[time-nuts] Working with SMT parts.
brooke at pacific.net
Thu Aug 11 21:57:36 EDT 2016
The Mantis is very expensive and the arm in the EEVblog review is not as stable as my arm.
about US$ 3300 retail, maybe $2000 eBay.
In the review he is confused about 3D vs. perspective.
The working distance does not look as long as the B&L.
The lesser of evils is still evil.
-------- Original Message --------
> Lots of good suggestions have already been made, but for
> me, a boom style stereo microscope, with a distance between
> the objective, and the focal point of at least 3 inches works
> fairly well...
> One other thing that may force your decision, if you are
> older, your eyes will likely have lots of "floaters", which
> are debris that floats around in your eyeballs. This debris
> floats in and out of the center of your field of view, and
> looks like a bunch of translucent worms, or shadows.
> Your brain, the magnificent organ that it is, tries to compensate
> for your eye's degradation, and as long as your eyes can move
> about in your field of view, it effectively removes the floaters
> from the scenes you are viewing.
> However, if you use a stereo microscope, your eye position
> is fixed by the very limited amounts of off axis motion
> that will allow a through optical channel. This lack of off
> axis motion will emphasize your floaters in a great way, and you
> will see *every* *single* *one*, clearly, as if it were something
> you really wanted to view. Some times, the floaters will cover
> the exact thing you need to see clearly, and you will have to
> move it off axis by moving it on the microscope stage.
> The only answer to this problem, is to either have perfect eyes,
> or to use a microscope where you are looking at a screen, rather
> than through a pair of oculars. This way, your eyes can dart
> around, and inspect what they need to see clearly, and the
> floaters will be ignored by your brain.
> As far as I know, there is only one optical microscope built this
> way, and it is the very expensive Mantis.
> Because of the great expense of flat screen optical microscopes,
> most modern SMD viewing equipment is going to the trivially cheap
> method of using a CCD/CMOS color video camera and an LCD screen.
> You can do a lot with a cheap USB camera mounted to a boom, a fiber
> optic light source, or a ring light, and a laptop computer to
> display the image.
> -Chuck Harris
> Bob Albert via time-nuts wrote:
>> What are the important parameters regarding purchase of a stereo microscope? I
>> see some on ebay for around $50; are those good? Bob
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