New Speedy 400 on order - lens choice?

[Keith Winter]

I just placed an order for a new Speedy 400 120w, I'm very excited!

I'm going to be cutting and engraving 1/4" and 1/2" birch plywood with it quite a bit. I had a question on the lens choice, my gut says I should get the 2.5" lens for these two depths of wood, but I wanted to get your opinions? Is that the optimal focal length or would a different lens size be better?

[Michael Kowalczyk]

wow nice machine. I use a 4" lens because of the longer depth of field but i only have a 60 watt. 2.5 might be an overall lens but not the best for a specific situation. I'd get both and run tests.