On Sat, 29 Mar 2014 16:52:50 -0000, "Gareth Magennis"
wrote:
I must admit it was a few years ago that I was looking at microscope/webcams
and I found nothing remotely in budget that was better than VGA. Seems
they've improved technology since then.
To the best of my limited knowledge, the microscope resolution
followed the introduction of higher resolution imagers (sensors) for
digital cameras and USB computer cameras. I don't recall the exact
time frame, but I think the cheaper megapixel CMOS imagers arrived in
about 2004.
http://en.wikipedia.org/wiki/Active_pixel_sensor
I've had my various microscope camera for about 5 years. I don't know
what went wrong, but you may have been looking at computer cameras,
which go through amazing lengths to lie about their optical resolution
and usually offering electronically zoomed pixel figures.
Anyway, with regards using USB microscopes/cameras on the bench, I've just
taken a couple of rough screenshots with my Canon 100D with the kit 18-55mm
lens reversed.
The reversal ring cost £3.59 on Ebay.
The screenshot of a stick of DDR RAM is just to demonstrate that this is
exactly what you would see when the camera is connected to a computer using
Liveview. (The software comes free with the camera)
One is max zoom at 18mm, the other at 55mm.
These focal lengths equate to 28.8mm and 88mm in the old 35mm film camera
world, and on full frame DSLR cameras. (The D100 is a cropped sensor)
Nice, but my DSLR (Canon S5-IS) does not have a removable lens.
Unfortunately the camera has to be pretty close to the subject using lens
reversal - 7cm at 55mm and 4.5cm at 18mm, so how useful this would actually
be in practice is pretty subjective I guess.
That's a very real problem, which I also mentioned in my comments on
using a cheap USB microscope. The lens has to be so close, that my
hot hair SMT desoldering tool can easily melt the plastic lens. Same
with splatter from solder flux. That's what's nice about the Bausch
and Lomb microscope. The distance between the lens and the work is
about 10 cm and there's a slot for a protective lens cover.
http://tinypic.com/r/m8mp9s/8
http://tinypic.com/r/2hdntyp/8
Good photos. Are those tin whiskers between the IC leads? Offhand,
it looks more like steel wool residue.
I'm at home now and don't have any pictures handy. The best I can do
is this series of photos of an RJ45 plug, taken with the cheap USB
microscope:
http://802.11junk.com/jeffl/pics/RJ45/index.html
What I really want is a Mantis viewer from Vision Engineering.
http://www.visioneng.us
All are beyond my limited budget. Maybe used:
http://www.ebay.com/bhp/mantis-microscope
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558