On Fri, 28 Mar 2014 21:51:14 -0000, "Gareth Magennis"
wrote:
I investigated microscopic photography using various cheap microscopes and
webcams etc.
I very soon came to the conclusion that:
1. All these devices are VGA at best. They claim otherwise, but they lie.
Well, 640x480 VGA is 0.3M pixels. Physically, it's difficult to cram
a larger CMOS (or CCD) imager into a 23mm eyepiece tube or into an
endoscope. Usually, the 0.3M pixel variety is often a tiny 1/6"
sensor. The better 3M pixel cameras use 1/2" sensors with 2048x1536
such as the Aptina MT9T001:
https://www.aptina.com/products/image_sensors/mt9t001c12stc/
https://www.aptina.com/products/image_sensors/
I think (not sure) that 1/2" is about as big a sensor as can be
practically crammed into the 23mm microscope tube. With a 0.5x
expander, a larger imager can be used that covers the entire field of
view. For example:
http://www.ebay.com/itm/191110578518
With that arrangement, higher resolutions are possible. 5M pixels are
common and not too outrageously expensive:
http://www.ebay.com/itm/190519880676
Amscope specifies the (Aptina) sensor they use, which I think you'll
find is far better than VGA resolution.
2. The optics are plastic and totally ****e.
Yeah, that's a problem at the bottom end. I don't have a clue where
to find a microscope with glass optics or what it will cost, but I'm
sure it's not cheap.
Incidentally, I use both glass and plastic eyeglasses. The glass
lenses last many years longer than the plastic lenses.
3. You can get much better results from a cheap half decent camera by simply
zooming in on the far superior image.
True, but there are limits. I've used old digital cameras as
microscopes with good results. The first Sony Mavica FD73 digital
camera has a collection of screw on closeup lenses that were really
nice for use as a microscope or for taking macro photos. However,
past about 100x, it was useless because spherical aberration and poor
depth of field conspired to ruin the photo. For larger
magnifications, a real microscope is better. However, both are better
than the USB microscope.
You need to remember that no amount of hardware/software is going to improve
the image from a piece of ****e lens that probably costs less than a dollar.
My hardware. I cut-n-paste into Irfanview to clean up the photos:
http://802.11junk.com/jeffl/pics/white-plastic-rot/slides/microscope-setup.html
http://802.11junk.com/jeffl/pics/drivel/slides/Olympus-BHC-Microscope.html
I also have Bausch and Lomb inspection microscope, which I sometimes
use for SMT work.
http://802.11junk.com/jeffl/crud/Bausch-and-Lomb-microscope.jpg
Note the large work area.
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558