Loupe Info

[bsshog40]

I'm lookin to purchase me a loupe for my coins. I'm looking at some reasonable Baush & Lombs. I'm a little confused at what the Diopter size represents. I'm looking at a 10x with 40 diopter or a 7x (which I prefer better) but is 29 diopter. Can someone explain to me what is best? Thanks!!

[rbrown4]

I use a 10X for normal use and a 16X for variety/error examination.

 

Diopter (d): A term used to identify the refractive (light bending) capacity of a lens. In magnifiers, there is a direct correlation between focal length and diopter. To find the diopter of a magnification lens, follow these steps. With the eyes 10" above the lens, move the object to be viewed to the point the greatest distance below the lens where it remains in sharp focus. Measure this distance and divide into 1 meter (39.37"). The result is the diopter of the lens - e.g., if the object is at a 13" distance than it is a 3-diopter lens (39.37/13 = 3d). Each diopter increases the size of the viewed object by 1/4 (25%) when the object is at its full focal length from the lens.

 

Magnification: The degree to which the viewed object is enlarged. Magnification is usually expressed by a number followed by an "x", the symbol used to express power or the size of the object in relationship to its actual size. The formula for calculation Magnification Power is:

 

Common diopter/power relationships

Diopter Power % Bigger than object Focal Length

3 1.75X 75% 13"

4 2.00X 100% 10"

5 2.25X 125% 8"

7 2.75X 175% 5.5"

8 3.00X 200% 5"

9 3.25X 225% 4.5"

11 3.75X 275% 3.75"

13 4.25X 325% 3"

16 5.00X 400% 2.5"

18 5.50X 450% 2.25"

20 6.00X 500% 2"

 

 

If a dime was this small unmagnified ...

 

3 diopter

 

5 diopter

 

10 diopter

 

15 diopter

 

 

[MAULEMALL]

Just to add to Reys post;

 

Diopters Explained

 

The optical power of a lens with a focal length of 1 meter (about 39 inches) is said to be 1 diopter. Because the formula is based on the reciprocal of the focal length, a 2 diopter lens is not 2 meters but 1/2 meter, a 3 diopter lens is 1/3 meter and so forth. This is important because magnification increases as the focal length gets shorter, which is why a prescription for a higher diopter correction means you need more magnification.

 

The optical power of the human eye is about 40 diopters. The eye of a normal young person can adjust an additional 20 diopters. By age 25 this accommodation is usually reduced to about 10 diopters and by age 50 to a mere 1 diopter. It is this diminishing capacity for adjustment, called presbyopia, that warrants reading glasses.

 

[MunkyMan95]

I usually use a 5X for general use, 10X for more defined look, and 16X for varieties, and 100X Microscope for very small things.

 

Zeiss also makes some very nice loupes, albeit pricey.

[XpipedreamR]

That's rather complicated with the diopters and all, so I'd say to make it easy on yourself and get a Zeiss or Eschenbach 3/6/9 loupe. The B&L 7X Hastings Triplet is good, too, and much less expensive. I'd go with that over the 10X because I think 10X is way too much for general use.

[bsshog40]

I appreciate ya'll responses. I kind of read what you explained Rey and Maulemall at Wikepidia, but was still left a little confused. I have a cheap "Peer" that has a 10x & a 15x, but the lenses seems to distort unless I hold them a certain way. Here are the two lenses I was looking at. I was leaning towards the 10x but thinking just looking at details, the 7x would be better to take to a coin show or shop. Any preferences? Chad, I know the Ziess's are nice but they are out of my price range.

7x

10x

[MikeKing]

I've been using a 7X BL hastings triplet for years. If what you're linking is the same thing, that's a good buy.

[MAULEMALL]

I appreciate ya'll responses. I kind of read what you explained Rey and Maulemall at Wikepidia, but was still left a little confused. I have a cheap "Peer" that has a 10x & a 15x, but the lenses seems to distort unless I hold them a certain way. Here are the two lenses I was looking at. I was leaning towards the 10x but thinking just looking at details, the 7x would be better to take to a coin show or shop. Any preferences? Chad, I know the Ziess's are nice but they are out of my price range.

7x

10x

I have seen that from cheaper Loupes,, I have a B&L 10X that I paid No more than $40.00 and I have it on my key ring.. No distortion in the lens at all.. I Love the thing..

 

The 10X you posted from Ebay is the one I have.. (thumbs u

[bsshog40]

That's what I'm looking at Mike. Thanks also Maulemall

 

Btw, I downloaded iespell. I bet I test it out. (thumbs u

[hoard]

i have been using a B&L 5X 7X 10X (i believe they call it a triplet) and it works just fine for the 10 or $15 dollars expended

[TJ'S Coins]

If you want a great loupe at a very competitive price. Consider this one from Belomo, a Belorussian optical firm that makes high quality products. I've used it for a year or more and wouldn't trade it for anything. Shop around, the link has about the most expensive price I have seen on these. I got mine for $13.95 plus shipping last year.

Belomo Loup

[XpipedreamR]

It looks like he already bought the B&L 7X , and at a pretty decent price (thumbs u

[bsshog40]

It looks like he already bought the B&L 7X , and at a pretty decent price (thumbs u

 

Yea I did. Thanks TJ.

[MikeKing]

congrats!

[bsshog40]

Well thank ya Mke