WP34s Birthday Gift @ ISU

[matthiaspaul]

(03-23-2015 05:33 PM)BarryMead Wrote:  A while back, I bought a 10X Stereographic Microscope with a large working height for soldering SMT parts. It really helps to get a good look at what you are doing, and the stereographic scope gives you depth perception which is needed to coordinate the positioning of the solder and iron in 3 dimensions.

I second this. Compared to a simple magnifier lamp or a USB microscope, it is a great relief to work with them, however, they are also somewhat more expensive (although still reasonable priced compared to really professional equipment from Zeiss and Leica in the range of ten-thousands of dollars). I use a trinocular stereo zoom microscope with large working height and solid double-arm stand similar (but not identical) to this one:

http://www.amazon.com/AmScope-SM-4TZ-144...124&sr=1-7

It was custom-built and is from a different (local) manufacturer, but is based on the same (or similarly looking) parts, however, there are various subtle differences.

A trinocular version is only needed when you also want to mount a camera (via T2 adapter). Somewhat cheaper, these scopes are also available as binoculars. However, it is important that you look for a stereo microscope, as there are also binocular and trinocular microscopes, which are not stereo microscopes. They do not deliver a three-dimensional view and are thus not well suited for this purpose.
Although it is a bit clumsy to work with I chosed the massive double-arm stand, so that it can be used also with larger items to be inspected. For convenient viewing it is important that the head can be tilted and rotated as well.
The head should have adjustable ocular mounts to adjust the interpupillary distance. If you use glasses, make sure that the relative height of the two viewing oculars is adjustable for proper diopter correction, so that you can use the microscope without glasses as well. The protective rubber eye-pieces should be foldable or removable. If the eye-pieces are contoured, either they or the oculars should be freely rotatable in their mounts. This may also be useful for special applications with polarization filters.
10x oculars provide enough magnification for this purpose, the field-of-view of 20x oculars is too narrow for this application. Since different versions are available, make sure to get extra wide-field oculars, ideally with a high eyepoint, however, if you have to make a choice, the width of the field of view is more important.
There are also different versions of the base 0.7-4.5x zoom lens; some will slightly change the focal plane when zooming, that is, you will have to re-adjust focus after changing the magnification. Others are parfocal and therefore do not require refocusing. While this is more convenient, there's also a drawback. Parfocal lenses are more complex to design and build and if they should deliver the same optical performance they are typically considerably more expensive. Those I have seen offered for more or less the same price had a slightly smaller field-of-view. This may be recognized as uneven illumination or vignetting.
For soldering, you almost certainly need a 0.5x Barlow lens in order to increase the working height to 10-15 cm. This combination gives an effective magnification range of ca. 4-22x, which is perfect for soldering SMD parts.
A multitude of ring lights are available for these microscopes, from old fluorescent lamp ones to different kinds of ring lights with white LEDs. There are significant differences in the quality of white LEDs. If proper color reproduction is important, get a ring light with continuous-spectrum daylight white LEDs, however, they are much more expensive than normal white LEDs, unfortunately. While not absolutely necessary, white LED ring lights with adjustable illumination are convenient. On some you can even adjust multiple zones to modulate shadows. Not necessary for soldering, but nice to have for documentation. However, for serious photo-documentation I recommend a swan head spot light adapter for a photographic TTL flash like the Novoflex MAKL-150.

Hope it helps,

Matthias