external lens question

[knifebright]

Hey all
I don't post in the laser forum all that often but recently my laser love has been re-kindled. I have a 50mw greenie and Recently picked up a Pulsar125mw red. I've been playing with the red, focusing/unfocusing ect. then i read that you need an external lens to focus upclose to light matches ect. I randomly rememberd that i a small single convex lens that i pulled from a pair of binoculars years ago. Its really cool cause when i place it over the apperature i can light matches, smoke wood, cut through tape instantly ect. It seems that it has a focal point of just about 1 inch. the coolest part is that it is the same diameter as my laser so i'm going to make a little attachment point that's better than my current taped on model. My question is do any of you have links or sources for an external lens that you really think is good for this application. I'm thinking that my one with a 1 inch focal point may be as good as i can get but i want to check with the experts!!
all in all i love my 125 red already and am very surprised that i can see the beam and all!
thanks
jimmy

 

[FNinjaP90]

Any focal length will do. What matters is the optical transmittance of the lens and the perfection of the grinding of the lens. You want to put the most power into the smallest area, which will do a better job of heating surfaces up.

www.mellesgriot.com has a wide lens selection, with many advanced materials. They're expensive though, but that's expected from high quality optics.