.

DUST. Most old binoculars contain some dust, even if only a couple of tiny specs. Some enthusiast-perfectionists tell me that even brand new binoculars have some microscopic signs of dust (though a good make shouldn't have any!).

I use the same term ("dust") when it's not really dust but fine white marks, possibly left over from cleaning or from damp that has dried out (not to be confused with damp or mould which I always describe)...and this is how I describe 'dust' -

- VERY SLIGHT DUST: just a few specs, often in the form of very small black 'pinpricks.'

- SLIGHT DUST: a perfectionist might give this a Clean & Overhaul, most wouldn't bother

- DUSTY: rarely visible in use but will lessen performance, would benefit from Clean & Overhaul.

- GRUBBY: thick dust, grime, bits of dead insect etc, in need of a Clean & Overhaul.

ALIGNMENT. The prisms inside can move so that each half of the binoculars is pointing in a slightly different direction. Nearly all old binoculars are out of alignment to some degree, though you would have to put it on a collimator (special machine) to notice. Most people don't notice (the eyes compensate) and I don't mention it.

If it's bad enough to give a double image (for three or four seconds until your eyes compensate) I say: OUT OF ALIGNMENT.

If it's so bad that the binoculars is unusable I say BADLY OUT OF ALIGNMENT.


Firstly, look into it from the wrong end. Do not try to look through the binoculars, look into them, as if looking into a box. If you can't see anything at all, it must be 'clean'' since all the lenses and prisms should be transparent.

More likely, you will see specs of dust, grubby marks, perhaps a crack or chip on a prism in the middle; or you might not see any bad marks but a fine 'haze' of dust. Itís unlikely that, in old binoculars, they will be completely clean. Tell me what you see.

Secondly, check to see if it is in alignment. Hold it very still and look at a distant point (e.g. a chimney, tree or pylon), so that the point is in the very centre of one side (shut one eye). Then, open that eye and shut the other. Keep swapping eyes, holding the binoculars absolutely steady. Does the image appear to Ďjumpí? If so, the binocular is out of alignment, each side is pointing in a slightly different direction.

When describing an item you have for sale, please be very critical about the condition. There is no such description as 'in excellent condition for its age and considering its history'. An item that is in perfect condition is perfect quite irrespective of its history; an item that is externally tatty and optically grubby does not become 'in excellent condition' simply because it has served in two world wars; and an item that is described as 'new' or 'mint' must be new enough to be put back on a shop shelf and be indistinguishable from the other factory-fresh items on the shelf. Please use the descriptions listed above.




Secondhand Binoculars:

** Military binoculars up to £100 ** Domestic binoculars up to £100.00 ** All binoculars over £100.00 **

Other secondhand optics:

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