Review on 6-Piece Mini 30X 21mm Jeweler's Loupe Magnifier Magnifying Glass Set in Silver with Box for Jewelry by Carrie Spencer

Second update: They seem to have a focal length of about 2.5cm. I believe the power of a basic handheld magnifier comes from using a 10" lens and zooming it in to 1x. A lens with a focal length of five inches has a magnification of two or two times. A lens with a base length of two inches has a 5X magnification or a 5X magnification. I have a 5x lens that really focuses to about two inches. In other words, a lens with a focal length of one meter, which equals a thousand millimeters, is called a one-diopter lens. A two diopter lens is a lens with a focal length of half a meter or five hundred millimeters and so on. So if a lens has a focal length of about thirty-three millimeters, which is just over an inch, which is 25.4 millimeters, that lens has thirty diopters. So these loupes are probably close to thirty diopters, but linearly speaking, as they should be judged, they're about ten times that power or a little less. Since, as I might say below, 10x magnification is fairly standard, if not the most common standard, for this type of loupe, it can be assumed that this is around 10x magnification. However, it is still unclear as I actually had a magnifier with five and seven and a half magnifications in my loupe collection. With all of this clear, just remember these are great buys. It's a particularly good buy if it's a triple lens, but at the moment with my eyesight I don't have the ambition to unscrew the retaining ring to remove the lens. True Hastings triplets and even achromatic doublets can be, and used to be, quite expensive lenses. When my sister was taking a botany class in the 1970's she had to buy a $10 magnifying glass with 10 magnifications which, although it worked well, was actually two simple lenses with an air shutter between them. UPDATE: I think, purely conventionally, the strength of simple magnifying glasses is that they are usually based on a typical reading distance, which is conventionally 10 inches. If so, then these lenses, which seem to focus about an inch, should have about a tenfold linear magnification. At only a rough estimate they appear to be five to ten degrees, which is a useful magnifying glass. Based on this, if you take the standard viewing or reading distance on the screen in rough feet, then that would be roughly a foot, and they could, wildly guessed, be written as thirty x. Just look into one and if you need more power use a more expensive magnifying glass or even a stereo microscope. Everything below that is still up, including whether they are in fact quite expensive threesomes as they claim. It could be a mislabeled item that cannot be sold without much or a consideration from disgruntled scientists or jewelers. However, they are great. As I grow my loop collection, I might update it again and subject you to my crappy math. These things are falsely labeled with their power. They're labeled 30 x 21mm, which, using standard terminology, should mean they're 30x magnified and 21mm in diameter. They're closer to 10x or maybe less, but they really are great and deliver a sharp, crisp image. The way you use a magnifying glass is to bring it up to your eye and bring what you are trying to see into the magnifying glass. Don't try to hold a magnifying glass over an object like Sherlock Holmes. Most people think a magnifying glass can be used this way, but it's only good with large diameter pressure glasses. My paternal grandfather was an entymologist and worked for the Alabama Department of Agriculture in Cullman County, Alabama, just north of Birmingham. . In 1954, when I was eight years old, he gave me two used but very good magnifying glasses, both triplets made by Hastings. One had the standard 10x power and the other, slightly smaller, was 14x. These appear to be standard abilities, or were. Over the years I've acquired a collection of bows. I have 5x, 10x, 14x, 20x even a real 3x which is small and quite difficult to use because it focuses so close to the subject. Glass is glued together. The result is a heavily corrected image with no color fringes. This is followed by a two-lens achromat, cemented or with an air gap. Then you can get two plain lenses with air space between them. You can always get a simple but powerful lens. All of this works quite well, especially when it's made of glass and not plastic. My late nerd sister needed a ten dollar magnifying glass from the seventies, and these are two lenses with an air gap. It's raised to the tenth power, and she bought it with her textbook at the University of Maryland bookstore. Works perfectly. This magnifying glass is marked with a C, but I don't feel like unscrewing it to see if it's true or not. At two bucks and thirty cents a loupe, I don't care, but if they're not triplets, they'll be mislabeled the second time around, which can lead to legal issues and maybe explains why these things are so cheap to start with. be glassy. An easy way to test this when removing the lens is to listen to the paperclip wire glowing red and touch the edge of the lens. Any plastic melts. Although they look like glass, so why bother. I would buy them again. In fact, I bought a Toral 24 on two separate orders. They make the fanciest little gifts and hosiery imaginable and I intend to put my stash to good use. I have already gifted two to a couple my wife and I eat lunch with regularly and they have been very impressed. Most people have never seen magnifying glasses, so they are fascinated by them. Again, I am assuming they have a tenfold or possibly a fivefold increase. Now I remember that one of my old magnifying glasses has a magnification of seven and a half times. Conclusion: The magnification of lenses, binoculars, telescopes, microscopes, etc. is usually linear. That is, a glass magician with two powers, a 5 inch line looks like 10 inches. A two-by-two square will actually have an increase of four powers as opposed to a one-to-one square, but that is not how the increase is calculated, except in some parts of Asia, it seems, where there are, it seems higher number is desirable. I have seen super cheap binoculars advertised on TV as 100x which means they actually have 10x performance. Buyer's Reward.