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490 blue beauty

paul1598419

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You can see from your first photo that the lens is closer to the side facing the camera. This is the correct way. If you cannot screw the lens in far enough it will never collimate because the FL of these lenses is very short. Less than 3 mm. Take the focus ring off and screw it in further, but don't bottom it out. At some point a little over 2 mm it will collimate the laser diode.
 

Kookapeli

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Normally the end with the groove is for the tentioning spring but now it's loose, any ideas how to stifen it ?
 

paul1598419

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The spring that fits between the lens housing and the diode in the module will work as it is smaller in diameter than the 9 mm lens housing. The slotted side is never used as that is the side that goes toward the focus ring. There are two types of springs I have seen. The old one is longer, but has less tension and a newer version that is shorter, but has a lot more tension than the older version. I don't like the new version and never use it. I always use the longer spring with less tension. Now, when I use an acrylic lens the housing is too short to screw all the way into a focus ring. So, I used fingernail polish to attach it to the focus ring and only allow the ring to grab the first thread. This is because you can remove all of the polish with acetone if you make a mistake and need to do it over. But, I never use a spring with an acrylic lens because the tension will break loose the polish, but it still works fine as I normally have to tweak the focus anyway, because it moves when I remove the lens cap.
 

Kookapeli

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I didn't want to risk scratching the lens but I've put it on an all works fine now
 

paul1598419

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Great! I have used many of these lenses over the years and it is difficult to scratch the glass lens even if you touch the diode's window with it. Do you have the rectangular artifact I told you about on the side of the focused dot? Every single glass lens except for one two element one give this reflection of the laser's die. The G2s are the worst.
 

paul1598419

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The rectangular artifact is only with certain diodes. The new Sharp diodes are among these. So, that 490nm one will have it with a G2.
 




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