Magnifiers

What I used the most is very low-tech. 3x glasses from the discount store, $5 or so. That gets it down to TSSOP packages for me.

Regards, Joerg

I buy a selection of cheap glasses from the local Dollarama. A buck each, so it doesn't matter if they get scratched or splattered with solder. The ones with metal frames. The plastic frames simply fall apart.

The 3X glasses are convenient to use with a 7X to 30X stereo zoom microscope. That way I can take my eyes from the microscope and still read small parts on the microscope stand, and still use the microscope without having to take the glasses off. The stereo zoom is invaluable for checking the quality of solder joints. At my age, my eyes are no longer good enough without a lot of help:) Regards,

Mike Monett

well I got one of those helping hands with magnifying glass as it was so cheap to be iresistable,

this gives me almost 2x wich makes gouging out 0.5mm pitch tracks on a pcb go from almost impossible to almost easy (to see) looking through with one eye is quite easy to see and get good magnification, using both eyes is possible but have to line it up carefully and it makes my eyes feel a bit cross eyed after a while. the lense itself is ideal for my project anyway so I might get another one, but preferably with a larger lense wich wil presumably make it easier to see with both eyes but im wondering how they calculate the magnification, the magnifying glass is 60mm dia with a focal length of about 120mm the add claimed 6 times maginification although I didnt believe that, I was expecting about 2 if I put a ruler behind the glass it obscures 90mm of it and I can see 45 mm of it through the glass, so it is X2 or do they take into acount that you can view things closer in focus and therefore larger ? with my glasses off I can view things realy close anyway, if i put my glasses back on I can get it up to about 3x mag measured this way but I have to move my head back to see it so it ends up not looking any bigger, I wonder if its posible to arange a combination of lenses to be better.

I think I like the idea of a hands free magnyfying glass as its still easy to see tools to work with rather than a visor.

Colin =^.^=

Your calculations are exactly right. Magnification is usually reckoned as anywhere from 250mm/F to (250mm/F)+1 depending on exactly where you hold the lens, so with F=120mm, you should be getting about 2 to 3 power. (The basis of this is that they figure 250 mm is the normal working distance for a young person with good vision doing close work.)

I have no idea how they figured 6x. Some unscrupulous vendors square the magnification and tell you "makes objects look N times larger" in *area*, not linear extent. Or they may have tossed out the 250mm figure and adopted a much larger number for older people.

The working distance (magnifier to object) is equal to the focal length or a little less.

The "power" of reading glasses is of course not the magnification (which is essentially 1x) but rather the reciprocal of the focal length in meters. Thus, +3.00 reading glasses don't magnify 3x; they let you work at 1/3 meter.

There are lots of good ways to build magnifiers. What you're generally up against is that the higher the power, the closer the working distance.

One very good brand of handheld magnifiers is Eschenbach. Google them and look on eBay. There are also Zeiss magnifiers, said to be very good but not very widely available. More affordable are those from Edmund Scientific and from Anchor Optical Surplus.

There is a whole industry of gadgets for people with "low vision" (vision that isn't very sharp even when they wear glasses, due to a damaged retina). They use magnifiers all the time and have many different kinds, all cleverly engineered.

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Thanks, thats handy information, I think I might invest a reasonable amount of money in a realy good magnifier/lamp now I know what specifictions to check for, such as a focal length of about the same but with a larger lense, as it makes things so much easier I tend to want to use it all the time.

I remember doing at school all those line drawings of lenses with lines from the object arrow throgh the focal point/lense center to the upside down image arrow etc, I wonder if I could convert it easily to electrical equivalent so I could run it through a simulator, I'm sure theres optical simulators anyway, it would be interesting to see if a simple combination of lenses wich would give improved maginification versus viewing distance.

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I just managed to cut 2 tracks going underneath a 5 leg sot353 device wich is probably about the limit I can do now, before it was just 1 track and that seemed a challange.

Colin =^.^=