On Fri, 23 Mar 2012 13:27:05 -0700, Jeff Liebermann
wrote:

On Fri, 23 Mar 2012 12:48:47 -0700, "William Sommerwerck"
wrote:

'Course the minuscule size of today's electronics and my aging
eyesight makes it a no-win game for me to try and do much
fixing of that kind of stuff those days.

I just bought an illuminated head-mount magnifier from Harbor Freight for
$5. It's surprisingly good. The optics have little distortion and no
chromatic aberration. There are four magnifications, but the lights "focus"
at only the lowest magnification.

I don't really like the plastic head mounted magnifiers. I'm
constantly going from whatever I'm working on, to picking up tools,
soldering iron, parts, probes, etc, on the bench. I have to keep
raising and lowering the magnifier in order to switch. With an LCD
screen, everything is roughly the same distance away, so no raising or
lowering.

If I were to buy a head mounted magnifier, it will probably be a
surgical loupe.
https://www.google.com/search?q=surgical+loupe&tbm=isch
Lots of styles and types to choose from, all seriously expensive. I've
played with some and am rather impressed. If I can keep the working
distance constant, it's as good or better than my USB camera
microscope. Mounted on eyeglasses, they are a bit heavy, but headband
mounts are available.
I use magnifiers in my work regularly and have been using a camera and
display for some of the work I do. I bought a camera and lens and
display and set it up for lathe work. But I need to get better
components because some of the details I need to see accurately are
less than .001". So even though the system I put together seemed at
first to be fine it is still has problems with contrast and
distortion. One thing that has really helped with magnifiers though is
bright lights. The really bright lighting, by causing my pupils to
constrict, gives me much more depth of field.
Eric