Amlong Crystal Premium Optical Glass Double Convex and Double Concave Lens Set, 50mm Diameter with 3 Convex (20, 30, 50cm FL) and 3 Concave (20, 30, 50cm FL)

Bought these for my middle school science class to make their own telescopes. Was a really fun lab and they worked great!

I got these for a personal project. I needed to modify the focus of a laser. The clarity and quality on these was great.

good quality

Believe it or not, I use these for wood burning from the sun. Learned this trick in Girl Scouts LOL

I got the double concave to use with art, to check my accuracy in likenesses for portraits. The double concave ends up giving you a virtual image, as if you are looking at your drawing in the mirror, except it's not reversed. Don't ask me how it works, but it lets you see what's "off" more easily. I also bought the double convex just because it was included, but I have already used it several times to magnify small print, or zoom in on a drawing reference detail. Don't know why, but I find it much more enjoyable to use than a magnifying glass -- maybe because there's no distracting handle or frame. Very nice purchase. Glad I got both.

Like the title says, focal lengths are not as advertised: they're 200, 300, and 500, not 20, 30, and 50.

20, 30 and 50 CENTIMETERS power, not millimeters. VERY little magnification. My mistake. They are thin, but very clear.

not the greatest lenses, but good for what I'm doing.

Is what it says it is. Very quick delivery to the UK