Which way does the lens go?

[tsteele93]

I have a green all taken apart. I'm trying to put it together and the focus lens (final piece of glass) is apart. I'm ASSUMING that the curved piece is outward.

laserbeam -----> |)

Not

laserbeam -----> (|

thanks

 

[DrSid]

Yep .. flat toward divergent beam (ie source), round toward collimated beam (ie output aperture). When divergent beam hits spherical surface, so called spherical anomaly is created. That's why the flat side is there.

 

[tsteele93]

Thanks, I was pretty sure but I didn't want to glue it in wrong and have to start over with the acetone again.

 

[Blord]

Do you glue the lens in place ? The retainer ring will hold every lens in the barrel, no need for glue.

 

[DrSid]

I second no glue near optics.

Btw. if unsure, simply try it. Sometimes it makes no difference at all. Spherical anomaly looks like spot with distinct peak in the middle. As you decrease spot size when focusing, the peak will start to increase and you never get small dot. With correct orientation the spot will look more or less same during focusing, just the size will change.

 

[tsteele93]

I just used a toothpick and some Elmer's on the outer edge. Didn't seem to be a problem. Thanks, it is back up and working.