General > General Technical Chat
Damned tiny components, old eyes.
thm_w:
If its been sitting for 10 years untouched, in an area that gets damp, could be some kind of mold growth inside the lenses.
--- Quote from: DeanA on September 14, 2021, 08:29:35 am ---I've had an Amscope for a while, I think same or similar to this one https://amscope.com/collections/stereo-microscope/products/zm-4tn3 but I've never been able to get it to stay in focus across the different zoom levels (have to refocus after change zoom levels) is that normal or am I doing something wrong?
--- End quote ---
Normal, since you didn't specifically buy a parfocal head: https://amscope.com/products/zmdg6745t
jfiresto:
As in, normal with Amscope? I do not think I have used a fully functional, stereo microscope made in the last few decades that could not be made parfocal.
thinkfat:
--- Quote from: jfiresto on September 15, 2021, 07:57:32 am ---As in, normal with Amscope? I do not think I have used a fully functional, stereo microscope made in the last few decades that could not be made parfocal.
--- End quote ---
Seems to me, too. I didn't explicitly buy a parfocal head, but still I can make it stay in focus over the whole zoom range.
Works similar to this, this just deals with fixed-focus objectives, but it applies obviously also to stepless zoom heads.
https://www.microscopeworld.com/p-3359-how-to-adjust-focusing-microscope-eyepieces.aspx
thm_w:
OK I lied, I tried it with the Amscope at work which is not stated as parfocal head and was able to hold focus.
Going to try with my cheap Amscope at home and see if it can do the same.
Odd that the one linked specifically stated "excellent Parfocality". Maybe its harder to achieve on higher magnification units?
jfiresto:
Perhaps not in this world, but in the profitable world of marketing. ;)
Just for fun, I listed and grouped Amscope's list of features, and struck-through and lightened the fluff, redundancy and exaggeration:
Both Ocular-Tubes with Adjustable Diopter
All Metal Mechanical Components
Rubber Eyeguards Included
Manufactured under ISO 9001 Quality Control Standard
Excellent Five (5) Year Manufacturer Warranty
6.7X-45X Continuous Zoom Magnification Offering Top-Level Quality Images & Parfocality
45-degree Inclined Trinocular Head with Extreme Widefield High-Eyepoint Eyepieces
30mm Extreme Widefield WH10X/22 Eyepieces
Large Working Distance (4" (100mm) at all magnifications!)
High Resolution with Great Flatness and Contrast
Sharp Stereo Erect Images over a Wide Field View
Crystal Clear Original True Color Images
Accurate Alignment Ensuring a Fatigue-Free Viewing
Full Optical Glass Elements
Precise Ground Glass Lens
Adjustable Interpupillary Distance
Most of the bullets do not survive unscathed.
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