G1 or G2 or 2 piece Lens for burning

[exclr8]

I am getting a 2watt 445nm for burning aiptasia in a reef tank. They can rang in size from microscopic to 1/2 in. in diameter at the stalk. I am wondering the pros and cons of both lenses? What would be your recommendations?

 

[Blord]

Re: G1 or G2 Lens for burning

They have the same focal length. Only the coating is different :
405-G-2: Multi- Layer "A" Coating
405-G-1: Single Layer MgF2

In practice there is not much difference in power.

 

[exclr8]

Re: G1 or G2 Lens for burning

Well I just ordered the kit and it is not a g2 but a lens with 2 pieces of glass. The stated rating through the 2 piece lens is 1.7watts and 2 watts through the G1. Is there a big difference between the G1/G2 and these less expensive lenses?

 

[DTR]

The three element element lens will have a lower divergence and is pretty inexpensive but it has a lot of splash with 445. The G-1/2 lenses will pass 300-500mW more power @ 1.8A with a M140 and has a much cleaner output but since it does not do much to correct the beam it has a more elongated line output and it is much more expensive. So it is a give and take. You cant really say one is better than the other. It is personal preference.:beer:

 

[exclr8]

Forgive my ignorance. So the multi element will give a finer end point when focused and the G1 will be a bit of a bar at the end point?

 

[DTR]

Neither make a point with 445. The three element lens will just make a less elongated line.

http://laserpointerforums.com/f65/there-something-wrong-my-beam-spot-59400.html

 

[ApexProxy]

3-Element Lens: Improved dot size at far distance. Minor output power loss. Smaller beam size over distance.

G1/2 Lens: Improved output power. Brighter beam. Improved burning power. Smaller dot size at close range.

From what you describe as your intended use I would suggest the G1/2 lenses.