In article ,
tiredofspam nospam.nospam.com wrote:

I need to get an illuminated magnifier for some scroll work. I can't see
the blade and line.

I was noticing that there are 3,5 and 11 diopter lenses.

A 5 diopter winds up being a magnification of 2.25 5 * 1/4 +1

So the question is, what should I get? Is 5 too powerful, is 3 to little.
Is 11 necessary?

Would like to get one today to get some Christmas work done.

How far from the end of your nose do you need to work? Barring more
complex telescopic magnifiers, simple lenses have a tradeoff between how
much they magnify and how far out you can see before everything goes
blurry. With a large lens, if you lose a little magnification (the +1)
by moving your eye back from the lens, you can gain some working
distance (eye to object being worked on - lens to object stays the same,
I think.)

11 is almost undoubtedly too much - too close to work. Assuming that you
start out "seeing correctly", 5 diopters should give a working distance
of about 20 cm or 8 inches. 3 would give you ~33 cm or a foot or so, and
11 would be 9 cm, or 3.5 inches. At least, if I didn't screw up the math.

More light, LOTS more light, will also help a great deal.

I use some +5 glasses for fiddly electronic work, and would not want to
go higher due to working distance.

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