When i was looking at it, it said something like $9.50 or so, but that was with the forum discount..
It figures, that shipping would cost just as much. But proper IR filters are completelly different from what you can find in a camera.
Otherwise, depending on the power of the pointer, IR might not really be a problem..
In the cheap chinese pointers, the IR is not collimated, before it enters the crystals. The green comes out very narrow, while the IR is already spread out. The expander lense mostly expands the green and a little of IR, while it blocks most of it. The collimator lense further blocks some IR, and collimates mostly the green. But with a camera, you san still see the IR glow around the green beam at the collimator. At the top of the laser, you usually can't see any IR anymore, since it is blocked by the narrow aperture, and the little, that is left is overpowered by the green.
This is the reason the green DX lasers only put out very little IR. There are no IR filters, but the way it is built blocks most of it.
More expensive CNI lasers (Nova Lasers...) have a pump diode, which has the fast axis already collimated. This puts more IR into the crystals and achieves better efficiency. If they didn't have a filter, they would leak much more IR, because they have the collimator at the top, and there is no narrow aperture above it, to block it further.
Which laser are we talking about exactly?
If it's one of the DX pen style lasers of a low power, there is nothing to worry about. The simplest way to elliminate the IR even further, would be to make the aperture even narrower, and only allow the green beam to go out.
