What is the correct orientation of the lens, flat side up or down?

Lasers
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1

What is the correct orientation of the lens, flat side up or down?

2

Flat down crown up.

3

Thanks.

4

Plano-convex lenses (flat on one side, curved on the other) are used on the K40 and the flat side goes towards the table (convex side toward the incoming beam - or the beam won’t be bent/focused).

The easy way is to look at the lens and the side that you can see your reflection in is the “up” side of the lens.

5

@Jim_Hatch hi Jim,
can you please confirm
for k40 12mm stock lens. one side is reflective and the other isn’t so much.
You said above 'the side that you can see your reflection should be ‘up’.

Doesn’t that reflect the laser back up then?
Shouldn’t the NON-reflective side be on the ‘up’ side of the lens?

I am confused now - please clarify

thanks.

6

Bumps go up - easy way to remember.