After much looking around I've just ordered one of these microscopes (despite the horrendous USA --> Australia shipping fee!)
http://www.amscope.com/7x-45x-stereo-binocular-microscope-with-14-pillar-stand.htmlThe main use will be for soldering and inspecting some 0.5mm pitch PLCCs etc. It has a working distance of 100mm, I'd like to increase this by adding a Barlow lens but have some questions on how all this Barlow lens business works.
1) It seems the microscope has a 48mm lens thread so I'm guessing any 48mm Barlow will fit is this correct?
2) Is there a difference in the width of view with different Barlow lenses?
3) Do I need a 0.5X or a 0.7X Barlow (the scope is 7.5X - 45X Zoom). Is the following correct?
0.5X will give 3.75X - 22.5X and a working distance of 1/0.5 x 100mm = ~200mm
0.7X will give 5.25X - 31.5X and a working distance of 1/0.7 x 100mm = ~140mm
4) Is fitting a UV filter in front of the Barlow lens a good idea for protecting the lens against flux and mechanical damage?
5) Do the Barlow lenses usually have a 48 mm thread on the front that I can fit a UV filter to for protecting the lens?
Cheers.