Thread: Magnify small parts

Originally Posted by cba_melbourne

.........To calibrate you can use its calibration slide made for exactly this purpose:
http://www.microscope.com/digital-mi...icrometer.html
It is actually very affordable at US$49. Just using a very thin and flat and well defined object of known length works too. It is about like using a ball bearing race to calibrate a micrometer, it may be close, but you are never sure....

Hey Chris,

Even more affordable is one like this, looks identical. - http://www.ebay.com/itm/191139231949...949%26_rdc%3D1

Based on a recommendation from Stuart, I bought one. Appears accurate. https://www.woodworkforums.com/showth...29#post1797829

BT

Originally Posted by Anorak Bob

Hey Chris,
Even more affordable is one like this,......

These things used to cost several 100's of $$, and almost 1k$ with a calibration certificate. Incredible how cheap this one is. Thanks for sharing.



Another thing to be aware of when using an USB microscope: it needs to be calibrated EVERY TIME you change magnification or focus! In practice this means that everytime you take it out of the box to do a measurement, you first must calibrate it. This is unlike a conventional microscope, which when once calibrated for a given eyepiece and objective combination will stay calibrated forever. And unlike a simple measuring magnifier, which is calibrated for life.

Also keep in mind that a 40 year old conventional microscope or measuring magnifier, if looked after and stored well, will still work perfectly today. An USB microscope is hopelessly obsolete in less than 10 years, even in the unlikely case its software still runs on future operating systems.

If more than say 10X magnification is needed, a better alternative to a plastic USB microscope is a real microscope. It too can be fitted with a TV camera eyepiecev to share the image on a TV screen or to hook up to a PC to store pictures. But the camera eyepiece can easily be exchanged when obsolete and removed when not needed. You only need to calibrate it once. It can use far superior exchangeable lenses and eyepieces, and it always measures orthogonally to the sample.

If 5-10X magnification is needed, a measuring magnifier is the way to go. No calibration needed at all. Small and lightweight, can be used everywhere. No batteries or laptop needed to use it. Never obsolete.

Where things like USB cameras excel is for small diameter borescopes, and snake cameras that you can look at 20m down a drain pipe. Plastic USB microscopes can be useful in certain situations where the sample is not easily accessible, or in a dirty environment, but for the vast majority of uses it's more of a toy to play with than a tool.